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

/// Full-screen WebView that loads the TWP phone page.
///
/// Handles:
/// - Microphone permission grants for WebRTC
/// - JavaScript bridge (TwpMobile channel) for native communication
/// - Session expiry detection (redirect to wp-login.php)
/// - Back button confirmation to prevent accidental exit
/// - Network error retry UI
class PhoneScreen extends StatefulWidget {
  final String serverUrl;
  final VoidCallback onLogout;
  final VoidCallback onSessionExpired;

  const PhoneScreen({
    super.key,
    required this.serverUrl,
    required this.onLogout,
    required this.onSessionExpired,
  });

  @override
  State<PhoneScreen> createState() => _PhoneScreenState();
}

class _PhoneScreenState extends State<PhoneScreen> with WidgetsBindingObserver {
  late final WebViewController _controller;
  late final PushNotificationService _pushService;
  bool _loading = true;
  bool _hasError = false;
  String? _errorMessage;
  bool _sessionExpired = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _pushService = PushNotificationService();
    _initWebView();
    _initPush();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  Future<void> _initPush() async {
    await _pushService.initialize();
  }

  void _initWebView() {
    _controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setUserAgent('TWPMobile/2.0 (Android; WebView)')
      ..setNavigationDelegate(
        NavigationDelegate(
          onPageStarted: (url) {
            if (mounted) {
              setState(() {
                _loading = true;
                _hasError = false;
              });
            }
            // Detect session expiry: if we get redirected to wp-login.php
            if (url.contains('/wp-login.php')) {
              _sessionExpired = true;
            }
          },
          onPageFinished: (url) {
            if (mounted) {
              setState(() => _loading = false);
            }
            if (_sessionExpired && url.contains('/wp-login.php')) {
              widget.onSessionExpired();
              return;
            }
            _sessionExpired = false;

            // Inject the FCM token into the page if available
            _injectFcmToken();
          },
          onWebResourceError: (error) {
            // Only handle main frame errors
            if (error.isForMainFrame ?? true) {
              if (mounted) {
                setState(() {
                  _loading = false;
                  _hasError = true;
                  _errorMessage = error.description;
                });
              }
            }
          },
          onNavigationRequest: (request) {
            // Allow all navigation within our server
            if (request.url.startsWith(widget.serverUrl)) {
              return NavigationDecision.navigate;
            }
            // Allow blob: and data: URLs (for downloads, etc.)
            if (request.url.startsWith('blob:') ||
                request.url.startsWith('data:')) {
              return NavigationDecision.navigate;
            }
            // Block external navigation
            return NavigationDecision.prevent;
          },
        ),
      )
      ..addJavaScriptChannel(
        'TwpMobile',
        onMessageReceived: _handleJsMessage,
      );

    // Configure Android-specific settings
    final androidController =
        _controller.platform as AndroidWebViewController;
    // Auto-grant microphone permission for WebRTC calls
    androidController.setOnPlatformPermissionRequest(
      (PlatformWebViewPermissionRequest request) {
        request.grant();
      },
    );
    // Allow media playback without user gesture (for ringtones)
    androidController.setMediaPlaybackRequiresUserGesture(false);

    // Load the phone page
    final phoneUrl = '${widget.serverUrl}/twp-phone/';
    _controller.loadRequest(Uri.parse(phoneUrl));
  }

  void _handleJsMessage(JavaScriptMessage message) {
    final msg = message.message;

    if (msg == 'onSessionExpired') {
      widget.onSessionExpired();
    } else if (msg == 'requestFcmToken') {
      _injectFcmToken();
    } else if (msg == 'onPageReady') {
      // Phone page loaded successfully
      _injectFcmToken();
    }
  }

  Future<void> _injectFcmToken() async {
    final token = _pushService.fcmToken;
    if (token != null) {
      // Send the FCM token to the web page via the TwpMobile bridge
      await _controller.runJavaScript(
        'if (window.TwpMobile && window.TwpMobile.setFcmToken) { window.TwpMobile.setFcmToken("$token"); }',
      );
    }
  }

  Future<void> _retry() async {
    setState(() {
      _hasError = false;
      _loading = true;
    });
    final phoneUrl = '${widget.serverUrl}/twp-phone/';
    await _controller.loadRequest(Uri.parse(phoneUrl));
  }

  Future<bool> _onWillPop() async {
    // Check if WebView can go back
    if (await _controller.canGoBack()) {
      await _controller.goBack();
      return false;
    }
    // Show confirmation dialog
    if (!mounted) return true;
    final result = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Exit'),
        content: const Text('Are you sure you want to exit the phone?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: const Text('Exit'),
          ),
        ],
      ),
    );
    return result ?? false;
  }

  void _showMenu() {
    showModalBottomSheet(
      context: context,
      builder: (context) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.refresh),
              title: const Text('Reload'),
              onTap: () {
                Navigator.pop(context);
                _controller.reload();
              },
            ),
            ListTile(
              leading: const Icon(Icons.logout),
              title: const Text('Logout'),
              onTap: () {
                Navigator.pop(context);
                _confirmLogout();
              },
            ),
          ],
        ),
      ),
    );
  }

  void _confirmLogout() async {
    final result = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Logout'),
        content: const Text(
            'This will clear your session. You will need to sign in again.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: const Text('Logout'),
          ),
        ],
      ),
    );

    if (result == true) {
      // Clear WebView cookies
      await WebViewCookieManager().clearCookies();
      widget.onLogout();
    }
  }

  @override
  Widget build(BuildContext context) {
    // ignore: deprecated_member_use
    return WillPopScope(
      onWillPop: _onWillPop,
      child: Scaffold(
        body: SafeArea(
          child: Stack(
            children: [
              if (!_hasError) WebViewWidget(controller: _controller),
              if (_hasError) _buildErrorView(),
              if (_loading && !_hasError)
                const Center(child: CircularProgressIndicator()),
            ],
          ),
        ),
        floatingActionButton: (!_hasError && !_loading)
            ? FloatingActionButton.small(
                onPressed: _showMenu,
                child: const Icon(Icons.more_vert),
              )
            : null,
      ),
    );
  }

  Widget _buildErrorView() {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Icon(Icons.wifi_off, size: 64, color: Colors.grey),
            const SizedBox(height: 16),
            const Text(
              'Connection Error',
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 8),
            Text(
              _errorMessage ?? 'Could not load the phone page.',
              textAlign: TextAlign.center,
              style: const TextStyle(color: Colors.grey),
            ),
            const SizedBox(height: 24),
            FilledButton.icon(
              onPressed: _retry,
              icon: const Icon(Icons.refresh),
              label: const Text('Retry'),
            ),
            const SizedBox(height: 12),
            TextButton(
              onPressed: widget.onLogout,
              child: const Text('Change Server'),
            ),
          ],
        ),
      ),
    );
  }
}