import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:flutter_login_yandex/flutter_login_yandex.dart';
import 'package:eatvio_app/core/app_router.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 = dotenv.maybeGet('VK_CLIENT_ID')?.trim() ?? Platform.environment['VK_CLIENT_ID'];
    if (clientIdStr == null || clientIdStr.isEmpty) {
      return null;
    }

    try {
      dynamic controller = VkIDController(clID: int.parse(clientIdStr));
      final authUri = controller.generateAuthorizeLinkWithCodeVerifier();
      final redirectScheme = 'vk$clientIdStr://';
      final redirectParams = await _presentOAuthWebView(context: context, initialUrl: authUri.toString(), redirectSchemePrefix: redirectScheme);
      if (redirectParams == null) return null;
      final code = redirectParams['code'];
      final deviceId = redirectParams['device_id'];
      if (code == null || deviceId == null) return null;

      final tokenResponse = await controller.exchangeAuthorizationCodeForToken(code: code, deviceId: deviceId);
      final accessToken = _extractAccessToken(tokenResponse);
      if (accessToken == null) return null;
      return VkAuthResult(accessToken: accessToken);
    } catch (_) {
      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 = dotenv.maybeGet('YANDEX_CLIENT_ID')?.trim() ?? Platform.environment['YANDEX_CLIENT_ID'];
    final redirectUri = dotenv.maybeGet('YANDEX_REDIRECT_URI')?.trim() ?? Platform.environment['YANDEX_REDIRECT_URI'];

    if (clientId == null || clientId.isEmpty || redirectUri == null || redirectUri.isEmpty) {
      return null;
    }
    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 = dotenv.maybeGet('VK_CLIENT_ID')?.trim() ?? Platform.environment['VK_CLIENT_ID'];
    if (clientIdStr == null || clientIdStr.isEmpty) {
      return null;
    }
    try {
      dynamic controller = VkIDController(clID: int.parse(clientIdStr));
      final authUri = controller.generateAuthorizeLinkWithCodeVerifier(provider: provider);
      final redirectScheme = 'vk$clientIdStr://';
      final redirectParams = await _presentOAuthWebView(context: context, initialUrl: authUri.toString(), redirectSchemePrefix: redirectScheme);
      if (redirectParams == null) return null;
      final code = redirectParams['code'];
      final deviceId = redirectParams['device_id'];
      if (code == null || deviceId == null) return null;
      final tokenResponse = await controller.exchangeAuthorizationCodeForToken(code: code, deviceId: deviceId, provider: provider);
      final accessToken = _extractAccessToken(tokenResponse);
      return accessToken;
    } catch (_) {
      return null;
    }
  }

  static String? _extractAccessToken(dynamic tokenResponse) {
    if (tokenResponse == null) return null;
    if (tokenResponse is Map) {
      return (tokenResponse['access_token'] as String?) ?? (tokenResponse['token'] as String?);
    }
    try {
      final token = (tokenResponse as dynamic).accessToken as String?;
      if (token != null && token.isNotEmpty) return token;
    } catch (_) {}
    try {
      final token = (tokenResponse as dynamic).token as String?;
      if (token != null && token.isNotEmpty) return token;
    } catch (_) {}
    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);
              Navigator.of(context, rootNavigator: true).pop(params);
              return NavigationDecision.prevent;
            }
            return NavigationDecision.navigate;
          },
        ),
      )
      ..loadRequest(Uri.parse(initialUrl));

    return showDialog<Map<String, String>>(
      context: context,
      barrierDismissible: false,
      builder: (_) {
        return Dialog(
          insetPadding: const EdgeInsets.all(16),
          child: SizedBox(height: 560, child: WebViewWidget(controller: controller)),
        );
      },
    );
  }
}