import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:webview_flutter_android/webview_flutter_android.dart';

import 'config/app_config.dart';

const _shellBackground = Color(0xFFF6FAFF);
const _shellAccent = Color(0xFF168CFF);
const _shellAccentDeep = Color(0xFF0066D9);
const _shellInk = Color(0xFF17233D);
const _shellSubText = Color(0xFF7C8AA3);
const _shellBrandingChannel =
    MethodChannel('io.openim.flutter.im_webview_app/shell_branding');
const _androidFilePickerChannel =
    MethodChannel('io.openim.flutter.openim/file_picker');
const _keyboardAnimationDuration = Duration(milliseconds: 250);

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setSystemUIOverlayStyle(
    const SystemUiOverlayStyle(
      statusBarColor: Colors.white,
      statusBarIconBrightness: Brightness.dark,
      systemNavigationBarColor: _shellBackground,
      systemNavigationBarIconBrightness: Brightness.dark,
    ),
  );
  runApp(const ImWebViewApp());
}

class ShellBranding {
  const ShellBranding({
    required this.appName,
    required this.appLogo,
  });

  static const fallback = ShellBranding(
    appName: AppConfig.appName,
    appLogo: AppConfig.appLogo,
  );

  final String appName;
  final String appLogo;

  static Future<ShellBranding> load() async {
    try {
      final data = await _shellBrandingChannel
          .invokeMapMethod<String, String>('getShellBranding');
      final appName = _trim(data?['appName']);
      final appLogo = _trim(data?['appLogo']);

      return ShellBranding(
        appName: appName.isNotEmpty ? appName : fallback.appName,
        appLogo: appLogo.isNotEmpty ? appLogo : fallback.appLogo,
      );
    } catch (_) {
      return fallback;
    }
  }

  static String _trim(String? value) => value?.trim() ?? '';
}

class ImWebViewApp extends StatelessWidget {
  const ImWebViewApp({
    super.key,
    this.shellBranding = ShellBranding.fallback,
  });

  final ShellBranding shellBranding;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: shellBranding.appName,
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: const Color(0xFF1F6FEB)),
        scaffoldBackgroundColor: Colors.white,
        useMaterial3: true,
      ),
      home: H5ShellPage(initialShellBranding: shellBranding),
    );
  }
}

class H5ShellPage extends StatefulWidget {
  const H5ShellPage({super.key, required this.initialShellBranding});

  final ShellBranding initialShellBranding;

  @override
  State<H5ShellPage> createState() => _H5ShellPageState();
}

class _H5ShellPageState extends State<H5ShellPage> {
  late final List<H5Line> _h5Lines;
  late final List<_H5LineWebViewSlot> _lineSlots;

  bool _shellBrandingLoaded = false;
  int _currentLineIndex = 0;
  double _lastKeyboardInset = 0;
  bool _lastKeyboardVisible = false;
  int _keyboardSyncToken = 0;
  late ShellBranding _shellBranding;

  H5Line get _currentLine => _h5Lines[_currentLineIndex];
  _H5LineWebViewSlot get _currentSlot => _lineSlots[_currentLineIndex];

  @override
  void initState() {
    super.initState();
    _h5Lines = AppConfig.h5Lines;
    _shellBranding = widget.initialShellBranding;
    _lineSlots = [
      for (var index = 0; index < _h5Lines.length; index += 1)
        _H5LineWebViewSlot(
          line: _h5Lines[index],
          controller: _buildController(index),
        ),
    ];
    unawaited(_ensureLineLoaded(_currentLineIndex));
  }

  WebViewController _buildController(int lineIndex) {
    final controller = WebViewController(
      onPermissionRequest: (request) {
        unawaited(_handleWebViewPermissionRequest(request));
      },
    )
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..addJavaScriptChannel(
        'OpenIMShell',
        onMessageReceived: (message) => _handleShellMessage(lineIndex, message),
      )
      ..addJavaScriptChannel(
        'OpenIMFlutterShell',
        onMessageReceived: (message) =>
            _handleFlutterShellMessage(lineIndex, message),
      )
      ..setBackgroundColor(Colors.white)
      ..setNavigationDelegate(
        NavigationDelegate(
          onProgress: (progress) {
            final slot = _lineSlots[lineIndex];
            final nextProgress = progress.clamp(0, 100).toInt();
            if (slot.progress == nextProgress) {
              return;
            }

            slot.progress = nextProgress;
            if (mounted &&
                lineIndex == _currentLineIndex &&
                slot.isAwaitingFirstScreen) {
              setState(() {});
            }
          },
          onPageStarted: (url) {
            final slot = _lineSlots[lineIndex];
            final shouldShowCover = !slot.hasPresentedFirstScreen;
            slot.shellCoverFallbackTimer?.cancel();
            slot.setCurrentUrl(url);
            slot.loadError = null;
            slot.progress = 0;
            slot.showShellCover = shouldShowCover;
            if (mounted && lineIndex == _currentLineIndex) {
              setState(() {});
            }
          },
          onPageFinished: (_) {
            unawaited(_handlePageFinished(lineIndex));
          },
          onUrlChange: (change) {
            _updateSlotUrl(lineIndex, change.url);
          },
          onWebResourceError: (error) {
            if (error.isForMainFrame ?? true) {
              final slot = _lineSlots[lineIndex];
              slot.shellCoverFallbackTimer?.cancel();
              slot.loadError = error.description;
              slot.showShellCover = false;
              if (mounted && lineIndex == _currentLineIndex) {
                setState(() {});
              }
            }
          },
          onNavigationRequest: _handleNavigationRequest,
        ),
      );

    _configurePlatformController(controller);
    return controller;
  }

  void _configurePlatformController(WebViewController controller) {
    final platformController = controller.platform;
    if (platformController is AndroidWebViewController) {
      unawaited(
        platformController.setOnShowFileSelector(_handleAndroidFileSelection),
      );
    }
  }

  Future<List<String>> _handleAndroidFileSelection(
    FileSelectorParams params,
  ) async {
    if (params.mode == FileSelectorMode.save) {
      return <String>[];
    }

    try {
      final result = await _androidFilePickerChannel.invokeListMethod<String>(
        'pickFiles',
        {
          'acceptTypes': params.acceptTypes,
          'allowMultiple': params.mode == FileSelectorMode.openMultiple,
        },
      );
      return result ?? <String>[];
    } catch (_) {
      return <String>[];
    }
  }

  @override
  void dispose() {
    for (final slot in _lineSlots) {
      slot.dispose();
    }
    super.dispose();
  }

  Future<void> _runJavaScriptSafely(int lineIndex, String source) async {
    try {
      await _lineSlots[lineIndex].controller.runJavaScript(source);
    } catch (_) {
      // WebView can reject JavaScript while a page is still navigating.
    }
  }

  Future<void> _handlePageFinished(int lineIndex) async {
    await _loadShellBrandingIfNeeded();
    await _syncShellBranding(lineIndex);
    await _installRouteObserver(lineIndex);
    await _syncKeyboardState(lineIndex);
    final slot = _lineSlots[lineIndex];
    slot.progress = 100;
    if (mounted &&
        lineIndex == _currentLineIndex &&
        slot.isAwaitingFirstScreen) {
      setState(() {});
    }
    if (slot.showShellCover) {
      _scheduleShellCoverFallback(lineIndex);
    } else {
      slot.shellCoverFallbackTimer?.cancel();
    }
  }

  void _handleShellMessage(int lineIndex, JavaScriptMessage message) {
    try {
      final decoded = jsonDecode(message.message);
      if (decoded is Map && decoded['type'] == 'first-screen-ready') {
        _hideShellCover(lineIndex);
      } else if (decoded is Map && decoded['type'] == 'route-changed') {
        _updateSlotUrl(lineIndex, decoded['url']?.toString());
      } else if (decoded is Map && decoded['type'] == 'keyboard-bridge-ready') {
        unawaited(_syncKeyboardState(lineIndex));
      }
    } catch (_) {
      if (message.message == 'first-screen-ready') {
        _hideShellCover(lineIndex);
      }
    }
  }

  void _handleFlutterShellMessage(int lineIndex, JavaScriptMessage message) {
    try {
      final decoded = jsonDecode(message.message);
      if (decoded is! Map) {
        return;
      }

      switch (decoded['type']) {
        case 'requestMediaPermissions':
          final requestId = decoded['requestId']?.toString();
          if (requestId == null || requestId.isEmpty) {
            return;
          }
          unawaited(
            _handleShellMediaPermissionRequest(
              lineIndex: lineIndex,
              requestId: requestId,
              audio: decoded['audio'] == true,
              video: decoded['video'] == true,
            ),
          );
        case 'openAppSettings':
          unawaited(openAppSettings());
        case 'keyboard-bridge-ready':
          unawaited(_syncKeyboardState(lineIndex));
      }
    } catch (_) {
      // Ignore malformed shell messages from web content.
    }
  }

  void _scheduleShellCoverFallback(int lineIndex) {
    final slot = _lineSlots[lineIndex];
    if (!slot.showShellCover) {
      return;
    }

    slot.shellCoverFallbackTimer?.cancel();
    slot.shellCoverFallbackTimer = Timer(
      const Duration(milliseconds: 1800),
      () => _hideShellCover(lineIndex),
    );
  }

  void _hideShellCover(int lineIndex) {
    final slot = _lineSlots[lineIndex];
    slot.shellCoverFallbackTimer?.cancel();
    if (slot.hasPresentedFirstScreen && !slot.showShellCover) {
      return;
    }

    slot.hasPresentedFirstScreen = true;
    slot.progress = 100;
    slot.showShellCover = false;
    if (!mounted || lineIndex != _currentLineIndex) {
      return;
    }

    setState(() {});
  }

  Future<void> _loadShellBrandingIfNeeded() async {
    if (_shellBrandingLoaded) {
      return;
    }

    final shellBranding = await ShellBranding.load();
    _shellBrandingLoaded = true;
    if (!mounted) {
      _shellBranding = shellBranding;
      return;
    }

    setState(() {
      _shellBranding = shellBranding;
    });
  }

  Future<void> _syncShellBranding(int lineIndex) {
    final payload = jsonEncode({
      'name': _shellBranding.appName,
      'logo': _shellBranding.appLogo,
    });
    final script = '''
(() => {
  try {
    const brand = $payload;
    window.sessionStorage.setItem('OPENIM_FLUTTER_SHELL_BRAND', JSON.stringify(brand));
    window.dispatchEvent(new CustomEvent('openim-shell-branding-updated', { detail: brand }));
  } catch (_) {}
})();
''';
    return _runJavaScriptSafely(lineIndex, script);
  }

  void _scheduleKeyboardStateSync(double bottomInset) {
    final nextInset = bottomInset < 1 ? 0.0 : bottomInset;
    final nextVisible = nextInset > 0;
    if ((nextInset - _lastKeyboardInset).abs() < 1 &&
        nextVisible == _lastKeyboardVisible) {
      return;
    }

    _lastKeyboardInset = nextInset;
    _lastKeyboardVisible = nextVisible;
    final token = ++_keyboardSyncToken;

    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (!mounted || token != _keyboardSyncToken) {
        return;
      }
      unawaited(_syncKeyboardState(_currentLineIndex));
    });
  }

  Future<void> _syncKeyboardState(int lineIndex) {
    if (lineIndex < 0 || lineIndex >= _lineSlots.length) {
      return Future<void>.value();
    }

    final payload = jsonEncode({
      'height': _lastKeyboardInset.round(),
      'visible': _lastKeyboardVisible,
      'duration': _keyboardAnimationDuration.inMilliseconds,
    });
    final script = '''
(() => {
  try {
    const keyboard = $payload;
    if (typeof window.__OPENIM_KEYBOARD_UPDATE__ === 'function') {
      window.__OPENIM_KEYBOARD_UPDATE__(keyboard);
      return;
    }
    if (typeof window.openIMKeyboardUpdate === 'function') {
      window.openIMKeyboardUpdate(keyboard);
    }
  } catch (_) {}
})();
''';
    return _runJavaScriptSafely(lineIndex, script);
  }

  Future<void> _installRouteObserver(int lineIndex) {
    const script = '''
(() => {
  try {
    const notify = () => {
      try {
        window.OpenIMShell.postMessage(JSON.stringify({
          type: 'route-changed',
          url: window.location.href
        }));
      } catch (_) {}
    };

    if (window.__OPENIM_FLUTTER_ROUTE_OBSERVER__) {
      window.__OPENIM_FLUTTER_ROUTE_OBSERVER__.notify();
      return;
    }

    const originalPushState = window.history.pushState;
    const originalReplaceState = window.history.replaceState;

    window.history.pushState = function() {
      const result = originalPushState.apply(this, arguments);
      notify();
      return result;
    };

    window.history.replaceState = function() {
      const result = originalReplaceState.apply(this, arguments);
      notify();
      return result;
    };

    window.addEventListener('popstate', notify);
    window.__OPENIM_FLUTTER_ROUTE_OBSERVER__ = { notify };
    notify();
  } catch (_) {}
})();
''';
    return _runJavaScriptSafely(lineIndex, script);
  }

  Future<void> _handleShellMediaPermissionRequest({
    required int lineIndex,
    required String requestId,
    required bool audio,
    required bool video,
  }) async {
    final result = await _requestNativeMediaPermissions(
      audio: audio,
      video: video,
    );
    final payload = jsonEncode({
      'requestId': requestId,
      'granted': result.granted,
      'permanentlyDenied': result.permanentlyDenied,
      'restricted': result.restricted,
    });
    final script = '''
(() => {
  try {
    window.dispatchEvent(new CustomEvent('openim-shell-media-permission-result', { detail: $payload }));
  } catch (_) {}
})();
''';
    await _runJavaScriptSafely(lineIndex, script);
  }

  Future<void> _handleWebViewPermissionRequest(
    WebViewPermissionRequest request,
  ) async {
    final requestsOnlySupportedMediaTypes = request.types.every(
      (type) =>
          type == WebViewPermissionResourceType.camera ||
          type == WebViewPermissionResourceType.microphone,
    );
    if (!requestsOnlySupportedMediaTypes) {
      await request.deny();
      return;
    }

    final result = await _requestNativeMediaPermissions(
      audio: request.types.contains(WebViewPermissionResourceType.microphone),
      video: request.types.contains(WebViewPermissionResourceType.camera),
    );

    if (result.granted) {
      await request.grant();
    } else {
      await request.deny();
    }
  }

  Future<_NativeMediaPermissionResult> _requestNativeMediaPermissions({
    required bool audio,
    required bool video,
  }) async {
    final permissions = <Permission>[
      if (audio) Permission.microphone,
      if (video) Permission.camera,
    ];

    if (permissions.isEmpty) {
      return const _NativeMediaPermissionResult(granted: true);
    }

    var granted = true;
    var permanentlyDenied = false;
    var restricted = false;

    for (final permission in permissions) {
      final status = await permission.request();
      granted = granted && status.isGranted;
      permanentlyDenied = permanentlyDenied || status.isPermanentlyDenied;
      restricted = restricted || status.isRestricted;
    }

    return _NativeMediaPermissionResult(
      granted: granted,
      permanentlyDenied: permanentlyDenied,
      restricted: restricted,
    );
  }

  void _updateSlotUrl(int lineIndex, String? url) {
    if (url == null || lineIndex < 0 || lineIndex >= _lineSlots.length) {
      return;
    }

    final slot = _lineSlots[lineIndex];
    final changed = slot.setCurrentUrl(url);
    if (changed && mounted && lineIndex == _currentLineIndex) {
      setState(() {});
    }
  }

  Future<void> _ensureLineLoaded(int lineIndex) async {
    final slot = _lineSlots[lineIndex];
    if (slot.hasLoadedInitialRequest) {
      return;
    }

    slot.hasLoadedInitialRequest = true;
    final shouldShowCover = !slot.hasPresentedFirstScreen;
    if (mounted) {
      slot.shellCoverFallbackTimer?.cancel();
      setState(() {
        slot.setCurrentUrl(slot.line.url);
        slot.loadError = null;
        slot.progress = 0;
        slot.showShellCover = shouldShowCover;
      });
    }

    await slot.controller.loadRequest(Uri.parse(slot.line.url));
  }

  Future<void> _reloadCurrentLine() async {
    final slot = _currentSlot;
    final shouldShowCover = !slot.hasPresentedFirstScreen;
    slot.shellCoverFallbackTimer?.cancel();
    if (mounted) {
      setState(() {
        slot.loadError = null;
        slot.progress = 0;
        slot.showShellCover = shouldShowCover;
      });
    }

    if (slot.hasLoadedInitialRequest) {
      await slot.controller.reload();
    } else {
      await _ensureLineLoaded(_currentLineIndex);
    }
  }

  Future<void> _loadLine(int index) async {
    final safeIndex = index < 0 || index >= _h5Lines.length ? 0 : index;
    if (mounted) {
      setState(() {
        _currentLineIndex = safeIndex;
      });
    }

    await _ensureLineLoaded(safeIndex);
    await _syncKeyboardState(safeIndex);
  }

  Widget _buildWebViewWidget(int index) {
    PlatformWebViewWidgetCreationParams params =
        PlatformWebViewWidgetCreationParams(
      controller: _lineSlots[index].controller.platform,
    );

    if (_lineSlots[index].controller.platform is AndroidWebViewController) {
      params = AndroidWebViewWidgetCreationParams
          .fromPlatformWebViewWidgetCreationParams(
        params,
        displayWithHybridComposition: true,
      );
    }

    return RepaintBoundary(
      child: WebViewWidget.fromPlatformCreationParams(
        key: ValueKey<int>(index),
        params: params,
      ),
    );
  }

  void _showLineSwitcher() {
    showModalBottomSheet<void>(
      context: context,
      useSafeArea: true,
      showDragHandle: true,
      backgroundColor: Colors.white,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (sheetContext) {
        return _LineSwitcherSheet(
          lines: _h5Lines,
          currentIndex: _currentLineIndex,
          onSelect: (index) {
            Navigator.of(sheetContext).pop();
            if (index != _currentLineIndex) {
              unawaited(_loadLine(index));
            }
          },
        );
      },
    );
  }

  Future<NavigationDecision> _handleNavigationRequest(
    NavigationRequest request,
  ) async {
    final uri = Uri.tryParse(request.url);
    if (uri == null) {
      return NavigationDecision.prevent;
    }

    const webSchemes = {'http', 'https', 'about', 'data'};
    if (webSchemes.contains(uri.scheme)) {
      return NavigationDecision.navigate;
    }

    try {
      await launchUrl(uri, mode: LaunchMode.externalApplication);
    } catch (_) {
      // Ignore unsupported custom schemes so the WebView does not navigate to
      // an error page.
    }
    return NavigationDecision.prevent;
  }

  Future<void> _handleBackNavigation() async {
    final controller = _currentSlot.controller;
    if (await controller.canGoBack()) {
      await controller.goBack();
    } else {
      await SystemNavigator.pop();
    }
  }

  @override
  Widget build(BuildContext context) {
    final currentSlot = _currentSlot;
    final topInset = MediaQuery.paddingOf(context).top;
    final bottomInset = MediaQuery.viewInsetsOf(context).bottom;
    _scheduleKeyboardStateSync(bottomInset);
    final showLineSwitch = !currentSlot.showShellCover &&
        currentSlot.loadError == null &&
        currentSlot.isLoginPage &&
        bottomInset == 0;
    final shouldPaintShellFallback =
        currentSlot.isAwaitingFirstScreen && currentSlot.loadError == null;

    return PopScope(
      canPop: false,
      onPopInvokedWithResult: (didPop, _) {
        if (!didPop) {
          unawaited(_handleBackNavigation());
        }
      },
      child: Scaffold(
        backgroundColor: Colors.white,
        body: Stack(
          children: [
            SafeArea(
              bottom: false,
              child: Stack(
                children: [
                  if (shouldPaintShellFallback)
                    Positioned.fill(
                      child: _ShellFallback(progress: currentSlot.progress),
                    ),
                  Positioned.fill(
                    child: IndexedStack(
                      index: _currentLineIndex,
                      children: [
                        for (var index = 0;
                            index < _lineSlots.length;
                            index += 1)
                          _buildWebViewWidget(index),
                      ],
                    ),
                  ),
                  if (currentSlot.showShellCover &&
                      !currentSlot.hasPresentedFirstScreen)
                    Positioned.fill(
                      child: IgnorePointer(
                        child: _ShellFallback(progress: currentSlot.progress),
                      ),
                    ),
                  if (!currentSlot.hasPresentedFirstScreen &&
                      !currentSlot.showShellCover &&
                      currentSlot.progress < 100)
                    LinearProgressIndicator(
                      value: currentSlot.progress == 0
                          ? null
                          : currentSlot.progress / 100,
                      minHeight: 2,
                    ),
                  if (currentSlot.loadError != null)
                    _ErrorPanel(
                      message: currentSlot.loadError!,
                      onRetry: () => unawaited(_reloadCurrentLine()),
                    ),
                  if (showLineSwitch)
                    Positioned(
                      left: 20,
                      right: 20,
                      bottom: MediaQuery.paddingOf(context).bottom + 14,
                      child: _LineSwitchBar(
                        currentLine: _currentLine,
                        onSwitch: _showLineSwitcher,
                      ),
                    ),
                ],
              ),
            ),
            Positioned(
              top: 0,
              left: 0,
              right: 0,
              height: topInset,
              child: ColoredBox(
                color:
                    shouldPaintShellFallback ? _shellBackground : Colors.white,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _NativeMediaPermissionResult {
  const _NativeMediaPermissionResult({
    required this.granted,
    this.permanentlyDenied = false,
    this.restricted = false,
  });

  final bool granted;
  final bool permanentlyDenied;
  final bool restricted;
}

class _H5LineWebViewSlot {
  _H5LineWebViewSlot({
    required this.line,
    required this.controller,
  });

  final H5Line line;
  final WebViewController controller;

  int progress = 0;
  String? loadError;
  bool showShellCover = true;
  bool hasPresentedFirstScreen = false;
  bool hasLoadedInitialRequest = false;
  bool isLoginPage = false;
  String? currentUrl;
  Timer? shellCoverFallbackTimer;

  bool get isAwaitingFirstScreen => !hasPresentedFirstScreen;

  bool setCurrentUrl(String url) {
    final nextIsLoginPage = AppConfig.isLoginPageUrl(url);
    if (currentUrl == url && isLoginPage == nextIsLoginPage) {
      return false;
    }

    currentUrl = url;
    isLoginPage = nextIsLoginPage;
    return true;
  }

  void dispose() {
    shellCoverFallbackTimer?.cancel();
  }
}

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

  final String message;
  final VoidCallback onRetry;

  @override
  Widget build(BuildContext context) {
    return ColoredBox(
      color: Colors.white,
      child: Center(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Icon(Icons.wifi_off_rounded, size: 44),
              const SizedBox(height: 16),
              const Text(
                '页面加载失败',
                style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
              ),
              const SizedBox(height: 8),
              Text(
                message,
                textAlign: TextAlign.center,
                style: Theme.of(context).textTheme.bodyMedium,
              ),
              const SizedBox(height: 20),
              FilledButton(
                onPressed: onRetry,
                child: const Text('重新加载'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _LineSwitchBar extends StatelessWidget {
  const _LineSwitchBar({
    required this.currentLine,
    required this.onSwitch,
  });

  final H5Line currentLine;
  final VoidCallback onSwitch;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 560),
        child: SizedBox(
          width: double.infinity,
          child: Material(
            color: Colors.white.withValues(alpha: 0.94),
            elevation: 8,
            shadowColor: const Color(0xFF0F4C81).withValues(alpha: 0.12),
            borderRadius: BorderRadius.circular(32),
            child: InkWell(
              onTap: onSwitch,
              borderRadius: BorderRadius.circular(32),
              child: Container(
                height: 64,
                padding: const EdgeInsets.symmetric(horizontal: 18),
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(32),
                  border: Border.all(color: const Color(0xFFE1EAF5)),
                ),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    const Icon(
                      Icons.sync_rounded,
                      size: 19,
                      color: _shellSubText,
                    ),
                    const SizedBox(width: 8),
                    const Text(
                      '当前: ',
                      style: TextStyle(
                        color: _shellSubText,
                        fontSize: 15,
                        height: 1.2,
                        fontWeight: FontWeight.w600,
                        letterSpacing: 0,
                      ),
                    ),
                    Flexible(
                      child: Text(
                        currentLine.label,
                        overflow: TextOverflow.ellipsis,
                        style: const TextStyle(
                          color: Color(0xFF17233D),
                          fontSize: 16,
                          height: 1.2,
                          fontWeight: FontWeight.w700,
                          letterSpacing: 0,
                        ),
                      ),
                    ),
                    const SizedBox(width: 12),
                    const Text(
                      '切换',
                      style: TextStyle(
                        color: _shellAccent,
                        fontSize: 15,
                        height: 1.2,
                        fontWeight: FontWeight.w700,
                        letterSpacing: 0,
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _LineSwitcherSheet extends StatelessWidget {
  const _LineSwitcherSheet({
    required this.lines,
    required this.currentIndex,
    required this.onSelect,
  });

  final List<H5Line> lines;
  final int currentIndex;
  final ValueChanged<int> onSelect;

  @override
  Widget build(BuildContext context) {
    final sheetHeight = MediaQuery.sizeOf(context).height * 0.58;
    final maxHeight = sheetHeight > 420 ? 420.0 : sheetHeight;

    return Padding(
      padding: const EdgeInsets.fromLTRB(20, 0, 20, 16),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '切换线路',
            style: TextStyle(
              color: Color(0xFF17233D),
              fontSize: 18,
              height: 1.2,
              fontWeight: FontWeight.w700,
              letterSpacing: 0,
            ),
          ),
          const SizedBox(height: 14),
          ConstrainedBox(
            constraints: BoxConstraints(maxHeight: maxHeight),
            child: ListView.separated(
              shrinkWrap: true,
              itemCount: lines.length,
              separatorBuilder: (context, index) => const SizedBox(height: 10),
              itemBuilder: (context, index) {
                final line = lines[index];
                final selected = index == currentIndex;

                return _LineOptionTile(
                  line: line,
                  selected: selected,
                  onTap: () => onSelect(index),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class _LineOptionTile extends StatelessWidget {
  const _LineOptionTile({
    required this.line,
    required this.selected,
    required this.onTap,
  });

  final H5Line line;
  final bool selected;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: selected ? const Color(0xFFEFF7FF) : Colors.white,
      borderRadius: BorderRadius.circular(8),
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(8),
        child: Container(
          constraints: const BoxConstraints(minHeight: 64),
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(8),
            border: Border.all(
              color: selected ? _shellAccent : const Color(0xFFE1EAF5),
            ),
          ),
          child: Row(
            children: [
              Icon(
                selected
                    ? Icons.radio_button_checked_rounded
                    : Icons.radio_button_unchecked_rounded,
                color: selected ? _shellAccent : _shellSubText,
                size: 22,
              ),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text(
                      line.label,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: const TextStyle(
                        color: Color(0xFF17233D),
                        fontSize: 16,
                        height: 1.2,
                        fontWeight: FontWeight.w700,
                        letterSpacing: 0,
                      ),
                    ),
                    const SizedBox(height: 4),
                    Text(
                      line.displayAddress,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: const TextStyle(
                        color: _shellSubText,
                        fontSize: 12,
                        height: 1.2,
                        fontWeight: FontWeight.w500,
                        letterSpacing: 0,
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(width: 8),
              const Icon(
                Icons.chevron_right_rounded,
                color: _shellSubText,
                size: 22,
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _ShellFallback extends StatelessWidget {
  const _ShellFallback({required this.progress});

  final int progress;

  @override
  Widget build(BuildContext context) {
    final clampedProgress = progress.clamp(0, 100).toDouble();
    final progressValue =
        progress <= 0 ? 0.28 : 0.22 + clampedProgress * 0.0072;

    return CustomPaint(
      painter: const _H5LoadingBackgroundPainter(),
      child: LayoutBuilder(
        builder: (context, constraints) {
          final markSize = (constraints.maxWidth * 0.34).clamp(116.0, 148.0);
          final contentTop = constraints.maxHeight * 0.28;
          final progressWidth =
              (constraints.maxWidth * 0.32).clamp(116.0, 152.0);

          return Align(
            alignment: Alignment.topCenter,
            child: Padding(
              padding: EdgeInsets.only(top: contentTop),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  _ShellMark(size: markSize),
                  SizedBox(height: markSize * 0.16),
                  const Text(
                    '心有回响',
                    style: TextStyle(
                      color: _shellInk,
                      fontSize: 24,
                      height: 1.2,
                      fontWeight: FontWeight.w700,
                      letterSpacing: 0,
                    ),
                  ),
                  const SizedBox(height: 8),
                  const Text(
                    '正在连接会话',
                    style: TextStyle(
                      color: _shellSubText,
                      fontSize: 12,
                      height: 1.2,
                      letterSpacing: 0,
                    ),
                  ),
                  const SizedBox(height: 30),
                  _H5LoadingProgress(
                    width: progressWidth,
                    value: progressValue.clamp(0.18, 0.96).toDouble(),
                  ),
                ],
              ),
            ),
          );
        },
      ),
    );
  }
}

class _ShellMark extends StatelessWidget {
  const _ShellMark({required this.size});

  final double size;

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      size: Size(size, size * 0.92),
      painter: const _BubbleCheckPainter(),
    );
  }
}

class _H5LoadingProgress extends StatelessWidget {
  const _H5LoadingProgress({required this.width, required this.value});

  final double width;
  final double value;

  @override
  Widget build(BuildContext context) {
    return ClipRRect(
      borderRadius: BorderRadius.circular(99),
      child: SizedBox(
        width: width,
        height: 4,
        child: Stack(
          fit: StackFit.expand,
          children: [
            const ColoredBox(color: Color(0xFFD9EAF8)),
            TweenAnimationBuilder<double>(
              tween: Tween<double>(end: value),
              duration: const Duration(milliseconds: 260),
              curve: Curves.easeOutCubic,
              builder: (context, animatedValue, _) {
                return FractionallySizedBox(
                  alignment: Alignment.centerLeft,
                  widthFactor: animatedValue,
                  child: const DecoratedBox(
                    decoration: BoxDecoration(
                      gradient: LinearGradient(
                        colors: [
                          Color(0xFF48D4C8),
                          _shellAccent,
                          _shellAccentDeep,
                        ],
                      ),
                    ),
                  ),
                );
              },
            ),
          ],
        ),
      ),
    );
  }
}

class _H5LoadingBackgroundPainter extends CustomPainter {
  const _H5LoadingBackgroundPainter();

  static const _sourceSize = Size(1080, 2400);

  @override
  void paint(Canvas canvas, Size size) {
    final scale =
        (size.width / _sourceSize.width) > (size.height / _sourceSize.height)
            ? size.width / _sourceSize.width
            : size.height / _sourceSize.height;
    final dx = (size.width - _sourceSize.width * scale) / 2;
    final dy = (size.height - _sourceSize.height * scale) / 2;

    canvas.save();
    canvas.translate(dx, dy);
    canvas.scale(scale);

    final pageRect = Offset.zero & _sourceSize;
    final pagePaint = Paint()
      ..shader = const LinearGradient(
        begin: Alignment.topCenter,
        end: Alignment.bottomCenter,
        colors: [
          Color(0xFFEAF7FF),
          Color(0xFFF8FCFF),
          Colors.white,
        ],
        stops: [0, 0.52, 1],
      ).createShader(pageRect);
    canvas.drawRect(pageRect, pagePaint);

    final topWave = Path()
      ..moveTo(0, 0)
      ..lineTo(1080, 0)
      ..lineTo(1080, 390)
      ..cubicTo(906, 332, 756, 330, 630, 386)
      ..cubicTo(478, 454, 332, 448, 214, 374)
      ..cubicTo(124, 318, 54, 310, 0, 350)
      ..close();
    canvas.drawPath(
      topWave,
      Paint()..color = const Color(0xFFDDF2FF).withValues(alpha: 0.72),
    );

    final bottomWave = Path()
      ..moveTo(1080, 1510)
      ..lineTo(1080, 2400)
      ..lineTo(0, 2400)
      ..lineTo(0, 1878)
      ..cubicTo(142, 1802, 294, 1786, 456, 1832)
      ..cubicTo(632, 1882, 786, 1832, 918, 1682)
      ..cubicTo(978, 1614, 1032, 1572, 1080, 1510)
      ..close();
    canvas.drawPath(
      bottomWave,
      Paint()..color = const Color(0xFFEFF9FF).withValues(alpha: 0.9),
    );

    final softPanelPaint = Paint()
      ..color = Colors.white.withValues(alpha: 0.42)
      ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 18);
    canvas.drawRRect(
      RRect.fromRectAndRadius(
        const Rect.fromLTWH(126, 688, 828, 136),
        const Radius.circular(42),
      ),
      softPanelPaint,
    );
    canvas.drawRRect(
      RRect.fromRectAndRadius(
        const Rect.fromLTWH(180, 1528, 720, 128),
        const Radius.circular(40),
      ),
      softPanelPaint,
    );

    final linePaint = Paint()
      ..color = const Color(0xFFB6D7F2).withValues(alpha: 0.32)
      ..strokeWidth = 2;
    for (var y = 470.0; y < 840; y += 72) {
      canvas.drawLine(Offset(130, y), Offset(950, y - 46), linePaint);
    }

    void drawMessageCard({
      required Rect rect,
      required Color color,
      required double alpha,
      required bool alignRight,
    }) {
      final cardPaint = Paint()..color = color.withValues(alpha: alpha);
      canvas.drawRRect(
        RRect.fromRectAndRadius(rect, const Radius.circular(44)),
        cardPaint,
      );

      final firstLineWidth = rect.width * (alignRight ? 0.48 : 0.56);
      final secondLineWidth = rect.width * 0.34;
      final x = alignRight ? rect.right - firstLineWidth - 44 : rect.left + 44;
      final lineY = rect.top + rect.height * 0.38;
      final messageLinePaint = Paint()
        ..color = const Color(0xFF9FC2DE).withValues(alpha: 0.38)
        ..strokeCap = StrokeCap.round
        ..strokeWidth = 12;
      canvas.drawLine(
        Offset(x, lineY),
        Offset(x + firstLineWidth, lineY),
        messageLinePaint,
      );
      canvas.drawLine(
        Offset(x, lineY + 34),
        Offset(x + secondLineWidth, lineY + 34),
        messageLinePaint,
      );
    }

    drawMessageCard(
      rect: const Rect.fromLTWH(96, 1008, 438, 118),
      color: Colors.white,
      alpha: 0.52,
      alignRight: false,
    );
    drawMessageCard(
      rect: const Rect.fromLTWH(548, 1160, 436, 118),
      color: const Color(0xFFE0F7F4),
      alpha: 0.56,
      alignRight: true,
    );

    canvas.restore();
  }

  @override
  bool shouldRepaint(covariant _H5LoadingBackgroundPainter oldDelegate) {
    return false;
  }
}

class _BubbleCheckPainter extends CustomPainter {
  const _BubbleCheckPainter();

  static const _viewBox = Size(420, 360);

  @override
  void paint(Canvas canvas, Size size) {
    final scale =
        (size.width / _viewBox.width) < (size.height / _viewBox.height)
            ? size.width / _viewBox.width
            : size.height / _viewBox.height;
    final dx = (size.width - _viewBox.width * scale) / 2;
    final dy = (size.height - _viewBox.height * scale) / 2;

    canvas.save();
    canvas.translate(dx, dy);
    canvas.scale(scale);

    final shadowPaint = Paint()
      ..color = const Color(0xFF026CD5).withValues(alpha: 0.18)
      ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 32);
    final backShadowPaint = Paint()
      ..color = const Color(0xFF0AAE9D).withValues(alpha: 0.12)
      ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 24);

    final backBubble = RRect.fromRectAndRadius(
      const Rect.fromLTWH(34, 42, 176, 124),
      const Radius.circular(54),
    );
    canvas.save();
    canvas.translate(0, 18);
    canvas.drawRRect(backBubble, backShadowPaint);
    canvas.restore();

    final backBubblePaint = Paint()
      ..shader = const LinearGradient(
        begin: Alignment.topLeft,
        end: Alignment.bottomRight,
        colors: [
          Color(0xFFE8FBF8),
          Color(0xFFAEECE4),
        ],
      ).createShader(backBubble.outerRect);
    canvas.drawRRect(backBubble, backBubblePaint);

    final frontRect = const Rect.fromLTWH(78, 86, 284, 190);
    final frontBubble = RRect.fromRectAndRadius(
      frontRect,
      const Radius.circular(72),
    );
    final frontTail = Path()
      ..moveTo(282, 250)
      ..cubicTo(316, 284, 352, 300, 388, 310)
      ..cubicTo(360, 284, 348, 252, 354, 222)
      ..close();

    canvas.save();
    canvas.translate(0, 22);
    canvas.drawRRect(frontBubble, shadowPaint);
    canvas.drawPath(frontTail, shadowPaint);
    canvas.restore();

    final bubblePaint = Paint()
      ..shader = const LinearGradient(
        begin: Alignment.topLeft,
        end: Alignment.bottomRight,
        colors: [
          Color(0xFFA8DDFF),
          _shellAccent,
          _shellAccentDeep,
        ],
        stops: [0, 0.48, 1],
      ).createShader(frontRect);
    canvas.drawPath(frontTail, bubblePaint);
    canvas.drawRRect(frontBubble, bubblePaint);

    final highlightPaint = Paint()
      ..shader = LinearGradient(
        begin: Alignment.topLeft,
        end: Alignment.bottomRight,
        colors: [
          Colors.white.withValues(alpha: 0.38),
          Colors.white.withValues(alpha: 0),
        ],
      ).createShader(frontRect);
    canvas.drawRRect(frontBubble, highlightPaint);

    final glyphPaint = Paint()
      ..color = Colors.white.withValues(alpha: 0.94)
      ..style = PaintingStyle.stroke
      ..strokeWidth = 22
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round;
    canvas.drawLine(const Offset(154, 154), const Offset(288, 154), glyphPaint);
    canvas.drawLine(const Offset(154, 204), const Offset(238, 204), glyphPaint);
    canvas.drawCircle(
      const Offset(306, 204),
      12,
      Paint()..color = Colors.white.withValues(alpha: 0.94),
    );

    canvas.restore();
  }

  @override
  bool shouldRepaint(covariant _BubbleCheckPainter oldDelegate) {
    return false;
  }
}