テーマをインストールできるように

lib/providers.dart

@@ -4,6 +4,7 @@ import 'package:file/local.dart';
 import 'package:flutter/widgets.dart';
 import 'package:miria/model/account.dart';
 import 'package:miria/model/acct.dart';
+import 'package:miria/model/color_theme.dart';
 import 'package:miria/model/tab_setting.dart';
 import 'package:miria/repository/account_repository.dart';
 import 'package:miria/repository/account_settings_repository.dart';
@@ -14,6 +15,7 @@ import 'package:miria/repository/favorite_repository.dart';
 import 'package:miria/repository/general_settings_repository.dart';
 import 'package:miria/repository/hybrid_timeline_repository.dart';
 import 'package:miria/repository/import_export_repository.dart';
+import 'package:miria/repository/color_theme_repository.dart';
 import 'package:miria/repository/main_stream_repository.dart';
 import 'package:miria/repository/global_time_line_repository.dart';
 import 'package:miria/repository/home_time_line_repository.dart';
@@ -266,3 +268,13 @@ final misskeyServerListNotifierProvider = AsyncNotifierProvider.autoDispose<
 );
 
 final cacheManagerProvider = Provider<BaseCacheManager?>((ref) => null);
+
+final colorThemeRepositoryProvider =
+    NotifierProvider<ColorThemeRepository, List<ColorTheme>>(
+  ColorThemeRepository.new,
+);
+
+final installedThemeCodeRepositoryProvider =
+    NotifierProvider<InstalledThemeCodeRepository, List<String>>(
+  InstalledThemeCodeRepository.new,
+);

lib/repository/color_theme_repository.dart

@@ -0,0 +1,88 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:json5/json5.dart';
+import 'package:miria/model/color_theme.dart';
+import 'package:miria/model/misskey_theme.dart';
+import 'package:miria/providers.dart';
+import 'package:miria/view/common/error_dialog_handler.dart';
+import 'package:miria/view/themes/built_in_color_themes.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class ColorThemeRepository extends Notifier<List<ColorTheme>> {
+  @override
+  List<ColorTheme> build() {
+    final codes = ref.watch(installedThemeCodeRepositoryProvider);
+    return [
+      ...builtInColorThemes,
+      ...codes.map((code) {
+        try {
+          return ColorTheme.misskey(
+            MisskeyTheme.fromJson(json5Decode(code) as Map<String, dynamic>),
+          );
+        } catch (e) {
+          return null;
+        }
+      }).nonNulls,
+    ];
+  }
+
+  Future<void> addTheme(String code) async {
+    final ColorTheme theme;
+    try {
+      theme = ColorTheme.misskey(
+        MisskeyTheme.fromJson(json5Decode(code) as Map<String, dynamic>),
+      );
+    } catch (e) {
+      throw SpecifiedException("テーマの形式が間違っています");
+    }
+    if (state.any((element) => element.id == theme.id)) {
+      throw SpecifiedException("このテーマは既にインストールされています");
+    }
+
+    await ref
+        .read(installedThemeCodeRepositoryProvider.notifier)
+        .addTheme(code);
+  }
+
+  Future<void> removeTheme(String id) async {
+    await ref
+        .read(installedThemeCodeRepositoryProvider.notifier)
+        .removeTheme(id);
+  }
+}
+
+class InstalledThemeCodeRepository extends Notifier<List<String>> {
+  final prefsKey = "themes";
+
+  @override
+  List<String> build() {
+    Future(load);
+    return [];
+  }
+
+  Future<void> load() async {
+    final prefs = await SharedPreferences.getInstance();
+    final themes = prefs.getStringList(prefsKey);
+    if (themes == null) {
+      return;
+    }
+    state = themes;
+  }
+
+  Future<void> addTheme(String code) async {
+    final prefs = await SharedPreferences.getInstance();
+    final codes = prefs.getStringList(prefsKey) ?? [];
+    codes.add(code);
+    await prefs.setStringList(prefsKey, codes);
+    state = codes;
+  }
+
+  Future<void> removeTheme(String id) async {
+    final prefs = await SharedPreferences.getInstance();
+    final codes = prefs.getStringList(prefsKey);
+    codes!.removeWhere(
+      (code) => (json5Decode(code) as Map<String, dynamic>)["id"] == id,
+    );
+    await prefs.setStringList(prefsKey, codes);
+    state = codes;
+  }
+}

lib/router/app_router.dart

@@ -25,6 +25,7 @@ import 'package:miria/view/photo_edit_page/photo_edit_page.dart';
 import 'package:miria/view/settings_page/account_settings_page/account_list.dart';
 import 'package:miria/view/settings_page/app_info_page/app_info_page.dart';
 import 'package:miria/view/settings_page/general_settings_page/general_settings_page.dart';
+import 'package:miria/view/settings_page/general_settings_page/installed_themes_page.dart';
 import 'package:miria/view/settings_page/import_export_page/import_export_page.dart';
 import 'package:miria/view/settings_page/tab_settings_page/tab_settings_list_page.dart';
 import 'package:miria/view/several_account_settings_page/hard_mute_page/hard_mute_page.dart';
@@ -97,5 +98,6 @@ class AppRouter extends _$AppRouter {
     AutoRoute(page: SharingAccountSelectRoute.page),
     // きしょ……
     AutoRoute(page: MisskeyRouteRoute.page),
+    AutoRoute(page: InstalledThemesRoute.page),
   ];
 }