import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_clock/model/timer_data.dart';
import 'package:flutter_clock/model/timer_settings.dart';
import 'package:flutter_clock/pages/timer/timer_settings_page.dart';
import 'package:flutter_clock/utils/audio_manager.dart';
import 'package:flutter_clock/utils/screen_manager.dart';
import 'package:flutter_clock/utils/background_timer_service.dart';

/// Description: 倒计时页面
/// Time       : 04/06/2025 Sunday
/// Author     : liuyuqi.gov@msn.cn
class TimerPage extends StatefulWidget {
  @override
  _TimerPageState createState() => _TimerPageState();
}

enum TimerState { prepare, running, pause, finish, waiting }

class _TimerPageState extends State<TimerPage> with WidgetsBindingObserver {
  // Timer duration values
  int _hours = 0;
  int _minutes = 10;
  int _seconds = 0;

  // For timer controller
  TimerState timerState = TimerState.prepare;
  int _remainingSeconds = 0;
  
  // Waiting for alignment timer
  Timer? _alignmentTimer;
  DateTime? _alignmentTargetTime;
  DateTime? _alignmentStartTime; // 记录开始等待的时间点
  Timer? _alignmentUIUpdateTimer; // For refreshing UI during waiting

  // Total timer duration in seconds (for progress calculation)
  int _totalDurationSeconds = 0;

  // Background services
  final BackgroundTimerService _backgroundTimerService =
      BackgroundTimerService();

  // Settings
  late TimerSettings _settings;
  bool _settingsLoaded = false;
  final AudioManager _audioManager = AudioManager();

  // Wheel controllers
  final FixedExtentScrollController _hoursController =
      FixedExtentScrollController(initialItem: 0);
  final FixedExtentScrollController _minutesController =
      FixedExtentScrollController(initialItem: 10);
  final FixedExtentScrollController _secondsController =
      FixedExtentScrollController(initialItem: 0);

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _initializeBackgroundTimer();
    _loadSettings();
    _restoreTimerState();
  }

  @override
  void dispose() {
    _audioManager.dispose();
    _backgroundTimerService.dispose();
    _alignmentTimer?.cancel();
    _alignmentUIUpdateTimer?.cancel(); // Cancel UI update timer
    if (ScreenManager.isWakeLockEnabled) {
      ScreenManager.disableWakeLock();
    }
    WidgetsBinding.instance.removeObserver(this);
    _hoursController.dispose();
    _minutesController.dispose();
    _secondsController.dispose();
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    // No additional handling required as background service handles the state
  }

  /// Restore timer state from persistent storage
  Future<void> _restoreTimerState() async {
    final timerData = await TimerData.load();

    if (timerData.isRunning) {
      setState(() {
        timerState = TimerState.running;
        _remainingSeconds = timerData.calculateRemainingSeconds();
        _totalDurationSeconds = _backgroundTimerService.totalDurationSeconds;
      });
    } else if (timerData.isPaused && timerData.pausedRemaining != null) {
      setState(() {
        timerState = TimerState.pause;
        _remainingSeconds = timerData.pausedRemaining!;
        _totalDurationSeconds = _backgroundTimerService.totalDurationSeconds;
      });
    }
  }

  /// Initialize the background timer service
  Future<void> _initializeBackgroundTimer() async {
    await _backgroundTimerService.initialize(
      onTimerComplete: _timerCompleted,
      onTimerTick: (remainingSeconds) {
        setState(() {
          _remainingSeconds = remainingSeconds;
          if (remainingSeconds <= 0 && timerState != TimerState.finish) {
            timerState = TimerState.finish;
          }
        });
      },
    );
  }

  Future<void> _loadSettings() async {
    _settings = await TimerSettings.loadSettings();
    setState(() {
      _settingsLoaded = true;
    });
  }

  /// Calculate the next 10-minute alignment time
  DateTime _calculateNextAlignmentTime() {
    final now = DateTime.now();
    // 计算下一个整10分钟的时间点
    int nextMinutes = ((now.minute ~/ 10) + 1) * 10;
    int nextHour = now.hour;
    
    // 处理进位
    if (nextMinutes >= 60) {
      nextMinutes = 0;
      nextHour = (nextHour + 1) % 24;
    }
    
    return DateTime(
      now.year, 
      now.month, 
      now.day, 
      nextHour, 
      nextMinutes, 
      0, 
      0, 
      0
    );
  }

  // 计算等待进度
  double _calculateWaitingProgress() {
    if (_alignmentTargetTime == null) return 0.0;
    
    final now = DateTime.now();
    final targetTime = _alignmentTargetTime!;
    final startTime = _alignmentStartTime ?? now;
    
    // 如果还没开始等待或已经过了目标时间
    if (now.isAfter(targetTime)) return 1.0;
    if (now.isBefore(startTime)) return 0.0;
    
    // 计算总等待时间和已等待时间
    final totalWaitDuration = targetTime.difference(startTime).inMilliseconds;
    final elapsedWaitDuration = now.difference(startTime).inMilliseconds;
    
    // 计算进度比例
    if (totalWaitDuration <= 0) return 1.0;
    final progress = elapsedWaitDuration / totalWaitDuration;
    
    // 确保进度在0.0到1.0之间
    return progress.clamp(0.0, 1.0);
  }
  
  /// Wait until the next 10-minute mark and then start the timer
  void _startTimerWithAlignment(int totalSeconds) {
    // 取消任何现有的对齐定时器
    _alignmentTimer?.cancel();
    _alignmentUIUpdateTimer?.cancel();
    
    // 计算下一个整10分钟的时间点
    final alignmentTime = _calculateNextAlignmentTime();
    _alignmentTargetTime = alignmentTime;
    _alignmentStartTime = DateTime.now(); // 记录开始等待的时间
    
    // 设置状态为等待
    setState(() {
      timerState = TimerState.waiting;
    });
    
    // 计算等待时间（毫秒）
    final waitDuration = alignmentTime.difference(DateTime.now());
    
    // 创建定时器等待到指定时间
    _alignmentTimer = Timer(waitDuration, () {
      // 时间到了，启动实际的倒计时
      setState(() {
        timerState = TimerState.running;
        _remainingSeconds = totalSeconds;
        _totalDurationSeconds = totalSeconds;
        _alignmentTargetTime = null;
        _alignmentStartTime = null;
      });
      
      _backgroundTimerService.startTimer(totalSeconds);
      _alignmentUIUpdateTimer?.cancel(); // Cancel UI update timer when alignment is done
    });
    
    // 创建UI刷新定时器，每秒更新一次
    _alignmentUIUpdateTimer = Timer.periodic(Duration(seconds: 1), (timer) {
      if (mounted) {
        setState(() {
          // 仅用于刷新UI
        });
      }
    });
  }

  /// Start a new timer or resume an existing paused timer
  void _startTimer(String status) {
    if (status == "resume") {
      setState(() {
        timerState = TimerState.running;
      });
      _backgroundTimerService.resumeTimer(
          _remainingSeconds, _totalDurationSeconds);
    } else if (status == "start") {
      // 获取界面输入的时间
      int _hourstmp = _hoursController.selectedItem;
      int _minutestmp = _minutesController.selectedItem;
      int _secondstmp = _secondsController.selectedItem;
      // 计算总秒数
      final totalSeconds = _hourstmp * 3600 + _minutestmp * 60 + _secondstmp;
      if (totalSeconds <= 0) return;
      
      // 保存选择的时间值
      _hours = _hourstmp;
      _minutes = _minutestmp;
      _seconds = _secondstmp;
      
      // 检查是否需要整点对齐
      if (_settings.alignToHour && _settings.loop && totalSeconds >= 600) { // 只有在循环模式、时间至少10分钟时才启用整点对齐
        _startTimerWithAlignment(totalSeconds);
      } else {
        setState(() {
          timerState = TimerState.running;
          _remainingSeconds = totalSeconds;
          _totalDurationSeconds = totalSeconds;
        });
        
        _backgroundTimerService.startTimer(totalSeconds);
      }
    } else if (status == "loop") {
      // 计算总秒数
      final totalSeconds = _hours * 3600 + _minutes * 60 + _seconds;
      if (totalSeconds <= 0) return;
      
      // 检查是否需要整点对齐
      if (_settings.alignToHour && _settings.loop && totalSeconds >= 600) { // 只有在循环模式、时间至少10分钟时才启用整点对齐
        _startTimerWithAlignment(totalSeconds);
      } else {
        setState(() {
          timerState = TimerState.running;
          _remainingSeconds = totalSeconds;
          _totalDurationSeconds = totalSeconds;
        });
        
        _backgroundTimerService.startTimer(totalSeconds);
      }
    }
  }

  /// Pause the running timer
  void _pauseTimer() {
    if (timerState == TimerState.waiting) {
      // 如果在等待对齐状态，取消等待定时器
      _alignmentTimer?.cancel();
      _alignmentUIUpdateTimer?.cancel(); // Cancel UI update timer
      _alignmentTargetTime = null;
      _alignmentStartTime = null;
    } else {
      _backgroundTimerService.pauseTimer();
    }
    
    setState(() {
      timerState = TimerState.pause;
    });
  }

  /// Reset the timer to initial state
  void _resetTimer() {
    _backgroundTimerService.cancelTimer();
    _audioManager.stopSound();
    _audioManager.stopVibration();
    _alignmentTimer?.cancel();
    _alignmentUIUpdateTimer?.cancel(); // Cancel UI update timer
    _alignmentTargetTime = null;
    _alignmentStartTime = null;
    
    setState(() {
      timerState = TimerState.prepare;
    });
  }

  /// Handle timer completion
  Future<void> _timerCompleted() async {
    setState(() {
      timerState = TimerState.finish;
    });

    // Play sound and vibrate
    if (_settings.vibrate) {
      _audioManager.triggerVibration();
    }
    _audioManager.playSound(_settings.sound, _settings.volume, _settings.loop);
    
    // If loop is enabled, restart the timer
    if (_settings.loop) {
      Future.delayed(Duration(seconds: 5), () {
        _audioManager.stopSound();
        _audioManager.stopVibration();
      });
      _startTimer("loop");
    }
  }

  String _formatTime(int seconds) {
    final hours = seconds ~/ 3600;
    final minutes = (seconds % 3600) ~/ 60;
    final secs = seconds % 60;
    return '${hours.toString().padLeft(2, '0')}:${minutes.toString().padLeft(2, '0')}:${secs.toString().padLeft(2, '0')}';
  }
  
  // 格式化剩余等待时间
  String _formatWaitingTime() {
    if (_alignmentTargetTime == null) return "00:00";
    
    final now = DateTime.now();
    final difference = _alignmentTargetTime!.difference(now);
    
    // 如果差异为负，说明已经过了目标时间
    if (difference.isNegative) return "00:00";
    
    // 计算分钟和秒数
    final minutes = difference.inMinutes;
    final seconds = difference.inSeconds % 60;
    
    return '${minutes.toString().padLeft(2, '0')}:${seconds.toString().padLeft(2, '0')}';
  }

  @override
  Widget build(BuildContext context) {
    if (!_settingsLoaded) {
      return Center(child: CircularProgressIndicator());
    }

    if (timerState != TimerState.prepare) {
      return _buildCountdownView();
    } else {
      return _buildTimerSetupView();
    }
  }

  Widget _buildTimerSetupView() {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Expanded(
            child: Row(
              children: [
                Expanded(
                  child: _buildTimerWheel(
                    _hoursController,
                    List.generate(24, (index) => index),
                    (value) {
                      setState(() {
                        _hours = value;
                      });
                    },
                    'H',
                  ),
                ),
                Expanded(
                  child: _buildTimerWheel(
                    _minutesController,
                    List.generate(60, (index) => index),
                    (value) {
                      setState(() {
                        _minutes = value;
                      });
                    },
                    'M',
                  ),
                ),
                Expanded(
                  child: _buildTimerWheel(
                    _secondsController,
                    List.generate(60, (index) => index),
                    (value) {
                      setState(() {
                        _seconds = value;
                      });
                    },
                    'S',
                  ),
                ),
              ],
            ),
          ),
          SizedBox(height: 20),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 50, vertical: 20),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                _buildCircleButton(
                  Icons.sunny,
                  Colors.grey[600]!,
                  () {
                    ScreenManager.toggleWakeLock();
                    setState(() {});
                  },
                  isActive: ScreenManager.isWakeLockEnabled,
                ),
                _buildCircleButton(
                  Icons.play_arrow,
                  Colors.blue,
                  () => _startTimer("start"),
                ),
                _buildCircleButton(
                  Icons.settings,
                  Colors.grey[600]!,
                  () async {
                    final result = await Navigator.push(
                      context,
                      MaterialPageRoute(
                          builder: (context) =>
                              TimerSettingsPage(settings: _settings)),
                    );
                    if (result != null) {
                      setState(() {
                        _settings = result;
                      });
                    }
                  },
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildCountdownView() {
    final totalMinutes = _remainingSeconds ~/ 60;
    
    // 如果处于等待整点对齐状态，显示不同的UI
    if (timerState == TimerState.waiting) {
      return _buildWaitingForAlignmentView();
    }
    
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Expanded(
            child: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Container(
                    width: 300,
                    height: 300,
                    decoration: BoxDecoration(
                      shape: BoxShape.circle,
                      border: Border.all(
                        color: Colors.blue.withOpacity(0.3),
                        width: 3,
                      ),
                    ),
                    child: Stack(
                      alignment: Alignment.center,
                      children: [
                        // Timer progress
                        SizedBox(
                          width: 300,
                          height: 300,
                          child: CircularProgressIndicator(
                            value: timerState == TimerState.finish
                                ? 1
                                : _totalDurationSeconds > 0
                                    ? _remainingSeconds / _totalDurationSeconds
                                    : 0,
                            strokeWidth: 5,
                            backgroundColor: Colors.grey.withOpacity(0.1),
                            color: Colors.blue,
                          ),
                        ),
                        // Time display
                        Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Text(
                              _formatTime(_remainingSeconds),
                              style: TextStyle(
                                  fontSize: 40, fontWeight: FontWeight.bold),
                            ),
                            Text(
                              'Total ${totalMinutes} minutes',
                              style:
                                  TextStyle(fontSize: 16, color: Colors.grey),
                            ),
                          ],
                        ),
                        // Indicator dot
                        Positioned(
                          bottom: 0,
                          child: Container(
                            width: 20,
                            height: 20,
                            decoration: BoxDecoration(
                              color: Colors.blue,
                              shape: BoxShape.circle,
                            ),
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            ),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 50, vertical: 20),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                // 唤醒屏幕
                _buildCircleButton(
                  Icons.sunny,
                  Colors.grey[600]!,
                  () {
                    ScreenManager.toggleWakeLock();
                    setState(() {});
                  },
                  isActive: ScreenManager.isWakeLockEnabled,
                ),
                // 暂停/开始
                timerState == TimerState.running
                    ? _buildCircleButton(
                        Icons.pause,
                        Colors.blue,
                        () => _pauseTimer(),
                      )
                    : _buildCircleButton(
                        Icons.play_arrow,
                        Colors.blue,
                        () => _startTimer("resume"),
                      ),
                // 重置
                _buildCircleButton(
                  Icons.stop,
                  Colors.red,
                  () => _resetTimer(),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
  
  // 构建等待整点对齐的视图
  Widget _buildWaitingForAlignmentView() {
    final nextAlignmentTime = _alignmentTargetTime;
    final waitingProgress = _calculateWaitingProgress();
    
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Expanded(
            child: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Container(
                    width: 300,
                    height: 300,
                    decoration: BoxDecoration(
                      shape: BoxShape.circle,
                      border: Border.all(
                        color: Colors.orange.withOpacity(0.3),
                        width: 3,
                      ),
                    ),
                    child: Stack(
                      alignment: Alignment.center,
                      children: [
                        // 等待进度指示器
                        SizedBox(
                          width: 300,
                          height: 300,
                          child: CircularProgressIndicator(
                            value: waitingProgress, // 显示确定的等待进度
                            strokeWidth: 5,
                            backgroundColor: Colors.grey.withOpacity(0.1),
                            color: Colors.orange,
                          ),
                        ),
                        // 等待时间显示
                        Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Text(
                              _formatWaitingTime(),
                              style: TextStyle(
                                  fontSize: 40, fontWeight: FontWeight.bold),
                            ),
                            Text(
                              '等待对齐整10分钟',
                              style: TextStyle(fontSize: 16, color: Colors.grey),
                            ),
                            SizedBox(height: 10),
                            if (nextAlignmentTime != null)
                              Text(
                                '将在 ${nextAlignmentTime.hour.toString().padLeft(2, '0')}:${nextAlignmentTime.minute.toString().padLeft(2, '0')} 开始',
                                style: TextStyle(fontSize: 14, color: Colors.orange),
                              ),
                          ],
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            ),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 50, vertical: 20),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                // 唤醒屏幕
                _buildCircleButton(
                  Icons.sunny,
                  Colors.grey[600]!,
                  () {
                    ScreenManager.toggleWakeLock();
                    setState(() {});
                  },
                  isActive: ScreenManager.isWakeLockEnabled,
                ),
                // 在等待状态只显示取消按钮
                _buildCircleButton(
                  Icons.stop,
                  Colors.red,
                  () => _resetTimer(),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildCircleButton(IconData icon, Color color, VoidCallback onPressed,
      {bool isActive = false}) {
    return Container(
      width: 70,
      height: 70,
      decoration: BoxDecoration(
        shape: BoxShape.circle,
        color: isActive ? color : Colors.white,
        boxShadow: [
          BoxShadow(
            color: Colors.black.withOpacity(0.1),
            blurRadius: 8,
            offset: Offset(0, 2),
          ),
        ],
      ),
      child: IconButton(
        icon: Icon(icon, size: 30),
        color: isActive ? Colors.white : color,
        onPressed: onPressed,
      ),
    );
  }

  Widget _buildTimerWheel(
    FixedExtentScrollController controller,
    List<int> items,
    ValueChanged<int> onChanged,
    String unit,
  ) {
    return Container(
      height: 400,
      decoration: BoxDecoration(
        border: Border(
          top: BorderSide(color: Colors.grey.withOpacity(0.3), width: 1),
          bottom: BorderSide(color: Colors.grey.withOpacity(0.3), width: 1),
        ),
      ),
      child: Stack(
        children: [
          // Center highlight
          Positioned.fill(
            child: Center(
              child: Container(
                height: 50,
                decoration: BoxDecoration(
                  color: Colors.blue.withOpacity(0.1),
                  borderRadius: BorderRadius.circular(8),
                ),
              ),
            ),
          ),
          Container(
            alignment: Alignment.centerRight,
            padding: EdgeInsets.only(right: 15),
            child: Text(
              unit,
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          ListWheelScrollView(
            controller: controller,
            physics: FixedExtentScrollPhysics(),
            diameterRatio: 1.5,
            itemExtent: 50,
            children: items.map((value) {
              return Center(
                child: Text(
                  value.toString().padLeft(2, '0'),
                  style: TextStyle(
                    fontSize: 30,
                    color: Colors.black,
                    fontWeight: FontWeight.w500,
                  ),
                ),
              );
            }).toList(),
            onSelectedItemChanged: onChanged,
          ),
        ],
      ),
    );
  }
}