Sync notifications using WorkManager (#5545)

* Initial implementation of notification sync using `WorkManager`

* Use custom `MetroWorkerFactory` to allow assisted injection in WorkManager Workers

* Add tests for `FetchNotificationWorker`. Create `FakeNotificationResolverQueue` to help testing.

* Add more tests, fix Konsist checks

* Add tests for `SyncNotificationWorkManagerRequest`

* Simplify `FakeNotificationResolverQueue`

libraries/workmanager/api/build.gradle.kts

@@ -0,0 +1,23 @@
+import extension.setupDependencyInjection
+
+/*
+ * Copyright 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.
+ */
+plugins {
+    id("io.element.android-library")
+}
+
+android {
+    namespace = "io.element.android.libraries.workmanager.api"
+}
+
+setupDependencyInjection()
+
+dependencies {
+    api(libs.androidx.workmanager.runtime)
+
+    implementation(projects.libraries.matrix.api)
+}

libraries/workmanager/api/src/main/kotlin/io/element/android/libraries/workmanager/api/WorkManagerRequest.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright 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.libraries.workmanager.api
+
+import androidx.work.WorkRequest
+
+interface WorkManagerRequest {
+    fun build(): Result<WorkRequest>
+}

libraries/workmanager/api/src/main/kotlin/io/element/android/libraries/workmanager/api/WorkManagerScheduler.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 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.libraries.workmanager.api
+
+import io.element.android.libraries.matrix.api.core.SessionId
+
+interface WorkManagerScheduler {
+    fun submit(workManagerRequest: WorkManagerRequest)
+    fun cancel(sessionId: SessionId)
+}
+
+fun workManagerTag(sessionId: SessionId, requestType: WorkManagerRequestType): String {
+    val prefix = when (requestType) {
+        WorkManagerRequestType.NOTIFICATION_SYNC -> "notifications"
+    }
+    return "$prefix-$sessionId"
+}
+
+enum class WorkManagerRequestType {
+    NOTIFICATION_SYNC,
+}

libraries/workmanager/api/src/main/kotlin/io/element/android/libraries/workmanager/api/di/MetroWorkerFactory.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 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.libraries.workmanager.api.di
+
+import android.content.Context
+import androidx.work.ListenableWorker
+import androidx.work.WorkerFactory
+import androidx.work.WorkerParameters
+import dev.zacsweers.metro.AppScope
+import dev.zacsweers.metro.ContributesBinding
+import dev.zacsweers.metro.Inject
+import kotlin.reflect.KClass
+
+@ContributesBinding(AppScope::class)
+@Inject
+class MetroWorkerFactory(
+    val workerProviders: Map<KClass<out ListenableWorker>, WorkerInstanceFactory<*>>
+) : WorkerFactory() {
+    override fun createWorker(
+        appContext: Context,
+        workerClassName: String,
+        workerParameters: WorkerParameters,
+    ): ListenableWorker? {
+      return workerProviders[Class.forName(workerClassName).kotlin]?.create(workerParameters)
+    }
+
+    interface WorkerInstanceFactory<T : ListenableWorker> {
+      fun create(params: WorkerParameters): T
+    }
+}

libraries/workmanager/api/src/main/kotlin/io/element/android/libraries/workmanager/api/di/WorkerKey.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 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.libraries.workmanager.api.di
+
+import androidx.work.ListenableWorker
+import dev.zacsweers.metro.MapKey
+import kotlin.reflect.KClass
+
+/** A [MapKey] annotation for binding Worker in a multibinding map. */
+@MapKey
+@Target(AnnotationTarget.CLASS, AnnotationTarget.PROPERTY)
+@Retention(AnnotationRetention.RUNTIME)
+annotation class WorkerKey(val value: KClass<out ListenableWorker>)