Use formatter for LLS duration

libraries/dateformatter/api/src/main/kotlin/io/element/android/libraries/dateformatter/api/DurationFormatter.kt

@@ -11,6 +11,19 @@ package io.element.android.libraries.dateformatter.api
 import java.util.Locale
 import kotlin.time.Duration
 
+/**
+ * Formats a duration in a localized, human-readable way.
+ * Uses the largest appropriate unit (hours, minutes, or seconds).
+ *
+ * Examples (in English):
+ * - 2 hours 30 minutes → "3 hours" (rounded)
+ * - 45 minutes → "45 minutes"
+ * - 30 seconds → "30 seconds"
+ */
+interface DurationFormatter {
+    fun format(duration: Duration): String
+}
+
 /**
  * Convert milliseconds to human readable duration.
  * Hours in 1 digit or more.

libraries/dateformatter/impl/src/main/kotlin/io/element/android/libraries/dateformatter/impl/DefaultDurationFormatter.kt

@@ -0,0 +1,69 @@
+/*
+ * 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.dateformatter.impl
+
+import android.icu.text.MeasureFormat
+import android.icu.text.MeasureFormat.FormatWidth
+import android.icu.util.Measure
+import android.icu.util.MeasureUnit
+import android.text.format.DateUtils
+import dev.zacsweers.metro.AppScope
+import dev.zacsweers.metro.ContributesBinding
+import dev.zacsweers.metro.SingleIn
+import dev.zacsweers.metro.binding
+import io.element.android.libraries.dateformatter.api.DurationFormatter
+import java.util.Locale
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.minutes
+
+/**
+ * Formats durations in a localized, human-readable way using Android's MeasureFormat.
+ *
+ * Uses WIDE format for readability (e.g., "5 hours", "3 minutes", "10 seconds").
+ * Rounds to the nearest unit for cleaner display.
+ */
+@SingleIn(AppScope::class)
+@ContributesBinding(AppScope::class, binding = binding<DurationFormatter>())
+class DefaultDurationFormatter(
+    localeChangeObserver: LocaleChangeObserver,
+    locale: Locale,
+) : DurationFormatter, LocaleChangeListener {
+    init {
+        localeChangeObserver.addListener(this)
+    }
+
+    // Cache formatter, recreate only on locale change
+    private var formatter: MeasureFormat = MeasureFormat.getInstance(locale, FormatWidth.WIDE)
+
+    override fun onLocaleChange() {
+        formatter = MeasureFormat.getInstance(Locale.getDefault(), FormatWidth.WIDE)
+    }
+
+    override fun format(duration: Duration): String {
+        val millis = duration.inWholeMilliseconds
+
+        return when {
+            duration >= 1.hours -> {
+                // Round to nearest hour (add 30 minutes before dividing)
+                val hours = ((millis + 30 * DateUtils.MINUTE_IN_MILLIS) / DateUtils.HOUR_IN_MILLIS).toInt()
+                formatter.format(Measure(hours, MeasureUnit.HOUR))
+            }
+            duration >= 1.minutes -> {
+                // Round to nearest minute (add 30 seconds before dividing)
+                val minutes = ((millis + 30 * DateUtils.SECOND_IN_MILLIS) / DateUtils.MINUTE_IN_MILLIS).toInt()
+                formatter.format(Measure(minutes, MeasureUnit.MINUTE))
+            }
+            else -> {
+                // Round to nearest second (add 500ms before dividing)
+                val seconds = ((millis + 500) / DateUtils.SECOND_IN_MILLIS).toInt()
+                formatter.format(Measure(seconds, MeasureUnit.SECOND))
+            }
+        }
+    }
+}

libraries/dateformatter/impl/src/test/kotlin/io/element/android/libraries/dateformatter/impl/DefaultDurationFormatterTest.kt

@@ -0,0 +1,133 @@
+/*
+ * 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.dateformatter.impl
+
+import android.os.Build
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.annotation.Config
+import java.util.Locale
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.Duration.Companion.seconds
+
+@RunWith(AndroidJUnit4::class)
+@Config(qualifiers = "en", sdk = [Build.VERSION_CODES.TIRAMISU])
+class DefaultDurationFormatterTest {
+    private fun createDurationFormatter(): DefaultDurationFormatter {
+        return DefaultDurationFormatter(
+            localeChangeObserver = {},
+            locale = Locale.US,
+        )
+    }
+
+    @Test
+    fun `test zero duration`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(0.seconds)).isEqualTo("0 seconds")
+    }
+
+    @Test
+    fun `test 1 second`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.seconds)).isEqualTo("1 second")
+    }
+
+    @Test
+    fun `test 30 seconds`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(30.seconds)).isEqualTo("30 seconds")
+    }
+
+    @Test
+    fun `test 59 seconds`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(59.seconds)).isEqualTo("59 seconds")
+    }
+
+    @Test
+    fun `test 1 minute`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.minutes)).isEqualTo("1 minute")
+    }
+
+    @Test
+    fun `test 1 minute 29 seconds rounds to 1 minute`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.minutes + 29.seconds)).isEqualTo("1 minute")
+    }
+
+    @Test
+    fun `test 1 minute 30 seconds rounds to 2 minutes`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.minutes + 30.seconds)).isEqualTo("2 minutes")
+    }
+
+    @Test
+    fun `test 45 minutes`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(45.minutes)).isEqualTo("45 minutes")
+    }
+
+    @Test
+    fun `test 59 minutes`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(59.minutes)).isEqualTo("59 minutes")
+    }
+
+    @Test
+    fun `test 1 hour`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.hours)).isEqualTo("1 hour")
+    }
+
+    @Test
+    fun `test 1 hour 29 minutes rounds to 1 hour`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.hours + 29.minutes)).isEqualTo("1 hour")
+    }
+
+    @Test
+    fun `test 1 hour 30 minutes rounds to 2 hours`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(1.hours + 30.minutes)).isEqualTo("2 hours")
+    }
+
+    @Test
+    fun `test 2 hours 30 minutes rounds to 3 hours`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(2.hours + 30.minutes)).isEqualTo("3 hours")
+    }
+
+    @Test
+    fun `test 5 hours`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(5.hours)).isEqualTo("5 hours")
+    }
+
+    @Test
+    fun `test 24 hours`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(24.hours)).isEqualTo("24 hours")
+    }
+
+    @Test
+    fun `test rounding at seconds threshold - 499ms rounds to 0 seconds`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(499.milliseconds)).isEqualTo("0 seconds")
+    }
+
+    @Test
+    fun `test rounding at seconds threshold - 500ms rounds to 1 second`() {
+        val formatter = createDurationFormatter()
+        assertThat(formatter.format(500.milliseconds)).isEqualTo("1 second")
+    }
+}

libraries/dateformatter/test/src/main/kotlin/io/element/android/libraries/dateformatter/test/FakeDurationFormatter.kt

@@ -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.
+ */
+
+package io.element.android.libraries.dateformatter.test
+
+import io.element.android.libraries.dateformatter.api.DurationFormatter
+import kotlin.time.Duration
+
+class FakeDurationFormatter(
+    private val formatLambda: (Duration) -> String = { it.toString() },
+) : DurationFormatter {
+    override fun format(duration: Duration): String {
+        return formatLambda(duration)
+    }
+}