Merge pull request #5909 from element-hq/feature/bma/qrCodeLogin

Link new device using QrCode - First version

appnav/build.gradle.kts

@@ -48,6 +48,7 @@ dependencies {
 
     implementation(projects.features.announcement.api)
     implementation(projects.features.ftue.api)
+    implementation(projects.features.linknewdevice.api)
     implementation(projects.features.share.api)
 
     implementation(projects.services.apperror.impl)

appnav/src/main/kotlin/io/element/android/appnav/LoggedInFlowNode.kt

@@ -53,6 +53,7 @@ import io.element.android.features.ftue.api.FtueEntryPoint
 import io.element.android.features.ftue.api.state.FtueService
 import io.element.android.features.ftue.api.state.FtueState
 import io.element.android.features.home.api.HomeEntryPoint
+import io.element.android.features.linknewdevice.api.LinkNewDeviceEntryPoint
 import io.element.android.features.networkmonitor.api.NetworkMonitor
 import io.element.android.features.networkmonitor.api.NetworkStatus
 import io.element.android.features.networkmonitor.api.ui.ConnectivityIndicatorContainer
@@ -123,6 +124,7 @@ class LoggedInFlowNode(
     private val secureBackupEntryPoint: SecureBackupEntryPoint,
     private val userProfileEntryPoint: UserProfileEntryPoint,
     private val ftueEntryPoint: FtueEntryPoint,
+    private val linkNewDeviceEntryPoint: LinkNewDeviceEntryPoint,
     @SessionCoroutineScope
     private val sessionCoroutineScope: CoroutineScope,
     private val ftueService: FtueService,
@@ -293,6 +295,9 @@ class LoggedInFlowNode(
         @Parcelize
         data object Ftue : NavTarget
 
+        @Parcelize
+        data object LinkNewDevice : NavTarget
+
         @Parcelize
         data object RoomDirectory : NavTarget
 
@@ -419,6 +424,10 @@ class LoggedInFlowNode(
                         callback.navigateToAddAccount()
                     }
 
+                    override fun navigateToLinkNewDevice() {
+                        backstack.push(NavTarget.LinkNewDevice)
+                    }
+
                     override fun navigateToBugReport() {
                         callback.navigateToBugReport()
                     }
@@ -475,6 +484,14 @@ class LoggedInFlowNode(
             NavTarget.Ftue -> {
                 ftueEntryPoint.createNode(this, buildContext)
             }
+            NavTarget.LinkNewDevice -> {
+                val callback = object : LinkNewDeviceEntryPoint.Callback {
+                    override fun onDone() {
+                        backstack.pop()
+                    }
+                }
+                linkNewDeviceEntryPoint.createNode(this, buildContext, callback)
+            }
             NavTarget.RoomDirectory -> {
                 roomDirectoryEntryPoint.createNode(
                     parentNode = this,

features/ftue/impl/src/main/kotlin/io/element/android/features/ftue/impl/sessionverification/choosemode/ChooseSelfVerificationModeView.kt

@@ -25,6 +25,7 @@ import io.element.android.compound.theme.ElementTheme
 import io.element.android.compound.tokens.generated.CompoundIcons
 import io.element.android.features.ftue.impl.R
 import io.element.android.libraries.architecture.AsyncData
+import io.element.android.libraries.designsystem.atomic.atoms.LoadingButtonAtom
 import io.element.android.libraries.designsystem.atomic.molecules.ButtonColumnMolecule
 import io.element.android.libraries.designsystem.atomic.molecules.IconTitleSubtitleMolecule
 import io.element.android.libraries.designsystem.atomic.pages.HeaderFooterPage
@@ -111,13 +112,7 @@ private fun ChooseSelfVerificationModeButtons(
             AsyncData.Uninitialized,
             is AsyncData.Failure,
             is AsyncData.Loading -> {
-                Button(
-                    modifier = Modifier.fillMaxWidth(),
-                    enabled = false,
-                    showProgress = true,
-                    text = stringResource(CommonStrings.common_loading),
-                    onClick = {},
-                )
+                LoadingButtonAtom()
             }
             is AsyncData.Success -> {
                 if (state.buttonsState.data.canUseAnotherDevice) {

features/linknewdevice/api/build.gradle.kts

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+plugins {
+    id("io.element.android-library")
+}
+
+android {
+    namespace = "io.element.android.features.linknewdevice.api"
+}
+
+dependencies {
+    implementation(projects.libraries.architecture)
+}

features/linknewdevice/api/src/main/kotlin/io/element/android/features/linknewdevice/api/LinkNewDeviceEntryPoint.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.api
+
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import io.element.android.libraries.architecture.FeatureEntryPoint
+
+interface LinkNewDeviceEntryPoint : FeatureEntryPoint {
+    interface Callback : Plugin {
+        fun onDone()
+    }
+
+    fun createNode(
+        parentNode: Node,
+        buildContext: BuildContext,
+        callback: Callback,
+    ): Node
+}

features/linknewdevice/impl/build.gradle.kts

@@ -0,0 +1,63 @@
+import extension.setupDependencyInjection
+import extension.testCommonDependencies
+
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+plugins {
+    id("io.element.android-compose-library")
+    id("kotlin-parcelize")
+    alias(libs.plugins.kotlin.serialization)
+}
+
+android {
+    namespace = "io.element.android.features.linknewdevice.impl"
+
+    testOptions {
+        unitTests {
+            isIncludeAndroidResources = true
+        }
+    }
+}
+
+setupDependencyInjection()
+
+dependencies {
+    // TODO Cleanup
+    implementation(projects.appconfig)
+    implementation(projects.features.enterprise.api)
+    implementation(projects.features.rageshake.api)
+    implementation(projects.libraries.core)
+    implementation(projects.libraries.androidutils)
+    implementation(projects.libraries.architecture)
+    implementation(projects.libraries.featureflag.api)
+    implementation(projects.libraries.matrix.api)
+    implementation(projects.libraries.matrix.api)
+    implementation(projects.libraries.designsystem)
+    implementation(projects.libraries.testtags)
+    implementation(projects.libraries.uiStrings)
+    implementation(projects.libraries.permissions.api)
+    implementation(projects.libraries.sessionStorage.api)
+    implementation(projects.libraries.qrcode)
+    implementation(projects.libraries.oidc.api)
+    implementation(projects.libraries.uiUtils)
+    implementation(projects.libraries.wellknown.api)
+    implementation(libs.androidx.browser)
+    implementation(libs.androidx.webkit)
+    implementation(libs.serialization.json)
+    api(projects.features.linknewdevice.api)
+
+    testCommonDependencies(libs, true)
+    testImplementation(projects.features.linknewdevice.test)
+    testImplementation(projects.features.enterprise.test)
+    testImplementation(projects.libraries.featureflag.test)
+    testImplementation(projects.libraries.matrix.test)
+    testImplementation(projects.libraries.oidc.test)
+    testImplementation(projects.libraries.permissions.test)
+    testImplementation(projects.libraries.sessionStorage.test)
+    testImplementation(projects.libraries.wellknown.test)
+}

features/linknewdevice/impl/src/main/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (c) 2025 Element Creations Ltd.
+  ~
+  ~ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+  ~ Please see LICENSE files in the repository root for full details.
+  -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <queries>
+        <!-- To open URL in CustomTab (prefetch, etc.). It makes CustomTabsClient.getPackageName() work
+         see https://developer.android.com/training/package-visibility/use-cases#open-urls-custom-tabs -->
+        <intent>
+            <action android:name="android.support.customtabs.action.CustomTabsService" />
+        </intent>
+    </queries>
+
+</manifest>

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/DefaultLinkNewDeviceEntryPoint.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl
+
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import dev.zacsweers.metro.ContributesBinding
+import io.element.android.features.linknewdevice.api.LinkNewDeviceEntryPoint
+import io.element.android.libraries.architecture.createNode
+import io.element.android.libraries.di.SessionScope
+
+@ContributesBinding(SessionScope::class)
+class DefaultLinkNewDeviceEntryPoint : LinkNewDeviceEntryPoint {
+    override fun createNode(
+        parentNode: Node,
+        buildContext: BuildContext,
+        callback: LinkNewDeviceEntryPoint.Callback,
+    ): Node {
+        return parentNode.createNode<LinkNewDeviceFlowNode>(
+            buildContext = buildContext,
+            plugins = listOf(
+                callback,
+            )
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewDesktopHandler.kt

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl
+
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.SingleIn
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.di.SessionScope
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
+import timber.log.Timber
+
+private val loggerTag = LoggerTag("LinkNewDesktopHandler", LoggerTags.linkNewDevice)
+
+@Inject
+@SingleIn(SessionScope::class)
+class LinkNewDesktopHandler(
+    private val matrixClient: MatrixClient,
+) {
+    private val sessionScope = matrixClient.sessionCoroutineScope
+    private val linkDesktopStepFlow = MutableStateFlow<LinkDesktopStep>(
+        LinkDesktopStep.Uninitialized
+    )
+
+    val stepFlow: StateFlow<LinkDesktopStep>
+        get() = linkDesktopStepFlow.asStateFlow()
+
+    private var currentJob: Job? = null
+    private var handler: LinkDesktopHandler? = null
+
+    fun createNewHandler() {
+        currentJob?.cancel()
+        currentJob = null
+        handler = matrixClient.createLinkDesktopHandler().getOrNull()
+    }
+
+    fun reset() {
+        currentJob?.cancel()
+        currentJob = null
+        sessionScope.launch {
+            linkDesktopStepFlow.emit(LinkDesktopStep.Uninitialized)
+        }
+    }
+
+    fun onScannedCode(data: ByteArray) {
+        currentJob?.cancel()
+        currentJob = null
+        val currentHandler = handler
+        if (currentHandler == null) {
+            Timber.tag(loggerTag.value).e("onScannedCode: Handler is not initialized. Call createNewHandler() first.")
+        } else {
+            currentJob = matrixClient.sessionCoroutineScope.launch {
+                currentHandler.linkDesktopStep.onEach {
+                    linkDesktopStepFlow.emit(it)
+                }.launchIn(this)
+                currentHandler.handleScannedQrCode(data)
+            }
+        }
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewDeviceFlowNode.kt

@@ -0,0 +1,287 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl
+
+import android.app.Activity
+import android.os.Parcelable
+import androidx.activity.compose.LocalActivity
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.lifecycle.subscribe
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import com.bumble.appyx.navmodel.backstack.BackStack
+import com.bumble.appyx.navmodel.backstack.operation.newRoot
+import com.bumble.appyx.navmodel.backstack.operation.pop
+import com.bumble.appyx.navmodel.backstack.operation.push
+import com.bumble.appyx.navmodel.backstack.operation.replace
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.features.linknewdevice.api.LinkNewDeviceEntryPoint
+import io.element.android.features.linknewdevice.impl.screens.desktop.DesktopNoticeNode
+import io.element.android.features.linknewdevice.impl.screens.error.ErrorNode
+import io.element.android.features.linknewdevice.impl.screens.error.ErrorScreenType
+import io.element.android.features.linknewdevice.impl.screens.number.EnterNumberNode
+import io.element.android.features.linknewdevice.impl.screens.qrcode.ShowQrCodeNode
+import io.element.android.features.linknewdevice.impl.screens.root.LinkNewDeviceRootNode
+import io.element.android.features.linknewdevice.impl.screens.scan.ScanQrCodeNode
+import io.element.android.libraries.androidutils.browser.openUrlInChromeCustomTab
+import io.element.android.libraries.architecture.BackstackView
+import io.element.android.libraries.architecture.BaseFlowNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.architecture.createNode
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.di.SessionScope
+import io.element.android.libraries.di.annotations.SessionCoroutineScope
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.parcelize.Parcelize
+import timber.log.Timber
+
+private val tag = LoggerTag("LinkNewDeviceFlowNode", LoggerTags.linkNewDevice)
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class LinkNewDeviceFlowNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+    @SessionCoroutineScope
+    private val sessionCoroutineScope: CoroutineScope,
+    private val linkNewMobileHandler: LinkNewMobileHandler,
+    private val linkNewDesktopHandler: LinkNewDesktopHandler,
+) : BaseFlowNode<LinkNewDeviceFlowNode.NavTarget>(
+    backstack = BackStack(
+        initialElement = NavTarget.Root,
+        savedStateMap = buildContext.savedStateMap,
+    ),
+    buildContext = buildContext,
+    plugins = plugins,
+) {
+    private val callback: LinkNewDeviceEntryPoint.Callback = callback()
+    private var activity: Activity? = null
+    private var darkTheme: Boolean = false
+
+    override fun onBuilt() {
+        super.onBuilt()
+        var linkMobileHandlerJob: Job? = null
+        var linkDesktopHandlerJob: Job? = null
+
+        lifecycle.subscribe(
+            onCreate = {
+                linkNewMobileHandler.reset()
+                linkNewDesktopHandler.reset()
+                @Suppress("AssignedValueIsNeverRead")
+                linkMobileHandlerJob = observeLinkNewMobileHandler()
+                @Suppress("AssignedValueIsNeverRead")
+                linkDesktopHandlerJob = observeLinkNewDesktopHandler()
+            },
+            onDestroy = {
+                linkMobileHandlerJob?.cancel()
+                linkDesktopHandlerJob?.cancel()
+            }
+        )
+    }
+
+    sealed interface NavTarget : Parcelable {
+        // Will display the not supported state or the device type selection
+        @Parcelize
+        data object Root : NavTarget
+
+        @Parcelize
+        data class MobileShowQrCode(
+            val data: String,
+        ) : NavTarget
+
+        @Parcelize
+        data object MobileEnterNumber : NavTarget
+
+        @Parcelize
+        data object DesktopNotice : NavTarget
+
+        @Parcelize
+        data object DesktopScanQrCode : NavTarget
+
+        @Parcelize
+        data class Error(
+            val errorScreenType: ErrorScreenType,
+        ) : NavTarget
+    }
+
+    private fun observeLinkNewMobileHandler(): Job {
+        Timber.tag(tag.value).d("startObservingLinkNewMobileHandler")
+        return linkNewMobileHandler.stepFlow
+            .onEach { linkMobileStep ->
+                Timber.tag(tag.value).d("step: ${linkMobileStep::class.java.simpleName}")
+                when (linkMobileStep) {
+                    LinkMobileStep.Uninitialized -> Unit
+                    LinkMobileStep.Done -> {
+                        callback.onDone()
+                    }
+                    is LinkMobileStep.Error -> {
+                        navigateToError(linkMobileStep.errorType)
+                    }
+                    is LinkMobileStep.QrReady -> {
+                        // The QrCode is ready, navigate to its display
+                        backstack.push(NavTarget.MobileShowQrCode(linkMobileStep.data))
+                    }
+                    is LinkMobileStep.QrScanned -> {
+                        backstack.replace(NavTarget.MobileEnterNumber)
+                    }
+                    LinkMobileStep.Starting -> {
+                        // This step is not received at the moment, so do nothing
+                    }
+                    LinkMobileStep.SyncingSecrets -> {
+                        // LinkMobileStep.Done is not received at the moment, so consider that the flow is done here
+                        callback.onDone()
+                    }
+                    is LinkMobileStep.WaitingForAuth -> {
+                        navigateToBrowser(linkMobileStep.verificationUri)
+                    }
+                }
+            }
+            .launchIn(sessionCoroutineScope)
+    }
+
+    private fun observeLinkNewDesktopHandler(): Job {
+        Timber.tag(tag.value).d("startObservingLinkNewDesktopHandler")
+        return linkNewDesktopHandler.stepFlow.onEach { linkDesktopStep ->
+            Timber.tag(tag.value).d("step: ${linkDesktopStep::class.java.simpleName}")
+            when (linkDesktopStep) {
+                LinkDesktopStep.Done -> callback.onDone()
+                is LinkDesktopStep.Error -> {
+                    navigateToError(linkDesktopStep.errorType)
+                }
+                is LinkDesktopStep.EstablishingSecureChannel -> Unit
+                is LinkDesktopStep.InvalidQrCode -> {
+                    // This error will be handled by the ScanQrCodeNode
+                }
+                LinkDesktopStep.Starting -> Unit
+                LinkDesktopStep.SyncingSecrets -> Unit
+                LinkDesktopStep.Uninitialized -> Unit
+                is LinkDesktopStep.WaitingForAuth -> {
+                    navigateToBrowser(linkDesktopStep.verificationUri)
+                }
+            }
+        }
+            .launchIn(sessionCoroutineScope)
+    }
+
+    private fun navigateToError(errorType: ErrorType) {
+        // Map the error to an error screen
+        // TODO Update this mapping
+        val error = when (errorType) {
+            is ErrorType.DeviceIdAlreadyInUse -> ErrorScreenType.UnknownError
+            is ErrorType.InvalidCheckCode -> ErrorScreenType.InsecureChannelDetected
+            is ErrorType.MissingSecretsBackup -> ErrorScreenType.UnknownError
+            is ErrorType.NotFound -> ErrorScreenType.Expired
+            is ErrorType.UnableToCreateDevice -> ErrorScreenType.UnknownError
+            is ErrorType.Unknown -> ErrorScreenType.UnknownError
+            is ErrorType.UnsupportedProtocol -> ErrorScreenType.UnknownError
+        }
+        // It is OK to push on backstack, since when user leaves the error screen, a new root will be set
+        backstack.push(NavTarget.Error(error))
+    }
+
+    override fun resolve(navTarget: NavTarget, buildContext: BuildContext): Node {
+        return when (navTarget) {
+            NavTarget.Root -> {
+                val callback = object : LinkNewDeviceRootNode.Callback {
+                    override fun onDone() {
+                        callback.onDone()
+                    }
+
+                    override fun linkDesktopDevice() {
+                        linkNewDesktopHandler.reset()
+                        backstack.push(NavTarget.DesktopNotice)
+                    }
+                }
+                createNode<LinkNewDeviceRootNode>(buildContext, listOf(callback))
+            }
+            NavTarget.DesktopNotice -> {
+                val callback = object : DesktopNoticeNode.Callback {
+                    override fun navigateBack() {
+                        backstack.pop()
+                    }
+
+                    override fun navigateToQrCodeScanner() {
+                        backstack.push(NavTarget.DesktopScanQrCode)
+                    }
+                }
+                createNode<DesktopNoticeNode>(buildContext, listOf(callback))
+            }
+            NavTarget.DesktopScanQrCode -> {
+                val callback = object : ScanQrCodeNode.Callback {
+                    override fun cancel() {
+                        backstack.pop()
+                    }
+                }
+                createNode<ScanQrCodeNode>(buildContext, listOf(callback))
+            }
+            NavTarget.MobileEnterNumber -> {
+                val callback = object : EnterNumberNode.Callback {
+                    override fun navigateToWrongNumberError() {
+                        backstack.push(NavTarget.Error(ErrorScreenType.Mismatch2Digits))
+                    }
+
+                    override fun navigateBack() {
+                        backstack.pop()
+                    }
+                }
+                createNode<EnterNumberNode>(buildContext, listOf(callback))
+            }
+            is NavTarget.MobileShowQrCode -> {
+                val callback = object : ShowQrCodeNode.Callback {
+                    override fun navigateBack() {
+                        linkNewMobileHandler.reset()
+                        backstack.pop()
+                    }
+                }
+                val inputs = ShowQrCodeNode.Inputs(
+                    data = navTarget.data,
+                )
+                createNode<ShowQrCodeNode>(buildContext, listOf(inputs, callback))
+            }
+            is NavTarget.Error -> {
+                val callback = object : ErrorNode.Callback {
+                    override fun onRetry() {
+                        linkNewMobileHandler.reset()
+                        linkNewDesktopHandler.reset()
+                        backstack.newRoot(NavTarget.Root)
+                    }
+                }
+                createNode<ErrorNode>(buildContext, listOf(callback, navTarget.errorScreenType))
+            }
+        }
+    }
+
+    private fun navigateToBrowser(url: String) {
+        activity?.openUrlInChromeCustomTab(null, darkTheme, url)
+    }
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        activity = requireNotNull(LocalActivity.current)
+        darkTheme = !ElementTheme.isLightTheme
+        DisposableEffect(Unit) {
+            onDispose {
+                activity = null
+            }
+        }
+        BackstackView()
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewMobileHandler.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl
+
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.SingleIn
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.di.SessionScope
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
+import timber.log.Timber
+
+private val loggerTag = LoggerTag("LinkNewMobileHandler", LoggerTags.linkNewDevice)
+
+@Inject
+@SingleIn(SessionScope::class)
+class LinkNewMobileHandler(
+    private val matrixClient: MatrixClient,
+) {
+    private val sessionScope = matrixClient.sessionCoroutineScope
+    private var currentJob: Job? = null
+    private var handler: LinkMobileHandler? = null
+
+    private val linkMobileStepFlow = MutableStateFlow<LinkMobileStep>(
+        LinkMobileStep.Uninitialized
+    )
+
+    val stepFlow: StateFlow<LinkMobileStep>
+        get() = linkMobileStepFlow.asStateFlow()
+
+    fun createAndStartNewHandler() {
+        Timber.tag(loggerTag.value).d("createAndStartNewHandler()")
+        currentJob?.cancel()
+        handler = matrixClient.createLinkMobileHandler().getOrNull()
+        handler?.let { h ->
+            currentJob = sessionScope.launch {
+                h.linkMobileStep
+                    .onEach {
+                        linkMobileStepFlow.emit(it)
+                    }
+                    .launchIn(this)
+                h.start()
+            }
+        }
+    }
+
+    fun reset() {
+        currentJob?.cancel()
+        currentJob = null
+        sessionScope.launch {
+            linkMobileStepFlow.emit(LinkMobileStep.Uninitialized)
+        }
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeEvent.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+sealed interface DesktopNoticeEvent {
+    data object Continue : DesktopNoticeEvent
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeNode.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.di.SessionScope
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class DesktopNoticeNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+    private val presenter: DesktopNoticePresenter,
+) : Node(buildContext, plugins = plugins) {
+    interface Callback : Plugin {
+        fun navigateBack()
+        fun navigateToQrCodeScanner()
+    }
+
+    private val callback: Callback = callback()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        val state = presenter.present()
+        DesktopNoticeView(
+            state = state,
+            modifier = modifier,
+            onBackClick = callback::navigateBack,
+            onReadyToScanClick = callback::navigateToQrCodeScanner,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticePresenter.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import android.Manifest
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import dev.zacsweers.metro.Inject
+import io.element.android.libraries.architecture.Presenter
+import io.element.android.libraries.permissions.api.PermissionsEvent
+import io.element.android.libraries.permissions.api.PermissionsPresenter
+
+@Inject
+class DesktopNoticePresenter(
+    permissionsPresenterFactory: PermissionsPresenter.Factory,
+) : Presenter<DesktopNoticeState> {
+    private val cameraPermissionPresenter: PermissionsPresenter = permissionsPresenterFactory.create(Manifest.permission.CAMERA)
+    private var pendingPermissionRequest by mutableStateOf(false)
+
+    @Composable
+    override fun present(): DesktopNoticeState {
+        val cameraPermissionState = cameraPermissionPresenter.present()
+        var canContinue by remember { mutableStateOf(false) }
+        LaunchedEffect(cameraPermissionState.permissionGranted) {
+            if (cameraPermissionState.permissionGranted && pendingPermissionRequest) {
+                pendingPermissionRequest = false
+                canContinue = true
+            }
+        }
+
+        fun handleEvent(event: DesktopNoticeEvent) {
+            when (event) {
+                DesktopNoticeEvent.Continue -> if (cameraPermissionState.permissionGranted) {
+                    canContinue = true
+                } else {
+                    pendingPermissionRequest = true
+                    cameraPermissionState.eventSink(PermissionsEvent.RequestPermissions)
+                }
+            }
+        }
+
+        return DesktopNoticeState(
+            cameraPermissionState = cameraPermissionState,
+            canContinue = canContinue,
+            eventSink = ::handleEvent,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeState.kt

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import io.element.android.libraries.permissions.api.PermissionsState
+
+data class DesktopNoticeState(
+    val cameraPermissionState: PermissionsState,
+    val canContinue: Boolean,
+    val eventSink: (DesktopNoticeEvent) -> Unit,
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeStateProvider.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ * Copyright 2024, 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import android.Manifest
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import io.element.android.libraries.permissions.api.PermissionsState
+import io.element.android.libraries.permissions.api.aPermissionsState
+
+open class DesktopNoticeStateProvider : PreviewParameterProvider<DesktopNoticeState> {
+    override val values: Sequence<DesktopNoticeState>
+        get() = sequenceOf(
+            aDesktopNoticeState(),
+            aDesktopNoticeState(cameraPermissionState = aPermissionsState(showDialog = true, permission = Manifest.permission.CAMERA)),
+        )
+}
+
+fun aDesktopNoticeState(
+    cameraPermissionState: PermissionsState = aPermissionsState(
+        showDialog = false,
+        permission = Manifest.permission.CAMERA,
+    ),
+    canContinue: Boolean = false,
+    eventSink: (DesktopNoticeEvent) -> Unit = {},
+) = DesktopNoticeState(
+    cameraPermissionState = cameraPermissionState,
+    canContinue = canContinue,
+    eventSink = eventSink
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeView.kt

@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalMaterial3Api::class)
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.designsystem.atomic.organisms.NumberedListOrganism
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.LocalBuildMeta
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.Icon
+import io.element.android.libraries.designsystem.utils.annotatedTextWithBold
+import io.element.android.libraries.permissions.api.PermissionsView
+import kotlinx.collections.immutable.persistentListOf
+
+/**
+ * Desktop notice screen:
+ * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2027-23618
+ */
+@Composable
+fun DesktopNoticeView(
+    state: DesktopNoticeState,
+    onBackClick: () -> Unit,
+    onReadyToScanClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val latestOnReadyToScanClick by rememberUpdatedState(onReadyToScanClick)
+    LaunchedEffect(state.canContinue) {
+        if (state.canContinue) {
+            latestOnReadyToScanClick()
+        }
+    }
+
+    val appName = LocalBuildMeta.current.applicationName
+    FlowStepPage(
+        onBackClick = onBackClick,
+        title = stringResource(R.string.screen_link_new_device_desktop_title, appName),
+        iconStyle = BigIcon.Style.Default(CompoundIcons.Computer()),
+        modifier = modifier,
+        buttons = {
+            Button(
+                text = stringResource(R.string.screen_link_new_device_desktop_submit),
+                onClick = { state.eventSink(DesktopNoticeEvent.Continue) },
+                modifier = Modifier.fillMaxWidth(),
+            )
+        }
+    ) {
+        Column(
+            Modifier.fillMaxWidth()
+        ) {
+            Spacer(modifier = Modifier.height(40.dp))
+            NumberedListOrganism(
+                modifier = Modifier.fillMaxSize(),
+                items = persistentListOf(
+                    AnnotatedString(stringResource(R.string.screen_link_new_device_desktop_step1, appName)),
+                    annotatedTextWithBold(
+                        text = stringResource(
+                            id = R.string.screen_link_new_device_mobile_step2,
+                            stringResource(R.string.screen_link_new_device_mobile_step2_action),
+                        ),
+                        boldText = stringResource(R.string.screen_link_new_device_mobile_step2_action)
+                    ),
+                    AnnotatedString(stringResource(R.string.screen_link_new_device_desktop_step3)),
+                )
+            )
+        }
+    }
+
+    PermissionsView(
+        title = stringResource(R.string.screen_qr_code_login_no_camera_permission_state_title),
+        content = stringResource(R.string.screen_qr_code_login_no_camera_permission_state_description, appName),
+        icon = { Icon(imageVector = CompoundIcons.TakePhotoSolid(), contentDescription = null) },
+        state = state.cameraPermissionState,
+    )
+}
+
+@PreviewsDayNight
+@Composable
+internal fun DesktopNoticeViewPreview(
+    @PreviewParameter(DesktopNoticeStateProvider::class) state: DesktopNoticeState,
+) = ElementPreview {
+    DesktopNoticeView(
+        state = state,
+        onBackClick = { },
+        onReadyToScanClick = { },
+    )
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/error/ErrorNode.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.error
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.architecture.inputs
+import io.element.android.libraries.di.SessionScope
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class ErrorNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+) : Node(buildContext = buildContext, plugins = plugins) {
+    interface Callback : Plugin {
+        fun onRetry()
+    }
+
+    private val callback: Callback = callback()
+    private val errorScreenType = inputs<ErrorScreenType>()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        ErrorView(
+            modifier = modifier,
+            errorScreenType = errorScreenType,
+            onRetry = callback::onRetry,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/error/ErrorScreenType.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.error
+
+import android.os.Parcelable
+import androidx.compose.runtime.Immutable
+import io.element.android.libraries.architecture.NodeInputs
+import kotlinx.parcelize.Parcelize
+
+@Immutable
+sealed interface ErrorScreenType : NodeInputs, Parcelable {
+    @Parcelize
+    data object Cancelled : ErrorScreenType
+
+    @Parcelize
+    data object Expired : ErrorScreenType
+
+    @Parcelize
+    data object Mismatch2Digits : ErrorScreenType
+
+    @Parcelize
+    data object InsecureChannelDetected : ErrorScreenType
+
+    @Parcelize
+    data object Declined : ErrorScreenType
+
+    @Parcelize
+    data object ProtocolNotSupported : ErrorScreenType
+
+    @Parcelize
+    data object SlidingSyncNotAvailable : ErrorScreenType
+
+    @Parcelize
+    data object UnknownError : ErrorScreenType
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/error/ErrorScreenTypeProvider.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.error
+
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+
+class ErrorScreenTypeProvider : PreviewParameterProvider<ErrorScreenType> {
+    override val values: Sequence<ErrorScreenType> = sequenceOf(
+        ErrorScreenType.Cancelled,
+        ErrorScreenType.Declined,
+        ErrorScreenType.Expired,
+        ErrorScreenType.ProtocolNotSupported,
+        ErrorScreenType.Mismatch2Digits,
+        ErrorScreenType.InsecureChannelDetected,
+        ErrorScreenType.SlidingSyncNotAvailable,
+        ErrorScreenType.UnknownError,
+    )
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/error/ErrorView.kt

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.error
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.designsystem.atomic.organisms.NumberedListOrganism
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.LocalBuildMeta
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.Text
+import io.element.android.libraries.ui.strings.CommonStrings
+import kotlinx.collections.immutable.persistentListOf
+
+@Composable
+fun ErrorView(
+    errorScreenType: ErrorScreenType,
+    onRetry: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val appName = LocalBuildMeta.current.applicationName
+    BackHandler(onBack = onRetry)
+    FlowStepPage(
+        modifier = modifier,
+        iconStyle = BigIcon.Style.AlertSolid,
+        title = titleText(errorScreenType, appName),
+        subTitle = subtitleText(errorScreenType, appName),
+        content = { Content(errorScreenType) },
+        buttons = { Buttons(onRetry) },
+    )
+}
+
+@Composable
+private fun titleText(errorScreenType: ErrorScreenType, appName: String) = when (errorScreenType) {
+    ErrorScreenType.Cancelled -> stringResource(R.string.screen_qr_code_login_error_cancelled_title)
+    ErrorScreenType.Declined -> stringResource(R.string.screen_qr_code_login_error_declined_title)
+    ErrorScreenType.Expired -> stringResource(R.string.screen_qr_code_login_error_expired_title)
+    ErrorScreenType.ProtocolNotSupported -> stringResource(R.string.screen_qr_code_login_error_linking_not_suported_title)
+    ErrorScreenType.InsecureChannelDetected -> stringResource(id = R.string.screen_qr_code_login_connection_note_secure_state_title)
+    ErrorScreenType.Mismatch2Digits -> stringResource(id = R.string.screen_link_new_device_wrong_number_title)
+    ErrorScreenType.SlidingSyncNotAvailable -> stringResource(id = R.string.screen_qr_code_login_error_sliding_sync_not_supported_title, appName)
+    is ErrorScreenType.UnknownError -> stringResource(CommonStrings.common_something_went_wrong)
+}
+
+@Composable
+private fun subtitleText(errorScreenType: ErrorScreenType, appName: String) = when (errorScreenType) {
+    ErrorScreenType.Cancelled -> stringResource(R.string.screen_qr_code_login_error_cancelled_subtitle)
+    ErrorScreenType.Declined -> stringResource(R.string.screen_qr_code_login_error_declined_subtitle)
+    ErrorScreenType.Expired -> stringResource(R.string.screen_qr_code_login_error_expired_subtitle)
+    ErrorScreenType.ProtocolNotSupported -> stringResource(R.string.screen_qr_code_login_error_linking_not_suported_subtitle, appName)
+    ErrorScreenType.Mismatch2Digits -> stringResource(id = R.string.screen_link_new_device_wrong_number_subtitle)
+    ErrorScreenType.InsecureChannelDetected -> stringResource(id = R.string.screen_qr_code_login_connection_note_secure_state_description)
+    ErrorScreenType.SlidingSyncNotAvailable -> stringResource(id = R.string.screen_qr_code_login_error_sliding_sync_not_supported_subtitle, appName)
+    is ErrorScreenType.UnknownError -> stringResource(R.string.screen_qr_code_login_unknown_error_description)
+}
+
+@Composable
+private fun ColumnScope.InsecureChannelDetectedError() {
+    Text(
+        modifier = Modifier
+            .fillMaxWidth()
+            .verticalScroll(rememberScrollState()),
+        text = stringResource(R.string.screen_qr_code_login_connection_note_secure_state_list_header),
+        style = ElementTheme.typography.fontBodyLgMedium,
+        textAlign = TextAlign.Center,
+    )
+    NumberedListOrganism(
+        modifier = Modifier.fillMaxSize(),
+        items = persistentListOf(
+            AnnotatedString(stringResource(R.string.screen_qr_code_login_connection_note_secure_state_list_item_1)),
+            AnnotatedString(stringResource(R.string.screen_qr_code_login_connection_note_secure_state_list_item_2)),
+            AnnotatedString(stringResource(R.string.screen_qr_code_login_connection_note_secure_state_list_item_3)),
+        )
+    )
+}
+
+@Composable
+private fun Content(errorScreenType: ErrorScreenType) {
+    when (errorScreenType) {
+        ErrorScreenType.InsecureChannelDetected -> {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(top = 20.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(24.dp)
+            ) {
+                InsecureChannelDetectedError()
+            }
+        }
+        else -> Unit
+    }
+}
+
+@Composable
+private fun Buttons(onRetry: () -> Unit) {
+    Button(
+        modifier = Modifier.fillMaxWidth(),
+        text = stringResource(CommonStrings.action_start_over),
+        onClick = onRetry
+    )
+}
+
+@PreviewsDayNight
+@Composable
+internal fun ErrorViewPreview(@PreviewParameter(ErrorScreenTypeProvider::class) errorScreenType: ErrorScreenType) {
+    ElementPreview {
+        ErrorView(
+            errorScreenType = errorScreenType,
+            onRetry = {},
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/Config.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+object Config {
+    const val VERIFICATION_CODE_LENGTH = 2
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberEvent.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+sealed interface EnterNumberEvent {
+    data class UpdateNumber(val number: String) : EnterNumberEvent
+    data object Continue : EnterNumberEvent
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberNode.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.di.SessionScope
+
+interface EnterNumberNavigator {
+    fun navigateToWrongNumberError()
+}
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class EnterNumberNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+    presenterFactory: EnterNumberPresenter.Factory,
+) : Node(buildContext, plugins = plugins), EnterNumberNavigator {
+    private val presenter = presenterFactory.create(this)
+
+    interface Callback : Plugin {
+        fun navigateToWrongNumberError()
+        fun navigateBack()
+    }
+
+    private val callback: Callback = callback()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        val state = presenter.present()
+        EnterNumberView(
+            state = state,
+            modifier = modifier,
+            onBackClick = callback::navigateBack,
+        )
+    }
+
+    override fun navigateToWrongNumberError() {
+        callback.navigateToWrongNumberError()
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberPresenter.kt

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedFactory
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.features.linknewdevice.impl.LinkNewMobileHandler
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.architecture.Presenter
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.matrix.api.linknewdevice.CheckCodeSender
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import kotlinx.coroutines.launch
+import timber.log.Timber
+
+private val tag = LoggerTag("EnterNumberPresenter", LoggerTags.linkNewDevice)
+
+@AssistedInject
+class EnterNumberPresenter(
+    @Assisted private val navigator: EnterNumberNavigator,
+    private val linkNewMobileHandler: LinkNewMobileHandler,
+) : Presenter<EnterNumberState> {
+    @AssistedFactory
+    interface Factory {
+        fun create(navigator: EnterNumberNavigator): EnterNumberPresenter
+    }
+
+    @Composable
+    override fun present(): EnterNumberState {
+        val coroutineScope = rememberCoroutineScope()
+        var number by remember { mutableStateOf("") }
+        var sendingCode by remember<MutableState<AsyncAction<Unit>>> { mutableStateOf(AsyncAction.Uninitialized) }
+
+        // Observe the flow to react on ErrorType.InvalidCheckCode
+        val linkMobileStep by linkNewMobileHandler.stepFlow.collectAsState()
+
+        var checkCodeSender: CheckCodeSender? by remember { mutableStateOf(null) }
+
+        LaunchedEffect(linkMobileStep) {
+            when (val step = linkMobileStep) {
+                is LinkMobileStep.QrScanned -> {
+                    checkCodeSender = step.checkCodeSender
+                }
+                else -> Unit
+            }
+        }
+
+        fun handleEvent(event: EnterNumberEvent) {
+            when (event) {
+                is EnterNumberEvent.UpdateNumber -> {
+                    sendingCode = AsyncAction.Uninitialized
+                    // Keep only digits as a safety measure
+                    number = event.number.filter { it.isDigit() }
+                }
+                EnterNumberEvent.Continue -> coroutineScope.launch {
+                    // Get the current code sender
+                    val sender = checkCodeSender
+                    if (sender == null) {
+                        Timber.tag(tag.value).e("No check code sender available")
+                        sendingCode = AsyncAction.Failure(IllegalStateException("No check code sender available"))
+                    } else {
+                        sendingCode = AsyncAction.Loading
+                        val uByte = number.toUByte()
+                        val isValid = sender.validate(uByte)
+                        if (isValid) {
+                            sender.send(uByte)
+                                .fold(
+                                    onSuccess = {
+                                        Timber.tag(tag.value).d("Code sent successfully")
+                                        // Keep loading, do not set sendingCode to AsyncAction.Success(Unit)
+                                    },
+                                    onFailure = {
+                                        Timber.tag(tag.value).e(it, "Failed to send number code")
+                                        sendingCode = AsyncAction.Failure(it)
+                                    }
+                                )
+                        } else {
+                            // Navigate to the error state
+                            navigator.navigateToWrongNumberError()
+                        }
+                    }
+                }
+            }
+        }
+
+        return EnterNumberState(
+            number = number,
+            sendingCode = sendingCode,
+            eventSink = ::handleEvent,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberState.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import io.element.android.features.linknewdevice.impl.screens.number.model.Number
+import io.element.android.libraries.architecture.AsyncAction
+
+data class EnterNumberState(
+    val number: String,
+    val sendingCode: AsyncAction<Unit>,
+    val eventSink: (EnterNumberEvent) -> Unit,
+) {
+    val numberEntry = Number.createEmpty(Config.VERIFICATION_CODE_LENGTH).fillWith(number)
+    val isContinueButtonEnabled: Boolean
+        get() = numberEntry.isComplete() && !sendingCode.isLoading()
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberStateProvider.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+
+open class EnterNumberStateProvider : PreviewParameterProvider<EnterNumberState> {
+    override val values: Sequence<EnterNumberState>
+        get() = sequenceOf(
+            aEnterNumberState(),
+            aEnterNumberState(number = "1"),
+            aEnterNumberState(number = "12"),
+            aEnterNumberState(number = "12", sendingCode = AsyncAction.Loading),
+            aEnterNumberState(number = "12", sendingCode = AsyncAction.Failure(ErrorType.InvalidCheckCode("Invalid"))),
+            aEnterNumberState(number = "12", sendingCode = AsyncAction.Failure(Exception("Failed to send code"))),
+        )
+}
+
+fun aEnterNumberState(
+    number: String = "",
+    sendingCode: AsyncAction<Unit> = AsyncAction.Uninitialized,
+    eventSink: (EnterNumberEvent) -> Unit = {},
+) = EnterNumberState(
+    number = number,
+    sendingCode = sendingCode,
+    eventSink = eventSink,
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberView.kt

@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalMaterial3Api::class)
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.features.linknewdevice.impl.screens.number.component.NumberTextField
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.Icon
+import io.element.android.libraries.designsystem.theme.components.Text
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+import io.element.android.libraries.ui.strings.CommonStrings
+
+/**
+ * Form to enter number:
+ * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2076-81604
+ */
+@Composable
+fun EnterNumberView(
+    state: EnterNumberState,
+    onBackClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    FlowStepPage(
+        onBackClick = onBackClick,
+        title = stringResource(R.string.screen_link_new_device_enter_number_title),
+        subTitle = stringResource(R.string.screen_link_new_device_enter_number_subtitle),
+        iconStyle = BigIcon.Style.Default(CompoundIcons.Computer()),
+        modifier = modifier,
+        buttons = {
+            Button(
+                text = stringResource(CommonStrings.action_continue),
+                onClick = { state.eventSink(EnterNumberEvent.Continue) },
+                enabled = state.isContinueButtonEnabled,
+                showProgress = state.sendingCode.isLoading(),
+                modifier = Modifier.fillMaxWidth(),
+            )
+        }
+    ) {
+        Column(
+            Modifier.fillMaxWidth(),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Spacer(modifier = Modifier.height(24.dp))
+            Text(
+                text = stringResource(R.string.screen_link_new_device_enter_number_notice),
+                textAlign = TextAlign.Center,
+                style = ElementTheme.typography.fontBodyMdRegular,
+                color = ElementTheme.colors.textPrimary,
+            )
+            Spacer(modifier = Modifier.height(8.dp))
+            NumberTextField(
+                number = state.numberEntry,
+                onValueChange = { state.eventSink(EnterNumberEvent.UpdateNumber(it)) },
+                onDone = {
+                    if (state.isContinueButtonEnabled) {
+                        state.eventSink(EnterNumberEvent.Continue)
+                    }
+                },
+            )
+            val failure = state.sendingCode.errorOrNull()
+            if (failure != null) {
+                Spacer(modifier = Modifier.height(4.dp))
+                Row(
+                    verticalAlignment = Alignment.CenterVertically,
+                    horizontalArrangement = Arrangement.spacedBy(4.dp)
+                ) {
+                    Icon(
+                        modifier = Modifier.size(14.dp),
+                        imageVector = CompoundIcons.ErrorSolid(),
+                        contentDescription = null,
+                        tint = ElementTheme.colors.iconCriticalPrimary,
+                    )
+                    val errorMessage = when (failure) {
+                        is ErrorType.InvalidCheckCode -> stringResource(R.string.screen_link_new_device_enter_number_error_numbers_do_not_match)
+                        else -> failure.message ?: stringResource(CommonStrings.error_unknown)
+                    }
+                    Text(
+                        text = errorMessage,
+                        style = ElementTheme.typography.fontBodySmRegular,
+                        color = ElementTheme.colors.textCriticalPrimary,
+                    )
+                }
+            }
+        }
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun EnterNumberViewPreview(
+    @PreviewParameter(EnterNumberStateProvider::class) state: EnterNumberState,
+) = ElementPreview {
+    EnterNumberView(
+        state = state,
+        onBackClick = { },
+    )
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/component/NumberTextField.kt

@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number.component
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsFocusedAsState
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.BasicTextField
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalInspectionMode
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.features.linknewdevice.impl.screens.number.model.Digit
+import io.element.android.features.linknewdevice.impl.screens.number.model.Number
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import kotlinx.coroutines.delay
+
+@Composable
+fun NumberTextField(
+    number: Number,
+    onValueChange: (String) -> Unit,
+    onDone: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val interactionSource = remember { MutableInteractionSource() }
+    val isFocused = LocalInspectionMode.current || interactionSource.collectIsFocusedAsState().value
+    BasicTextField(
+        modifier = modifier,
+        value = number.toText(),
+        onValueChange = {
+            onValueChange(it)
+        },
+        interactionSource = interactionSource,
+        maxLines = 1,
+        keyboardOptions = KeyboardOptions(
+            keyboardType = KeyboardType.Number,
+            imeAction = ImeAction.Done,
+        ),
+        keyboardActions = KeyboardActions(
+            onDone = {
+                onDone()
+            }
+        ),
+        decorationBox = {
+            NumberRow(
+                number = number,
+                hasFocus = isFocused,
+            )
+        }
+    )
+}
+
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+private fun NumberRow(
+    number: Number,
+    hasFocus: Boolean,
+) {
+    FlowRow(
+        horizontalArrangement = Arrangement.spacedBy(12.dp, alignment = Alignment.CenterHorizontally),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        val length = number.length()
+        number.digits.forEachIndexed { index, digit ->
+            DigitView(
+                digit = digit,
+                isCurrent = index == length,
+                drawCursor = hasFocus,
+            )
+        }
+    }
+}
+
+@Composable
+private fun DigitView(
+    digit: Digit,
+    isCurrent: Boolean,
+    drawCursor: Boolean,
+) {
+    val shape = RoundedCornerShape(4.dp)
+    val appearanceModifier = when (digit) {
+        Digit.Empty -> {
+            val color = if (isCurrent) {
+                ElementTheme.colors.textPrimary
+            } else {
+                ElementTheme.colors.borderInteractiveSecondary
+            }
+            Modifier.border(1.dp, color, shape)
+        }
+        is Digit.Filled -> {
+            Modifier.background(ElementTheme.colors.bgActionSecondaryPressed, shape)
+        }
+    }
+    Box(
+        modifier = Modifier
+            .size(42.dp, 56.dp)
+            .then(appearanceModifier),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (digit is Digit.Filled) {
+            Text(
+                text = digit.value.toString(),
+                style = ElementTheme.typography.fontHeadingLgBold,
+                color = ElementTheme.colors.textPrimary,
+            )
+        } else if (drawCursor && isCurrent) {
+            // Draw a blinking cursor
+            BlinkingCursor()
+        }
+    }
+}
+
+@Composable
+private fun BlinkingCursor() {
+    var isCursorVisible by remember { mutableStateOf(true) }
+    LaunchedEffect(isCursorVisible) {
+        delay(500)
+        // Toggle cursor visibility
+        isCursorVisible = !isCursorVisible
+    }
+    if (isCursorVisible) {
+        Spacer(
+            modifier = Modifier
+                .size(2.dp, 24.dp)
+                .offset(x = (-5).dp)
+                .background(ElementTheme.colors.textPrimary, RoundedCornerShape(1.dp))
+        )
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun NumberTextFieldPreview() {
+    ElementPreview {
+        val number = Number.createEmpty(4).fillWith("12")
+        NumberTextField(
+            number = number,
+            onValueChange = {},
+            onDone = {},
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/model/Digit.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number.model
+
+import androidx.compose.runtime.Immutable
+
+@Immutable
+sealed interface Digit {
+    data object Empty : Digit
+    data class Filled(val value: Char) : Digit
+
+    fun toText(): String {
+        return when (this) {
+            is Empty -> ""
+            is Filled -> value.toString()
+        }
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/number/model/Number.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number.model
+
+import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.toImmutableList
+
+data class Number(
+    val digits: ImmutableList<Digit>,
+) {
+    companion object {
+        fun createEmpty(size: Int): Number {
+            val digits = List(size) { Digit.Empty }
+            return Number(
+                digits = digits.toImmutableList()
+            )
+        }
+    }
+
+    val size = digits.size
+
+    /**
+     * Fill the first digits with the given text.
+     * Can't be more than the size of the NumberEntry
+     * Keep the Empty digits at the end
+     * @return the new NumberEntry
+     */
+    fun fillWith(text: String): Number {
+        val newDigits = MutableList<Digit>(size) { Digit.Empty }
+        text.forEachIndexed { index, char ->
+            if (index < size && char.isDigit()) {
+                newDigits[index] = Digit.Filled(char)
+            }
+        }
+        return copy(digits = newDigits.toImmutableList())
+    }
+
+    fun length(): Int {
+        return digits.count { it is Digit.Filled }
+    }
+
+    fun toText(): String {
+        return digits.joinToString("") {
+            it.toText()
+        }
+    }
+
+    fun isComplete(): Boolean {
+        return digits.all { it is Digit.Filled }
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeNode.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.qrcode
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.NodeInputs
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.architecture.inputs
+import io.element.android.libraries.di.SessionScope
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class ShowQrCodeNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+) : Node(buildContext, plugins = plugins) {
+    class Inputs(
+        val data: String,
+    ) : NodeInputs
+
+    interface Callback : Plugin {
+        fun navigateBack()
+    }
+
+    private val inputs: Inputs = inputs<Inputs>()
+    private val callback: Callback = callback()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        ShowQrCodeView(
+            data = inputs.data,
+            modifier = modifier,
+            onBackClick = callback::navigateBack,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeView.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalMaterial3Api::class)
+
+package io.element.android.features.linknewdevice.impl.screens.qrcode
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.designsystem.atomic.organisms.NumberedListOrganism
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.LocalBuildMeta
+import io.element.android.libraries.designsystem.utils.annotatedTextWithBold
+import io.element.android.libraries.qrcode.QrCodeImage
+import kotlinx.collections.immutable.persistentListOf
+
+/**
+ * QrCode display screen:
+ * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2027-23617
+ */
+@Composable
+fun ShowQrCodeView(
+    data: String,
+    onBackClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val appName = LocalBuildMeta.current.applicationName
+    FlowStepPage(
+        onBackClick = onBackClick,
+        title = stringResource(R.string.screen_link_new_device_mobile_title, appName),
+        iconStyle = BigIcon.Style.Default(CompoundIcons.TakePhotoSolid()),
+        modifier = modifier,
+    ) {
+        Column(
+            Modifier.fillMaxWidth(),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            QrCodeImage(
+                data = data,
+                modifier = Modifier
+                    .size(220.dp)
+            )
+            Spacer(modifier = Modifier.height(32.dp))
+            NumberedListOrganism(
+                modifier = Modifier.fillMaxSize(),
+                items = persistentListOf(
+                    AnnotatedString(stringResource(R.string.screen_link_new_device_mobile_step1, appName)),
+                    annotatedTextWithBold(
+                        text = stringResource(
+                            id = R.string.screen_link_new_device_mobile_step2,
+                            stringResource(R.string.screen_link_new_device_mobile_step2_action),
+                        ),
+                        boldText = stringResource(R.string.screen_link_new_device_mobile_step2_action)
+                    ),
+                    AnnotatedString(stringResource(R.string.screen_link_new_device_mobile_step3)),
+                )
+            )
+        }
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun ShowQrCodeViewPreview() = ElementPreview {
+    ShowQrCodeView(
+        data = "DATA",
+        onBackClick = { },
+    )
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootEvent.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+sealed interface LinkNewDeviceRootEvent {
+    data object LinkMobileDevice : LinkNewDeviceRootEvent
+    data object CloseDialog : LinkNewDeviceRootEvent
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootNode.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.di.SessionScope
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class LinkNewDeviceRootNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+    private val presenter: LinkNewDeviceRootPresenter,
+) : Node(buildContext, plugins = plugins) {
+    interface Callback : Plugin {
+        fun onDone()
+        fun linkDesktopDevice()
+    }
+
+    private val callback: Callback = callback()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        val state = presenter.present()
+        LinkNewDeviceRootView(
+            state = state,
+            modifier = modifier,
+            onBackClick = callback::onDone,
+            onLinkDesktopDeviceClick = callback::linkDesktopDevice,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootPresenter.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import dev.zacsweers.metro.Inject
+import io.element.android.features.linknewdevice.impl.LinkNewMobileHandler
+import io.element.android.libraries.architecture.AsyncData
+import io.element.android.libraries.architecture.Presenter
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import kotlinx.coroutines.launch
+
+@Inject
+class LinkNewDeviceRootPresenter(
+    private val matrixClient: MatrixClient,
+    private val linkNewMobileHandler: LinkNewMobileHandler,
+) : Presenter<LinkNewDeviceRootState> {
+    @Composable
+    override fun present(): LinkNewDeviceRootState {
+        val coroutineScope = rememberCoroutineScope()
+        var isSupported by remember { mutableStateOf<AsyncData<Boolean>>(AsyncData.Uninitialized) }
+        var qrCodeData by remember { mutableStateOf<AsyncData<Unit>>(AsyncData.Uninitialized) }
+
+        LaunchedEffect(Unit) {
+            matrixClient.canLinkNewDevice().fold(
+                onSuccess = { supported ->
+                    isSupported = AsyncData.Success(supported)
+                },
+                onFailure = {
+                    isSupported = AsyncData.Failure(it)
+                }
+            )
+        }
+
+        val step by linkNewMobileHandler.stepFlow.collectAsState()
+
+        LaunchedEffect(step) {
+            when (val finalStep = step) {
+                is LinkMobileStep.Uninitialized -> {
+                    qrCodeData = AsyncData.Uninitialized
+                }
+                is LinkMobileStep.QrReady -> {
+                    qrCodeData = AsyncData.Success(Unit)
+                }
+                is LinkMobileStep.Error -> {
+                    qrCodeData = AsyncData.Failure(finalStep.errorType)
+                }
+                else -> Unit
+            }
+        }
+
+        fun handleEvent(event: LinkNewDeviceRootEvent) {
+            when (event) {
+                LinkNewDeviceRootEvent.LinkMobileDevice -> coroutineScope.launch {
+                    qrCodeData = AsyncData.Loading()
+                    // Wait for the QrCode to be ready
+                    linkNewMobileHandler.reset()
+                    linkNewMobileHandler.createAndStartNewHandler()
+                }
+                LinkNewDeviceRootEvent.CloseDialog -> coroutineScope.launch {
+                    linkNewMobileHandler.reset()
+                }
+            }
+        }
+
+        return LinkNewDeviceRootState(
+            isSupported = isSupported,
+            qrCodeData = qrCodeData,
+            eventSink = ::handleEvent,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootState.kt

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import io.element.android.libraries.architecture.AsyncData
+
+data class LinkNewDeviceRootState(
+    val isSupported: AsyncData<Boolean>,
+    val qrCodeData: AsyncData<Unit>,
+    val eventSink: (LinkNewDeviceRootEvent) -> Unit,
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootStateProvider.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import io.element.android.libraries.architecture.AsyncData
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+
+open class LinkNewDeviceRootStateProvider : PreviewParameterProvider<LinkNewDeviceRootState> {
+    override val values: Sequence<LinkNewDeviceRootState>
+        get() = sequenceOf(
+            aLinkNewDeviceRootState(),
+            aLinkNewDeviceRootState(isSupported = AsyncData.Success(true)),
+            aLinkNewDeviceRootState(isSupported = AsyncData.Success(false)),
+            aLinkNewDeviceRootState(isSupported = AsyncData.Failure(Exception("Should not happen"))),
+            aLinkNewDeviceRootState(
+                isSupported = AsyncData.Success(true),
+                qrCodeData = AsyncData.Loading(),
+            ),
+            aLinkNewDeviceRootState(
+                isSupported = AsyncData.Success(true),
+                qrCodeData = AsyncData.Failure(ErrorType.NotFound("The rendezvous session was not found and might have expired")),
+            ),
+        )
+}
+
+fun aLinkNewDeviceRootState(
+    isSupported: AsyncData<Boolean> = AsyncData.Uninitialized,
+    qrCodeData: AsyncData<Unit> = AsyncData.Uninitialized,
+    eventSink: (LinkNewDeviceRootEvent) -> Unit = { },
+) = LinkNewDeviceRootState(
+    isSupported = isSupported,
+    qrCodeData = qrCodeData,
+    eventSink = eventSink,
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootView.kt

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalMaterial3Api::class)
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.architecture.AsyncData
+import io.element.android.libraries.designsystem.atomic.atoms.LoadingButtonAtom
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.components.dialogs.ErrorDialog
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.IconSource
+import io.element.android.libraries.designsystem.theme.components.Text
+import io.element.android.libraries.ui.strings.CommonStrings
+
+/**
+ * Device selection screen:
+ * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2027-23616
+ * Not supported screen:
+ * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2186-70004
+ */
+@Composable
+fun LinkNewDeviceRootView(
+    state: LinkNewDeviceRootState,
+    onBackClick: () -> Unit,
+    onLinkDesktopDeviceClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val (title, subtitle, iconStyle) = if (state.isSupported.dataOrNull() == false) {
+        Triple(
+            stringResource(R.string.screen_link_new_device_error_not_supported_title),
+            stringResource(R.string.screen_link_new_device_error_not_supported_subtitle),
+            BigIcon.Style.AlertSolid
+        )
+    } else {
+        Triple(
+            stringResource(R.string.screen_link_new_device_root_title),
+            null,
+            BigIcon.Style.Default(CompoundIcons.Devices())
+        )
+    }
+    FlowStepPage(
+        onBackClick = onBackClick,
+        title = title,
+        subTitle = subtitle,
+        iconStyle = iconStyle,
+        buttons = {
+            when (state.isSupported) {
+                is AsyncData.Uninitialized,
+                is AsyncData.Loading -> {
+                    LoadingButtonAtom()
+                }
+                is AsyncData.Failure -> {
+                    Text(
+                        text = stringResource(id = CommonStrings.error_unknown),
+                        color = ElementTheme.colors.textCriticalPrimary,
+                        style = ElementTheme.typography.fontBodyMdRegular,
+                        textAlign = TextAlign.Center,
+                    )
+                    Button(
+                        onClick = onBackClick,
+                        text = stringResource(CommonStrings.action_dismiss),
+                        modifier = Modifier.fillMaxWidth(),
+                    )
+                }
+                is AsyncData.Success -> {
+                    if (state.isSupported.data) {
+                        when (state.qrCodeData) {
+                            AsyncData.Uninitialized,
+                            is AsyncData.Failure -> {
+                                Button(
+                                    onClick = { state.eventSink(LinkNewDeviceRootEvent.LinkMobileDevice) },
+                                    text = stringResource(id = R.string.screen_link_new_device_root_mobile_device),
+                                    modifier = Modifier.fillMaxWidth(),
+                                    leadingIcon = IconSource.Vector(CompoundIcons.Mobile()),
+                                )
+                                Button(
+                                    onClick = onLinkDesktopDeviceClick,
+                                    text = stringResource(id = R.string.screen_link_new_device_root_desktop_computer),
+                                    modifier = Modifier.fillMaxWidth(),
+                                    leadingIcon = IconSource.Vector(CompoundIcons.Computer()),
+                                )
+                            }
+                            is AsyncData.Loading,
+                            is AsyncData.Success -> {
+                                Button(
+                                    onClick = { state.eventSink(LinkNewDeviceRootEvent.LinkMobileDevice) },
+                                    text = stringResource(id = R.string.screen_link_new_device_root_loading_qr_code),
+                                    showProgress = true,
+                                    enabled = false,
+                                    modifier = Modifier.fillMaxWidth(),
+                                )
+                                Button(
+                                    onClick = onLinkDesktopDeviceClick,
+                                    text = stringResource(id = R.string.screen_link_new_device_root_desktop_computer),
+                                    modifier = Modifier.fillMaxWidth(),
+                                    enabled = false,
+                                    leadingIcon = IconSource.Vector(CompoundIcons.Computer()),
+                                )
+                            }
+                        }
+                    } else {
+                        Button(
+                            onClick = onBackClick,
+                            text = stringResource(CommonStrings.action_dismiss),
+                            modifier = Modifier.fillMaxWidth(),
+                        )
+                    }
+                }
+            }
+        },
+        modifier = modifier,
+    )
+
+    val failure = state.qrCodeData.errorOrNull()
+    if (failure != null) {
+        ErrorDialog(
+            content = failure.message ?: stringResource(CommonStrings.error_unknown),
+            onSubmit = { state.eventSink(LinkNewDeviceRootEvent.CloseDialog) },
+        )
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun LinkNewDeviceRootViewPreview(
+    @PreviewParameter(LinkNewDeviceRootStateProvider::class) state: LinkNewDeviceRootState
+) = ElementPreview {
+    LinkNewDeviceRootView(
+        state = state,
+        onBackClick = { },
+        onLinkDesktopDeviceClick = { },
+    )
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeEvent.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+sealed interface ScanQrCodeEvent {
+    data class QrCodeScanned(val data: ByteArray) : ScanQrCodeEvent
+    data object TryAgain : ScanQrCodeEvent
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeNode.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.plugin.Plugin
+import dev.zacsweers.metro.Assisted
+import dev.zacsweers.metro.AssistedInject
+import io.element.android.annotations.ContributesNode
+import io.element.android.libraries.architecture.callback
+import io.element.android.libraries.di.SessionScope
+
+@ContributesNode(SessionScope::class)
+@AssistedInject
+class ScanQrCodeNode(
+    @Assisted buildContext: BuildContext,
+    @Assisted plugins: List<Plugin>,
+    private val presenter: ScanQrCodePresenter,
+) : Node(buildContext, plugins = plugins) {
+    interface Callback : Plugin {
+        fun cancel()
+    }
+
+    private val callback: Callback = callback()
+
+    @Composable
+    override fun View(modifier: Modifier) {
+        val state = presenter.present()
+        ScanQrCodeView(
+            state = state,
+            onBackClick = callback::cancel,
+            modifier = modifier
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodePresenter.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import dev.zacsweers.metro.Inject
+import io.element.android.features.linknewdevice.impl.LinkNewDesktopHandler
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.architecture.Presenter
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import kotlinx.coroutines.launch
+
+@Inject
+class ScanQrCodePresenter(
+    private val linkNewDesktopHandler: LinkNewDesktopHandler,
+) : Presenter<ScanQrCodeState> {
+    @Composable
+    override fun present(): ScanQrCodeState {
+        val coroutineScope = rememberCoroutineScope()
+        var scanAction: AsyncAction<Unit> by remember { mutableStateOf(AsyncAction.Loading) }
+
+        // Observe the flow to react on LinkDesktopStep.InvalidQrCode
+        val linkDesktopStep by linkNewDesktopHandler.stepFlow.collectAsState()
+
+        LaunchedEffect(Unit) {
+            linkNewDesktopHandler.createNewHandler()
+        }
+
+        LaunchedEffect(linkDesktopStep) {
+            when (val step = linkDesktopStep) {
+                is LinkDesktopStep.InvalidQrCode -> {
+                    scanAction = AsyncAction.Failure(Exception(step.error))
+                }
+                else -> Unit
+            }
+        }
+
+        fun handleEvent(event: ScanQrCodeEvent) {
+            when (event) {
+                ScanQrCodeEvent.TryAgain -> {
+                    scanAction = AsyncAction.Loading
+                }
+                is ScanQrCodeEvent.QrCodeScanned -> coroutineScope.launch {
+                    // In this case the scanning will stop and a loader will be shown
+                    scanAction = AsyncAction.Success(Unit)
+                    try {
+                        linkNewDesktopHandler.onScannedCode(event.data)
+                    } catch (e: Exception) {
+                        // Should not happen as errors are handled through the LinkDesktopStep flow
+                        scanAction = AsyncAction.Failure(e)
+                    }
+                }
+            }
+        }
+
+        return ScanQrCodeState(
+            scanAction = scanAction,
+            eventSink = ::handleEvent,
+        )
+    }
+}

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeState.kt

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import io.element.android.libraries.architecture.AsyncAction
+
+data class ScanQrCodeState(
+    val scanAction: AsyncAction<Unit>,
+    val eventSink: (ScanQrCodeEvent) -> Unit,
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeStateProvider.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import io.element.android.libraries.architecture.AsyncAction
+
+open class ScanQrCodeStateProvider : PreviewParameterProvider<ScanQrCodeState> {
+    override val values: Sequence<ScanQrCodeState>
+        get() = sequenceOf(
+            aScanQrCodeState(),
+            aScanQrCodeState(scanAction = AsyncAction.Loading),
+            aScanQrCodeState(scanAction = AsyncAction.Success(Unit)),
+            aScanQrCodeState(scanAction = AsyncAction.Failure(Exception("Scan failed"))),
+        )
+}
+
+fun aScanQrCodeState(
+    scanAction: AsyncAction<Unit> = AsyncAction.Uninitialized,
+    eventSink: (ScanQrCodeEvent) -> Unit = {},
+) = ScanQrCodeState(
+    scanAction = scanAction,
+    eventSink = eventSink
+)

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeView.kt

@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.progressSemantics
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.unit.dp
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.designsystem.atomic.pages.FlowStepPage
+import io.element.android.libraries.designsystem.components.BigIcon
+import io.element.android.libraries.designsystem.modifiers.cornerBorder
+import io.element.android.libraries.designsystem.modifiers.squareSize
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.CircularProgressIndicator
+import io.element.android.libraries.designsystem.theme.components.Icon
+import io.element.android.libraries.designsystem.theme.components.Text
+import io.element.android.libraries.qrcode.QrCodeCameraView
+import io.element.android.libraries.ui.strings.CommonStrings
+
+@Composable
+fun ScanQrCodeView(
+    state: ScanQrCodeState,
+    onBackClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    FlowStepPage(
+        modifier = modifier,
+        onBackClick = onBackClick,
+        iconStyle = BigIcon.Style.Default(CompoundIcons.Computer()),
+        title = stringResource(R.string.screen_link_new_device_desktop_scanning_title),
+        content = { Content(state = state) },
+        buttons = { Buttons(state = state) }
+    )
+}
+
+@Composable
+private fun Content(
+    state: ScanQrCodeState,
+) {
+    BoxWithConstraints(
+        modifier = Modifier.fillMaxWidth(),
+        contentAlignment = Alignment.Center,
+    ) {
+        val modifier = if (constraints.maxWidth > constraints.maxHeight) {
+            Modifier.fillMaxHeight()
+        } else {
+            Modifier.fillMaxWidth()
+        }.then(
+            Modifier
+                .padding(start = 20.dp, end = 20.dp, top = 50.dp, bottom = 32.dp)
+                .squareSize()
+                .cornerBorder(
+                    strokeWidth = 4.dp,
+                    color = ElementTheme.colors.textPrimary,
+                    cornerSizeDp = 42.dp,
+                )
+        )
+        Box(
+            modifier = modifier,
+            contentAlignment = Alignment.Center,
+        ) {
+            QrCodeCameraView(
+                modifier = Modifier.fillMaxSize(),
+                onScanQrCode = { state.eventSink.invoke(ScanQrCodeEvent.QrCodeScanned(it)) },
+                isScanning = state.scanAction.isLoading(),
+            )
+        }
+    }
+}
+
+@Composable
+private fun ColumnScope.Buttons(
+    state: ScanQrCodeState,
+) {
+    Column(Modifier.heightIn(min = 130.dp)) {
+        when (state.scanAction) {
+            is AsyncAction.Failure -> {
+                Button(
+                    text = stringResource(id = CommonStrings.action_try_again),
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .padding(bottom = 16.dp),
+                    onClick = {
+                        state.eventSink.invoke(ScanQrCodeEvent.TryAgain)
+                    }
+                )
+                Column(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    verticalArrangement = Arrangement.spacedBy(2.dp),
+                ) {
+                    Row(
+                        verticalAlignment = Alignment.CenterVertically,
+                    ) {
+                        Icon(
+                            imageVector = CompoundIcons.ErrorSolid(),
+                            tint = ElementTheme.colors.iconCriticalPrimary,
+                            contentDescription = null,
+                            modifier = Modifier.size(24.dp)
+                        )
+                        Spacer(modifier = Modifier.width(4.dp))
+                        Text(
+                            text = stringResource(R.string.screen_qr_code_login_invalid_scan_state_subtitle),
+                            textAlign = TextAlign.Center,
+                            color = ElementTheme.colors.textCriticalPrimary,
+                            style = ElementTheme.typography.fontBodySmMedium,
+                        )
+                    }
+                    Text(
+                        text = stringResource(R.string.screen_qr_code_login_invalid_scan_state_description),
+                        textAlign = TextAlign.Center,
+                        style = ElementTheme.typography.fontBodySmRegular,
+                        color = ElementTheme.colors.textSecondary,
+                    )
+                }
+            }
+            is AsyncAction.Success -> {
+                Column(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    verticalArrangement = Arrangement.spacedBy(8.dp),
+                ) {
+                    CircularProgressIndicator(
+                        modifier = Modifier
+                            .progressSemantics()
+                            .size(20.dp),
+                        strokeWidth = 2.dp
+                    )
+                }
+            }
+            AsyncAction.Loading,
+            AsyncAction.Uninitialized,
+            is AsyncAction.Confirming -> Unit
+        }
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun ScanQrCodeViewPreview(@PreviewParameter(ScanQrCodeStateProvider::class) state: ScanQrCodeState) = ElementPreview {
+    ScanQrCodeView(
+        state = state,
+        onBackClick = {},
+    )
+}

features/linknewdevice/impl/src/main/res/values/localazy.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+  <string name="screen_link_new_device_desktop_scanning_title">"Scan the QR code"</string>
+  <string name="screen_link_new_device_desktop_step1">"Open %1$s on a laptop or desktop computer"</string>
+  <string name="screen_link_new_device_desktop_step3">"Scan the QR code with this device"</string>
+  <string name="screen_link_new_device_desktop_submit">"Ready to scan"</string>
+  <string name="screen_link_new_device_desktop_title">"Open %1$s on a desktop computer to get the QR code"</string>
+  <string name="screen_link_new_device_enter_number_error_numbers_do_not_match">"The numbers don’t match"</string>
+  <string name="screen_link_new_device_enter_number_notice">"Enter 2-digit code"</string>
+  <string name="screen_link_new_device_enter_number_subtitle">"This will verify that the connection to your other device is secure."</string>
+  <string name="screen_link_new_device_enter_number_title">"Enter the number shown on your other device"</string>
+  <string name="screen_link_new_device_error_app_not_supported_subtitle">"Your account provider does not support %1$s."</string>
+  <string name="screen_link_new_device_error_app_not_supported_title">"%1$s not supported"</string>
+  <string name="screen_link_new_device_error_not_supported_subtitle">"Your account provider doesn’t support signing into a new device with a QR code."</string>
+  <string name="screen_link_new_device_error_not_supported_title">"QR code not supported"</string>
+  <string name="screen_link_new_device_error_request_cancelled_subtitle">"The sign in was cancelled on the other device."</string>
+  <string name="screen_link_new_device_error_request_cancelled_title">"Sign in request cancelled"</string>
+  <string name="screen_link_new_device_error_request_timeout_subtitle">"Sign in expired. Please try again."</string>
+  <string name="screen_link_new_device_error_request_timeout_title">"The sign in was not completed in time"</string>
+  <string name="screen_link_new_device_mobile_step1">"Open %1$s on the other device"</string>
+  <string name="screen_link_new_device_mobile_step2">"Select %1$s"</string>
+  <string name="screen_link_new_device_mobile_step2_action">"“Sign in with QR code”"</string>
+  <string name="screen_link_new_device_mobile_step3">"Scan the QR code shown here with the other device"</string>
+  <string name="screen_link_new_device_mobile_title">"Open %1$s on the other device"</string>
+  <string name="screen_link_new_device_root_desktop_computer">"Desktop computer"</string>
+  <string name="screen_link_new_device_root_loading_qr_code">"Loading QR code…"</string>
+  <string name="screen_link_new_device_root_mobile_device">"Mobile device"</string>
+  <string name="screen_link_new_device_root_title">"What type of device do you want to link?"</string>
+  <string name="screen_link_new_device_wrong_number_subtitle">"Please try again and make sure that you’ve entered the 2-digit code correctly. If the numbers still don’t match then contact your account provider."</string>
+  <string name="screen_link_new_device_wrong_number_title">"The numbers don’t match"</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_description">"A secure connection could not be made to the new device. Your existing devices are still safe and you don\'t need to worry about them."</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_list_header">"What now?"</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_list_item_1">"Try signing in again with a QR code in case this was a network problem"</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_list_item_2">"If you encounter the same problem, try a different wifi network or use your mobile data instead of wifi"</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_list_item_3">"If that doesn’t work, sign in manually"</string>
+  <string name="screen_qr_code_login_connection_note_secure_state_title">"Connection not secure"</string>
+  <string name="screen_qr_code_login_error_cancelled_subtitle">"The sign in was cancelled on the other device."</string>
+  <string name="screen_qr_code_login_error_cancelled_title">"Sign in request cancelled"</string>
+  <string name="screen_qr_code_login_error_declined_subtitle">"The sign in was declined on the other device."</string>
+  <string name="screen_qr_code_login_error_declined_title">"Sign in declined"</string>
+  <string name="screen_qr_code_login_error_device_already_signed_in_subtitle">"You don’t need to do anything else."</string>
+  <string name="screen_qr_code_login_error_device_already_signed_in_title">"Your other device is already signed in"</string>
+  <string name="screen_qr_code_login_error_expired_subtitle">"Sign in expired. Please try again."</string>
+  <string name="screen_qr_code_login_error_expired_title">"The sign in was not completed in time"</string>
+  <string name="screen_qr_code_login_error_linking_not_suported_subtitle">"Your other device does not support signing in to %s with a QR code.
+
+Try signing in manually, or scan the QR code with another device."</string>
+  <string name="screen_qr_code_login_error_linking_not_suported_title">"QR code not supported"</string>
+  <string name="screen_qr_code_login_error_sliding_sync_not_supported_subtitle">"Your account provider does not support %1$s."</string>
+  <string name="screen_qr_code_login_error_sliding_sync_not_supported_title">"%1$s not supported"</string>
+  <string name="screen_qr_code_login_invalid_scan_state_description">"Use the QR code shown on the other device."</string>
+  <string name="screen_qr_code_login_invalid_scan_state_retry_button">"Try again"</string>
+  <string name="screen_qr_code_login_invalid_scan_state_subtitle">"Wrong QR code"</string>
+  <string name="screen_qr_code_login_no_camera_permission_state_description">"You need to give permission for %1$s to use your device’s camera in order to continue."</string>
+  <string name="screen_qr_code_login_no_camera_permission_state_title">"Allow camera access to scan the QR code"</string>
+  <string name="screen_qr_code_login_unknown_error_description">"An unexpected error occurred. Please try again."</string>
+</resources>

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/DefaultLinkNewDeviceEntryPointTest.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import com.bumble.appyx.core.modality.BuildContext
+import com.bumble.appyx.testing.junit4.util.MainDispatcherRule
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.api.LinkNewDeviceEntryPoint
+import io.element.android.libraries.matrix.test.FakeMatrixClient
+import io.element.android.tests.testutils.lambda.lambdaError
+import io.element.android.tests.testutils.node.TestParentNode
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+class DefaultLinkNewDeviceEntryPointTest {
+    @get:Rule
+    val instantTaskExecutorRule = InstantTaskExecutorRule()
+
+    @get:Rule
+    val mainDispatcherRule = MainDispatcherRule()
+
+    @Test
+    fun `test node creation`() = runTest {
+        val entryPoint = DefaultLinkNewDeviceEntryPoint()
+        val client = FakeMatrixClient()
+        val parentNode = TestParentNode.create { buildContext, plugins ->
+            LinkNewDeviceFlowNode(
+                buildContext = buildContext,
+                plugins = plugins,
+                sessionCoroutineScope = backgroundScope,
+                linkNewMobileHandler = LinkNewMobileHandler(client),
+                linkNewDesktopHandler = LinkNewDesktopHandler(client),
+            )
+        }
+        val callback: LinkNewDeviceEntryPoint.Callback = object : LinkNewDeviceEntryPoint.Callback {
+            override fun onDone() = lambdaError()
+        }
+        val result = entryPoint.createNode(parentNode, BuildContext.root(null), callback)
+        assertThat(result).isInstanceOf(LinkNewDeviceFlowNode::class.java)
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticePresenterTest.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.permissions.test.FakePermissionsPresenter
+import io.element.android.libraries.permissions.test.FakePermissionsPresenterFactory
+import io.element.android.tests.testutils.test
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+
+class DesktopNoticePresenterTest {
+    @Test
+    fun `present - initial state`() = runTest {
+        val presenter = createPresenter()
+        presenter.test {
+            awaitItem().run {
+                assertThat(cameraPermissionState.permission).isEqualTo("android.permission.POST_NOTIFICATIONS")
+                assertThat(canContinue).isFalse()
+            }
+        }
+    }
+
+    @Test
+    fun `present - Continue with camera permissions can continue`() = runTest {
+        val permissionsPresenter = FakePermissionsPresenter().apply { setPermissionGranted() }
+        val permissionsPresenterFactory = FakePermissionsPresenterFactory(permissionsPresenter)
+        val presenter = createPresenter(permissionsPresenterFactory = permissionsPresenterFactory)
+        presenter.test {
+            awaitItem().eventSink(DesktopNoticeEvent.Continue)
+            assertThat(awaitItem().canContinue).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - Continue with unknown camera permissions opens permission dialog`() = runTest {
+        val permissionsPresenter = FakePermissionsPresenter()
+        val permissionsPresenterFactory = FakePermissionsPresenterFactory(permissionsPresenter)
+        val presenter = createPresenter(permissionsPresenterFactory = permissionsPresenterFactory)
+        presenter.test {
+            awaitItem().eventSink(DesktopNoticeEvent.Continue)
+            assertThat(awaitItem().cameraPermissionState.showDialog).isTrue()
+        }
+    }
+}
+
+private fun createPresenter(
+    permissionsPresenterFactory: FakePermissionsPresenterFactory = FakePermissionsPresenterFactory(),
+) = DesktopNoticePresenter(
+    permissionsPresenterFactory = permissionsPresenterFactory,
+)

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/desktop/DesktopNoticeViewTest.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.desktop
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.tests.testutils.EnsureNeverCalled
+import io.element.android.tests.testutils.EventsRecorder
+import io.element.android.tests.testutils.clickOn
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBack
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class DesktopNoticeViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aDesktopNoticeState(),
+                onBackClicked = callback,
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    @Test
+    fun `on back button clicked - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aDesktopNoticeState(),
+                onBackClicked = callback,
+            )
+            rule.pressBack()
+        }
+    }
+
+    @Test
+    fun `when can continue - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aDesktopNoticeState(canContinue = true),
+                onReadyToScanClick = callback,
+            )
+        }
+    }
+
+    @Test
+    fun `on submit button clicked - emits the Continue event`() {
+        val eventRecorder = EventsRecorder<DesktopNoticeEvent>()
+        rule.setView(
+            state = aDesktopNoticeState(eventSink = eventRecorder),
+        )
+        rule.clickOn(R.string.screen_link_new_device_desktop_submit)
+        eventRecorder.assertSingle(DesktopNoticeEvent.Continue)
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setView(
+        state: DesktopNoticeState,
+        onBackClicked: () -> Unit = EnsureNeverCalled(),
+        onReadyToScanClick: () -> Unit = EnsureNeverCalled(),
+    ) {
+        setContent {
+            DesktopNoticeView(
+                state = state,
+                onBackClick = onBackClicked,
+                onReadyToScanClick = onReadyToScanClick,
+            )
+        }
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/error/ErrorViewTest.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.error
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.libraries.ui.strings.CommonStrings
+import io.element.android.tests.testutils.clickOn
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ErrorViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the onRetry callback`() {
+        ensureCalledOnce { callback ->
+            rule.setErrorView(
+                onRetry = callback
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    @Test
+    fun `on start over button clicked - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setErrorView(
+                onRetry = callback
+            )
+            rule.clickOn(CommonStrings.action_start_over)
+        }
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setErrorView(
+        onRetry: () -> Unit,
+        errorScreenType: ErrorScreenType = ErrorScreenType.UnknownError,
+    ) {
+        setContent {
+            ErrorView(
+                errorScreenType = errorScreenType,
+                onRetry = onRetry,
+            )
+        }
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberPresenterTest.kt

@@ -0,0 +1,191 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.impl.LinkNewMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.test.AN_EXCEPTION
+import io.element.android.libraries.matrix.test.FakeMatrixClient
+import io.element.android.libraries.matrix.test.linknewdevice.FakeCheckCodeSender
+import io.element.android.libraries.matrix.test.linknewdevice.FakeLinkMobileHandler
+import io.element.android.tests.testutils.WarmUpRule
+import io.element.android.tests.testutils.lambda.lambdaRecorder
+import io.element.android.tests.testutils.lambda.value
+import io.element.android.tests.testutils.test
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+class EnterNumberPresenterTest {
+    @get:Rule
+    val warmUpRule = WarmUpRule()
+
+    @Test
+    fun `present - initial state`() = runTest {
+        createPresenter().test {
+            val initialState = awaitItem()
+            assertThat(initialState.number).isEmpty()
+            assertThat(initialState.sendingCode.isUninitialized()).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - enter numbers`() = runTest {
+        createPresenter().test {
+            val initialState = awaitItem()
+            assertThat(initialState.number).isEmpty()
+            initialState.eventSink(EnterNumberEvent.UpdateNumber("12"))
+            val state2 = awaitItem()
+            assertThat(state2.number).isEqualTo("12")
+            // Non numeric characters are ignored
+            state2.eventSink(EnterNumberEvent.UpdateNumber("1a"))
+            val state3 = awaitItem()
+            assertThat(state3.number).isEqualTo("1")
+        }
+    }
+
+    @Test
+    fun `present - continue in wrong state generates an error`() = runTest {
+        createPresenter().test {
+            val initialState = awaitItem()
+            initialState.eventSink(EnterNumberEvent.Continue)
+            val state2 = awaitItem()
+            assertThat(state2.sendingCode.isFailure()).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - continue when number is not valid invokes the navigator`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val validateResult = lambdaRecorder<UByte, Boolean> { false }
+        val checkCodeSender = FakeCheckCodeSender(
+            validateResult = validateResult,
+        )
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = { Result.success(linkMobileHandler) }
+        )
+        val linkNewMobileHandler = LinkNewMobileHandler(matrixClient)
+        linkNewMobileHandler.createAndStartNewHandler()
+        val navigateToWrongNumberErrorLambda = lambdaRecorder<Unit> { }
+        val navigator = FakeEnterNumberNavigator(
+            navigateToWrongNumberErrorLambda = navigateToWrongNumberErrorLambda,
+        )
+        createPresenter(
+            navigator = navigator,
+            linkNewMobileHandler = linkNewMobileHandler,
+        ).test {
+            val initialState = awaitItem()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrScanned(checkCodeSender)
+            )
+            runCurrent()
+            initialState.eventSink(EnterNumberEvent.UpdateNumber("88"))
+            skipItems(1)
+            initialState.eventSink(EnterNumberEvent.Continue)
+            skipItems(1)
+            val finalState = awaitItem()
+            assertThat(finalState.sendingCode.isLoading()).isTrue()
+            advanceUntilIdle()
+            validateResult.assertions().isCalledOnce().with(value(88.toUByte()))
+            navigateToWrongNumberErrorLambda.assertions().isCalledOnce()
+        }
+    }
+
+    @Test
+    fun `present - continue when the number is valid but sending fails`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val validateResult = lambdaRecorder<UByte, Boolean> { true }
+        val sendResult = lambdaRecorder<UByte, Result<Unit>> { Result.failure(AN_EXCEPTION) }
+        val checkCodeSender = FakeCheckCodeSender(
+            validateResult = validateResult,
+            sendResult = sendResult,
+        )
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = { Result.success(linkMobileHandler) }
+        )
+        val linkNewMobileHandler = LinkNewMobileHandler(matrixClient)
+        linkNewMobileHandler.createAndStartNewHandler()
+        createPresenter(
+            linkNewMobileHandler = linkNewMobileHandler,
+        ).test {
+            val initialState = awaitItem()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrScanned(checkCodeSender)
+            )
+            runCurrent()
+            initialState.eventSink(EnterNumberEvent.UpdateNumber("88"))
+            skipItems(1)
+            initialState.eventSink(EnterNumberEvent.Continue)
+            skipItems(1)
+            val loadingState = awaitItem()
+            assertThat(loadingState.sendingCode.isLoading()).isTrue()
+            val finalState = awaitItem()
+            assertThat(finalState.sendingCode.isFailure()).isTrue()
+            validateResult.assertions().isCalledOnce().with(value(88.toUByte()))
+            sendResult.assertions().isCalledOnce().with(value(88.toUByte()))
+        }
+    }
+
+    @Test
+    fun `present - continue when the number is valid and sending is successful`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val validateResult = lambdaRecorder<UByte, Boolean> { true }
+        val sendResult = lambdaRecorder<UByte, Result<Unit>> { Result.success(Unit) }
+        val checkCodeSender = FakeCheckCodeSender(
+            validateResult = validateResult,
+            sendResult = sendResult,
+        )
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = { Result.success(linkMobileHandler) }
+        )
+        val linkNewMobileHandler = LinkNewMobileHandler(matrixClient)
+        linkNewMobileHandler.createAndStartNewHandler()
+        createPresenter(
+            linkNewMobileHandler = linkNewMobileHandler,
+        ).test {
+            val initialState = awaitItem()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrScanned(checkCodeSender)
+            )
+            runCurrent()
+            initialState.eventSink(EnterNumberEvent.UpdateNumber("88"))
+            skipItems(1)
+            initialState.eventSink(EnterNumberEvent.Continue)
+            skipItems(1)
+            val loadingState = awaitItem()
+            assertThat(loadingState.sendingCode.isLoading()).isTrue()
+            expectNoEvents()
+            advanceUntilIdle()
+            validateResult.assertions().isCalledOnce().with(value(88.toUByte()))
+            sendResult.assertions().isCalledOnce().with(value(88.toUByte()))
+        }
+    }
+
+    private fun createPresenter(
+        navigator: EnterNumberNavigator = FakeEnterNumberNavigator(),
+        linkNewMobileHandler: LinkNewMobileHandler = LinkNewMobileHandler(FakeMatrixClient()),
+    ) = EnterNumberPresenter(
+        navigator = navigator,
+        linkNewMobileHandler = linkNewMobileHandler,
+    )
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberStateTest.kt

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.impl.screens.number.model.Digit
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.matrix.test.AN_EXCEPTION
+import org.junit.Test
+
+class EnterNumberStateTest {
+    @Test
+    fun `isContinueButtonEnabled is false if number is not complete`() {
+        val sut = aEnterNumberState(
+            number = "",
+            sendingCode = AsyncAction.Uninitialized,
+        )
+        assertThat(sut.copy(number = "1").isContinueButtonEnabled).isFalse()
+    }
+
+    @Test
+    fun `isContinueButtonEnabled is true if number is complete`() {
+        val sut = aEnterNumberState(
+            number = "12",
+            sendingCode = AsyncAction.Uninitialized,
+        )
+        assertThat(sut.isContinueButtonEnabled).isTrue()
+    }
+
+    @Test
+    fun `isContinueButtonEnabled is false if number is complete and sending is loading`() {
+        val sut = aEnterNumberState(
+            number = "12",
+            sendingCode = AsyncAction.Loading,
+        )
+        assertThat(sut.isContinueButtonEnabled).isFalse()
+    }
+
+    @Test
+    fun `isContinueButtonEnabled is true if number is complete and sending is not loading`() {
+        listOf(
+            AsyncAction.Uninitialized,
+            AsyncAction.Failure(AN_EXCEPTION),
+            AsyncAction.Success(Unit),
+        ).forEach { action ->
+            val sut = aEnterNumberState(
+                number = "12",
+                sendingCode = action,
+            )
+            assertThat(sut.isContinueButtonEnabled).isTrue()
+        }
+    }
+
+    @Test
+    fun `numberEntry is computed from number - case empty`() {
+        val sut = aEnterNumberState(
+            number = "",
+        )
+        assertThat(sut.numberEntry.size).isEqualTo(2)
+        assertThat(sut.numberEntry.digits).containsExactly(
+            Digit.Empty,
+            Digit.Empty,
+        )
+    }
+
+    @Test
+    fun `numberEntry is computed from number - case half filled`() {
+        val sut = aEnterNumberState(
+            number = "1",
+        )
+        assertThat(sut.numberEntry.size).isEqualTo(2)
+        assertThat(sut.numberEntry.digits).containsExactly(
+            Digit.Filled('1'),
+            Digit.Empty,
+        )
+    }
+
+    @Test
+    fun `numberEntry is computed from number - case filled`() {
+        val sut = aEnterNumberState(
+            number = "12",
+        )
+        assertThat(sut.numberEntry.size).isEqualTo(2)
+        assertThat(sut.numberEntry.digits).containsExactly(
+            Digit.Filled('1'),
+            Digit.Filled('2'),
+        )
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/number/EnterNumberViewTest.kt

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.assertIsNotEnabled
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.libraries.ui.strings.CommonStrings
+import io.element.android.tests.testutils.EnsureNeverCalled
+import io.element.android.tests.testutils.EventsRecorder
+import io.element.android.tests.testutils.clickOn
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBack
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class EnterNumberViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aEnterNumberState(),
+                onBackClicked = callback,
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    @Test
+    fun `on back button clicked - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aEnterNumberState(),
+                onBackClicked = callback,
+            )
+            rule.pressBack()
+        }
+    }
+
+    @Test
+    fun `on continue button clicked - emits the Continue event`() {
+        val eventRecorder = EventsRecorder<EnterNumberEvent>()
+        rule.setView(
+            state = aEnterNumberState(
+                number = "12",
+                eventSink = eventRecorder,
+            ),
+        )
+        rule.clickOn(CommonStrings.action_continue)
+        eventRecorder.assertSingle(EnterNumberEvent.Continue)
+    }
+
+    @Test
+    fun `when the number is not complete, continue button is disabled`() {
+        val eventRecorder = EventsRecorder<EnterNumberEvent>(expectEvents = false)
+        rule.setView(
+            state = aEnterNumberState(
+                number = "1",
+                eventSink = eventRecorder,
+            ),
+        )
+        val continueStr = rule.activity.getString(CommonStrings.action_continue)
+        rule.onNodeWithText(continueStr).assertIsNotEnabled()
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setView(
+        state: EnterNumberState,
+        onBackClicked: () -> Unit = EnsureNeverCalled(),
+    ) {
+        setContent {
+            EnterNumberView(
+                state = state,
+                onBackClick = onBackClicked,
+            )
+        }
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/number/FakeEnterNumberNavigator.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.number
+
+import io.element.android.tests.testutils.lambda.lambdaError
+
+class FakeEnterNumberNavigator(
+    private val navigateToWrongNumberErrorLambda: () -> Unit = { lambdaError() },
+) : EnterNumberNavigator {
+    override fun navigateToWrongNumberError() {
+        navigateToWrongNumberErrorLambda()
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeViewTest.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.qrcode
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.tests.testutils.EnsureNeverCalled
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ShowQrCodeViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the expected callback`() {
+        ensureCalledOnce { callback ->
+            rule.setView(
+                onBackClick = callback
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setView(
+        onBackClick: () -> Unit = EnsureNeverCalled(),
+    ) {
+        setContent {
+            ShowQrCodeView(
+                data = "DATA",
+                onBackClick = onBackClick,
+            )
+        }
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootPresenterTest.kt

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.impl.LinkNewMobileHandler
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.test.AN_EXCEPTION
+import io.element.android.libraries.matrix.test.FakeMatrixClient
+import io.element.android.libraries.matrix.test.linknewdevice.FakeLinkMobileHandler
+import io.element.android.tests.testutils.WarmUpRule
+import io.element.android.tests.testutils.test
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+class LinkNewDeviceRootPresenterTest {
+    @get:Rule
+    val warmUpRule = WarmUpRule()
+
+    @Test
+    fun `present - initial state`() = runTest {
+        val matrixClient = FakeMatrixClient(
+            canLinkNewDeviceResult = { Result.success(true) },
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.isSupported.isUninitialized()).isTrue()
+            assertThat(awaitItem().isSupported.dataOrNull()).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - new login device not supported`() = runTest {
+        val matrixClient = FakeMatrixClient(
+            canLinkNewDeviceResult = { Result.success(false) },
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.isSupported.isUninitialized()).isTrue()
+            assertThat(awaitItem().isSupported.dataOrNull()).isFalse()
+        }
+    }
+
+    @Test
+    fun `present - error`() = runTest {
+        val matrixClient = FakeMatrixClient(
+            canLinkNewDeviceResult = { Result.failure(AN_EXCEPTION) },
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.isSupported.isUninitialized()).isTrue()
+            assertThat(awaitItem().isSupported.isFailure()).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - link new mobile device`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val matrixClient = FakeMatrixClient(
+            canLinkNewDeviceResult = { Result.success(true) },
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = { Result.success(linkMobileHandler) }
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            skipItems(1)
+            val initialState = awaitItem()
+            assertThat(initialState.isSupported.dataOrNull()).isTrue()
+            initialState.eventSink(LinkNewDeviceRootEvent.LinkMobileDevice)
+            val loadingState = awaitItem()
+            assertThat(loadingState.qrCodeData.isLoading()).isTrue()
+        }
+    }
+
+    private fun createPresenter(
+        matrixClient: MatrixClient = FakeMatrixClient(),
+        linkNewMobileHandler: LinkNewMobileHandler = LinkNewMobileHandler(matrixClient),
+    ) = LinkNewDeviceRootPresenter(
+        matrixClient = matrixClient,
+        linkNewMobileHandler = linkNewMobileHandler,
+    )
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/root/LinkNewDeviceRootViewTest.kt

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.root
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.features.linknewdevice.impl.R
+import io.element.android.libraries.architecture.AsyncData
+import io.element.android.libraries.ui.strings.CommonStrings
+import io.element.android.tests.testutils.EnsureNeverCalled
+import io.element.android.tests.testutils.EventsRecorder
+import io.element.android.tests.testutils.clickOn
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class LinkNewDeviceRootViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the onRetry callback`() {
+        val eventRecorder = EventsRecorder<LinkNewDeviceRootEvent>(expectEvents = false)
+        ensureCalledOnce { callback ->
+            rule.setLinkNewDeviceRootView(
+                state = aLinkNewDeviceRootState(
+                    eventSink = eventRecorder,
+                ),
+                onBackClick = callback
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    @Test
+    fun `link desktop button clicked - calls the expected callback`() {
+        val eventRecorder = EventsRecorder<LinkNewDeviceRootEvent>(expectEvents = false)
+        ensureCalledOnce { callback ->
+            rule.setLinkNewDeviceRootView(
+                state = aLinkNewDeviceRootState(
+                    isSupported = AsyncData.Success(true),
+                    eventSink = eventRecorder,
+                ),
+                onLinkDesktopDeviceClick = callback,
+            )
+            rule.clickOn(R.string.screen_link_new_device_root_desktop_computer)
+        }
+    }
+
+    @Test
+    fun `link mobile button clicked - emits the expected event`() {
+        val eventRecorder = EventsRecorder<LinkNewDeviceRootEvent>()
+        rule.setLinkNewDeviceRootView(
+            state = aLinkNewDeviceRootState(
+                isSupported = AsyncData.Success(true),
+                eventSink = eventRecorder,
+            )
+        )
+        rule.clickOn(R.string.screen_link_new_device_root_mobile_device)
+        eventRecorder.assertSingle(LinkNewDeviceRootEvent.LinkMobileDevice)
+    }
+
+    @Test
+    fun `not supported - dismiss click - invokes the expected callback`() {
+        val eventRecorder = EventsRecorder<LinkNewDeviceRootEvent>(expectEvents = false)
+        ensureCalledOnce { callback ->
+            rule.setLinkNewDeviceRootView(
+                state = aLinkNewDeviceRootState(
+                    isSupported = AsyncData.Success(false),
+                    eventSink = eventRecorder,
+                ),
+                onBackClick = callback,
+            )
+            rule.clickOn(CommonStrings.action_dismiss)
+        }
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setLinkNewDeviceRootView(
+        state: LinkNewDeviceRootState = aLinkNewDeviceRootState(),
+        onBackClick: () -> Unit = EnsureNeverCalled(),
+        onLinkDesktopDeviceClick: () -> Unit = EnsureNeverCalled(),
+    ) {
+        setContent {
+            LinkNewDeviceRootView(
+                state = state,
+                onBackClick = onBackClick,
+                onLinkDesktopDeviceClick = onLinkDesktopDeviceClick,
+            )
+        }
+    }
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodePresenterTest.kt

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.impl.LinkNewDesktopHandler
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.auth.qrlogin.QrCodeDecodeException
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.libraries.matrix.test.FakeMatrixClient
+import io.element.android.libraries.matrix.test.QR_CODE_DATA_RECIPROCATE
+import io.element.android.libraries.matrix.test.linknewdevice.FakeLinkDesktopHandler
+import io.element.android.tests.testutils.WarmUpRule
+import io.element.android.tests.testutils.lambda.lambdaRecorder
+import io.element.android.tests.testutils.lambda.value
+import io.element.android.tests.testutils.test
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+class ScanQrCodePresenterTest {
+    @get:Rule
+    val warmUpRule = WarmUpRule()
+
+    @Test
+    fun `present - initial state`() = runTest {
+        val matrixClient = FakeMatrixClient(
+            createLinkDesktopHandlerResult = { Result.success(FakeLinkDesktopHandler()) }
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.scanAction.isLoading()).isTrue()
+        }
+    }
+
+    @Test
+    fun `present - handle scanned event - success`() = runTest {
+        val handleScannedQrCodeResult = lambdaRecorder<ByteArray, Unit> { }
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkDesktopHandlerResult = {
+                Result.success(
+                    FakeLinkDesktopHandler(
+                        handleScannedQrCodeResult = handleScannedQrCodeResult,
+                    )
+                )
+            }
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.scanAction.isLoading()).isTrue()
+            initialState.eventSink(ScanQrCodeEvent.QrCodeScanned(QR_CODE_DATA_RECIPROCATE))
+            val scannedState = awaitItem()
+            assertThat(scannedState.scanAction.isSuccess()).isTrue()
+            runCurrent()
+            handleScannedQrCodeResult.assertions().isCalledOnce().with(value(QR_CODE_DATA_RECIPROCATE))
+        }
+    }
+
+    @Test
+    fun `present - handle scanned event - failure`() = runTest {
+        val handleScannedQrCodeResult = lambdaRecorder<ByteArray, Unit> { }
+        val handler = FakeLinkDesktopHandler(
+            handleScannedQrCodeResult = handleScannedQrCodeResult,
+        )
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkDesktopHandlerResult = {
+                Result.success(handler)
+            }
+        )
+        createPresenter(
+            matrixClient = matrixClient,
+        ).test {
+            val initialState = awaitItem()
+            assertThat(initialState.scanAction.isLoading()).isTrue()
+            initialState.eventSink(ScanQrCodeEvent.QrCodeScanned(QR_CODE_DATA_RECIPROCATE))
+            val scannedState = awaitItem()
+            assertThat(scannedState.scanAction.isSuccess()).isTrue()
+            handler.emitStep(LinkDesktopStep.InvalidQrCode(QrCodeDecodeException.Crypto("Invalid QR Code")))
+            skipItems(1)
+            val errorState = awaitItem()
+            assertThat(errorState.scanAction.isFailure()).isTrue()
+            handleScannedQrCodeResult.assertions().isCalledOnce().with(value(QR_CODE_DATA_RECIPROCATE))
+            // Reset by trying again
+            errorState.eventSink(ScanQrCodeEvent.TryAgain)
+            val resetState = awaitItem()
+            assertThat(resetState.scanAction.isLoading()).isTrue()
+        }
+    }
+}
+
+private fun createPresenter(
+    matrixClient: MatrixClient,
+) = ScanQrCodePresenter(
+    linkNewDesktopHandler = LinkNewDesktopHandler(matrixClient),
+)

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/scan/ScanQrCodeViewTest.kt

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.linknewdevice.impl.screens.scan
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.element.android.libraries.architecture.AsyncAction
+import io.element.android.libraries.matrix.test.AN_EXCEPTION
+import io.element.android.libraries.ui.strings.CommonStrings
+import io.element.android.tests.testutils.EnsureNeverCalled
+import io.element.android.tests.testutils.EventsRecorder
+import io.element.android.tests.testutils.clickOn
+import io.element.android.tests.testutils.ensureCalledOnce
+import io.element.android.tests.testutils.pressBackKey
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ScanQrCodeViewTest {
+    @get:Rule
+    val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun `on back pressed - calls the expected callback`() {
+        val eventRecorder = EventsRecorder<ScanQrCodeEvent>(expectEvents = false)
+        ensureCalledOnce { callback ->
+            rule.setView(
+                state = aScanQrCodeState(
+                    eventSink = eventRecorder,
+                ),
+                onBackClick = callback
+            )
+            rule.pressBackKey()
+        }
+    }
+
+    @Test
+    fun `try again button clicked - emits the expected event`() {
+        val eventRecorder = EventsRecorder<ScanQrCodeEvent>()
+        rule.setView(
+            state = aScanQrCodeState(
+                scanAction = AsyncAction.Failure(AN_EXCEPTION),
+                eventSink = eventRecorder,
+            )
+        )
+        rule.clickOn(CommonStrings.action_try_again)
+        eventRecorder.assertSingle(ScanQrCodeEvent.TryAgain)
+    }
+
+    private fun <R : TestRule> AndroidComposeTestRule<R, ComponentActivity>.setView(
+        state: ScanQrCodeState = aScanQrCodeState(),
+        onBackClick: () -> Unit = EnsureNeverCalled(),
+    ) {
+        setContent {
+            ScanQrCodeView(
+                state = state,
+                onBackClick = onBackClick,
+            )
+        }
+    }
+}

features/linknewdevice/test/build.gradle.kts

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+plugins {
+    id("io.element.android-compose-library")
+}
+
+android {
+    namespace = "io.element.android.features.linknewdevice.test"
+}
+
+dependencies {
+    implementation(projects.features.linknewdevice.api)
+    implementation(projects.tests.testutils)
+}

features/login/impl/src/main/res/values/localazy.xml

@@ -60,6 +60,8 @@
   <string name="screen_qr_code_login_error_cancelled_title">"Sign in request cancelled"</string>
   <string name="screen_qr_code_login_error_declined_subtitle">"The sign in was declined on the other device."</string>
   <string name="screen_qr_code_login_error_declined_title">"Sign in declined"</string>
+  <string name="screen_qr_code_login_error_device_already_signed_in_subtitle">"You don’t need to do anything else."</string>
+  <string name="screen_qr_code_login_error_device_already_signed_in_title">"Your other device is already signed in"</string>
   <string name="screen_qr_code_login_error_expired_subtitle">"Sign in expired. Please try again."</string>
   <string name="screen_qr_code_login_error_expired_title">"The sign in was not completed in time"</string>
   <string name="screen_qr_code_login_error_linking_not_suported_subtitle">"Your other device does not support signing in to %s with a QR code.

features/preferences/api/src/main/kotlin/io/element/android/features/preferences/api/PreferencesEntryPoint.kt

@@ -41,6 +41,7 @@ interface PreferencesEntryPoint : FeatureEntryPoint {
 
     interface Callback : Plugin {
         fun navigateToAddAccount()
+        fun navigateToLinkNewDevice()
         fun navigateToBugReport()
         fun navigateToSecureBackup()
         fun navigateToRoomNotificationSettings(roomId: RoomId)

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/PreferencesFlowNode.kt

@@ -163,6 +163,10 @@ class PreferencesFlowNode(
                         backstack.push(NavTarget.Labs)
                     }
 
+                    override fun navigateToLinkNewDevice() {
+                        callback.navigateToLinkNewDevice()
+                    }
+
                     override fun navigateToUserProfile(matrixUser: MatrixUser) {
                         backstack.push(NavTarget.UserProfile(matrixUser))
                     }

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootNode.kt

@@ -45,6 +45,7 @@ class PreferencesRootNode(
         fun navigateToLockScreenSettings()
         fun navigateToAdvancedSettings()
         fun navigateToLabs()
+        fun navigateToLinkNewDevice()
         fun navigateToUserProfile(matrixUser: MatrixUser)
         fun navigateToBlockedUsers()
         fun startSignOutFlow()
@@ -84,6 +85,7 @@ class PreferencesRootNode(
             onOpenDeveloperSettings = callback::navigateToDeveloperSettings,
             onOpenAdvancedSettings = callback::navigateToAdvancedSettings,
             onOpenLabs = callback::navigateToLabs,
+            onLinkNewDeviceClick = callback::navigateToLinkNewDevice,
             onManageAccountClick = { onManageAccountClick(activity, it, isDark) },
             onOpenNotificationSettings = callback::navigateToNotificationSettings,
             onOpenLockScreenSettings = callback::navigateToLockScreenSettings,

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootPresenter.kt

@@ -69,6 +69,9 @@ class PreferencesRootPresenter(
         val isMultiAccountEnabled by remember {
             featureFlagService.isFeatureEnabledFlow(FeatureFlags.MultiAccount)
         }.collectAsState(initial = false)
+        val showLinkNewDevice by remember {
+            featureFlagService.isFeatureEnabledFlow(FeatureFlags.QrCodeLogin)
+        }.collectAsState(initial = false)
 
         val otherSessions by remember {
             sessionStore.sessionsFlow().map { list ->
@@ -146,6 +149,7 @@ class PreferencesRootPresenter(
             devicesManagementUrl = devicesManagementUrl.value,
             showAnalyticsSettings = hasAnalyticsProviders,
             canReportBug = canReportBug,
+            showLinkNewDevice = showLinkNewDevice,
             showDeveloperSettings = showDeveloperSettings,
             canDeactivateAccount = canDeactivateAccount,
             showBlockedUsersItem = showBlockedUsersItem,

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootState.kt

@@ -25,6 +25,7 @@ data class PreferencesRootState(
     val accountManagementUrl: String?,
     val devicesManagementUrl: String?,
     val canReportBug: Boolean,
+    val showLinkNewDevice: Boolean,
     val showAnalyticsSettings: Boolean,
     val showDeveloperSettings: Boolean,
     val canDeactivateAccount: Boolean,

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootStateProvider.kt

@@ -31,6 +31,7 @@ fun aPreferencesRootState(
     accountManagementUrl = "aUrl",
     devicesManagementUrl = "anOtherUrl",
     showAnalyticsSettings = true,
+    showLinkNewDevice = true,
     canReportBug = true,
     showDeveloperSettings = true,
     showBlockedUsersItem = true,

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootView.kt

@@ -54,6 +54,7 @@ fun PreferencesRootView(
     onAddAccountClick: () -> Unit,
     onSecureBackupClick: () -> Unit,
     onManageAccountClick: (url: String) -> Unit,
+    onLinkNewDeviceClick: () -> Unit,
     onOpenAnalytics: () -> Unit,
     onOpenRageShake: () -> Unit,
     onOpenLockScreenSettings: () -> Unit,
@@ -101,6 +102,7 @@ fun PreferencesRootView(
         ManageAccountSection(
             state = state,
             onManageAccountClick = onManageAccountClick,
+            onLinkNewDeviceClick = onLinkNewDeviceClick,
             onOpenBlockedUsers = onOpenBlockedUsers
         )
 
@@ -193,8 +195,16 @@ private fun ColumnScope.ManageAppSection(
 private fun ColumnScope.ManageAccountSection(
     state: PreferencesRootState,
     onManageAccountClick: (url: String) -> Unit,
+    onLinkNewDeviceClick: () -> Unit,
     onOpenBlockedUsers: () -> Unit,
 ) {
+    if (state.showLinkNewDevice) {
+        ListItem(
+            headlineContent = { Text(stringResource(id = CommonStrings.common_link_new_device)) },
+            leadingContent = ListItemContent.Icon(IconSource.Vector(CompoundIcons.Devices())),
+            onClick = onLinkNewDeviceClick,
+        )
+    }
     state.accountManagementUrl?.let { url ->
         ListItem(
             headlineContent = { Text(stringResource(id = CommonStrings.action_manage_account)) },
@@ -353,6 +363,7 @@ private fun ContentToPreview(matrixUser: MatrixUser) {
         onOpenAbout = {},
         onSecureBackupClick = {},
         onManageAccountClick = {},
+        onLinkNewDeviceClick = {},
         onOpenNotificationSettings = {},
         onOpenLockScreenSettings = {},
         onOpenUserProfile = {},

features/preferences/impl/src/test/kotlin/io/element/android/features/preferences/impl/DefaultPreferencesEntryPointTest.kt

@@ -50,6 +50,7 @@ class DefaultPreferencesEntryPointTest {
         }
         val callback = object : PreferencesEntryPoint.Callback {
             override fun navigateToAddAccount() = lambdaError()
+            override fun navigateToLinkNewDevice() = lambdaError()
             override fun navigateToBugReport() = lambdaError()
             override fun navigateToSecureBackup() = lambdaError()
             override fun navigateToRoomNotificationSettings(roomId: RoomId) = lambdaError()

features/preferences/impl/src/test/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootPresenterTest.kt

@@ -87,6 +87,7 @@ class PreferencesRootPresenterTest {
             assertThat(loadedState.accountManagementUrl).isNull()
             assertThat(loadedState.devicesManagementUrl).isNull()
             assertThat(loadedState.showAnalyticsSettings).isFalse()
+            assertThat(loadedState.showLinkNewDevice).isFalse()
             assertThat(loadedState.showDeveloperSettings).isTrue()
             assertThat(loadedState.canDeactivateAccount).isTrue()
             assertThat(loadedState.canReportBug).isTrue()
@@ -258,6 +259,22 @@ class PreferencesRootPresenterTest {
         }
     }
 
+    @Test
+    fun `present - link new device`() = runTest {
+        createPresenter(
+            matrixClient = FakeMatrixClient(
+                sessionId = A_SESSION_ID,
+                canDeactivateAccountResult = { true },
+            ),
+            featureFlagService = FakeFeatureFlagService(
+                initialState = mapOf(FeatureFlags.QrCodeLogin.key to true)
+            ),
+        ).test {
+            val state = awaitFirstItem()
+            assertThat(state.showLinkNewDevice).isTrue()
+        }
+    }
+
     private suspend fun <T> ReceiveTurbine<T>.awaitFirstItem(): T {
         skipItems(1)
         return awaitItem()

gradle/libs.versions.toml

@@ -211,6 +211,9 @@ maplibre_ktx = "org.maplibre.gl:android-sdk-ktx-v7:3.0.2"
 maplibre_annotation = "org.maplibre.gl:android-plugin-annotation-v9:3.0.2"
 opusencoder = "io.element.android:opusencoder:1.2.0"
 zxing_cpp = "io.github.zxing-cpp:android:2.3.0"
+# Stick to 3.3.3 because of https://github.com/zxing/zxing/issues/1170
+google_zxing = "com.google.zxing:core:3.3.3"
+
 haze = { module = "dev.chrisbanes.haze:haze", version.ref = "haze" }
 haze_materials = { module = "dev.chrisbanes.haze:haze-materials", version.ref = "haze" }
 color_picker = "io.mhssn:colorpicker:1.0.0"

libraries/androidutils/src/main/kotlin/io/element/android/libraries/androidutils/system/Brightness.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.androidutils.system
+
+import android.app.Activity
+import android.view.WindowManager
+
+/**
+ * Set the screen brightness for the given activity.
+ *
+ * @receiver current Activity.
+ * @param full If true, override brightness to full; otherwise, set to none (default).
+ */
+fun Activity.setFullBrightness(full: Boolean) {
+    window.attributes = window.attributes.apply {
+        screenBrightness = if (full) {
+            WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_FULL
+        } else {
+            WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_NONE
+        }
+    }
+}

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/atomic/atoms/LoadingButtonAtom.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.designsystem.atomic.atoms
+
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.ui.strings.CommonStrings
+
+@Composable
+fun LoadingButtonAtom(
+    modifier: Modifier = Modifier,
+) = Button(
+    modifier = modifier.fillMaxWidth(),
+    enabled = false,
+    showProgress = true,
+    text = stringResource(CommonStrings.common_loading),
+    onClick = {},
+)

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/utils/ForceMaxBrightness.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.designsystem.utils
+
+import androidx.activity.compose.LocalActivity
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import io.element.android.libraries.androidutils.system.setFullBrightness
+
+@Composable
+fun ForceMaxBrightness() {
+    val activity = LocalActivity.current ?: return
+    DisposableEffect(Unit) {
+        activity.setFullBrightness(true)
+        onDispose {
+            activity.setFullBrightness(false)
+        }
+    }
+}

libraries/featureflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlags.kt

@@ -125,4 +125,11 @@ enum class FeatureFlags(
         defaultValue = { true },
         isFinished = false,
     ),
+    QrCodeLogin(
+        key = "feature.qr_code_login",
+        title = "QR Code Login",
+        description = "Allow logging in on other devices using a QR code.",
+        defaultValue = { false },
+        isFinished = false,
+    ),
 }

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/MatrixClient.kt

@@ -20,6 +20,8 @@ import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.createroom.CreateRoomParameters
 import io.element.android.libraries.matrix.api.encryption.EncryptionService
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
 import io.element.android.libraries.matrix.api.media.MatrixMediaLoader
 import io.element.android.libraries.matrix.api.media.MediaPreviewService
 import io.element.android.libraries.matrix.api.notification.NotificationService
@@ -197,6 +199,21 @@ interface MatrixClient {
      */
     suspend fun markRoomAsFullyRead(roomId: RoomId, eventId: EventId): Result<Unit>
 
+    /**
+     * Check if linking a new device using QrCode is supported by the server.
+     */
+    suspend fun canLinkNewDevice(): Result<Boolean>
+
+    /**
+     * Create a handler to link a new mobile device, i.e. a device capable of scanning QrCodes.
+     */
+    fun createLinkMobileHandler(): Result<LinkMobileHandler>
+
+    /**
+     * Create a handler to link a new desktop device, i.e. a device not capable of scanning QrCodes.
+     */
+    fun createLinkDesktopHandler(): Result<LinkDesktopHandler>
+
     suspend fun performDatabaseVacuum(): Result<Unit>
 }
 

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/linknewdevice/CheckCodeSender.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.api.linknewdevice
+
+interface CheckCodeSender {
+    /**
+     * Validates the given [code]. Returns true if the code is valid, false otherwise.
+     * This method can be called multiple times to validate different codes.
+     */
+    suspend fun validate(code: UByte): Boolean
+
+    /**
+     * Sends the given [code].
+     * This method can be called only once.
+     */
+    suspend fun send(code: UByte): Result<Unit>
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/linknewdevice/ErrorType.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.api.linknewdevice
+
+sealed class ErrorType(message: String) : Exception(message) {
+    /**
+     * The requested device ID is already in use.
+     */
+    class DeviceIdAlreadyInUse(message: String) : ErrorType(message)
+
+    /**
+     * The check code was incorrect.
+     */
+    class InvalidCheckCode(message: String) : ErrorType(message)
+
+    /**
+     * The other client proposed an unsupported protocol.
+     */
+    class UnsupportedProtocol(message: String) : ErrorType(message)
+
+    /**
+     * Secrets backup not set up properly.
+     */
+    class MissingSecretsBackup(message: String) : ErrorType(message)
+
+    /**
+     * The rendezvous session was not found and might have expired.
+     */
+    class NotFound(message: String) : ErrorType(message)
+
+    /**
+     * The device could not be created.
+     */
+    class UnableToCreateDevice(message: String) : ErrorType(message)
+
+    /**
+     * An unknown error has happened.
+     */
+    class Unknown(message: String) : ErrorType(message)
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/linknewdevice/LinkDesktopHandler.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.api.linknewdevice
+
+import io.element.android.libraries.matrix.api.auth.qrlogin.QrCodeDecodeException
+import kotlinx.coroutines.flow.StateFlow
+
+interface LinkDesktopHandler {
+    val linkDesktopStep: StateFlow<LinkDesktopStep>
+    suspend fun handleScannedQrCode(data: ByteArray)
+}
+
+sealed interface LinkDesktopStep {
+    data object Uninitialized : LinkDesktopStep
+    data object Starting : LinkDesktopStep
+    data class WaitingForAuth(
+        val verificationUri: String,
+    ) : LinkDesktopStep
+
+    data class EstablishingSecureChannel(
+        val checkCode: UByte,
+        val checkCodeString: String,
+    ) : LinkDesktopStep
+
+    data class InvalidQrCode(
+        val error: QrCodeDecodeException,
+    ) : LinkDesktopStep
+
+    data class Error(
+        val errorType: ErrorType,
+    ) : LinkDesktopStep
+
+    data object SyncingSecrets : LinkDesktopStep
+
+    data object Done : LinkDesktopStep
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/linknewdevice/LinkMobileHandler.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.api.linknewdevice
+
+import kotlinx.coroutines.flow.Flow
+
+interface LinkMobileHandler {
+    val linkMobileStep: Flow<LinkMobileStep>
+    suspend fun start()
+}
+
+sealed interface LinkMobileStep {
+    data object Uninitialized : LinkMobileStep
+    data object Starting : LinkMobileStep
+    data class QrReady(val data: String) : LinkMobileStep
+    data class WaitingForAuth(val verificationUri: String) : LinkMobileStep
+    data class QrScanned(val checkCodeSender: CheckCodeSender) : LinkMobileStep
+    data class Error(val errorType: ErrorType) : LinkMobileStep
+    data object SyncingSecrets : LinkMobileStep
+    data object Done : LinkMobileStep
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/logs/LoggerTags.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.api.logs
+
+import io.element.android.libraries.core.log.logger.LoggerTag
+
+object LoggerTags {
+    val linkNewDevice = LoggerTag("LinkNewDevice")
+}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt

@@ -27,6 +27,8 @@ import io.element.android.libraries.matrix.api.core.RoomIdOrAlias
 import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.createroom.CreateRoomParameters
 import io.element.android.libraries.matrix.api.createroom.RoomPreset
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
 import io.element.android.libraries.matrix.api.media.MatrixMediaLoader
 import io.element.android.libraries.matrix.api.oidc.AccountManagementAction
 import io.element.android.libraries.matrix.api.room.BaseRoom
@@ -47,6 +49,9 @@ import io.element.android.libraries.matrix.api.user.MatrixSearchUserResults
 import io.element.android.libraries.matrix.api.user.MatrixUser
 import io.element.android.libraries.matrix.impl.encryption.RustEncryptionService
 import io.element.android.libraries.matrix.impl.exception.mapClientException
+import io.element.android.libraries.matrix.impl.linknewdevice.RustLinkDesktopHandler
+import io.element.android.libraries.matrix.impl.linknewdevice.RustLinkMobileHandler
+import io.element.android.libraries.matrix.impl.linknewdevice.RustQrCodeDataParser
 import io.element.android.libraries.matrix.impl.mapper.map
 import io.element.android.libraries.matrix.impl.media.RustMediaLoader
 import io.element.android.libraries.matrix.impl.media.RustMediaPreviewService
@@ -739,6 +744,35 @@ class RustMatrixClient(
         }
     }
 
+    override suspend fun canLinkNewDevice(): Result<Boolean> = withContext(sessionDispatcher) {
+        runCatchingExceptions {
+            innerClient.isLoginWithQrCodeSupported()
+        }
+    }
+
+    override fun createLinkMobileHandler(): Result<LinkMobileHandler> {
+        return runCatchingExceptions {
+            val handler = innerClient.newGrantLoginWithQrCodeHandler()
+            RustLinkMobileHandler(
+                inner = handler,
+                sessionCoroutineScope = sessionCoroutineScope,
+                sessionDispatcher = sessionDispatcher,
+            )
+        }
+    }
+
+    override fun createLinkDesktopHandler(): Result<LinkDesktopHandler> {
+        return runCatchingExceptions {
+            val handler = innerClient.newGrantLoginWithQrCodeHandler()
+            RustLinkDesktopHandler(
+                inner = handler,
+                sessionCoroutineScope = sessionCoroutineScope,
+                sessionDispatcher = sessionDispatcher,
+                qrCodeDataParser = RustQrCodeDataParser(),
+            )
+        }
+    }
+
     override suspend fun markRoomAsFullyRead(roomId: RoomId, eventId: EventId): Result<Unit> = withContext(sessionDispatcher) {
         runCatchingExceptions {
             val room = innerClient.getRoom(roomId.value) ?: error("Could not fetch associated room")

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/HumanQrGrantLoginExceptionExtension.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+import org.matrix.rustcomponents.sdk.HumanQrGrantLoginException
+
+internal fun HumanQrGrantLoginException.map() = when (this) {
+    is HumanQrGrantLoginException.DeviceIdAlreadyInUse -> ErrorType.DeviceIdAlreadyInUse(message.orEmpty())
+    is HumanQrGrantLoginException.InvalidCheckCode -> ErrorType.InvalidCheckCode(message.orEmpty())
+    is HumanQrGrantLoginException.MissingSecretsBackup -> ErrorType.MissingSecretsBackup(message.orEmpty())
+    is HumanQrGrantLoginException.NotFound -> ErrorType.NotFound(message.orEmpty())
+    is HumanQrGrantLoginException.UnableToCreateDevice -> ErrorType.UnableToCreateDevice(message.orEmpty())
+    is HumanQrGrantLoginException.Unknown -> ErrorType.Unknown(message.orEmpty())
+    is HumanQrGrantLoginException.UnsupportedProtocol -> ErrorType.UnsupportedProtocol(message.orEmpty())
+}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/QrCodeDataParser.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import org.matrix.rustcomponents.sdk.QrCodeData
+
+interface QrCodeDataParser {
+    fun parse(data: ByteArray): QrCodeData
+}
+
+class RustQrCodeDataParser : QrCodeDataParser {
+    override fun parse(data: ByteArray): QrCodeData {
+        return QrCodeData.fromBytes(data)
+    }
+}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustCheckCodeSender.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import io.element.android.libraries.core.extensions.runCatchingExceptions
+import io.element.android.libraries.matrix.api.linknewdevice.CheckCodeSender
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.withContext
+import org.matrix.rustcomponents.sdk.CheckCodeSender as FfiCheckCodeSender
+
+class RustCheckCodeSender(
+    private val inner: FfiCheckCodeSender,
+    private val sessionDispatcher: CoroutineDispatcher,
+) : CheckCodeSender {
+    override suspend fun validate(code: UByte): Boolean = withContext(sessionDispatcher) {
+        runCatchingExceptions {
+            // TODO https://github.com/matrix-org/matrix-rust-sdk/pull/5957
+            // inner.validate(code)
+            true
+        }.getOrNull() ?: true
+    }
+
+    override suspend fun send(code: UByte): Result<Unit> = withContext(sessionDispatcher) {
+        runCatchingExceptions {
+            inner.send(code)
+        }
+    }
+}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustLinkDesktopHandler.kt

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import io.element.android.libraries.matrix.impl.auth.qrlogin.QrErrorMapper
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import org.matrix.rustcomponents.sdk.GrantLoginWithQrCodeHandler
+import org.matrix.rustcomponents.sdk.GrantQrLoginProgress
+import org.matrix.rustcomponents.sdk.GrantQrLoginProgressListener
+import org.matrix.rustcomponents.sdk.HumanQrGrantLoginException
+import org.matrix.rustcomponents.sdk.QrCodeDecodeException
+import timber.log.Timber
+
+private val tag = LoggerTag("RustLinkDesktopHandler", LoggerTags.linkNewDevice)
+
+class RustLinkDesktopHandler(
+    private val inner: GrantLoginWithQrCodeHandler,
+    private val sessionCoroutineScope: CoroutineScope,
+    private val sessionDispatcher: CoroutineDispatcher,
+    private val qrCodeDataParser: QrCodeDataParser,
+) : LinkDesktopHandler {
+    private val _linkDesktopStep = MutableStateFlow<LinkDesktopStep>(LinkDesktopStep.Uninitialized)
+    override val linkDesktopStep: StateFlow<LinkDesktopStep> = _linkDesktopStep.asStateFlow()
+
+    override suspend fun handleScannedQrCode(data: ByteArray) = withContext(sessionDispatcher) {
+        Timber.tag(tag.value).d("Emit Uninitialized")
+        _linkDesktopStep.emit(LinkDesktopStep.Uninitialized)
+        try {
+            val qrCodeData = qrCodeDataParser.parse(data)
+            inner.scan(
+                qrCodeData = qrCodeData,
+                progressListener = object : GrantQrLoginProgressListener {
+                    override fun onUpdate(state: GrantQrLoginProgress) {
+                        sessionCoroutineScope.launch {
+                            val mappedState = state.map()
+                            Timber.tag(tag.value).d("Emit ${mappedState::class.java.simpleName}")
+                            _linkDesktopStep.emit(mappedState)
+                        }
+                    }
+                }
+            )
+        } catch (e: QrCodeDecodeException) {
+            Timber.tag(tag.value).w(e, "Invalid QR code scanned")
+            _linkDesktopStep.emit(
+                LinkDesktopStep.InvalidQrCode(
+                    error = QrErrorMapper.map(e)
+                )
+            )
+        } catch (e: HumanQrGrantLoginException) {
+            Timber.tag(tag.value).w(e, "Error during QR login grant")
+            _linkDesktopStep.emit(LinkDesktopStep.Error(e.map()))
+        }
+    }
+
+    private fun GrantQrLoginProgress.map() = when (this) {
+        GrantQrLoginProgress.Done -> LinkDesktopStep.Done
+        GrantQrLoginProgress.Starting -> LinkDesktopStep.Starting
+        GrantQrLoginProgress.SyncingSecrets -> LinkDesktopStep.SyncingSecrets
+        is GrantQrLoginProgress.WaitingForAuth -> LinkDesktopStep.WaitingForAuth(
+            verificationUri = verificationUri,
+        )
+        is GrantQrLoginProgress.EstablishingSecureChannel -> LinkDesktopStep.EstablishingSecureChannel(
+            checkCode = checkCode,
+            checkCodeString = checkCodeString,
+        )
+    }
+}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustLinkMobileHandler.kt

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.api.logs.LoggerTags
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import org.matrix.rustcomponents.sdk.GrantGeneratedQrLoginProgress
+import org.matrix.rustcomponents.sdk.GrantGeneratedQrLoginProgressListener
+import org.matrix.rustcomponents.sdk.GrantLoginWithQrCodeHandler
+import org.matrix.rustcomponents.sdk.HumanQrGrantLoginException
+import timber.log.Timber
+
+private val tag = LoggerTag("RustLinkMobileHandler", LoggerTags.linkNewDevice)
+
+class RustLinkMobileHandler(
+    private val inner: GrantLoginWithQrCodeHandler,
+    private val sessionCoroutineScope: CoroutineScope,
+    private val sessionDispatcher: CoroutineDispatcher,
+) : LinkMobileHandler {
+    private val _linkMobileStep = MutableStateFlow<LinkMobileStep>(LinkMobileStep.Uninitialized)
+    override val linkMobileStep: Flow<LinkMobileStep> = _linkMobileStep.asStateFlow()
+
+    override suspend fun start() = withContext(sessionDispatcher) {
+        Timber.tag(tag.value).d("Emit Uninitialized")
+        _linkMobileStep.emit(LinkMobileStep.Uninitialized)
+        try {
+            inner.generate(
+                progressListener = object : GrantGeneratedQrLoginProgressListener {
+                    override fun onUpdate(state: GrantGeneratedQrLoginProgress) {
+                        sessionCoroutineScope.launch {
+                            val mappedState = state.map()
+                            Timber.tag(tag.value).d("Emit ${mappedState::class.java.simpleName}")
+                            _linkMobileStep.emit(mappedState)
+                        }
+                    }
+                }
+            )
+        } catch (e: HumanQrGrantLoginException) {
+            Timber.tag(tag.value).w(e, "Error during QR login grant")
+            _linkMobileStep.emit(LinkMobileStep.Error(e.map()))
+        }
+    }
+
+    private fun GrantGeneratedQrLoginProgress.map(): LinkMobileStep {
+        return when (this) {
+            GrantGeneratedQrLoginProgress.Done -> LinkMobileStep.Done
+            is GrantGeneratedQrLoginProgress.QrReady -> {
+                LinkMobileStep.QrReady(String(qrCode.toBytes(), Charsets.ISO_8859_1))
+            }
+            is GrantGeneratedQrLoginProgress.QrScanned -> LinkMobileStep.QrScanned(
+                RustCheckCodeSender(
+                    inner = checkCodeSender,
+                    sessionDispatcher = sessionDispatcher,
+                )
+            )
+            GrantGeneratedQrLoginProgress.Starting -> LinkMobileStep.Starting
+            GrantGeneratedQrLoginProgress.SyncingSecrets -> LinkMobileStep.SyncingSecrets
+            is GrantGeneratedQrLoginProgress.WaitingForAuth -> LinkMobileStep.WaitingForAuth(verificationUri)
+        }
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/fixtures/fakes/FakeFfiCheckCodeSender.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.fixtures.fakes
+
+import io.element.android.tests.testutils.lambda.lambdaError
+import org.matrix.rustcomponents.sdk.CheckCodeSender
+import org.matrix.rustcomponents.sdk.NoHandle
+
+class FakeFfiCheckCodeSender(
+    private val sendResult: (UByte) -> Unit = { _ -> lambdaError() }
+) : CheckCodeSender(NoHandle) {
+    override suspend fun send(code: UByte) {
+        sendResult(code)
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/fixtures/fakes/FakeFfiGrantLoginWithQrCodeHandler.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.fixtures.fakes
+
+import org.matrix.rustcomponents.sdk.GrantGeneratedQrLoginProgress
+import org.matrix.rustcomponents.sdk.GrantGeneratedQrLoginProgressListener
+import org.matrix.rustcomponents.sdk.GrantLoginWithQrCodeHandler
+import org.matrix.rustcomponents.sdk.GrantQrLoginProgress
+import org.matrix.rustcomponents.sdk.GrantQrLoginProgressListener
+import org.matrix.rustcomponents.sdk.NoHandle
+import org.matrix.rustcomponents.sdk.QrCodeData
+
+class FakeFfiGrantLoginWithQrCodeHandler(
+    private val generateResult: () -> Unit = {},
+    private val scanResult: (QrCodeData) -> Unit = {},
+) : GrantLoginWithQrCodeHandler(NoHandle) {
+    private var generateProgressListener: GrantGeneratedQrLoginProgressListener? = null
+    private var scanProgressListener: GrantQrLoginProgressListener? = null
+    override suspend fun generate(progressListener: GrantGeneratedQrLoginProgressListener) {
+        generateProgressListener = progressListener
+        generateResult()
+    }
+
+    fun emitGenerateProgress(progress: GrantGeneratedQrLoginProgress) {
+        generateProgressListener?.onUpdate(progress)
+    }
+
+    override suspend fun scan(qrCodeData: QrCodeData, progressListener: GrantQrLoginProgressListener) {
+        scanProgressListener = progressListener
+        scanResult(qrCodeData)
+    }
+
+    fun emitScanProgress(progress: GrantQrLoginProgress) {
+        scanProgressListener?.onUpdate(progress)
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/fixtures/fakes/FakeFfiQrCodeData.kt

@@ -14,8 +14,13 @@ import org.matrix.rustcomponents.sdk.QrCodeData
 
 class FakeFfiQrCodeData(
     private val serverNameResult: () -> String? = { lambdaError() },
+    private val toBytesResult: () -> ByteArray = { lambdaError() },
 ) : QrCodeData(NoHandle) {
     override fun serverName(): String? {
         return serverNameResult()
     }
+
+    override fun toBytes(): ByteArray {
+        return toBytesResult()
+    }
 }

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/FakeQrCodeDataParser.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiQrCodeData
+import org.matrix.rustcomponents.sdk.QrCodeData
+
+class FakeQrCodeDataParser : QrCodeDataParser {
+    override fun parse(data: ByteArray): QrCodeData {
+        return FakeFfiQrCodeData()
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustCheckCodeSenderTest.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiCheckCodeSender
+import io.element.android.tests.testutils.lambda.lambdaRecorder
+import io.element.android.tests.testutils.lambda.value
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+
+class RustCheckCodeSenderTest {
+    @Test
+    fun `send invokes the Ffi object`() = runTest {
+        val sendResult = lambdaRecorder<UByte, Unit> { }
+        val sut = RustCheckCodeSender(
+            inner = FakeFfiCheckCodeSender(
+                sendResult = sendResult,
+            ),
+            sessionDispatcher = StandardTestDispatcher(testScheduler),
+        )
+        sut.send(1.toUByte())
+        sendResult.assertions().isCalledOnce().with(value(1.toUByte()))
+    }
+
+    @Test
+    fun `validate always returns true for now`() = runTest {
+        val sut = RustCheckCodeSender(
+            inner = FakeFfiCheckCodeSender(),
+            sessionDispatcher = StandardTestDispatcher(testScheduler),
+        )
+        val result = sut.validate(1.toUByte())
+        assertThat(result).isTrue()
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustLinkDesktopHandlerTest.kt

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import app.cash.turbine.test
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiGrantLoginWithQrCodeHandler
+import io.element.android.libraries.matrix.test.QR_CODE_DATA
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+import org.matrix.rustcomponents.sdk.GrantQrLoginProgress
+import org.matrix.rustcomponents.sdk.HumanQrGrantLoginException
+import org.matrix.rustcomponents.sdk.QrCodeDecodeException
+
+class RustLinkDesktopHandlerTest {
+    @Test
+    fun `handleScannedQrCode function works as expected`() = runTest {
+        val handler = FakeFfiGrantLoginWithQrCodeHandler()
+        val sut = createRustLinkDesktopHandler(
+            handler,
+        )
+        sut.linkDesktopStep.test {
+            val initialItem = awaitItem()
+            assertThat(initialItem).isEqualTo(LinkDesktopStep.Uninitialized)
+            backgroundScope.launch {
+                sut.handleScannedQrCode(QR_CODE_DATA)
+            }
+            runCurrent()
+            // progress from the handler is mapped and emitted
+            listOf(
+                GrantQrLoginProgress.Starting to LinkDesktopStep.Starting,
+                GrantQrLoginProgress.SyncingSecrets to LinkDesktopStep.SyncingSecrets,
+                GrantQrLoginProgress.WaitingForAuth("aVerificationUri")
+                    to LinkDesktopStep.WaitingForAuth("aVerificationUri"),
+                GrantQrLoginProgress.EstablishingSecureChannel(1.toUByte(), "1")
+                    to LinkDesktopStep.EstablishingSecureChannel(1.toUByte(), "1"),
+                GrantQrLoginProgress.Done to LinkDesktopStep.Done,
+            ).forEach { (progress, expectedStep) ->
+                handler.emitScanProgress(progress)
+                assertThat(awaitItem()).isEqualTo(expectedStep)
+            }
+        }
+    }
+
+    @Test
+    fun `when handleScannedQrCode throws QrCodeDecodeException, the handler emits error step`() = runTest {
+        val handler = FakeFfiGrantLoginWithQrCodeHandler(
+            scanResult = { throw QrCodeDecodeException.Crypto("Scan failed") }
+        )
+        val sut = createRustLinkDesktopHandler(
+            handler,
+        )
+        sut.linkDesktopStep.test {
+            val initialItem = awaitItem()
+            assertThat(initialItem).isEqualTo(LinkDesktopStep.Uninitialized)
+            backgroundScope.launch {
+                sut.handleScannedQrCode(QR_CODE_DATA)
+            }
+            runCurrent()
+            val errorState = awaitItem()
+            assertThat(errorState).isInstanceOf(LinkDesktopStep.InvalidQrCode::class.java)
+        }
+    }
+
+    @Test
+    fun `when handleScannedQrCode throws HumanQrGrantLoginException, the handler emits error step`() = runTest {
+        val handler = FakeFfiGrantLoginWithQrCodeHandler(
+            scanResult = { throw HumanQrGrantLoginException.InvalidCheckCode("Invalid check code") }
+        )
+        val sut = createRustLinkDesktopHandler(
+            handler,
+        )
+        sut.linkDesktopStep.test {
+            val initialItem = awaitItem()
+            assertThat(initialItem).isEqualTo(LinkDesktopStep.Uninitialized)
+            backgroundScope.launch {
+                sut.handleScannedQrCode(QR_CODE_DATA)
+            }
+            runCurrent()
+            val errorState = awaitItem()
+            assertThat(errorState).isInstanceOf(LinkDesktopStep.Error::class.java)
+            val errorType = (errorState as LinkDesktopStep.Error).errorType
+            assertThat(errorType).isInstanceOf(ErrorType.InvalidCheckCode::class.java)
+        }
+    }
+
+    private fun TestScope.createRustLinkDesktopHandler(
+        handler: FakeFfiGrantLoginWithQrCodeHandler = FakeFfiGrantLoginWithQrCodeHandler(),
+    ) = RustLinkDesktopHandler(
+        inner = handler,
+        sessionCoroutineScope = backgroundScope,
+        sessionDispatcher = StandardTestDispatcher(testScheduler),
+        qrCodeDataParser = FakeQrCodeDataParser(),
+    )
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/linknewdevice/RustLinkMobileHandlerTest.kt

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.libraries.matrix.impl.linknewdevice
+
+import app.cash.turbine.test
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiCheckCodeSender
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiGrantLoginWithQrCodeHandler
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiQrCodeData
+import io.element.android.libraries.matrix.test.QR_CODE_DATA_RECIPROCATE
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+import org.matrix.rustcomponents.sdk.GrantGeneratedQrLoginProgress
+import org.matrix.rustcomponents.sdk.HumanQrGrantLoginException
+
+class RustLinkMobileHandlerTest {
+    @Test
+    fun `start function works as expected`() = runTest {
+        val handler = FakeFfiGrantLoginWithQrCodeHandler()
+        val sut = createRustLinkMobileHandler(
+            handler,
+        )
+        sut.linkMobileStep.test {
+            val initialItem = awaitItem()
+            assertThat(initialItem).isEqualTo(LinkMobileStep.Uninitialized)
+            backgroundScope.launch {
+                sut.start()
+            }
+            runCurrent()
+            // progress from the handler is mapped and emitted
+            listOf(
+                GrantGeneratedQrLoginProgress.Starting to LinkMobileStep.Starting::class.java,
+                GrantGeneratedQrLoginProgress.SyncingSecrets to LinkMobileStep.SyncingSecrets::class.java,
+                GrantGeneratedQrLoginProgress.WaitingForAuth("aVerificationUri")
+                    to LinkMobileStep.WaitingForAuth::class.java,
+                GrantGeneratedQrLoginProgress.QrScanned(FakeFfiCheckCodeSender())
+                    to LinkMobileStep.QrScanned::class.java,
+                GrantGeneratedQrLoginProgress.QrReady(FakeFfiQrCodeData(toBytesResult = { QR_CODE_DATA_RECIPROCATE }))
+                    to LinkMobileStep.QrReady::class.java,
+                GrantGeneratedQrLoginProgress.Done to LinkMobileStep.Done::class.java,
+            ).forEach { (progress, expectedStepClass) ->
+                handler.emitGenerateProgress(progress)
+                assertThat(awaitItem()).isInstanceOf(expectedStepClass)
+            }
+        }
+    }
+
+    @Test
+    fun `when start throws HumanQrGrantLoginException, the handler emits error step`() = runTest {
+        val handler = FakeFfiGrantLoginWithQrCodeHandler(
+            generateResult = { throw HumanQrGrantLoginException.NotFound("Timeout") }
+        )
+        val sut = createRustLinkMobileHandler(
+            handler,
+        )
+        sut.linkMobileStep.test {
+            val initialItem = awaitItem()
+            assertThat(initialItem).isEqualTo(LinkMobileStep.Uninitialized)
+            backgroundScope.launch {
+                sut.start()
+            }
+            runCurrent()
+            val errorState = awaitItem()
+            assertThat(errorState).isInstanceOf(LinkMobileStep.Error::class.java)
+            val errorType = (errorState as LinkMobileStep.Error).errorType
+            assertThat(errorType).isInstanceOf(ErrorType.NotFound::class.java)
+        }
+    }
+
+    private fun TestScope.createRustLinkMobileHandler(
+        handler: FakeFfiGrantLoginWithQrCodeHandler = FakeFfiGrantLoginWithQrCodeHandler(),
+    ) = RustLinkMobileHandler(
+        inner = handler,
+        sessionCoroutineScope = backgroundScope,
+        sessionDispatcher = StandardTestDispatcher(testScheduler),
+    )
+}

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/FakeMatrixClient.kt

@@ -19,6 +19,8 @@ import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.createroom.CreateRoomParameters
 import io.element.android.libraries.matrix.api.encryption.EncryptionService
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
 import io.element.android.libraries.matrix.api.media.MatrixMediaLoader
 import io.element.android.libraries.matrix.api.media.MediaPreviewService
 import io.element.android.libraries.matrix.api.notification.NotificationService
@@ -96,6 +98,9 @@ class FakeMatrixClient(
     private val deactivateAccountResult: (String, Boolean) -> Result<Unit> = { _, _ -> lambdaError() },
     private val currentSlidingSyncVersionLambda: () -> Result<SlidingSyncVersion> = { lambdaError() },
     private val ignoreUserResult: (UserId) -> Result<Unit> = { lambdaError() },
+    private val canLinkNewDeviceResult: () -> Result<Boolean> = { lambdaError() },
+    private val createLinkMobileHandlerResult: () -> Result<LinkMobileHandler> = { lambdaError() },
+    private val createLinkDesktopHandlerResult: () -> Result<LinkDesktopHandler> = { lambdaError() },
     private var unIgnoreUserResult: (UserId) -> Result<Unit> = { Result.success(Unit) },
     private val canReportRoomLambda: () -> Boolean = { false },
     private val isLivekitRtcSupportedLambda: () -> Boolean = { false },
@@ -362,4 +367,16 @@ class FakeMatrixClient(
     override suspend fun performDatabaseVacuum(): Result<Unit> {
         return performDatabaseVacuumLambda()
     }
+
+    override suspend fun canLinkNewDevice(): Result<Boolean> = simulateLongTask {
+        return canLinkNewDeviceResult()
+    }
+
+    override fun createLinkDesktopHandler(): Result<LinkDesktopHandler> {
+        return createLinkDesktopHandlerResult()
+    }
+
+    override fun createLinkMobileHandler(): Result<LinkMobileHandler> {
+        return createLinkMobileHandlerResult()
+    }
 }

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/TestData.kt

@@ -100,3 +100,31 @@ const val A_LOGIN_HINT = "mxid:@alice:example.org"
 
 @ColorInt
 const val A_COLOR_INT: Int = 0xFFFF0000.toInt()
+
+// From https://github.com/matrix-org/matrix-rust-sdk/blob/3a63838cdb50cde3d74da920186fbae0a2e6db37/crates/matrix-sdk-crypto/src/types/qr_login.rs#L275
+// Test vector for the QR code data, copied from the MSC.
+@Suppress("ktlint:standard:argument-list-wrapping")
+val QR_CODE_DATA = listOf(
+    0x4D, 0x41, 0x54, 0x52, 0x49, 0x58, 0x02, 0x03, 0xd8, 0x86, 0x68, 0x6a, 0xb2, 0x19, 0x7b,
+    0x78, 0x0e, 0x30, 0x0a, 0x9d, 0x4a, 0x21, 0x47, 0x48, 0x07, 0x00, 0xd7, 0x92, 0x9f, 0x39,
+    0xab, 0x31, 0xb9, 0xe5, 0x14, 0x37, 0x02, 0x48, 0xed, 0x6b, 0x00, 0x47, 0x68, 0x74, 0x74,
+    0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x72, 0x65, 0x6e, 0x64, 0x65, 0x7a, 0x76, 0x6f, 0x75, 0x73,
+    0x2e, 0x6c, 0x61, 0x62, 0x2e, 0x65, 0x6c, 0x65, 0x6d, 0x65, 0x6e, 0x74, 0x2e, 0x64, 0x65,
+    0x76, 0x2f, 0x65, 0x38, 0x64, 0x61, 0x36, 0x33, 0x35, 0x35, 0x2d, 0x35, 0x35, 0x30, 0x62,
+    0x2d, 0x34, 0x61, 0x33, 0x32, 0x2d, 0x61, 0x31, 0x39, 0x33, 0x2d, 0x31, 0x36, 0x31, 0x39,
+    0x64, 0x39, 0x38, 0x33, 0x30, 0x36, 0x36, 0x38,
+).map { it.toByte() }.toByteArray()
+
+// Test vector for the QR code data, copied from the MSC, with the mode set to reciprocate.
+@Suppress("ktlint:standard:argument-list-wrapping")
+val QR_CODE_DATA_RECIPROCATE = listOf(
+    0x4D, 0x41, 0x54, 0x52, 0x49, 0x58, 0x02, 0x04, 0xd8, 0x86, 0x68, 0x6a, 0xb2, 0x19, 0x7b,
+    0x78, 0x0e, 0x30, 0x0a, 0x9d, 0x4a, 0x21, 0x47, 0x48, 0x07, 0x00, 0xd7, 0x92, 0x9f, 0x39,
+    0xab, 0x31, 0xb9, 0xe5, 0x14, 0x37, 0x02, 0x48, 0xed, 0x6b, 0x00, 0x47, 0x68, 0x74, 0x74,
+    0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x72, 0x65, 0x6e, 0x64, 0x65, 0x7a, 0x76, 0x6f, 0x75, 0x73,
+    0x2e, 0x6c, 0x61, 0x62, 0x2e, 0x65, 0x6c, 0x65, 0x6d, 0x65, 0x6e, 0x74, 0x2e, 0x64, 0x65,
+    0x76, 0x2f, 0x65, 0x38, 0x64, 0x61, 0x36, 0x33, 0x35, 0x35, 0x2d, 0x35, 0x35, 0x30, 0x62,
+    0x2d, 0x34, 0x61, 0x33, 0x32, 0x2d, 0x61, 0x31, 0x39, 0x33, 0x2d, 0x31, 0x36, 0x31, 0x39,
+    0x64, 0x39, 0x38, 0x33, 0x30, 0x36, 0x36, 0x38, 0x00, 0x0A, 0x6d, 0x61, 0x74, 0x72, 0x69,
+    0x78, 0x2e, 0x6f, 0x72, 0x67,
+).map { it.toByte() }.toByteArray()

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/linknewdevice/FakeCheckCodeSender.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.test.linknewdevice
+
+import io.element.android.libraries.matrix.api.linknewdevice.CheckCodeSender
+import io.element.android.tests.testutils.lambda.lambdaError
+import io.element.android.tests.testutils.simulateLongTask
+
+class FakeCheckCodeSender(
+    private val validateResult: (UByte) -> Boolean = { lambdaError() },
+    private val sendResult: (UByte) -> Result<Unit> = { lambdaError() },
+) : CheckCodeSender {
+    override suspend fun validate(code: UByte): Boolean = simulateLongTask {
+        validateResult(code)
+    }
+
+    override suspend fun send(code: UByte): Result<Unit> = simulateLongTask {
+        sendResult(code)
+    }
+}

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/linknewdevice/FakeLinkDesktopHandler.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.test.linknewdevice
+
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkDesktopStep
+import io.element.android.tests.testutils.lambda.lambdaError
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+class FakeLinkDesktopHandler(
+    private val handleScannedQrCodeResult: (ByteArray) -> Unit = { lambdaError() },
+) : LinkDesktopHandler {
+    private val mutableLinkDesktopStep: MutableStateFlow<LinkDesktopStep> = MutableStateFlow(LinkDesktopStep.Uninitialized)
+    override val linkDesktopStep: StateFlow<LinkDesktopStep>
+        get() = mutableLinkDesktopStep.asStateFlow()
+
+    override suspend fun handleScannedQrCode(data: ByteArray) {
+        handleScannedQrCodeResult(data)
+    }
+
+    suspend fun emitStep(step: LinkDesktopStep) {
+        mutableLinkDesktopStep.emit(step)
+    }
+}

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/linknewdevice/FakeLinkMobileHandler.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2025 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.test.linknewdevice
+
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.tests.testutils.lambda.lambdaError
+import io.element.android.tests.testutils.simulateLongTask
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+class FakeLinkMobileHandler(
+    private val startResult: () -> Unit = { lambdaError() },
+) : LinkMobileHandler {
+    private val mutableLinkMobileStep: MutableStateFlow<LinkMobileStep> = MutableStateFlow(LinkMobileStep.Uninitialized)
+    override val linkMobileStep: StateFlow<LinkMobileStep>
+        get() = mutableLinkMobileStep.asStateFlow()
+
+    override suspend fun start() = simulateLongTask {
+        startResult()
+    }
+
+    suspend fun emitStep(step: LinkMobileStep) {
+        mutableLinkMobileStep.emit(step)
+    }
+}

libraries/qrcode/build.gradle.kts

@@ -19,4 +19,5 @@ dependencies {
     implementation(libs.androidx.camera.view)
     implementation(libs.androidx.camera.camera2)
     implementation(libs.zxing.cpp)
+    implementation(libs.google.zxing)
 }