import 'dart:async';

import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/network/api_exception.dart';
import '../../../core/network/error_message.dart';
import '../../../core/storage/token_storage.dart';
import '../data/auth_providers.dart';
import '../domain/auth_models.dart';
import '../domain/auth_state.dart';

/// 认证控制器。
///
/// 承载登录 / 注册 / 发送验证码 / 倒计时等全部业务逻辑，UI 仅触发动作并消费状态。
/// 使用 keepAlive，避免登录流程中页面切换导致状态丢失。
class AuthController extends Notifier<AuthState> {
  AuthController();

  Timer? _countdownTimer;

  @override
  AuthState build() {
    ref.keepAlive();
    ref.onDispose(() => _countdownTimer?.cancel());
    return const AuthState();
  }

  String get _deviceId => TokenStorage.deviceId;

  /// 密码登录。
  Future<bool> loginByPassword({
    required String phone,
    required String password,
  }) async {
    return _run(() => ref.read(authRepositoryProvider).loginByPassword(
          phone: phone,
          password: password,
          deviceId: _deviceId,
        ));
  }

  /// 短信登录。
  Future<bool> loginBySms({
    required String phone,
    required String code,
  }) async {
    return _run(() => ref.read(authRepositoryProvider).loginBySms(
          phone: phone,
          code: code,
          deviceId: _deviceId,
        ));
  }

  /// 注册。
  Future<bool> register({
    required String phone,
    required String code,
    required String password,
  }) async {
    return _run(() => ref.read(authRepositoryProvider).register(
          phone: phone,
          code: code,
          password: password,
          deviceId: _deviceId,
        ));
  }

  /// 发送短信验证码并启动 60s 倒计时。
  ///
  /// 发送前先做本地校验：手机号为空或格式不正确时直接提示，不发起请求、
  /// 不启动倒计时，避免出现「空号也能点但弹报错」的体验问题。
  Future<void> sendSmsCode({
    required String phone,
    required SmsScene scene,
  }) async {
    if (state.isSendingCode || state.countdownSeconds > 0) return;
    final trimmed = phone.trim();
    final phoneError = _validatePhone(trimmed);
    if (phoneError != null) {
      state = state.copyWith(alert: phoneError);
      return;
    }
    state = state.copyWith(isSendingCode: true, clearAlert: true);
    try {
      await ref.read(authRepositoryProvider).sendSmsCode(
            phone: trimmed,
            scene: scene,
          );
      _startCountdown();
    } catch (e) {
      state = state.copyWith(
        isSendingCode: false,
        alert: userMessageOf(e),
      );
    }
  }

  /// 校验手机号：空或不符合 11 位中国大陆手机号规则时返回提示文案。
  String? _validatePhone(String phone) {
    if (phone.isEmpty) return '请输入手机号';
    // 1 开头的 11 位手机号。
    if (!RegExp(r'^1\d{10}$').hasMatch(phone)) return '手机号格式不正确';
    return null;
  }

  /// 重置密码（忘记密码流程）。
  Future<bool> resetPassword({
    required String phone,
    required String code,
    required String password,
  }) async {
    state = state.copyWith(isLoading: true, clearAlert: true);
    try {
      await ref.read(authRepositoryProvider).resetPassword(
            phone: phone,
            code: code,
            password: password,
          );
      state = state.copyWith(isLoading: false);
      return true;
    } catch (e) {
      state = state.copyWith(isLoading: false, alert: userMessageOf(e));
      return false;
    }
  }

  /// 消费一次性提示。
  void consumeAlert() {
    if (state.alert != null) {
      state = state.copyWith(clearAlert: true);
    }
  }

  /// 登出。
  void logout() {
    _countdownTimer?.cancel();
    TokenStorage.clear();
    state = const AuthState();
  }

  Future<bool> _run(Future<LoginResult> Function() action) async {
    state = state.copyWith(isLoading: true, clearAlert: true);
    try {
      await action();
      state = state.copyWith(isLoading: false);
      return true;
    } catch (e) {
      state = state.copyWith(isLoading: false, alert: userMessageOf(e));
      // 鉴权失效：本地令牌可能已作废，主动登出清理。
      if (_isUnauthorized(e)) {
        logout();
      }
      return false;
    }
  }

  /// 判断异常是否为鉴权失效（401）。
  bool _isUnauthorized(Object e) {
    if (e is ApiException) return e.code == '401';
    return false;
  }

  void _startCountdown() {
    state = state.copyWith(isSendingCode: false, countdownSeconds: 60);
    _countdownTimer?.cancel();
    _countdownTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
      final left = state.countdownSeconds - 1;
      if (left <= 0) {
        timer.cancel();
        state = state.copyWith(countdownSeconds: 0);
      } else {
        state = state.copyWith(countdownSeconds: left);
      }
    });
  }

}

/// 认证控制器 Provider（会话级 keepAlive 在 build 内通过 ref.keepAlive 实现）。
final authControllerProvider =
    NotifierProvider<AuthController, AuthState>(AuthController.new);