Implemented multi select interaction (#13)

mobile/lib/modules/home/models/home_page_state.model.dart

@@ -0,0 +1,66 @@
+import 'dart:convert';
+
+import 'package:collection/collection.dart';
+
+import 'package:immich_mobile/shared/models/immich_asset.model.dart';
+
+class HomePageState {
+  final bool isMultiSelectEnable;
+  final Set<ImmichAsset> selectedItems;
+  final Set<String> selectedDateGroup;
+  HomePageState({
+    required this.isMultiSelectEnable,
+    required this.selectedItems,
+    required this.selectedDateGroup,
+  });
+
+  HomePageState copyWith({
+    bool? isMultiSelectEnable,
+    Set<ImmichAsset>? selectedItems,
+    Set<String>? selectedDateGroup,
+  }) {
+    return HomePageState(
+      isMultiSelectEnable: isMultiSelectEnable ?? this.isMultiSelectEnable,
+      selectedItems: selectedItems ?? this.selectedItems,
+      selectedDateGroup: selectedDateGroup ?? this.selectedDateGroup,
+    );
+  }
+
+  Map<String, dynamic> toMap() {
+    return {
+      'isMultiSelectEnable': isMultiSelectEnable,
+      'selectedItems': selectedItems.map((x) => x.toMap()).toList(),
+      'selectedDateGroup': selectedDateGroup.toList(),
+    };
+  }
+
+  factory HomePageState.fromMap(Map<String, dynamic> map) {
+    return HomePageState(
+      isMultiSelectEnable: map['isMultiSelectEnable'] ?? false,
+      selectedItems: Set<ImmichAsset>.from(map['selectedItems']?.map((x) => ImmichAsset.fromMap(x))),
+      selectedDateGroup: Set<String>.from(map['selectedDateGroup']),
+    );
+  }
+
+  String toJson() => json.encode(toMap());
+
+  factory HomePageState.fromJson(String source) => HomePageState.fromMap(json.decode(source));
+
+  @override
+  String toString() =>
+      'HomePageState(isMultiSelectEnable: $isMultiSelectEnable, selectedItems: $selectedItems, selectedDateGroup: $selectedDateGroup)';
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    final setEquals = const DeepCollectionEquality().equals;
+
+    return other is HomePageState &&
+        other.isMultiSelectEnable == isMultiSelectEnable &&
+        setEquals(other.selectedItems, selectedItems) &&
+        setEquals(other.selectedDateGroup, selectedDateGroup);
+  }
+
+  @override
+  int get hashCode => isMultiSelectEnable.hashCode ^ selectedItems.hashCode ^ selectedDateGroup.hashCode;
+}