import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_login_yandex/flutter_login_yandex.dart';
import 'package:eatvio_app/core/app_router.dart';
import 'package:eatvio_app/core/env_config.dart';
import 'package:vk_id/vk_id.dart';
import 'package:webview_flutter/webview_flutter.dart';

class VkAuthResult {
  VkAuthResult({required this.accessToken, this.refreshToken, this.userId, this.firstName, this.lastName, this.email, this.phone, this.gender, this.birthDate});

  final String accessToken;
  final String? refreshToken;
  final String? userId;
  final String? firstName;
  final String? lastName;
  final String? email;
  final String? phone;
  final String? gender;
  final String? birthDate;
}

class SocialAuthFacade {
  static Future<String?> signInWithVk({required BuildContext context}) async {
    final result = await signInWithVkAndFetchProfile(context: context);
    return result?.accessToken;
  }

  static Future<VkAuthResult?> signInWithVkAndFetchProfile({required BuildContext context}) async {
    final clientIdStr = EnvConfig.vkClientId.trim();
    if (clientIdStr.isEmpty) {
      return null;
    }

    try {
      dynamic controller = VkIDController(clID: int.parse(clientIdStr));
      final authUri = controller.generateAuthorizeLinkWithCodeVerifier();

      String authUrl;
      if (authUri is MapEntry) {
        authUrl = authUri.value.toString();
      } else {
        authUrl = authUri.toString();
      }

      final redirectScheme = 'vk$clientIdStr://';

      final redirectParams = await _presentOAuthWebView(context: context, initialUrl: authUrl, redirectSchemePrefix: redirectScheme);
      if (redirectParams == null) {
        return null;
      }

      final code = redirectParams['code'];
      final deviceId = redirectParams['device_id'];
      if (code == null || deviceId == null) {
        return null;
      }
      return VkAuthResult(accessToken: code);
    } catch (e) {
      return null;
    }
  }

  static Future<String?> signInWithOk() async {
    final context = AppRouter.navigatorKey.currentContext;
    if (context == null) return null;
    return _signInWithVkIdProvider(context: context, provider: 'ok');
  }

  static Future<String?> signInWithMailRu() async {
    final context = AppRouter.navigatorKey.currentContext;
    if (context == null) return null;
    return _signInWithVkIdProvider(context: context, provider: 'mail');
  }

  static Future<String?> signInWithYandex() async {
    final clientId = EnvConfig.yandexClientId.trim();
    final redirectUri = EnvConfig.yandexRedirectUri.trim();

    if (clientId.isEmpty || redirectUri.isEmpty) {
      return null;
    }

    try {
      final context = AppRouter.navigatorKey.currentContext;
      if (context == null) return null;

      final authorizeUrl = Uri.https('oauth.yandex.ru', '/authorize', {
        'response_type': 'token', 
        'client_id': clientId,
        'redirect_uri': redirectUri,
        'force_confirm': 'yes',
      }).toString();

      final redirectSchemePrefix = redirectUri;

      final params = await _presentOAuthWebView(context: context, initialUrl: authorizeUrl, redirectSchemePrefix: redirectSchemePrefix);

      if (params == null) return null;

      final token = params['access_token'];
      if (token != null && token.isNotEmpty) {
        return token;
      }

      final code = params['code'];
      if (code != null && code.isNotEmpty) {
        return code;
      }

      return null;
    } catch (e) {
      try {
        final plugin = FlutterLoginYandex();
        final response = await plugin.signIn();
        final token = (response is Map) ? response['token'] as String? : null;
        return (token != null && token.isNotEmpty) ? token : null;
      } catch (_) {
        return null;
      }
    }
  }

  static Future<String?> _signInWithVkIdProvider({required BuildContext context, required String provider}) async {
    final clientIdStr = EnvConfig.vkClientId.trim();
    if (clientIdStr.isEmpty) {
      return null;
    }
    try {
      dynamic controller = VkIDController(clID: int.parse(clientIdStr));

      dynamic authUri;
      try {
        authUri = controller.generateAuthorizeLinkWithCodeVerifier(provider: provider);
      } catch (e) {
        try {
          authUri = controller.generateAuthorizeLinkWithCodeVerifier(provider: null);
        } catch (e2) {
          authUri = controller.generateAuthorizeLinkWithCodeVerifier();
        }
      }

      // Extract URL from MapEntry
      String authUrl;
      if (authUri is MapEntry) {
        authUrl = authUri.value.toString();
      } else {
        authUrl = authUri.toString();
      }
      final redirectScheme = 'vk$clientIdStr://';
      final redirectParams = await _presentOAuthWebView(context: context, initialUrl: authUrl, redirectSchemePrefix: redirectScheme);
      if (redirectParams == null) return null;
      final code = redirectParams['code'];
      final deviceId = redirectParams['device_id'];
      if (code == null || deviceId == null) return null;
      return code;
    } catch (e) {
      return null;
    }
  }

  static Future<Map<String, String>?> _presentOAuthWebView({
    required BuildContext context,
    required String initialUrl,
    required String redirectSchemePrefix,
  }) async {
    final controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setNavigationDelegate(
        NavigationDelegate(
          onNavigationRequest: (request) {
            final url = request.url;
            if (url.startsWith(redirectSchemePrefix)) {
              final uri = Uri.parse(url);
              final params = <String, String>{}..addAll(uri.queryParameters);
              if (uri.fragment.isNotEmpty) {
                final fragPairs = uri.fragment.split('&');
                for (final pair in fragPairs) {
                  final eq = pair.indexOf('=');
                  if (eq > 0 && eq < pair.length - 1) {
                    final key = Uri.decodeComponent(pair.substring(0, eq));
                    final value = Uri.decodeComponent(pair.substring(eq + 1));
                    params[key] = value;
                  }
                }
              }
              Navigator.of(context, rootNavigator: true).pop(params);
              return NavigationDecision.prevent;
            }
            return NavigationDecision.navigate;
          },
          onPageStarted: (url) {
          },
          onPageFinished: (url) {
          },
          onWebResourceError: (error) {
          },
        ),
      );

    try {
      await controller.loadRequest(Uri.parse(initialUrl));
    } catch (e) {
      return null;
    }

    return showDialog<Map<String, String>>(
      context: context,
      barrierDismissible: false,
      builder: (_) {
        const borderRadius = BorderRadius.all(Radius.circular(16));
        return Dialog(
          insetPadding: const EdgeInsets.all(16),
          shape: const RoundedRectangleBorder(borderRadius: borderRadius),
          elevation: 0,
          child: ClipRRect(
            borderRadius: borderRadius,
            child: SizedBox(height: 560, child: WebViewWidget(controller: controller)),
          ),
        );
      },
    );
  }
}