import 'dart:convert';
import 'dart:developer';

import 'package:auto_route/auto_route.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:shared_preferences/shared_preferences.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 'package:webview_flutter_wkwebview/webview_flutter_wkwebview.dart';

import '../../../application/wallet/wallet_loader/wallet_loader_bloc.dart';
import '../../../common/constant/app_constant.dart';
import '../../../common/constant/local_storage_key.dart';
import '../../../common/theme/theme.dart';
import '../../../env.dart';
import '../../../injection.dart';
import '../../components/button/button.dart';
import '../../router/app_router.gr.dart';
import '../wallet/widgets/wallet_confirm_dialog.dart';

/// EnakGame di webview layar penuh: web game.enaklo.com yang menampilkan
/// daftar game, memulai session, memotong EnakCoin, dan menampilkan hadiah.
/// Aplikasi hanya memberi token lewat bridge (§8.3) dan tidak pernah
/// menaruhnya di URL.
@RoutePage()
class EnakGamePage extends StatefulWidget {
  const EnakGamePage({super.key});

  @override
  State<EnakGamePage> createState() => _EnakGamePageState();
}

class _EnakGamePageState extends State<EnakGamePage> {
  /// Game → aplikasi: JavaScript channel dengan pesan berupa JSON string.
  static const String _hostChannel = 'EnakGameHost';

  static const _nativeChannel = MethodChannel(
    'com.apskel.enaklocustomer/webview',
  );

  late final WebViewController _controller;

  /// Lewat notifier, bukan setState, supaya WebView tidak ikut di-rebuild
  /// setiap progres berubah.
  final ValueNotifier<int> _progress = ValueNotifier(0);
  bool _hasError = false;
  bool _isRelogging = false;
  bool _isExiting = false;

  String? get _token =>
      getIt<SharedPreferences>().getString(LocalStorageKey.token);

  @override
  void initState() {
    super.initState();
    _controller = WebViewController();
    _load();
  }

  @override
  void dispose() {
    _progress.dispose();
    super.dispose();
  }

  Future<void> _load() async {
    try {
      await _controller.setJavaScriptMode(JavaScriptMode.unrestricted);
      await _controller.setBackgroundColor(AppConstant.gameBackgroundColor);
      await _controller.setNavigationDelegate(
        NavigationDelegate(
          onProgress: (progress) => _progress.value = progress,
          onPageStarted: (_) {
            if (mounted && _hasError) setState(() => _hasError = false);
          },
          onWebResourceError: (error) {
            // Error sub-resource (gambar, script pihak ketiga) diabaikan.
            if (error.isForMainFrame == false) return;
            if (mounted) setState(() => _hasError = true);
          },
          onNavigationRequest: _onNavigationRequest,
        ),
      );
      // Bridge dipasang sebelum halaman dimuat.
      await _controller.addJavaScriptChannel(
        _hostChannel,
        onMessageReceived: _onMessage,
      );

      final platform = _controller.platform;
      if (platform is AndroidWebViewController) {
        await _enableOffscreenPreRaster(platform);
      }
      // Swipe dari tepi kiri di iOS untuk mundur di riwayat web.
      if (platform is WebKitWebViewController) {
        await platform.setAllowsBackForwardNavigationGestures(true);
      }

      await _controller.loadRequest(Uri.parse(AppConstant.gameUrl));
    } catch (e, s) {
      log('load', name: 'EnakGamePage', error: e, stackTrace: s);
      if (mounted) setState(() => _hasError = true);
    }
  }

  /// Daftar game di web di-scroll; tanpa pre-raster, Android WebView
  /// menggambar ulang bagian yang kembali masuk layar. Lihat `MainActivity.kt`.
  Future<void> _enableOffscreenPreRaster(
    AndroidWebViewController platform,
  ) async {
    try {
      await _nativeChannel.invokeMethod('enableOffscreenPreRaster', {
        'webViewId': platform.webViewIdentifier,
      });
    } on PlatformException catch (e, s) {
      log('enableOffscreenPreRaster', error: e, stackTrace: s);
    }
  }

  void _onMessage(JavaScriptMessage message) {
    final Object? decoded;
    try {
      decoded = jsonDecode(message.message);
    } on FormatException {
      return;
    }
    if (decoded is! Map) return;

    switch (decoded['type']) {
      case 'ready':
        _sendInit();
      case 'token_expired':
        _relogin();
      case 'balance_changed':
        final coinBalance = decoded['coin_balance'];
        if (coinBalance is num) {
          context.read<WalletLoaderBloc>().add(
            WalletLoaderEvent.coinBalanceUpdated(coinBalance.toInt()),
          );
        }
      case 'close':
        if (!_isRelogging) _exit();
    }
    // Tipe lain diabaikan.
  }

  /// Tanpa `game_id`: game dipilih customer di web, bukan di aplikasi.
  void _sendInit() {
    final token = _token;
    if (token == null) {
      _relogin();
      return;
    }
    _send({
      'type': 'init',
      'api_base_url': '${getIt<Env>().baseUrl}/api/v1',
      'token': token,
    });
  }

  /// Aplikasi → game: `window.enakGame.receive('<json>')`.
  Future<void> _send(Map<String, Object?> message) async {
    // Encode dua kali: JSON pesan dijadikan string literal JavaScript.
    final argument = jsonEncode(jsonEncode(message));
    try {
      await _controller.runJavaScript(
        'window.enakGame && window.enakGame.receive($argument);',
      );
    } catch (e) {
      // Pesan berisi token: jangan ikut dicatat.
      log('send ${message['type']} failed', name: 'EnakGamePage');
    }
  }

  /// Belum ada refresh token: customer login ulang, lalu token baru dikirim
  /// ke game. Bila batal, game ditutup.
  Future<void> _relogin() async {
    if (_isRelogging || _isExiting) return;
    _isRelogging = true;

    final proceed = await showWalletConfirmDialog(
      context,
      title: 'Sesi berakhir',
      message: 'Masuk lagi untuk melanjutkan permainan.',
      confirmLabel: 'Masuk',
    );
    final loggedIn =
        proceed &&
        mounted &&
        await context.router.push<bool>(LoginRoute(returnAfterLogin: true)) ==
            true;

    _isRelogging = false;
    if (!mounted) return;

    final token = _token;
    if (loggedIn && token != null) {
      _send({'type': 'token', 'token': token});
    } else {
      _exit();
    }
  }

  /// Menutup game lalu memuat ulang saldo, karena EnakCoin bisa berubah
  /// selama main.
  void _exit() {
    if (_isExiting) return;
    _isExiting = true;
    context.read<WalletLoaderBloc>().add(const WalletLoaderEvent.fetched());

    // Dialog yang masih terbuka (mis. konfirmasi keluar) ikut ditutup.
    final navigator = Navigator.of(context);
    final route = ModalRoute.of(context);
    navigator.popUntil((r) => r == route);
    navigator.pop();
  }

  /// Tombol back Android mundur di riwayat web dulu. Di halaman pertama,
  /// game tidak langsung ditutup: minta konfirmasi.
  Future<void> _onPopInvoked(bool didPop, Object? result) async {
    if (didPop || _isExiting) return;
    if (_hasError) {
      _exit();
      return;
    }
    if (await _controller.canGoBack()) {
      await _controller.goBack();
      return;
    }
    if (!mounted) return;

    final leave = await showWalletConfirmDialog(
      context,
      title: 'Keluar dari game?',
      message: 'EnakCoin yang sudah dipakai untuk main tidak kembali.',
      confirmLabel: 'Keluar',
    );
    if (leave && mounted) _exit();
  }

  /// Skema selain http/https (tel:, mailto:, whatsapp:, intent:) diserahkan
  /// ke aplikasi luar karena WebView tidak bisa membukanya.
  Future<NavigationDecision> _onNavigationRequest(
    NavigationRequest request,
  ) async {
    final uri = Uri.tryParse(request.url);
    if (uri == null || uri.scheme == 'http' || uri.scheme == 'https') {
      return NavigationDecision.navigate;
    }

    await launchUrl(uri, mode: LaunchMode.externalApplication);
    return NavigationDecision.prevent;
  }

  void _reload() {
    setState(() => _hasError = false);
    _controller.reload();
  }

  @override
  Widget build(BuildContext context) {
    return AnnotatedRegion<SystemUiOverlayStyle>(
      value:
          (_hasError ? SystemUiOverlayStyle.dark : SystemUiOverlayStyle.light)
              .copyWith(statusBarColor: Colors.transparent),
      child: PopScope(
        canPop: false,
        onPopInvokedWithResult: _onPopInvoked,
        child: Scaffold(
          backgroundColor: AppConstant.gameBackgroundColor,
          // WebView tetap terpasang saat error, supaya "Coba lagi" tidak
          // membuat ulang native view-nya.
          body: Stack(
            children: [
              _buildWebView(),
              Positioned(
                top: MediaQuery.paddingOf(context).top,
                left: 0,
                right: 0,
                child: _buildProgress(),
              ),
              if (_hasError) Positioned.fill(child: _buildError()),
            ],
          ),
        ),
      ),
    );
  }

  /// Android memakai Hybrid Composition: WebView digambar langsung oleh
  /// Android, jauh lebih lancar untuk game yang terus beranimasi.
  Widget _buildWebView() {
    final platform = _controller.platform;
    return WebViewWidget.fromPlatformCreationParams(
      params: platform is AndroidWebViewController
          ? AndroidWebViewWidgetCreationParams(
              controller: platform,
              displayWithHybridComposition: true,
            )
          : PlatformWebViewWidgetCreationParams(controller: platform),
    );
  }

  Widget _buildProgress() {
    return ValueListenableBuilder<int>(
      valueListenable: _progress,
      builder: (context, progress, _) => progress < 100 && !_hasError
          ? LinearProgressIndicator(
              value: progress / 100,
              minHeight: 2,
              color: AppColor.primary,
              backgroundColor: AppColor.primaryWithOpacity(0.1),
            )
          : const SizedBox(height: 2),
    );
  }

  Widget _buildError() {
    return ColoredBox(
      color: AppColor.white,
      child: SafeArea(
        child: Stack(
          children: [
            Center(
              child: Padding(
                padding: const EdgeInsets.all(24),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    const Icon(
                      Icons.wifi_off,
                      size: 56,
                      color: AppColor.textSecondary,
                    ),
                    const SizedBox(height: 16),
                    Text(
                      'Game tidak bisa dimuat. Periksa koneksi internet kamu.',
                      style: AppStyle.md,
                      textAlign: TextAlign.center,
                    ),
                    const SizedBox(height: 16),
                    AppOutlineButton(
                      title: 'Coba lagi',
                      width: 160,
                      onPressed: _reload,
                    ),
                  ],
                ),
              ),
            ),
            Positioned(
              top: 4,
              left: 4,
              child: IconButton(
                icon: const Icon(Icons.close),
                tooltip: 'Tutup',
                onPressed: _exit,
              ),
            ),
          ],
        ),
      ),
    );
  }
}