feat: flutter ui integration

ui/flutter/lib/setting/setting.dart

@@ -0,0 +1,76 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:external_path/external_path.dart';
+import 'package:flutter/material.dart';
+import 'package:get/get.dart';
+import 'package:gopeed/api/api.dart';
+import 'package:path_provider/path_provider.dart';
+
+import '../api/model/server_config.dart';
+import '../util/util.dart';
+
+class Setting {
+  late String host;
+  late int port;
+  late int connections;
+  late String downloadDir;
+  late ThemeMode themeMode;
+
+  Setting({
+    required this.host,
+    required this.port,
+    required this.connections,
+    required this.downloadDir,
+    required this.themeMode,
+  });
+
+  // singleton pattern
+  static Setting? _instance;
+
+  static Setting get instance {
+    _instance ??= Setting._internal();
+    return _instance!;
+  }
+
+  Setting._internal();
+
+  Future<void> load() async {
+    final config = await getConfig();
+    host = config.host;
+    port = config.port;
+    connections = config.connections;
+    downloadDir = config.downloadDir;
+    final themeMode = config.extra?['themeMode'];
+    if (themeMode == null) {
+      this.themeMode = ThemeMode.system;
+    } else {
+      this.themeMode = ThemeMode.values.byName(themeMode);
+    }
+
+    if (Platform.isAndroid) {
+      downloadDir =
+      '${await ExternalPath.getExternalStoragePublicDirectory(ExternalPath.DIRECTORY_DOWNLOADS)}/com.gopeed';
+      return;
+    }
+
+    if (downloadDir.isEmpty) {
+      if (Util.isDesktop()) {
+        downloadDir = (await getDownloadsDirectory())!.path;
+      }
+    }
+  }
+
+  Future<void> save() async {
+    final config = ServerConfig(
+      host: host,
+      port: port,
+      connections: connections,
+      downloadDir: downloadDir,
+      extra: {
+        'themeMode': themeMode.name,
+      },
+    );
+    await putConfig(config);
+  }
+}