refactor: hashing service (#21997)

* download only backup selected assets

* android impl

* fix tests

* limit concurrent hashing to 16

* extension cleanup

* optimized hashing

* hash only selected albums

* remove concurrency limit

* address review comments

* log more info on failure

* add native cancellation

* small batch size on ios, large on android

* fix: get correct resources

* cleanup getResource

* ios better hash cancellation

* handle graceful cancellation android

* do not trigger multiple hashing ops

* ios: fix circular reference, improve cancellation

* kotlin: more cancellation checks

* no need to create result

* cancel previous task

* avoid race condition

* ensure cancellation gets called

* fix cancellation not happening

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>
Co-authored-by: mertalev <101130780+mertalev@users.noreply.github.com>
Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/Messages.g.kt

@@ -209,6 +209,40 @@ data class SyncDelta (
 
   override fun hashCode(): Int = toList().hashCode()
 }
+
+/** Generated class from Pigeon that represents data sent in messages. */
+data class HashResult (
+  val assetId: String,
+  val error: String? = null,
+  val hash: String? = null
+)
+ {
+  companion object {
+    fun fromList(pigeonVar_list: List<Any?>): HashResult {
+      val assetId = pigeonVar_list[0] as String
+      val error = pigeonVar_list[1] as String?
+      val hash = pigeonVar_list[2] as String?
+      return HashResult(assetId, error, hash)
+    }
+  }
+  fun toList(): List<Any?> {
+    return listOf(
+      assetId,
+      error,
+      hash,
+    )
+  }
+  override fun equals(other: Any?): Boolean {
+    if (other !is HashResult) {
+      return false
+    }
+    if (this === other) {
+      return true
+    }
+    return MessagesPigeonUtils.deepEquals(toList(), other.toList())  }
+
+  override fun hashCode(): Int = toList().hashCode()
+}
 private open class MessagesPigeonCodec : StandardMessageCodec() {
   override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
     return when (type) {
@@ -227,6 +261,11 @@ private open class MessagesPigeonCodec : StandardMessageCodec() {
           SyncDelta.fromList(it)
         }
       }
+      132.toByte() -> {
+        return (readValue(buffer) as? List<Any?>)?.let {
+          HashResult.fromList(it)
+        }
+      }
       else -> super.readValueOfType(type, buffer)
     }
   }
@@ -244,11 +283,16 @@ private open class MessagesPigeonCodec : StandardMessageCodec() {
         stream.write(131)
         writeValue(stream, value.toList())
       }
+      is HashResult -> {
+        stream.write(132)
+        writeValue(stream, value.toList())
+      }
       else -> super.writeValue(stream, value)
     }
   }
 }
 
+
 /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
 interface NativeSyncApi {
   fun shouldFullSync(): Boolean
@@ -259,7 +303,8 @@ interface NativeSyncApi {
   fun getAlbums(): List<PlatformAlbum>
   fun getAssetsCountSince(albumId: String, timestamp: Long): Long
   fun getAssetsForAlbum(albumId: String, updatedTimeCond: Long?): List<PlatformAsset>
-  fun hashPaths(paths: List<String>): List<ByteArray?>
+  fun hashAssets(assetIds: List<String>, allowNetworkAccess: Boolean, callback: (Result<List<HashResult>>) -> Unit)
+  fun cancelHashing()
 
   companion object {
     /** The codec used by NativeSyncApi. */
@@ -402,13 +447,33 @@ interface NativeSyncApi {
         }
       }
       run {
-        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashPaths$separatedMessageChannelSuffix", codec, taskQueue)
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashAssets$separatedMessageChannelSuffix", codec, taskQueue)
         if (api != null) {
           channel.setMessageHandler { message, reply ->
             val args = message as List<Any?>
-            val pathsArg = args[0] as List<String>
+            val assetIdsArg = args[0] as List<String>
+            val allowNetworkAccessArg = args[1] as Boolean
+            api.hashAssets(assetIdsArg, allowNetworkAccessArg) { result: Result<List<HashResult>> ->
+              val error = result.exceptionOrNull()
+              if (error != null) {
+                reply.reply(MessagesPigeonUtils.wrapError(error))
+              } else {
+                val data = result.getOrNull()
+                reply.reply(MessagesPigeonUtils.wrapResult(data))
+              }
+            }
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.cancelHashing$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { _, reply ->
             val wrapped: List<Any?> = try {
-              listOf(api.hashPaths(pathsArg))
+              api.cancelHashing()
+              listOf(null)
             } catch (exception: Throwable) {
               MessagesPigeonUtils.wrapError(exception)
             }

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/MessagesImplBase.kt

@@ -1,14 +1,25 @@
 package app.alextran.immich.sync
 
 import android.annotation.SuppressLint
+import android.content.ContentUris
 import android.content.Context
 import android.database.Cursor
 import android.provider.MediaStore
-import android.util.Log
+import android.util.Base64
 import androidx.core.database.getStringOrNull
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.awaitAll
+import kotlinx.coroutines.ensureActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Semaphore
+import kotlinx.coroutines.sync.withPermit
 import java.io.File
-import java.io.FileInputStream
 import java.security.MessageDigest
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.coroutines.coroutineContext
 
 sealed class AssetResult {
   data class ValidAsset(val asset: PlatformAsset, val albumId: String) : AssetResult()
@@ -19,8 +30,12 @@ sealed class AssetResult {
 open class NativeSyncApiImplBase(context: Context) {
   private val ctx: Context = context.applicationContext
 
+  private var hashTask: Job? = null
+
   companion object {
-    private const val TAG = "NativeSyncApiImplBase"
+    private const val MAX_CONCURRENT_HASH_OPERATIONS = 16
+    private val hashSemaphore = Semaphore(MAX_CONCURRENT_HASH_OPERATIONS)
+    private const val HASHING_CANCELLED_CODE = "HASH_CANCELLED"
 
     const val MEDIA_SELECTION =
       "(${MediaStore.Files.FileColumns.MEDIA_TYPE} = ? OR ${MediaStore.Files.FileColumns.MEDIA_TYPE} = ?)"
@@ -215,23 +230,74 @@ open class NativeSyncApiImplBase(context: Context) {
       .toList()
   }
 
-  fun hashPaths(paths: List<String>): List<ByteArray?> {
+  fun hashAssets(
-    val buffer = ByteArray(HASH_BUFFER_SIZE)
+    assetIds: List<String>,
-    val digest = MessageDigest.getInstance("SHA-1")
+    // allowNetworkAccess is only used on the iOS implementation
+    @Suppress("UNUSED_PARAMETER") allowNetworkAccess: Boolean,
+    callback: (Result<List<HashResult>>) -> Unit
+  ) {
+    if (assetIds.isEmpty()) {
+      callback(Result.success(emptyList()))
+      return
+    }
 
-    return paths.map { path ->
+    hashTask?.cancel()
+    hashTask = CoroutineScope(Dispatchers.IO).launch {
       try {
-        FileInputStream(path).use { file ->
+        val results = assetIds.map { assetId ->
-          var bytesRead: Int
+          async {
-          while (file.read(buffer).also { bytesRead = it } > 0) {
+            hashSemaphore.withPermit {
-            digest.update(buffer, 0, bytesRead)
+              ensureActive()
+              hashAsset(assetId)
+            }
           }
-        }
+        }.awaitAll()
-        digest.digest()
+
+        callback(Result.success(results))
+      } catch (e: CancellationException) {
+        callback(
+          Result.failure(
+            FlutterError(
+              HASHING_CANCELLED_CODE,
+              "Hashing operation was cancelled",
+              null
+            )
+          )
+        )
       } catch (e: Exception) {
-        Log.w(TAG, "Failed to hash file $path: $e")
+        callback(Result.failure(e))
-        null
       }
     }
   }
+
+  private suspend fun hashAsset(assetId: String): HashResult {
+    return try {
+      val assetUri = ContentUris.withAppendedId(
+        MediaStore.Files.getContentUri(MediaStore.VOLUME_EXTERNAL),
+        assetId.toLong()
+      )
+
+      val digest = MessageDigest.getInstance("SHA-1")
+      ctx.contentResolver.openInputStream(assetUri)?.use { inputStream ->
+        var bytesRead: Int
+        val buffer = ByteArray(HASH_BUFFER_SIZE)
+        while (inputStream.read(buffer).also { bytesRead = it } > 0) {
+          coroutineContext.ensureActive()
+          digest.update(buffer, 0, bytesRead)
+        }
+      } ?: return HashResult(assetId, "Cannot open input stream for asset", null)
+
+      val hashString = Base64.encodeToString(digest.digest(), Base64.NO_WRAP)
+      HashResult(assetId, null, hashString)
+    } catch (e: SecurityException) {
+      HashResult(assetId, "Permission denied accessing asset: ${e.message}", null)
+    } catch (e: Exception) {
+      HashResult(assetId, "Failed to hash asset: ${e.message}", null)
+    }
+  }
+
+  fun cancelHashing() {
+    hashTask?.cancel()
+    hashTask = null
+  }
 }

mobile/ios/.gitignore

@@ -4,7 +4,6 @@
 *.moved-aside
 *.pbxuser
 *.perspectivev3
-**/*sync/
 .sconsign.dblite
 .tags*
 **/.vagrant/

mobile/ios/Runner/Background/BackgroundWorkerApiImpl.swift

@@ -5,7 +5,7 @@ class BackgroundWorkerApiImpl: BackgroundWorkerFgHostApi {
   func enable() throws {
     BackgroundWorkerApiImpl.scheduleRefreshWorker()
     BackgroundWorkerApiImpl.scheduleProcessingWorker()
-    print("BackgroundUploadImpl:enbale Background worker scheduled")
+    print("BackgroundWorkerApiImpl:enable Background worker scheduled")
   }
   
   func configure(settings: BackgroundWorkerSettings) throws {
@@ -15,7 +15,7 @@ class BackgroundWorkerApiImpl: BackgroundWorkerFgHostApi {
   func disable() throws {
     BGTaskScheduler.shared.cancel(taskRequestWithIdentifier: BackgroundWorkerApiImpl.refreshTaskID);
     BGTaskScheduler.shared.cancel(taskRequestWithIdentifier: BackgroundWorkerApiImpl.processingTaskID);
-    print("BackgroundUploadImpl:disableUploadWorker Disabled background workers")
+    print("BackgroundWorkerApiImpl:disableUploadWorker Disabled background workers")
   }
   
   private static let refreshTaskID = "app.alextran.immich.background.refreshUpload"

mobile/ios/Runner/Sync/Messages.g.swift

@@ -267,6 +267,39 @@ struct SyncDelta: Hashable {
   }
 }
 
+/// Generated class from Pigeon that represents data sent in messages.
+struct HashResult: Hashable {
+  var assetId: String
+  var error: String? = nil
+  var hash: String? = nil
+
+
+  // swift-format-ignore: AlwaysUseLowerCamelCase
+  static func fromList(_ pigeonVar_list: [Any?]) -> HashResult? {
+    let assetId = pigeonVar_list[0] as! String
+    let error: String? = nilOrValue(pigeonVar_list[1])
+    let hash: String? = nilOrValue(pigeonVar_list[2])
+
+    return HashResult(
+      assetId: assetId,
+      error: error,
+      hash: hash
+    )
+  }
+  func toList() -> [Any?] {
+    return [
+      assetId,
+      error,
+      hash,
+    ]
+  }
+  static func == (lhs: HashResult, rhs: HashResult) -> Bool {
+    return deepEqualsMessages(lhs.toList(), rhs.toList())  }
+  func hash(into hasher: inout Hasher) {
+    deepHashMessages(value: toList(), hasher: &hasher)
+  }
+}
+
 private class MessagesPigeonCodecReader: FlutterStandardReader {
   override func readValue(ofType type: UInt8) -> Any? {
     switch type {
@@ -276,6 +309,8 @@ private class MessagesPigeonCodecReader: FlutterStandardReader {
       return PlatformAlbum.fromList(self.readValue() as! [Any?])
     case 131:
       return SyncDelta.fromList(self.readValue() as! [Any?])
+    case 132:
+      return HashResult.fromList(self.readValue() as! [Any?])
     default:
       return super.readValue(ofType: type)
     }
@@ -293,6 +328,9 @@ private class MessagesPigeonCodecWriter: FlutterStandardWriter {
     } else if let value = value as? SyncDelta {
       super.writeByte(131)
       super.writeValue(value.toList())
+    } else if let value = value as? HashResult {
+      super.writeByte(132)
+      super.writeValue(value.toList())
     } else {
       super.writeValue(value)
     }
@@ -313,6 +351,7 @@ class MessagesPigeonCodec: FlutterStandardMessageCodec, @unchecked Sendable {
   static let shared = MessagesPigeonCodec(readerWriter: MessagesPigeonCodecReaderWriter())
 }
 
+
 /// Generated protocol from Pigeon that represents a handler of messages from Flutter.
 protocol NativeSyncApi {
   func shouldFullSync() throws -> Bool
@@ -323,7 +362,8 @@ protocol NativeSyncApi {
   func getAlbums() throws -> [PlatformAlbum]
   func getAssetsCountSince(albumId: String, timestamp: Int64) throws -> Int64
   func getAssetsForAlbum(albumId: String, updatedTimeCond: Int64?) throws -> [PlatformAsset]
-  func hashPaths(paths: [String]) throws -> [FlutterStandardTypedData?]
+  func hashAssets(assetIds: [String], allowNetworkAccess: Bool, completion: @escaping (Result<[HashResult], Error>) -> Void)
+  func cancelHashing() throws
 }
 
 /// Generated setup class from Pigeon to handle messages through the `binaryMessenger`.
@@ -459,22 +499,38 @@ class NativeSyncApiSetup {
     } else {
       getAssetsForAlbumChannel.setMessageHandler(nil)
     }
-    let hashPathsChannel = taskQueue == nil
+    let hashAssetsChannel = taskQueue == nil
-      ? FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashPaths\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
+      ? FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashAssets\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
-      : FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashPaths\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec, taskQueue: taskQueue)
+      : FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashAssets\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec, taskQueue: taskQueue)
     if let api = api {
-      hashPathsChannel.setMessageHandler { message, reply in
+      hashAssetsChannel.setMessageHandler { message, reply in
         let args = message as! [Any?]
-        let pathsArg = args[0] as! [String]
+        let assetIdsArg = args[0] as! [String]
+        let allowNetworkAccessArg = args[1] as! Bool
+        api.hashAssets(assetIds: assetIdsArg, allowNetworkAccess: allowNetworkAccessArg) { result in
+          switch result {
+          case .success(let res):
+            reply(wrapResult(res))
+          case .failure(let error):
+            reply(wrapError(error))
+          }
+        }
+      }
+    } else {
+      hashAssetsChannel.setMessageHandler(nil)
+    }
+    let cancelHashingChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.NativeSyncApi.cancelHashing\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
+    if let api = api {
+      cancelHashingChannel.setMessageHandler { _, reply in
         do {
-          let result = try api.hashPaths(paths: pathsArg)
+          try api.cancelHashing()
-          reply(wrapResult(result))
+          reply(wrapResult(nil))
         } catch {
           reply(wrapError(error))
         }
       }
     } else {
-      hashPathsChannel.setMessageHandler(nil)
+      cancelHashingChannel.setMessageHandler(nil)
     }
   }
 }

mobile/ios/Runner/Sync/MessagesImpl.swift

@@ -17,30 +17,16 @@ struct AssetWrapper: Hashable, Equatable {
   }
 }
 
-extension PHAsset {
-  func toPlatformAsset() -> PlatformAsset {
-    return PlatformAsset(
-      id: localIdentifier,
-      name: title(),
-      type: Int64(mediaType.rawValue),
-      createdAt: creationDate.map { Int64($0.timeIntervalSince1970) },
-      updatedAt: modificationDate.map { Int64($0.timeIntervalSince1970) },
-      width: Int64(pixelWidth),
-      height: Int64(pixelHeight),
-      durationInSeconds: Int64(duration),
-      orientation: 0,
-      isFavorite: isFavorite
-    )
-  }
-}
-
 class NativeSyncApiImpl: NativeSyncApi {
   private let defaults: UserDefaults
   private let changeTokenKey = "immich:changeToken"
   private let albumTypes: [PHAssetCollectionType] = [.album, .smartAlbum]
   private let recoveredAlbumSubType = 1000000219
   
-  private let hashBufferSize = 2 * 1024 * 1024
+  private var hashTask: Task<Void, Error>?
+  private static let hashCancelledCode = "HASH_CANCELLED"
+  private static let hashCancelled = Result<[HashResult], Error>.failure(PigeonError(code: hashCancelledCode, message: "Hashing cancelled", details: nil))
+  
   
   init(with defaults: UserDefaults = .standard) {
     self.defaults = defaults
@@ -96,7 +82,7 @@ class NativeSyncApiImpl: NativeSyncApi {
       let collections = PHAssetCollection.fetchAssetCollections(with: type, subtype: .any, options: nil)
       for i in 0..<collections.count {
         let album = collections.object(at: i)
-      
+        
         // Ignore recovered album
         if(album.assetCollectionSubtype.rawValue == self.recoveredAlbumSubType) {
           continue;
@@ -254,7 +240,7 @@ class NativeSyncApiImpl: NativeSyncApi {
       let date = NSDate(timeIntervalSince1970: TimeInterval(updatedTimeCond!))
       options.predicate = NSPredicate(format: "creationDate > %@ OR modificationDate > %@", date, date)
     }
-
+    
     let result = PHAsset.fetchAssets(in: album, options: options)
     if(result.count == 0) {
       return []
@@ -267,23 +253,114 @@ class NativeSyncApiImpl: NativeSyncApi {
     return assets
   }
   
-  func hashPaths(paths: [String]) throws -> [FlutterStandardTypedData?] {
+  func hashAssets(assetIds: [String], allowNetworkAccess: Bool, completion: @escaping (Result<[HashResult], Error>) -> Void) {
-      return paths.map { path in
+    if let prevTask = hashTask {
-          guard let file = FileHandle(forReadingAtPath: path) else {
+      prevTask.cancel()
-              print("Cannot open file: \(path)")
+      hashTask = nil
-              return nil
+    }
-          }
+    hashTask = Task { [weak self] in
-          
+      var missingAssetIds = Set(assetIds)
-          var hasher = Insecure.SHA1()
+      var assets = [PHAsset]()
-          while autoreleasepool(invoking: {
+      assets.reserveCapacity(assetIds.count)
-              let chunk = file.readData(ofLength: hashBufferSize)
+      PHAsset.fetchAssets(withLocalIdentifiers: assetIds, options: nil).enumerateObjects { (asset, _, stop) in
-              guard !chunk.isEmpty else { return false }
+        if Task.isCancelled {
-              hasher.update(data: chunk)
+          stop.pointee = true
-              return true
+          return
-          }) { }
+        }
-          
+        missingAssetIds.remove(asset.localIdentifier)
-          let digest = hasher.finalize()
+        assets.append(asset)
-          return FlutterStandardTypedData(bytes: Data(digest))
       }
+      
+      if Task.isCancelled {
+        return completion(Self.hashCancelled)
+      }
+      
+      await withTaskGroup(of: HashResult?.self) { taskGroup in
+        var results = [HashResult]()
+        results.reserveCapacity(assets.count)
+        for asset in assets {
+          if Task.isCancelled {
+            return completion(Self.hashCancelled)
+          }
+          taskGroup.addTask {
+            guard let self = self else { return nil }
+            return await self.hashAsset(asset, allowNetworkAccess: allowNetworkAccess)
+          }
+        }
+        
+        for await result in taskGroup {
+          guard let result = result else {
+            return completion(Self.hashCancelled)
+          }
+          results.append(result)
+        }
+        
+        for missing in missingAssetIds {
+          results.append(HashResult(assetId: missing, error: "Asset not found in library", hash: nil))
+        }
+        
+        completion(.success(results))
+      }
+    }
+  }
+  
+  func cancelHashing() {
+    hashTask?.cancel()
+    hashTask = nil
+  }
+  
+  private func hashAsset(_ asset: PHAsset, allowNetworkAccess: Bool) async -> HashResult? {
+    class RequestRef {
+      var id: PHAssetResourceDataRequestID?
+    }
+    let requestRef = RequestRef()
+    return await withTaskCancellationHandler(operation: {
+      if Task.isCancelled {
+        return nil
+      }
+      
+      guard let resource = asset.getResource() else {
+        return HashResult(assetId: asset.localIdentifier, error: "Cannot get asset resource", hash: nil)
+      }
+      
+      if Task.isCancelled {
+        return nil
+      }
+      
+      let options = PHAssetResourceRequestOptions()
+      options.isNetworkAccessAllowed = allowNetworkAccess
+      
+      return await withCheckedContinuation { continuation in
+        var hasher = Insecure.SHA1()
+        
+        requestRef.id = PHAssetResourceManager.default().requestData(
+          for: resource,
+          options: options,
+          dataReceivedHandler: { data in
+            hasher.update(data: data)
+          },
+          completionHandler: { error in
+            let result: HashResult? = switch (error) {
+            case let e as PHPhotosError where e.code == .userCancelled: nil
+            case let .some(e): HashResult(
+              assetId: asset.localIdentifier,
+              error: "Failed to hash asset: \(e.localizedDescription)",
+              hash: nil
+            )
+            case .none:
+              HashResult(
+                assetId: asset.localIdentifier,
+                error: nil,
+                hash: Data(hasher.finalize()).base64EncodedString()
+              )
+            }
+            continuation.resume(returning: result)
+          }
+        )
+      }
+    }, onCancel: {
+      guard let requestId = requestRef.id else { return }
+      PHAssetResourceManager.default().cancelDataRequest(requestId)
+    })
   }
 }

mobile/ios/Runner/Sync/PHAssetExtensions.swift

@@ -0,0 +1,77 @@
+import Photos
+
+extension PHAsset {
+  func toPlatformAsset() -> PlatformAsset {
+    return PlatformAsset(
+      id: localIdentifier,
+      name: title,
+      type: Int64(mediaType.rawValue),
+      createdAt: creationDate.map { Int64($0.timeIntervalSince1970) },
+      updatedAt: modificationDate.map { Int64($0.timeIntervalSince1970) },
+      width: Int64(pixelWidth),
+      height: Int64(pixelHeight),
+      durationInSeconds: Int64(duration),
+      orientation: 0,
+      isFavorite: isFavorite
+    )
+  }
+
+  var title: String {
+    return filename ?? originalFilename ?? "<unknown>"
+  }
+
+  var filename: String? {
+    return value(forKey: "filename") as? String
+  }
+
+  // This method is expected to be slow as it goes through the asset resources to fetch the originalFilename
+  var originalFilename: String? {
+    return getResource()?.originalFilename
+  }
+
+  func getResource() -> PHAssetResource? {
+    let resources = PHAssetResource.assetResources(for: self)
+
+    let filteredResources = resources.filter { $0.isMediaResource && isValidResourceType($0.type) }
+
+    guard !filteredResources.isEmpty else {
+      return nil
+    }
+
+    if filteredResources.count == 1 {
+      return filteredResources.first
+    }
+
+    if let currentResource = filteredResources.first(where: { $0.isCurrent }) {
+      return currentResource
+    }
+
+    if let fullSizeResource = filteredResources.first(where: { isFullSizeResourceType($0.type) }) {
+      return fullSizeResource
+    }
+
+    return nil
+  }
+
+  private func isValidResourceType(_ type: PHAssetResourceType) -> Bool {
+    switch mediaType {
+    case .image:
+      return [.photo, .alternatePhoto, .fullSizePhoto].contains(type)
+    case .video:
+      return [.video, .fullSizeVideo, .fullSizePairedVideo].contains(type)
+    default:
+      return false
+    }
+  }
+
+  private func isFullSizeResourceType(_ type: PHAssetResourceType) -> Bool {
+    switch mediaType {
+    case .image:
+      return type == .fullSizePhoto
+    case .video:
+      return type == .fullSizeVideo
+    default:
+      return false
+    }
+  }
+}

mobile/ios/Runner/Sync/PHAssetResourceExtensions.swift

@@ -0,0 +1,16 @@
+
+import Photos
+
+extension PHAssetResource {
+  var isCurrent: Bool {
+    return value(forKey: "isCurrent") as? Bool ?? false
+  }
+  
+  var isMediaResource: Bool {
+    var isMedia = type != .adjustmentData
+    if #available(iOS 17, *) {
+      isMedia = isMedia && type != .photoProxy
+    }
+    return isMedia
+  }
+}

mobile/lib/constants/constants.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+
 const int noDbId = -9223372036854775808; // from Isar
 const double downloadCompleted = -1;
 const double downloadFailed = -2;
@@ -10,7 +12,7 @@ const int kSyncEventBatchSize = 5000;
 const int kFetchLocalAssetsBatchSize = 40000;
 
 // Hash batch limits
-const int kBatchHashFileLimit = 256;
+final int kBatchHashFileLimit = Platform.isIOS ? 32 : 512;
 const int kBatchHashSizeLimit = 1024 * 1024 * 1024; // 1GB
 
 // Secure storage keys

mobile/lib/domain/services/background_worker.service.dart

@@ -184,6 +184,7 @@ class BackgroundWorkerBgService extends BackgroundWorkerFlutterApi {
 
     try {
       final backgroundSyncManager = _ref.read(backgroundSyncProvider);
+      final nativeSyncApi = _ref.read(nativeSyncApiProvider);
       _isCleanedUp = true;
       _ref.dispose();
 
@@ -199,7 +200,7 @@ class BackgroundWorkerBgService extends BackgroundWorkerFlutterApi {
         _drift.close(),
         _driftLogger.close(),
         backgroundSyncManager.cancel(),
-        backgroundSyncManager.cancelLocal(),
+        nativeSyncApi.cancelHashing(),
       ];
 
       if (_isar.isOpen) {

mobile/lib/domain/services/hash.service.dart

@@ -1,20 +1,18 @@
-import 'dart:convert';
+import 'package:flutter/services.dart';
-
 import 'package:immich_mobile/constants/constants.dart';
 import 'package:immich_mobile/domain/models/album/local_album.model.dart';
 import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
 import 'package:immich_mobile/infrastructure/repositories/local_album.repository.dart';
 import 'package:immich_mobile/infrastructure/repositories/local_asset.repository.dart';
-import 'package:immich_mobile/infrastructure/repositories/storage.repository.dart';
 import 'package:immich_mobile/platform/native_sync_api.g.dart';
 import 'package:logging/logging.dart';
 
+const String _kHashCancelledCode = "HASH_CANCELLED";
+
 class HashService {
-  final int batchSizeLimit;
+  final int _batchSize;
-  final int batchFileLimit;
   final DriftLocalAlbumRepository _localAlbumRepository;
   final DriftLocalAssetRepository _localAssetRepository;
-  final StorageRepository _storageRepository;
   final NativeSyncApi _nativeSyncApi;
   final bool Function()? _cancelChecker;
   final _log = Logger('HashService');
@@ -22,37 +20,42 @@ class HashService {
   HashService({
     required DriftLocalAlbumRepository localAlbumRepository,
     required DriftLocalAssetRepository localAssetRepository,
-    required StorageRepository storageRepository,
     required NativeSyncApi nativeSyncApi,
     bool Function()? cancelChecker,
-    this.batchSizeLimit = kBatchHashSizeLimit,
+    int? batchSize,
-    this.batchFileLimit = kBatchHashFileLimit,
   }) : _localAlbumRepository = localAlbumRepository,
        _localAssetRepository = localAssetRepository,
-       _storageRepository = storageRepository,
        _cancelChecker = cancelChecker,
-       _nativeSyncApi = nativeSyncApi;
+       _nativeSyncApi = nativeSyncApi,
+       _batchSize = batchSize ?? kBatchHashFileLimit;
 
   bool get isCancelled => _cancelChecker?.call() ?? false;
 
   Future<void> hashAssets() async {
     _log.info("Starting hashing of assets");
     final Stopwatch stopwatch = Stopwatch()..start();
-    // Sorted by backupSelection followed by isCloud
+    try {
-    final localAlbums = await _localAlbumRepository.getAll(
+      // Sorted by backupSelection followed by isCloud
-      sortBy: {SortLocalAlbumsBy.backupSelection, SortLocalAlbumsBy.isIosSharedAlbum},
+      final localAlbums = await _localAlbumRepository.getBackupAlbums();
-    );
 
-    for (final album in localAlbums) {
+      for (final album in localAlbums) {
-      if (isCancelled) {
+        if (isCancelled) {
-        _log.warning("Hashing cancelled. Stopped processing albums.");
+          _log.warning("Hashing cancelled. Stopped processing albums.");
-        break;
+          break;
-      }
+        }
 
-      final assetsToHash = await _localAlbumRepository.getAssetsToHash(album.id);
+        final assetsToHash = await _localAlbumRepository.getAssetsToHash(album.id);
-      if (assetsToHash.isNotEmpty) {
+        if (assetsToHash.isNotEmpty) {
-        await _hashAssets(album, assetsToHash);
+          await _hashAssets(album, assetsToHash);
+        }
       }
+    } on PlatformException catch (e) {
+      if (e.code == _kHashCancelledCode) {
+        _log.warning("Hashing cancelled by platform");
+        return;
+      }
+    } catch (e, s) {
+      _log.severe("Error during hashing", e, s);
     }
 
     stopwatch.stop();
@@ -63,8 +66,7 @@ class HashService {
   /// with hash for those that were successfully hashed. Hashes are looked up in a table
   /// [LocalAssetHashEntity] by local id. Only missing entries are newly hashed and added to the DB.
   Future<void> _hashAssets(LocalAlbum album, List<LocalAsset> assetsToHash) async {
-    int bytesProcessed = 0;
+    final toHash = <String, LocalAsset>{};
-    final toHash = <_AssetToPath>[];
 
     for (final asset in assetsToHash) {
       if (isCancelled) {
@@ -72,21 +74,10 @@ class HashService {
         return;
       }
 
-      final file = await _storageRepository.getFileForAsset(asset.id);
+      toHash[asset.id] = asset;
-      if (file == null) {
+      if (toHash.length == _batchSize) {
-        _log.warning(
-          "Cannot get file for asset ${asset.id}, name: ${asset.name}, created on: ${asset.createdAt} from album: ${album.name}",
-        );
-        continue;
-      }
-
-      bytesProcessed += await file.length();
-      toHash.add(_AssetToPath(asset: asset, path: file.path));
-
-      if (toHash.length >= batchFileLimit || bytesProcessed >= batchSizeLimit) {
         await _processBatch(album, toHash);
         toHash.clear();
-        bytesProcessed = 0;
       }
     }
 
@@ -94,33 +85,36 @@ class HashService {
   }
 
   /// Processes a batch of assets.
-  Future<void> _processBatch(LocalAlbum album, List<_AssetToPath> toHash) async {
+  Future<void> _processBatch(LocalAlbum album, Map<String, LocalAsset> toHash) async {
     if (toHash.isEmpty) {
       return;
     }
 
     _log.fine("Hashing ${toHash.length} files");
 
-    final hashed = <LocalAsset>[];
+    final hashed = <String, String>{};
-    final hashes = await _nativeSyncApi.hashPaths(toHash.map((e) => e.path).toList());
+    final hashResults = await _nativeSyncApi.hashAssets(
+      toHash.keys.toList(),
+      allowNetworkAccess: album.backupSelection == BackupSelection.selected,
+    );
     assert(
-      hashes.length == toHash.length,
+      hashResults.length == toHash.length,
-      "Hashes length does not match toHash length: ${hashes.length} != ${toHash.length}",
+      "Hashes length does not match toHash length: ${hashResults.length} != ${toHash.length}",
     );
 
-    for (int i = 0; i < hashes.length; i++) {
+    for (int i = 0; i < hashResults.length; i++) {
       if (isCancelled) {
         _log.warning("Hashing cancelled. Stopped processing batch.");
         return;
       }
 
-      final hash = hashes[i];
+      final hashResult = hashResults[i];
-      final asset = toHash[i].asset;
+      if (hashResult.hash != null) {
-      if (hash?.length == 20) {
+        hashed[hashResult.assetId] = hashResult.hash!;
-        hashed.add(asset.copyWith(checksum: base64.encode(hash!)));
       } else {
+        final asset = toHash[hashResult.assetId];
         _log.warning(
-          "Failed to hash file for ${asset.id}: ${asset.name} created at ${asset.createdAt} from album: ${album.name}",
+          "Failed to hash asset with id: ${hashResult.assetId}, name: ${asset?.name}, createdAt: ${asset?.createdAt}, from album: ${album.name}. Error: ${hashResult.error ?? "unknown"}",
         );
       }
     }
@@ -128,13 +122,5 @@ class HashService {
     _log.fine("Hashed ${hashed.length}/${toHash.length} assets");
 
     await _localAssetRepository.updateHashes(hashed);
-    await _storageRepository.clearCache();
   }
 }
-
-class _AssetToPath {
-  final LocalAsset asset;
-  final String path;
-
-  const _AssetToPath({required this.asset, required this.path});
-}

mobile/lib/infrastructure/repositories/local_asset.repository.dart

@@ -36,17 +36,17 @@ class DriftLocalAssetRepository extends DriftDatabaseRepository {
 
   Stream<LocalAsset?> watch(String id) => _assetSelectable(id).watchSingleOrNull();
 
-  Future<void> updateHashes(Iterable<LocalAsset> hashes) {
+  Future<void> updateHashes(Map<String, String> hashes) {
     if (hashes.isEmpty) {
       return Future.value();
     }
 
     return _db.batch((batch) async {
-      for (final asset in hashes) {
+      for (final entry in hashes.entries) {
         batch.update(
           _db.localAssetEntity,
-          LocalAssetEntityCompanion(checksum: Value(asset.checksum)),
+          LocalAssetEntityCompanion(checksum: Value(entry.value)),
-          where: (e) => e.id.equals(asset.id),
+          where: (e) => e.id.equals(entry.key),
         );
       }
     });

mobile/lib/pages/backup/drift_backup_album_selection.page.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:io';
 
 import 'package:auto_route/auto_route.dart';
@@ -5,12 +6,14 @@ import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:immich_mobile/domain/models/album/local_album.model.dart';
+import 'package:immich_mobile/domain/services/sync_linked_album.service.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
 import 'package:immich_mobile/extensions/translate_extensions.dart';
 import 'package:immich_mobile/providers/app_settings.provider.dart';
-import 'package:immich_mobile/domain/services/sync_linked_album.service.dart';
+import 'package:immich_mobile/providers/background_sync.provider.dart';
 import 'package:immich_mobile/providers/backup/backup_album.provider.dart';
 import 'package:immich_mobile/providers/backup/drift_backup.provider.dart';
+import 'package:immich_mobile/providers/infrastructure/platform.provider.dart';
 import 'package:immich_mobile/providers/user.provider.dart';
 import 'package:immich_mobile/services/app_settings.service.dart';
 import 'package:immich_mobile/widgets/backup/drift_album_info_list_tile.dart';
@@ -64,16 +67,6 @@ class _DriftBackupAlbumSelectionPageState extends ConsumerState<DriftBackupAlbum
       });
       await _handleLinkedAlbumFuture;
     }
-
-    // Restart backup if total count changed and backup is enabled
-    final currentTotalAssetCount = ref.read(driftBackupProvider.select((p) => p.totalCount));
-    final totalChanged = currentTotalAssetCount != _initialTotalAssetCount;
-    final isBackupEnabled = ref.read(appSettingsServiceProvider).getSetting(AppSettingsEnum.enableBackup);
-
-    if (totalChanged && isBackupEnabled) {
-      await ref.read(driftBackupProvider.notifier).cancel();
-      await ref.read(driftBackupProvider.notifier).startBackup(user.id);
-    }
   }
 
   @override
@@ -102,6 +95,27 @@ class _DriftBackupAlbumSelectionPageState extends ConsumerState<DriftBackupAlbum
       onPopInvokedWithResult: (didPop, _) async {
         if (!didPop) {
           await _handlePagePopped();
+
+          final user = ref.read(currentUserProvider);
+          if (user == null) {
+            return;
+          }
+
+          final isBackupEnabled = ref.read(appSettingsServiceProvider).getSetting(AppSettingsEnum.enableBackup);
+          await ref.read(driftBackupProvider.notifier).getBackupStatus(user.id);
+          final currentTotalAssetCount = ref.read(driftBackupProvider.select((p) => p.totalCount));
+          final totalChanged = currentTotalAssetCount != _initialTotalAssetCount;
+          final backupNotifier = ref.read(driftBackupProvider.notifier);
+          final backgroundSync = ref.read(backgroundSyncProvider);
+          final nativeSync = ref.read(nativeSyncApiProvider);
+          if (totalChanged) {
+            // Waits for hashing to be cancelled before starting a new one
+            unawaited(nativeSync.cancelHashing().whenComplete(() => backgroundSync.hashAssets()));
+            if (isBackupEnabled) {
+              unawaited(backupNotifier.cancel().whenComplete(() => backupNotifier.startBackup(user.id)));
+            }
+          }
+
           Navigator.of(context).pop();
         }
       },

mobile/lib/platform/native_sync_api.g.dart

@@ -205,6 +205,45 @@ class SyncDelta {
   int get hashCode => Object.hashAll(_toList());
 }
 
+class HashResult {
+  HashResult({required this.assetId, this.error, this.hash});
+
+  String assetId;
+
+  String? error;
+
+  String? hash;
+
+  List<Object?> _toList() {
+    return <Object?>[assetId, error, hash];
+  }
+
+  Object encode() {
+    return _toList();
+  }
+
+  static HashResult decode(Object result) {
+    result as List<Object?>;
+    return HashResult(assetId: result[0]! as String, error: result[1] as String?, hash: result[2] as String?);
+  }
+
+  @override
+  // ignore: avoid_equals_and_hash_code_on_mutable_classes
+  bool operator ==(Object other) {
+    if (other is! HashResult || other.runtimeType != runtimeType) {
+      return false;
+    }
+    if (identical(this, other)) {
+      return true;
+    }
+    return _deepEquals(encode(), other.encode());
+  }
+
+  @override
+  // ignore: avoid_equals_and_hash_code_on_mutable_classes
+  int get hashCode => Object.hashAll(_toList());
+}
+
 class _PigeonCodec extends StandardMessageCodec {
   const _PigeonCodec();
   @override
@@ -221,6 +260,9 @@ class _PigeonCodec extends StandardMessageCodec {
     } else if (value is SyncDelta) {
       buffer.putUint8(131);
       writeValue(buffer, value.encode());
+    } else if (value is HashResult) {
+      buffer.putUint8(132);
+      writeValue(buffer, value.encode());
     } else {
       super.writeValue(buffer, value);
     }
@@ -235,6 +277,8 @@ class _PigeonCodec extends StandardMessageCodec {
         return PlatformAlbum.decode(readValue(buffer)!);
       case 131:
         return SyncDelta.decode(readValue(buffer)!);
+      case 132:
+        return HashResult.decode(readValue(buffer)!);
       default:
         return super.readValueOfType(type, buffer);
     }
@@ -468,15 +512,15 @@ class NativeSyncApi {
     }
   }
 
-  Future<List<Uint8List?>> hashPaths(List<String> paths) async {
+  Future<List<HashResult>> hashAssets(List<String> assetIds, {bool allowNetworkAccess = false}) async {
     final String pigeonVar_channelName =
-        'dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashPaths$pigeonVar_messageChannelSuffix';
+        'dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashAssets$pigeonVar_messageChannelSuffix';
     final BasicMessageChannel<Object?> pigeonVar_channel = BasicMessageChannel<Object?>(
       pigeonVar_channelName,
       pigeonChannelCodec,
       binaryMessenger: pigeonVar_binaryMessenger,
     );
-    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(<Object?>[paths]);
+    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(<Object?>[assetIds, allowNetworkAccess]);
     final List<Object?>? pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
     if (pigeonVar_replyList == null) {
       throw _createConnectionError(pigeonVar_channelName);
@@ -492,7 +536,30 @@ class NativeSyncApi {
         message: 'Host platform returned null value for non-null return value.',
       );
     } else {
-      return (pigeonVar_replyList[0] as List<Object?>?)!.cast<Uint8List?>();
+      return (pigeonVar_replyList[0] as List<Object?>?)!.cast<HashResult>();
+    }
+  }
+
+  Future<void> cancelHashing() async {
+    final String pigeonVar_channelName =
+        'dev.flutter.pigeon.immich_mobile.NativeSyncApi.cancelHashing$pigeonVar_messageChannelSuffix';
+    final BasicMessageChannel<Object?> pigeonVar_channel = BasicMessageChannel<Object?>(
+      pigeonVar_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: pigeonVar_binaryMessenger,
+    );
+    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(null);
+    final List<Object?>? pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
+    if (pigeonVar_replyList == null) {
+      throw _createConnectionError(pigeonVar_channelName);
+    } else if (pigeonVar_replyList.length > 1) {
+      throw PlatformException(
+        code: pigeonVar_replyList[0]! as String,
+        message: pigeonVar_replyList[1] as String?,
+        details: pigeonVar_replyList[2],
+      );
+    } else {
+      return;
     }
   }
 }

mobile/lib/providers/infrastructure/sync.provider.dart

@@ -10,7 +10,6 @@ import 'package:immich_mobile/providers/infrastructure/asset.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/cancel.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/db.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/platform.provider.dart';
-import 'package:immich_mobile/providers/infrastructure/storage.provider.dart';
 
 final syncStreamServiceProvider = Provider(
   (ref) => SyncStreamService(
@@ -35,7 +34,6 @@ final hashServiceProvider = Provider(
   (ref) => HashService(
     localAlbumRepository: ref.watch(localAlbumRepository),
     localAssetRepository: ref.watch(localAssetRepository),
-    storageRepository: ref.watch(storageRepositoryProvider),
     nativeSyncApi: ref.watch(nativeSyncApiProvider),
   ),
 );

mobile/lib/services/hash.service.dart

@@ -16,9 +16,10 @@ class HashService {
     required IsarDeviceAssetRepository deviceAssetRepository,
     required BackgroundService backgroundService,
     this.batchSizeLimit = kBatchHashSizeLimit,
-    this.batchFileLimit = kBatchHashFileLimit,
+    int? batchFileLimit,
   }) : _deviceAssetRepository = deviceAssetRepository,
-       _backgroundService = backgroundService;
+       _backgroundService = backgroundService,
+       batchFileLimit = batchFileLimit ?? kBatchHashFileLimit;
 
   final IsarDeviceAssetRepository _deviceAssetRepository;
   final BackgroundService _backgroundService;

mobile/pigeon/native_sync_api.dart

@@ -71,6 +71,14 @@ class SyncDelta {
   });
 }
 
+class HashResult {
+  final String assetId;
+  final String? error;
+  final String? hash;
+
+  const HashResult({required this.assetId, this.error, this.hash});
+}
+
 @HostApi()
 abstract class NativeSyncApi {
   bool shouldFullSync();
@@ -94,6 +102,9 @@ abstract class NativeSyncApi {
   @TaskQueue(type: TaskQueueType.serialBackgroundThread)
   List<PlatformAsset> getAssetsForAlbum(String albumId, {int? updatedTimeCond});
 
+  @async
   @TaskQueue(type: TaskQueueType.serialBackgroundThread)
-  List<Uint8List?> hashPaths(List<String> paths);
+  List<HashResult> hashAssets(List<String> assetIds, {bool allowNetworkAccess = false});
+
+  void cancelHashing();
 }

mobile/test/domain/services/hash_service_test.dart

@@ -1,11 +1,7 @@
-import 'dart:convert';
-import 'dart:io';
-import 'dart:typed_data';
-
 import 'package:flutter_test/flutter_test.dart';
-import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
+import 'package:immich_mobile/domain/models/album/local_album.model.dart';
 import 'package:immich_mobile/domain/services/hash.service.dart';
-import 'package:immich_mobile/infrastructure/repositories/local_album.repository.dart';
+import 'package:immich_mobile/platform/native_sync_api.g.dart';
 import 'package:mocktail/mocktail.dart';
 
 import '../../fixtures/album.stub.dart';
@@ -13,192 +9,137 @@ import '../../fixtures/asset.stub.dart';
 import '../../infrastructure/repository.mock.dart';
 import '../service.mock.dart';
 
-class MockFile extends Mock implements File {}
-
 void main() {
   late HashService sut;
   late MockLocalAlbumRepository mockAlbumRepo;
   late MockLocalAssetRepository mockAssetRepo;
-  late MockStorageRepository mockStorageRepo;
   late MockNativeSyncApi mockNativeApi;
-  final sortBy = {SortLocalAlbumsBy.backupSelection, SortLocalAlbumsBy.isIosSharedAlbum};
 
   setUp(() {
     mockAlbumRepo = MockLocalAlbumRepository();
     mockAssetRepo = MockLocalAssetRepository();
-    mockStorageRepo = MockStorageRepository();
     mockNativeApi = MockNativeSyncApi();
 
     sut = HashService(
       localAlbumRepository: mockAlbumRepo,
       localAssetRepository: mockAssetRepo,
-      storageRepository: mockStorageRepo,
       nativeSyncApi: mockNativeApi,
     );
 
     registerFallbackValue(LocalAlbumStub.recent);
     registerFallbackValue(LocalAssetStub.image1);
+    registerFallbackValue(<String, String>{});
 
     when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
-    when(() => mockStorageRepo.clearCache()).thenAnswer((_) async => {});
   });
 
   group('HashService hashAssets', () {
     test('skips albums with no assets to hash', () async {
       when(
-        () => mockAlbumRepo.getAll(sortBy: sortBy),
+        () => mockAlbumRepo.getBackupAlbums(),
       ).thenAnswer((_) async => [LocalAlbumStub.recent.copyWith(assetCount: 0)]);
       when(() => mockAlbumRepo.getAssetsToHash(LocalAlbumStub.recent.id)).thenAnswer((_) async => []);
 
       await sut.hashAssets();
 
-      verifyNever(() => mockStorageRepo.getFileForAsset(any()));
+      verifyNever(() => mockNativeApi.hashAssets(any(), allowNetworkAccess: any(named: 'allowNetworkAccess')));
-      verifyNever(() => mockNativeApi.hashPaths(any()));
     });
   });
 
   group('HashService _hashAssets', () {
-    test('skips assets without files', () async {
+    test('skips empty batches', () async {
       final album = LocalAlbumStub.recent;
-      final asset = LocalAssetStub.image1;
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
+      when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => []);
-      when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset]);
-      when(() => mockStorageRepo.getFileForAsset(asset.id)).thenAnswer((_) async => null);
 
       await sut.hashAssets();
 
-      verifyNever(() => mockNativeApi.hashPaths(any()));
+      verifyNever(() => mockNativeApi.hashAssets(any(), allowNetworkAccess: any(named: 'allowNetworkAccess')));
     });
 
     test('processes assets when available', () async {
       final album = LocalAlbumStub.recent;
       final asset = LocalAssetStub.image1;
-      final mockFile = MockFile();
-      final hash = Uint8List.fromList(List.generate(20, (i) => i));
 
-      when(() => mockFile.length()).thenAnswer((_) async => 1000);
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
-      when(() => mockFile.path).thenReturn('image-path');
-
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
       when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset]);
-      when(() => mockStorageRepo.getFileForAsset(asset.id)).thenAnswer((_) async => mockFile);
+      when(
-      when(() => mockNativeApi.hashPaths(['image-path'])).thenAnswer((_) async => [hash]);
+        () => mockNativeApi.hashAssets([asset.id], allowNetworkAccess: false),
+      ).thenAnswer((_) async => [HashResult(assetId: asset.id, hash: 'test-hash')]);
 
       await sut.hashAssets();
 
-      verify(() => mockNativeApi.hashPaths(['image-path'])).called(1);
+      verify(() => mockNativeApi.hashAssets([asset.id], allowNetworkAccess: false)).called(1);
-      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as List<LocalAsset>;
+      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as Map<String, String>;
       expect(captured.length, 1);
-      expect(captured[0].checksum, base64.encode(hash));
+      expect(captured[asset.id], 'test-hash');
     });
 
     test('handles failed hashes', () async {
       final album = LocalAlbumStub.recent;
       final asset = LocalAssetStub.image1;
-      final mockFile = MockFile();
-      when(() => mockFile.length()).thenAnswer((_) async => 1000);
-      when(() => mockFile.path).thenReturn('image-path');
 
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
       when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset]);
-      when(() => mockStorageRepo.getFileForAsset(asset.id)).thenAnswer((_) async => mockFile);
+      when(
-      when(() => mockNativeApi.hashPaths(['image-path'])).thenAnswer((_) async => [null]);
+        () => mockNativeApi.hashAssets([asset.id], allowNetworkAccess: false),
-      when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
+      ).thenAnswer((_) async => [HashResult(assetId: asset.id, error: 'Failed to hash')]);
 
       await sut.hashAssets();
 
-      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as List<LocalAsset>;
+      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as Map<String, String>;
       expect(captured.length, 0);
     });
 
-    test('handles invalid hash length', () async {
+    test('handles null hash results', () async {
       final album = LocalAlbumStub.recent;
       final asset = LocalAssetStub.image1;
-      final mockFile = MockFile();
-      when(() => mockFile.length()).thenAnswer((_) async => 1000);
-      when(() => mockFile.path).thenReturn('image-path');
 
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
       when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset]);
-      when(() => mockStorageRepo.getFileForAsset(asset.id)).thenAnswer((_) async => mockFile);
+      when(
-
+        () => mockNativeApi.hashAssets([asset.id], allowNetworkAccess: false),
-      final invalidHash = Uint8List.fromList([1, 2, 3]);
+      ).thenAnswer((_) async => [HashResult(assetId: asset.id, hash: null)]);
-      when(() => mockNativeApi.hashPaths(['image-path'])).thenAnswer((_) async => [invalidHash]);
-      when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
 
       await sut.hashAssets();
 
-      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as List<LocalAsset>;
+      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as Map<String, String>;
       expect(captured.length, 0);
     });
 
-    test('batches by file count limit', () async {
-      final sut = HashService(
-        localAlbumRepository: mockAlbumRepo,
-        localAssetRepository: mockAssetRepo,
-        storageRepository: mockStorageRepo,
-        nativeSyncApi: mockNativeApi,
-        batchFileLimit: 1,
-      );
-
-      final album = LocalAlbumStub.recent;
-      final asset1 = LocalAssetStub.image1;
-      final asset2 = LocalAssetStub.image2;
-      final mockFile1 = MockFile();
-      final mockFile2 = MockFile();
-      when(() => mockFile1.length()).thenAnswer((_) async => 100);
-      when(() => mockFile1.path).thenReturn('path-1');
-      when(() => mockFile2.length()).thenAnswer((_) async => 100);
-      when(() => mockFile2.path).thenReturn('path-2');
-
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
-      when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset1, asset2]);
-      when(() => mockStorageRepo.getFileForAsset(asset1.id)).thenAnswer((_) async => mockFile1);
-      when(() => mockStorageRepo.getFileForAsset(asset2.id)).thenAnswer((_) async => mockFile2);
-
-      final hash = Uint8List.fromList(List.generate(20, (i) => i));
-      when(() => mockNativeApi.hashPaths(any())).thenAnswer((_) async => [hash]);
-      when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
-
-      await sut.hashAssets();
-
-      verify(() => mockNativeApi.hashPaths(['path-1'])).called(1);
-      verify(() => mockNativeApi.hashPaths(['path-2'])).called(1);
-      verify(() => mockAssetRepo.updateHashes(any())).called(2);
-    });
-
     test('batches by size limit', () async {
+      const batchSize = 2;
       final sut = HashService(
         localAlbumRepository: mockAlbumRepo,
         localAssetRepository: mockAssetRepo,
-        storageRepository: mockStorageRepo,
         nativeSyncApi: mockNativeApi,
-        batchSizeLimit: 80,
+        batchSize: batchSize,
       );
 
       final album = LocalAlbumStub.recent;
       final asset1 = LocalAssetStub.image1;
       final asset2 = LocalAssetStub.image2;
-      final mockFile1 = MockFile();
+      final asset3 = LocalAssetStub.image1.copyWith(id: 'image3', name: 'image3.jpg');
-      final mockFile2 = MockFile();
-      when(() => mockFile1.length()).thenAnswer((_) async => 100);
-      when(() => mockFile1.path).thenReturn('path-1');
-      when(() => mockFile2.length()).thenAnswer((_) async => 100);
-      when(() => mockFile2.path).thenReturn('path-2');
 
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
+      final capturedCalls = <List<String>>[];
-      when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset1, asset2]);
-      when(() => mockStorageRepo.getFileForAsset(asset1.id)).thenAnswer((_) async => mockFile1);
-      when(() => mockStorageRepo.getFileForAsset(asset2.id)).thenAnswer((_) async => mockFile2);
 
-      final hash = Uint8List.fromList(List.generate(20, (i) => i));
-      when(() => mockNativeApi.hashPaths(any())).thenAnswer((_) async => [hash]);
       when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
+      when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset1, asset2, asset3]);
+      when(() => mockNativeApi.hashAssets(any(), allowNetworkAccess: any(named: 'allowNetworkAccess'))).thenAnswer((
+        invocation,
+      ) async {
+        final assetIds = invocation.positionalArguments[0] as List<String>;
+        capturedCalls.add(List<String>.from(assetIds));
+        return assetIds.map((id) => HashResult(assetId: id, hash: '$id-hash')).toList();
+      });
 
       await sut.hashAssets();
 
-      verify(() => mockNativeApi.hashPaths(['path-1'])).called(1);
+      expect(capturedCalls.length, 2, reason: 'Should make exactly 2 calls to hashAssets');
-      verify(() => mockNativeApi.hashPaths(['path-2'])).called(1);
+      expect(capturedCalls[0], [asset1.id, asset2.id], reason: 'First call should batch the first two assets');
+      expect(capturedCalls[1], [asset3.id], reason: 'Second call should have the remaining asset');
+
       verify(() => mockAssetRepo.updateHashes(any())).called(2);
     });
 
@@ -206,27 +147,43 @@ void main() {
       final album = LocalAlbumStub.recent;
       final asset1 = LocalAssetStub.image1;
       final asset2 = LocalAssetStub.image2;
-      final mockFile1 = MockFile();
-      final mockFile2 = MockFile();
-      when(() => mockFile1.length()).thenAnswer((_) async => 100);
-      when(() => mockFile1.path).thenReturn('path-1');
-      when(() => mockFile2.length()).thenAnswer((_) async => 100);
-      when(() => mockFile2.path).thenReturn('path-2');
 
-      when(() => mockAlbumRepo.getAll(sortBy: sortBy)).thenAnswer((_) async => [album]);
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [album]);
       when(() => mockAlbumRepo.getAssetsToHash(album.id)).thenAnswer((_) async => [asset1, asset2]);
-      when(() => mockStorageRepo.getFileForAsset(asset1.id)).thenAnswer((_) async => mockFile1);
+      when(() => mockNativeApi.hashAssets([asset1.id, asset2.id], allowNetworkAccess: false)).thenAnswer(
-      when(() => mockStorageRepo.getFileForAsset(asset2.id)).thenAnswer((_) async => mockFile2);
+        (_) async => [
-
+          HashResult(assetId: asset1.id, hash: 'asset1-hash'),
-      final validHash = Uint8List.fromList(List.generate(20, (i) => i));
+          HashResult(assetId: asset2.id, error: 'Failed to hash asset2'),
-      when(() => mockNativeApi.hashPaths(['path-1', 'path-2'])).thenAnswer((_) async => [validHash, null]);
+        ],
-      when(() => mockAssetRepo.updateHashes(any())).thenAnswer((_) async => {});
+      );
 
       await sut.hashAssets();
 
-      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as List<LocalAsset>;
+      final captured = verify(() => mockAssetRepo.updateHashes(captureAny())).captured.first as Map<String, String>;
       expect(captured.length, 1);
-      expect(captured.first.id, asset1.id);
+      expect(captured[asset1.id], 'asset1-hash');
+    });
+
+    test('uses allowNetworkAccess based on album backup selection', () async {
+      final selectedAlbum = LocalAlbumStub.recent.copyWith(backupSelection: BackupSelection.selected);
+      final nonSelectedAlbum = LocalAlbumStub.recent.copyWith(id: 'album2', backupSelection: BackupSelection.excluded);
+      final asset1 = LocalAssetStub.image1;
+      final asset2 = LocalAssetStub.image2;
+
+      when(() => mockAlbumRepo.getBackupAlbums()).thenAnswer((_) async => [selectedAlbum, nonSelectedAlbum]);
+      when(() => mockAlbumRepo.getAssetsToHash(selectedAlbum.id)).thenAnswer((_) async => [asset1]);
+      when(() => mockAlbumRepo.getAssetsToHash(nonSelectedAlbum.id)).thenAnswer((_) async => [asset2]);
+      when(() => mockNativeApi.hashAssets(any(), allowNetworkAccess: any(named: 'allowNetworkAccess'))).thenAnswer((
+        invocation,
+      ) async {
+        final assetIds = invocation.positionalArguments[0] as List<String>;
+        return assetIds.map((id) => HashResult(assetId: id, hash: '$id-hash')).toList();
+      });
+
+      await sut.hashAssets();
+
+      verify(() => mockNativeApi.hashAssets([asset1.id], allowNetworkAccess: true)).called(1);
+      verify(() => mockNativeApi.hashAssets([asset2.id], allowNetworkAccess: false)).called(1);
     });
   });
 }