import 'dart:convert';

import 'package:flutter/material.dart';

import '../presentation/pages/auth/captcha_challenge_page.dart';
import '../presentation/widgets/toast_helper.dart';
import '../services/auth_service.dart';
import '../services/server_service.dart';
import 'api_service.dart';

/// 验证码服务（单例）
///
/// 管理验证码的加载、状态和 UI 构建，供登录/注册/忘记密码页面共享。
class CaptchaService {
  CaptchaService._internal();
  static final CaptchaService _instance = CaptchaService._internal();
  static CaptchaService get instance => _instance;

  final TextEditingController captchaController = TextEditingController();

  String? _captchaType;
  String? _recaptchaSiteKey;
  String? _turnstileSiteKey;
  String? _capInstanceUrl;
  String? _capSiteKey;
  String? _capAssetServer;

  String? _captchaImage;
  String? _captchaTicket;
  String? _captchaToken;
  bool _isLoadingCaptcha = false;

  bool get isLoadingCaptcha => _isLoadingCaptcha;
  String? get captchaImage => _captchaImage;
  String? get captchaTicket => _captchaTicket;
  String? get captchaToken => _captchaToken;

  bool get isWebCaptcha => captchaWebConfig != null;

  CaptchaWebConfig? get captchaWebConfig {
    final type = _normalizedCaptchaType;
    if (type == 'turnstile' &&
        _turnstileSiteKey != null &&
        _turnstileSiteKey!.isNotEmpty) {
      return CaptchaWebConfig.turnstile(
        siteKey: _turnstileSiteKey!,
        displayName: 'Cloudflare Turnstile',
      );
    }

    if (type == 'recaptcha' &&
        _recaptchaSiteKey != null &&
        _recaptchaSiteKey!.isNotEmpty) {
      return CaptchaWebConfig.recaptchaV2(
        siteKey: _recaptchaSiteKey!,
        displayName: 'reCAPTCHA V2',
      );
    }

    if (type == 'cap' &&
        _capInstanceUrl != null &&
        _capInstanceUrl!.isNotEmpty &&
        _capSiteKey != null &&
        _capSiteKey!.isNotEmpty) {
      return CaptchaWebConfig.cap(
        instanceUrl: _capInstanceUrl!,
        siteKey: _capSiteKey!,
        assetServer: _capAssetServer,
        displayName: 'Cap',
      );
    }

    return null;
  }

  String get _normalizedCaptchaType {
    final raw = (_captchaType ?? '').trim().toLowerCase();
    if (raw == 'recaptcha_v2' ||
        raw == 'recaptchav2' ||
        raw == 'google' ||
        raw == 'google_recaptcha' ||
        raw == 'google-recaptcha') {
      return 'recaptcha';
    }
    if (raw == 'cloudflare_turnstile' || raw == 'cloudflare-turnstile') {
      return 'turnstile';
    }
    if (raw == 'image' || raw == 'graphic' || raw == 'captcha') {
      return 'normal';
    }
    return raw;
  }

  /// 加载验证码配置和图片
  Future<void> loadCaptcha(String baseUrl) async {
    if (_isLoadingCaptcha) return;

    _isLoadingCaptcha = true;

    try {
      await ApiService.instance.setBaseUrl(baseUrl);

      Map<String, dynamic> config = <String, dynamic>{};

      try {
        config = await AuthService.instance.getBasicSiteConfig().timeout(
          const Duration(seconds: 10),
        );
      } catch (_) {}

      final captchaType = _normalizeCaptchaType(
        (config['captcha_type'] ?? config['captchaType'] ?? config['captcha'])
            ?.toString(),
      );

      final recaptchaKey = _firstNonEmptyString(config, const [
        'captcha_ReCaptchaKey',
        'captcha_re_captcha_key',
        'captchaReCaptchaKey',
        'recaptcha_site_key',
        'recaptchaSiteKey',
        'recaptcha_key',
        'reCaptchaKey',
      ]);

      final turnstileSiteKey = _firstNonEmptyString(config, const [
        'turnstile_site_id',
        'turnstileSiteId',
        'turnstile_site_key',
        'turnstileSiteKey',
      ]);

      final capInstanceUrl = _firstNonEmptyString(config, const [
        'captcha_cap_instance_url',
        'captchaCapInstanceUrl',
        'cap_instance_url',
        'capInstanceUrl',
      ]);

      final capSiteKey = _firstNonEmptyString(config, const [
        'captcha_cap_site_key',
        'captchaCapSiteKey',
        'cap_site_key',
        'capSiteKey',
      ]);

      final capAssetServer = _firstNonEmptyString(config, const [
        'captcha_cap_asset_server',
        'captchaCapAssetServer',
        'cap_asset_server',
        'capAssetServer',
      ]);

      final isExternalCaptcha =
          captchaType == 'turnstile' ||
          captchaType == 'recaptcha' ||
          captchaType == 'cap';

      if (isExternalCaptcha) {
        _captchaType = captchaType;
        _recaptchaSiteKey = recaptchaKey;
        _turnstileSiteKey = turnstileSiteKey;
        _capInstanceUrl = capInstanceUrl;
        _capSiteKey = capSiteKey;
        _capAssetServer = capAssetServer;
        _captchaToken = null;

        _captchaImage = null;
        _captchaTicket = null;
        captchaController.clear();
        return;
      }

      final captcha = await AuthService.instance.getCaptcha();

      _captchaType = captchaType.isEmpty ? 'normal' : captchaType;
      _recaptchaSiteKey = null;
      _turnstileSiteKey = null;
      _capInstanceUrl = null;
      _capSiteKey = null;
      _capAssetServer = null;
      _captchaToken = null;

      _captchaImage = captcha['image'];
      _captchaTicket = captcha['ticket'];
      captchaController.clear();
    } catch (_) {
      clearCaptcha();
    } finally {
      _isLoadingCaptcha = false;
    }
  }

  /// 重新加载图形验证码图片
  Future<void> refreshCaptcha() async {
    final server = ServerService.instance.currentServer;
    if (server == null) return;
    await loadCaptcha(server.baseUrl);
  }

  /// 跳转到 Web 验证码页面
  Future<void> openCaptchaChallenge(BuildContext context) async {
    final server = ServerService.instance.currentServer;
    final config = captchaWebConfig;

    if (server == null || config == null) {
      ToastHelper.failure('验证码配置无效');
      return;
    }

    final token = await Navigator.of(context).push<String>(
      MaterialPageRoute(
        builder: (_) =>
            CaptchaChallengePage(config: config, baseUrl: server.baseUrl),
      ),
    );

    if (token != null && token.isNotEmpty) {
      _captchaToken = token;
      ToastHelper.success('人机验证完成');
    }
  }

  /// 清空所有验证码状态
  void clearCaptcha() {
    _captchaType = null;
    _recaptchaSiteKey = null;
    _turnstileSiteKey = null;
    _capInstanceUrl = null;
    _capSiteKey = null;
    _capAssetServer = null;
    _captchaToken = null;
    _captchaImage = null;
    _captchaTicket = null;
    captchaController.clear();
  }

  /// 获取验证码参数（用于提交登录/注册/忘记密码请求）
  ///
  /// 返回 `{captcha: ..., ticket: ...}` 或空 Map（无需验证码时）。
  Map<String, String> getCaptchaParams() {
    if (isWebCaptcha) {
      if (_captchaToken == null || _captchaToken!.isEmpty) return {};
      return {'captcha': _captchaToken!, 'ticket': _captchaToken!};
    }

    final userInput = captchaController.text.trim();
    if (userInput.isEmpty &&
        (_captchaTicket == null || _captchaTicket!.isEmpty)) {
      return {};
    }

    return {'captcha': userInput, 'ticket': _captchaTicket ?? ''};
  }

  /// Web 验证码是否已通过
  bool get isWebCaptchaVerified =>
      !isWebCaptcha || (_captchaToken != null && _captchaToken!.isNotEmpty);

  /// 构建验证码输入 Widget
  Widget buildCaptchaInput(BuildContext context) {
    if (isWebCaptcha) {
      final config = captchaWebConfig;
      final displayName = config?.displayName ?? '人机验证';

      return Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          OutlinedButton.icon(
            onPressed: _isLoadingCaptcha
                ? null
                : () => openCaptchaChallenge(context),
            icon: Icon(
              _captchaToken == null
                  ? Icons.verified_user_outlined
                  : Icons.verified,
            ),
            label: Text(
              _captchaToken == null
                  ? '点击完成 $displayName'
                  : '$displayName 已完成，点击重新验证',
            ),
          ),
          const SizedBox(height: 8),
          Text(
            '当前验证码类型：$displayName',
            style: TextStyle(fontSize: 12, color: Theme.of(context).hintColor),
          ),
        ],
      );
    }

    Widget captchaPreview;

    if (_isLoadingCaptcha) {
      captchaPreview = const SizedBox(
        width: 20,
        height: 20,
        child: CircularProgressIndicator(strokeWidth: 2),
      );
    } else if (_captchaImage != null && _captchaImage!.isNotEmpty) {
      try {
        final base64Part = _captchaImage!.contains(',')
            ? _captchaImage!.split(',').last
            : _captchaImage!;

        captchaPreview = Image.memory(
          base64Decode(base64Part),
          fit: BoxFit.contain,
          gaplessPlayback: true,
        );
      } catch (_) {
        captchaPreview = const Text('刷新');
      }
    } else {
      captchaPreview = const Text('刷新');
    }

    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Expanded(
          child: TextFormField(
            controller: captchaController,
            textInputAction: TextInputAction.done,
            decoration: const InputDecoration(
              labelText: '验证码',
              hintText: '请输入验证码',
              prefixIcon: Icon(Icons.verified_user_outlined),
            ),
            validator: (value) {
              final needCaptcha =
                  _captchaTicket != null && _captchaTicket!.isNotEmpty;

              if (needCaptcha && (value == null || value.trim().isEmpty)) {
                return '请输入验证码';
              }

              return null;
            },
          ),
        ),
        const SizedBox(width: 12),
        InkWell(
          onTap: _isLoadingCaptcha ? null : refreshCaptcha,
          borderRadius: BorderRadius.circular(8),
          child: Container(
            width: 130,
            height: 56,
            alignment: Alignment.center,
            padding: const EdgeInsets.all(4),
            decoration: BoxDecoration(
              border: Border.all(color: Theme.of(context).dividerColor),
              borderRadius: BorderRadius.circular(8),
            ),
            child: captchaPreview,
          ),
        ),
      ],
    );
  }

  String _normalizeCaptchaType(String? rawType) {
    final value = (rawType ?? '').trim().toLowerCase();
    if (value.isEmpty) return 'normal';

    if (value == 'image' || value == 'graphic' || value == 'captcha') {
      return 'normal';
    }

    if (value == 'recaptcha_v2' ||
        value == 'recaptchav2' ||
        value == 'google' ||
        value == 'google_recaptcha' ||
        value == 'google-recaptcha') {
      return 'recaptcha';
    }

    if (value == 'cloudflare_turnstile' || value == 'cloudflare-turnstile') {
      return 'turnstile';
    }

    return value;
  }

  String? _firstNonEmptyString(Map<String, dynamic> source, List<String> keys) {
    for (final key in keys) {
      final value = source[key];
      if (value == null) continue;
      final text = value.toString().trim();
      if (text.isNotEmpty) return text;
    }
    return null;
  }
}