Do not attempt to restore the pusher after 2 removal in a short time.

libraries/pushproviders/unifiedpush/src/main/kotlin/io/element/android/libraries/pushproviders/unifiedpush/UnifiedPushRemovedGatewayHandler.kt

@@ -9,11 +9,16 @@ package io.element.android.libraries.pushproviders.unifiedpush
 
 import dev.zacsweers.metro.AppScope
 import dev.zacsweers.metro.ContributesBinding
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.SingleIn
+import io.element.android.libraries.androidutils.throttler.FirstThrottler
 import io.element.android.libraries.core.extensions.flatMap
 import io.element.android.libraries.core.log.logger.LoggerTag
+import io.element.android.libraries.di.annotations.AppCoroutineScope
 import io.element.android.libraries.matrix.api.MatrixClientProvider
 import io.element.android.libraries.push.api.PushService
 import io.element.android.libraries.pushstore.api.clientsecret.PushClientSecret
+import kotlinx.coroutines.CoroutineScope
 import timber.log.Timber
 
 private val loggerTag = LoggerTag("UnifiedPushRemovedGatewayHandler", LoggerTag.PushLoggerTag)
@@ -25,12 +30,29 @@ fun interface UnifiedPushRemovedGatewayHandler {
     suspend fun handle(clientSecret: String): Result<Unit>
 }
 
+@Inject
+@SingleIn(AppScope::class)
+class UnifiedPushRemovedGatewayThrottler(
+    @AppCoroutineScope
+    private val appCoroutineScope: CoroutineScope,
+) {
+    private val firstThrottler = FirstThrottler(
+        minimumInterval = 60_000,
+        coroutineScope = appCoroutineScope,
+    )
+
+    fun canRegisterAgain(): Boolean {
+        return firstThrottler.canHandle()
+    }
+}
+
 @ContributesBinding(AppScope::class)
 class DefaultUnifiedPushRemovedGatewayHandler(
     private val unregisterUnifiedPushUseCase: UnregisterUnifiedPushUseCase,
     private val pushClientSecret: PushClientSecret,
     private val matrixClientProvider: MatrixClientProvider,
     private val pushService: PushService,
+    private val unifiedPushRemovedGatewayThrottler: UnifiedPushRemovedGatewayThrottler,
 ) : UnifiedPushRemovedGatewayHandler {
     override suspend fun handle(clientSecret: String): Result<Unit> {
         // Unregister the pusher for the session with this client secret.
@@ -58,14 +80,21 @@ class DefaultUnifiedPushRemovedGatewayHandler(
                         val distributor = pushProvider?.getCurrentDistributor(userId)
                         // Attempt to register again
                         if (pushProvider != null && distributor != null) {
-                            pushService.registerWith(
-                                client,
-                                pushProvider,
-                                distributor,
-                            )
-                                .onFailure {
-                                    Timber.tag(loggerTag.value).w(it, "Unable to register with current data")
-                                }
+                            if (unifiedPushRemovedGatewayThrottler.canRegisterAgain()) {
+                                pushService.registerWith(
+                                    client,
+                                    pushProvider,
+                                    distributor,
+                                )
+                                    .onFailure {
+                                        Timber.tag(loggerTag.value).w(it, "Unable to register with current data")
+                                    }
+                            } else {
+                                // Let the user know
+                                Timber.tag(loggerTag.value).w("Second removal in less than 1 minute, do not register again")
+                                pushService.onServiceUnregistered(userId)
+                                Result.success(Unit)
+                            }
                         } else {
                             Result.failure(IllegalStateException("Unable to register again"))
                         }

libraries/pushproviders/unifiedpush/src/test/kotlin/io/element/android/libraries/pushproviders/unifiedpush/DefaultUnifiedPushRemovedGatewayHandlerTest.kt

@@ -19,14 +19,19 @@ import io.element.android.libraries.matrix.test.FakeMatrixClientProvider
 import io.element.android.libraries.push.api.PushService
 import io.element.android.libraries.push.test.FakePushService
 import io.element.android.libraries.pushproviders.api.Distributor
+import io.element.android.libraries.pushproviders.api.PushProvider
 import io.element.android.libraries.pushproviders.test.FakePushProvider
 import io.element.android.libraries.pushstore.api.clientsecret.PushClientSecret
 import io.element.android.libraries.pushstore.test.userpushstore.clientsecret.FakePushClientSecret
 import io.element.android.tests.testutils.lambda.any
 import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.lambda.value
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.advanceTimeBy
 import kotlinx.coroutines.test.runTest
 import org.junit.Test
+import kotlin.time.Duration.Companion.seconds
 
 class DefaultUnifiedPushRemovedGatewayHandlerTest {
     @Test
@@ -188,7 +193,95 @@ class DefaultUnifiedPushRemovedGatewayHandlerTest {
         onServiceUnregisteredResult.assertions().isNeverCalled()
     }
 
-    private fun createDefaultUnifiedPushRemovedGatewayHandler(
+    @Test
+    fun `handle returns success if can register again, but after 2 removals user is notified`() = runTest {
+        val onServiceUnregisteredResult = lambdaRecorder<UserId, Unit> { }
+        val unregisterLambda = lambdaRecorder<MatrixClient, String, Boolean, Result<Unit>> { _, _, _ -> Result.success(Unit) }
+        val registerWithLambda = lambdaRecorder<MatrixClient, PushProvider, Distributor, Result<Unit>> { _, _, _ -> Result.success(Unit) }
+        val sut = createDefaultUnifiedPushRemovedGatewayHandler(
+            pushClientSecret = FakePushClientSecret(
+                getUserIdFromSecretResult = { A_SESSION_ID },
+            ),
+            matrixClientProvider = FakeMatrixClientProvider(
+                getClient = { Result.success(FakeMatrixClient()) },
+            ),
+            unregisterUnifiedPushUseCase = FakeUnregisterUnifiedPushUseCase(
+                unregisterLambda = unregisterLambda,
+            ),
+            pushService = FakePushService(
+                currentPushProvider = {
+                    FakePushProvider(
+                        currentDistributor = { Distributor("aValue", "aName") },
+                    )
+                },
+                registerWithLambda = registerWithLambda,
+                onServiceUnregisteredResult = onServiceUnregisteredResult,
+            ),
+        )
+        val result = sut.handle(A_SECRET)
+        assertThat(result.isSuccess).isTrue()
+        unregisterLambda.assertions().isCalledOnce().with(
+            any(),
+            value(A_SECRET),
+            value(false),
+        )
+        registerWithLambda.assertions().isCalledOnce()
+        onServiceUnregisteredResult.assertions().isNeverCalled()
+        // Second attempt in less than 1 minute
+        val result2 = sut.handle(A_SECRET)
+        assertThat(result2.isSuccess).isTrue()
+        unregisterLambda.assertions().isCalledExactly(2)
+        // Registration is not called twice
+        registerWithLambda.assertions().isCalledOnce()
+        onServiceUnregisteredResult.assertions().isCalledOnce().with(value(A_SESSION_ID))
+    }
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    @Test
+    fun `handle returns success if can register again, but after 2 distant removals user is not notified`() = runTest {
+        val onServiceUnregisteredResult = lambdaRecorder<UserId, Unit> { }
+        val unregisterLambda = lambdaRecorder<MatrixClient, String, Boolean, Result<Unit>> { _, _, _ -> Result.success(Unit) }
+        val registerWithLambda = lambdaRecorder<MatrixClient, PushProvider, Distributor, Result<Unit>> { _, _, _ -> Result.success(Unit) }
+        val sut = createDefaultUnifiedPushRemovedGatewayHandler(
+            pushClientSecret = FakePushClientSecret(
+                getUserIdFromSecretResult = { A_SESSION_ID },
+            ),
+            matrixClientProvider = FakeMatrixClientProvider(
+                getClient = { Result.success(FakeMatrixClient()) },
+            ),
+            unregisterUnifiedPushUseCase = FakeUnregisterUnifiedPushUseCase(
+                unregisterLambda = unregisterLambda,
+            ),
+            pushService = FakePushService(
+                currentPushProvider = {
+                    FakePushProvider(
+                        currentDistributor = { Distributor("aValue", "aName") },
+                    )
+                },
+                registerWithLambda = registerWithLambda,
+                onServiceUnregisteredResult = onServiceUnregisteredResult,
+            ),
+        )
+        val result = sut.handle(A_SECRET)
+        assertThat(result.isSuccess).isTrue()
+        unregisterLambda.assertions().isCalledOnce().with(
+            any(),
+            value(A_SECRET),
+            value(false),
+        )
+        registerWithLambda.assertions().isCalledOnce()
+        onServiceUnregisteredResult.assertions().isNeverCalled()
+        // Second attempt in more than 1 minute
+        advanceTimeBy(61.seconds)
+        val result2 = sut.handle(A_SECRET)
+        assertThat(result2.isSuccess).isTrue()
+        unregisterLambda.assertions().isCalledExactly(2)
+        // Registration is not called twice
+        registerWithLambda.assertions().isCalledExactly(2)
+        onServiceUnregisteredResult.assertions().isNeverCalled()
+    }
+
+    private fun TestScope.createDefaultUnifiedPushRemovedGatewayHandler(
         unregisterUnifiedPushUseCase: UnregisterUnifiedPushUseCase = FakeUnregisterUnifiedPushUseCase(),
         pushClientSecret: PushClientSecret = FakePushClientSecret(),
         matrixClientProvider: MatrixClientProvider = FakeMatrixClientProvider(),
@@ -198,5 +291,8 @@ class DefaultUnifiedPushRemovedGatewayHandlerTest {
         pushClientSecret = pushClientSecret,
         matrixClientProvider = matrixClientProvider,
         pushService = pushService,
+        unifiedPushRemovedGatewayThrottler = UnifiedPushRemovedGatewayThrottler(
+            appCoroutineScope = backgroundScope,
+        ),
     )
 }