refactor(mobile): services and providers (#9232)

* refactor(mobile): services and provider

* providers

mobile/lib/providers/image/immich_local_thumbnail_provider.dart

@@ -0,0 +1,92 @@
+import 'dart:async';
+import 'dart:ui' as ui;
+
+import 'package:cached_network_image/cached_network_image.dart';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/painting.dart';
+import 'package:immich_mobile/entities/asset.entity.dart';
+import 'package:photo_manager/photo_manager.dart';
+
+/// The local image provider for an asset
+/// Only viable
+class ImmichLocalThumbnailProvider
+    extends ImageProvider<ImmichLocalThumbnailProvider> {
+  final Asset asset;
+  final int height;
+  final int width;
+
+  ImmichLocalThumbnailProvider({
+    required this.asset,
+    this.height = 256,
+    this.width = 256,
+  }) : assert(asset.local != null, 'Only usable when asset.local is set');
+
+  /// Converts an [ImageProvider]'s settings plus an [ImageConfiguration] to a key
+  /// that describes the precise image to load.
+  @override
+  Future<ImmichLocalThumbnailProvider> obtainKey(
+    ImageConfiguration configuration,
+  ) {
+    return SynchronousFuture(this);
+  }
+
+  @override
+  ImageStreamCompleter loadImage(
+    ImmichLocalThumbnailProvider key,
+    ImageDecoderCallback decode,
+  ) {
+    final chunkEvents = StreamController<ImageChunkEvent>();
+    return MultiImageStreamCompleter(
+      codec: _codec(key.asset, decode, chunkEvents),
+      scale: 1.0,
+      chunkEvents: chunkEvents.stream,
+      informationCollector: () sync* {
+        yield ErrorDescription(asset.fileName);
+      },
+    );
+  }
+
+  // Streams in each stage of the image as we ask for it
+  Stream<ui.Codec> _codec(
+    Asset key,
+    ImageDecoderCallback decode,
+    StreamController<ImageChunkEvent> chunkEvents,
+  ) async* {
+    // Load a small thumbnail
+    final thumbBytes = await asset.local?.thumbnailDataWithSize(
+      const ThumbnailSize.square(32),
+      quality: 75,
+    );
+    if (thumbBytes != null) {
+      final buffer = await ui.ImmutableBuffer.fromUint8List(thumbBytes);
+      final codec = await decode(buffer);
+      yield codec;
+    } else {
+      debugPrint("Loading thumb for ${asset.fileName} failed");
+    }
+
+    final normalThumbBytes =
+        await asset.local?.thumbnailDataWithSize(ThumbnailSize(width, height));
+    if (normalThumbBytes == null) {
+      throw StateError(
+        "Loading thumb for local photo ${asset.fileName} failed",
+      );
+    }
+    final buffer = await ui.ImmutableBuffer.fromUint8List(normalThumbBytes);
+    final codec = await decode(buffer);
+    yield codec;
+
+    chunkEvents.close();
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (other is! ImmichLocalThumbnailProvider) return false;
+    if (identical(this, other)) return true;
+    return asset == other.asset;
+  }
+
+  @override
+  int get hashCode => asset.hashCode;
+}