feat(mobile): drift map page

mobile/lib/presentation/widgets/map/map.state.dart

@@ -0,0 +1,58 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:immich_mobile/presentation/widgets/map/marker_build.dart';
+import 'package:immich_mobile/providers/infrastructure/map.provider.dart';
+import 'package:maplibre_gl/maplibre_gl.dart';
+
+class MapState {
+  final LatLngBounds bounds;
+
+  const MapState({required this.bounds});
+
+  @override
+  bool operator ==(covariant MapState other) {
+    return bounds == other.bounds;
+  }
+
+  @override
+  int get hashCode => bounds.hashCode;
+
+  MapState copyWith({LatLngBounds? bounds}) {
+    return MapState(bounds: bounds ?? this.bounds);
+  }
+}
+
+class MapStateNotifier extends Notifier<MapState> {
+  MapStateNotifier();
+
+  void setBounds(LatLngBounds bounds) {
+    state = state.copyWith(bounds: bounds);
+  }
+
+  @override
+  MapState build() => MapState(
+        // TODO: set default bounds
+        bounds: LatLngBounds(
+          northeast: const LatLng(0, 0),
+          southwest: const LatLng(0, 0),
+        ),
+      );
+}
+
+// This provider watches the markers from the map service and serves the markers.
+// It should be used only after the map service provider is overridden
+final mapMarkerProvider =
+    StreamProvider.family<Map<String, dynamic>, LatLngBounds>(
+  (ref, bounds) async* {
+    final mapService = ref.watch(mapServiceProvider);
+    yield* mapService.watchMarkers(bounds).map((markers) {
+      return MarkerBuilder(
+        markers: markers,
+      ).generate();
+    });
+  },
+  dependencies: [mapServiceProvider],
+);
+
+final mapStateProvider = NotifierProvider<MapStateNotifier, MapState>(
+  MapStateNotifier.new,
+);