import 'dart:async';

import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../settings/services/settings_service.dart';

/// 认证状态枚举
enum AuthStatus { unauthenticated, authenticated }

/// 认证状态数据
class AuthState {
  final AuthStatus status;
  final int remainingAttempts;
  final DateTime? lockUntil;

  const AuthState({
    this.status = AuthStatus.unauthenticated,
    this.remainingAttempts = 5,
    this.lockUntil,
  });

  bool get isLocked => lockUntil != null && DateTime.now().isBefore(lockUntil!);

  int get lockSecondsRemaining {
    if (lockUntil == null) return 0;
    final diff = lockUntil!.difference(DateTime.now()).inSeconds;
    return diff > 0 ? diff : 0;
  }

  AuthState copyWith({
    AuthStatus? status,
    int? remainingAttempts,
    DateTime? Function()? lockUntil,
  }) {
    return AuthState(
      status: status ?? this.status,
      remainingAttempts: remainingAttempts ?? this.remainingAttempts,
      lockUntil: lockUntil != null ? lockUntil() : this.lockUntil,
    );
  }
}

/// 认证状态管理器
class AuthNotifier extends StateNotifier<AuthState> {
  AuthNotifier() : super(const AuthState());

  static const maxAttempts = 5;
  static const lockDuration = Duration(seconds: 30);

  /// 验证密码
  Future<bool> verify(String password) async {
    if (state.isLocked) {
      return false;
    }

    final isValid = await SettingsService.instance.verifyPassword(password);

    if (isValid) {
      state = const AuthState(status: AuthStatus.authenticated);
      return true;
    }

    final newAttempts = state.remainingAttempts - 1;

    if (newAttempts <= 0) {
      state = state.copyWith(
        remainingAttempts: 0,
        lockUntil: () => DateTime.now().add(lockDuration),
      );
      _startLockTimer();
    } else {
      state = state.copyWith(remainingAttempts: newAttempts);
    }

    return false;
  }

  /// 锁定倒计时结束后自动解锁
  void _startLockTimer() {
    Timer(lockDuration, () {
      if (state.status == AuthStatus.authenticated) return;
      state = AuthState(
        status: state.status,
        remainingAttempts: maxAttempts,
        lockUntil: null,
      );
    });
  }

  /// 重置认证状态（用于登出）
  void reset() {
    state = const AuthState();
  }
}

final authProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
  return AuthNotifier();
});