feat: manual stack assets (#4198)

mobile/lib/modules/home/models/selection_state.dart

@@ -0,0 +1,47 @@
+import 'package:immich_mobile/shared/models/asset.dart';
+
+class SelectionAssetState {
+  final bool hasRemote;
+  final bool hasLocal;
+  final bool hasMerged;
+
+  const SelectionAssetState({
+    this.hasRemote = false,
+    this.hasLocal = false,
+    this.hasMerged = false,
+  });
+
+  SelectionAssetState copyWith({
+    bool? hasRemote,
+    bool? hasLocal,
+    bool? hasMerged,
+  }) {
+    return SelectionAssetState(
+      hasRemote: hasRemote ?? this.hasRemote,
+      hasLocal: hasLocal ?? this.hasLocal,
+      hasMerged: hasMerged ?? this.hasMerged,
+    );
+  }
+
+  SelectionAssetState.fromSelection(Set<Asset> selection)
+      : hasLocal = selection.any((e) => e.storage == AssetState.local),
+        hasMerged = selection.any((e) => e.storage == AssetState.merged),
+        hasRemote = selection.any((e) => e.storage == AssetState.remote);
+
+  @override
+  String toString() =>
+      'SelectionAssetState(hasRemote: $hasRemote, hasMerged: $hasMerged, hasMerged: $hasMerged)';
+
+  @override
+  bool operator ==(covariant SelectionAssetState other) {
+    if (identical(this, other)) return true;
+
+    return other.hasRemote == hasRemote &&
+        other.hasLocal == hasLocal &&
+        other.hasMerged == hasMerged;
+  }
+
+  @override
+  int get hashCode =>
+      hasRemote.hashCode ^ hasLocal.hashCode ^ hasMerged.hashCode;
+}