import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'config.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  // 全面屏：内容延伸到状态栏/导航栏之下，刘海与手势区交给 SafeArea 处理
  await SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
  runApp(const DshApp());
}

class DshApp extends StatelessWidget {
  const DshApp({super.key});

  @override
  Widget build(BuildContext context) {
    return AnnotatedRegion<SystemUiOverlayStyle>(
      // 站点为深色主题：状态栏透明、图标反白
      value: const SystemUiOverlayStyle(
        statusBarColor: Colors.transparent,
        statusBarIconBrightness: Brightness.light,
        systemNavigationBarColor: Colors.transparent,
        systemNavigationBarIconBrightness: Brightness.light,
      ),
      child: MaterialApp(
        title: 'DSH 工作台',
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          useMaterial3: true,
          colorScheme: ColorScheme.fromSeed(
            seedColor: const Color(kThemeColorValue),
            brightness: Brightness.dark,
          ),
          scaffoldBackgroundColor: const Color(kThemeColorValue),
        ),
        home: const HomePage(),
      ),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  MethodChannel? _channel;
  bool _loading = true;
  String? _loadError;

  Future<void> _onViewCreated(int id) async {
    final channel = MethodChannel('dsh.workbench/gecko/$id');
    _channel = channel;
    channel.setMethodCallHandler((call) async {
      if (!mounted) return;
      switch (call.method) {
        case 'onPageStarted':
          setState(() {
            _loading = true;
            _loadError = null;
          });
        case 'onPageFinished':
          setState(() => _loading = false);
        case 'onLoadError':
          setState(() {
            _loading = false;
            _loadError = call.arguments as String? ?? '页面加载失败';
          });
        case 'onDownloadError':
          ScaffoldMessenger.of(context)
              .showSnackBar(SnackBar(content: Text('下载失败：${call.arguments}')));
      }
    });
    await _invoke('load');
  }

  Future<T?> _invoke<T>(String method) async {
    try {
      return await _channel?.invokeMethod<T>(method);
    } on PlatformException catch (error) {
      if (mounted) {
        setState(() {
          _loading = false;
          _loadError = error.message ?? '浏览器启动失败';
        });
      }
      return null;
    }
  }

  Future<void> _onPopInvoked(bool didPop, Object? result) async {
    if (didPop) return;
    if (await _invoke<bool>('goBack') == false && mounted) {
      await SystemNavigator.pop();
    }
  }

  void _retry() {
    setState(() {
      _loadError = null;
      _loading = true;
    });
    unawaited(_invoke<void>('reload'));
  }

  @override
  void dispose() {
    _channel?.setMethodCallHandler(null);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return PopScope(
      canPop: false,
      onPopInvokedWithResult: _onPopInvoked,
      child: Scaffold(
        backgroundColor: const Color(kThemeColorValue),
        body: SafeArea(
          child: Stack(
            children: [
              AndroidView(
                viewType: 'dsh.workbench/gecko',
                creationParams: const {'url': kSiteUrl},
                creationParamsCodec: const StandardMessageCodec(),
                onPlatformViewCreated: _onViewCreated,
              ),
              if (_loadError != null)
                _ErrorView(message: _loadError!, onRetry: _retry)
              else if (_loading)
                const _LoadingView(),
            ],
          ),
        ),
      ),
    );
  }
}

class _LoadingView extends StatelessWidget {
  const _LoadingView();

  @override
  Widget build(BuildContext context) {
    return const ColoredBox(
      color: Color(kThemeColorValue),
      child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            CircularProgressIndicator(color: Colors.white70),
            SizedBox(height: 16),
            Text('正在加载…', style: TextStyle(color: Colors.white70)),
          ],
        ),
      ),
    );
  }
}

class _ErrorView extends StatelessWidget {
  const _ErrorView({required this.message, required this.onRetry});

  final String message;
  final VoidCallback onRetry;

  @override
  Widget build(BuildContext context) {
    return ColoredBox(
      color: const Color(kThemeColorValue),
      child: Center(
        child: Padding(
          padding: const EdgeInsets.all(32),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Icon(Icons.cloud_off, size: 56, color: Colors.white54),
              const SizedBox(height: 16),
              const Text(
                '无法连接到服务器',
                style: TextStyle(color: Colors.white, fontSize: 16),
              ),
              const SizedBox(height: 8),
              Text(
                message,
                textAlign: TextAlign.center,
                maxLines: 3,
                overflow: TextOverflow.ellipsis,
                style: const TextStyle(color: Colors.white38, fontSize: 12),
              ),
              const SizedBox(height: 20),
              FilledButton.icon(
                onPressed: onRetry,
                icon: const Icon(Icons.refresh),
                label: const Text('重试'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}