fix: local sync task never runs on iOS (#21491)

* fix: local sync task never runs on iOS

* chore: rename ios register method

* refactor from using dart callback to dart entrypoint + more logs

* check if file exists before hashing

* reschedule local sync task

* chore: rename background worker logger

* refactor: move file exists check inside repo

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorker.g.kt

@@ -62,7 +62,7 @@ private open class BackgroundWorkerPigeonCodec : StandardMessageCodec() {
 /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
 interface BackgroundWorkerFgHostApi {
   fun enableSyncWorker()
-  fun enableUploadWorker(callbackHandle: Long)
+  fun enableUploadWorker()
   fun disableUploadWorker()
 
   companion object {
@@ -93,11 +93,9 @@ interface BackgroundWorkerFgHostApi {
       run {
         val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.BackgroundWorkerFgHostApi.enableUploadWorker$separatedMessageChannelSuffix", codec)
         if (api != null) {
-          channel.setMessageHandler { message, reply ->
-            val args = message as List<Any?>
-            val callbackHandleArg = args[0] as Long
+          channel.setMessageHandler { _, reply ->
             val wrapped: List<Any?> = try {
-              api.enableUploadWorker(callbackHandleArg)
+              api.enableUploadWorker()
               listOf(null)
             } catch (exception: Throwable) {
               BackgroundWorkerPigeonUtils.wrapError(exception)
@@ -130,6 +128,7 @@ interface BackgroundWorkerFgHostApi {
 /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
 interface BackgroundWorkerBgHostApi {
   fun onInitialized()
+  fun close()
 
   companion object {
     /** The codec used by BackgroundWorkerBgHostApi. */
@@ -156,6 +155,22 @@ interface BackgroundWorkerBgHostApi {
           channel.setMessageHandler(null)
         }
       }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.BackgroundWorkerBgHostApi.close$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { _, reply ->
+            val wrapped: List<Any?> = try {
+              api.close()
+              listOf(null)
+            } catch (exception: Throwable) {
+              BackgroundWorkerPigeonUtils.wrapError(exception)
+            }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
     }
   }
 }

mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorker.kt

@@ -11,9 +11,8 @@ import com.google.common.util.concurrent.ListenableFuture
 import com.google.common.util.concurrent.SettableFuture
 import io.flutter.FlutterInjector
 import io.flutter.embedding.engine.FlutterEngine
-import io.flutter.embedding.engine.dart.DartExecutor.DartCallback
+import io.flutter.embedding.engine.dart.DartExecutor
 import io.flutter.embedding.engine.loader.FlutterLoader
-import io.flutter.view.FlutterCallbackInformation
 
 private const val TAG = "BackgroundWorker"
 
@@ -58,25 +57,6 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :
     loader.ensureInitializationCompleteAsync(ctx, null, Handler(Looper.getMainLooper())) {
       engine = FlutterEngine(ctx)
 
-      // Retrieve the callback handle stored by the main Flutter app
-      // This handle points to the Flutter function that should be executed in the background
-      val callbackHandle =
-        ctx.getSharedPreferences(BackgroundWorkerApiImpl.SHARED_PREF_NAME, Context.MODE_PRIVATE)
-          .getLong(BackgroundWorkerApiImpl.SHARED_PREF_CALLBACK_HANDLE, 0L)
-
-      if (callbackHandle == 0L) {
-        // Without a valid callback handle, we cannot start the Flutter background execution
-        complete(Result.failure())
-        return@ensureInitializationCompleteAsync
-      }
-
-      // Start the Flutter engine with the specified callback as the entry point
-      val callback = FlutterCallbackInformation.lookupCallbackInformation(callbackHandle)
-      if (callback == null) {
-        complete(Result.failure())
-        return@ensureInitializationCompleteAsync
-      }
-
       // Register custom plugins
       MainActivity.registerPlugins(ctx, engine!!)
       flutterApi =
@@ -86,8 +66,12 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :
         api = this
       )
 
-      engine!!.dartExecutor.executeDartCallback(
-        DartCallback(ctx.assets, loader.findAppBundlePath(), callback)
+      engine!!.dartExecutor.executeDartEntrypoint(
+        DartExecutor.DartEntrypoint(
+          loader.findAppBundlePath(),
+          "package:immich_mobile/domain/services/background_worker.service.dart",
+          "backgroundSyncNativeEntrypoint"
+        )
       )
     }
 
@@ -109,14 +93,7 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :
     }
   }
 
-  /**
-   * Called when the system has to stop this worker because constraints are
-   * no longer met or the system needs resources for more important tasks
-   * This is also called when the worker has been explicitly cancelled or replaced
-   */
-  override fun onStopped() {
-    Log.d(TAG, "About to stop BackupWorker")
-
+  override fun close() {
     if (isComplete) {
       return
     }
@@ -134,6 +111,16 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :
     }, 5000)
   }
 
+  /**
+   * Called when the system has to stop this worker because constraints are
+   * no longer met or the system needs resources for more important tasks
+   * This is also called when the worker has been explicitly cancelled or replaced
+   */
+  override fun onStopped() {
+    Log.d(TAG, "About to stop BackupWorker")
+    close()
+  }
+
   private fun handleHostResult(result: kotlin.Result<Unit>) {
     if (isComplete) {
       return

mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerApiImpl.kt

@@ -21,9 +21,8 @@ class BackgroundWorkerApiImpl(context: Context) : BackgroundWorkerFgHostApi {
     Log.i(TAG, "Scheduled media observer")
   }
 
-  override fun enableUploadWorker(callbackHandle: Long) {
+  override fun enableUploadWorker() {
     updateUploadEnabled(ctx, true)
-    updateCallbackHandle(ctx, callbackHandle)
     Log.i(TAG, "Scheduled background upload tasks")
   }
 
@@ -41,7 +40,6 @@ class BackgroundWorkerApiImpl(context: Context) : BackgroundWorkerFgHostApi {
 
     const val SHARED_PREF_NAME = "Immich::Background"
     const val SHARED_PREF_BACKUP_ENABLED = "Background::backup::enabled"
-    const val SHARED_PREF_CALLBACK_HANDLE = "Background::backup::callbackHandle"
 
     private fun updateUploadEnabled(context: Context, enabled: Boolean) {
       context.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE).edit {
@@ -49,12 +47,6 @@ class BackgroundWorkerApiImpl(context: Context) : BackgroundWorkerFgHostApi {
       }
     }
 
-    private fun updateCallbackHandle(context: Context, callbackHandle: Long) {
-      context.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE).edit {
-        putLong(SHARED_PREF_CALLBACK_HANDLE, callbackHandle)
-      }
-    }
-
     fun enqueueMediaObserver(ctx: Context) {
       val constraints = Constraints.Builder()
         .addContentUriTrigger(MediaStore.Images.Media.INTERNAL_CONTENT_URI, true)