import 'package:flutter/foundation.dart' show kIsWeb;
import '../models/daily_stats.dart';
import '../models/app_usage.dart';
import '../database/app_usage_dao.dart';
import '../database/daily_stats_dao.dart';
import 'mock_data_service.dart';

class StatisticsService {
  final AppUsageDao _appUsageDao = AppUsageDao();
  final DailyStatsDao _dailyStatsDao = DailyStatsDao();

  // 获取今日统计（如果不存在则计算）
  Future<DailyStats> getTodayStats() async {
    // Web 平台返回测试数据
    if (kIsWeb) {
      return MockDataService.generateTodayStats();
    }

    final today = DateTime.now();
    
    // 先查数据库
    var stats = await _dailyStatsDao.getTodayStats();
    if (stats != null) {
      return stats;
    }

    // 如果不存在，计算并保存
    stats = await _calculateDailyStats(today);
    if (stats != null) {
      await _dailyStatsDao.upsertDailyStats(stats);
    } else {
      // 如果没有数据，返回空统计
      stats = DailyStats(
        date: today,
        totalTime: 0,
        createdAt: DateTime.now(),
        updatedAt: DateTime.now(),
      );
    }

    return stats;
  }

  // 计算指定日期的统计
  Future<DailyStats?> _calculateDailyStats(DateTime date) async {
    final startOfDay = DateTime(date.year, date.month, date.day);
    final endOfDay = startOfDay.add(const Duration(days: 1));

    // 获取该日期的所有应用使用记录
    final appUsages = await _appUsageDao.getAppUsages(
      startTime: startOfDay,
      endTime: endOfDay,
    );

    if (appUsages.isEmpty) return null;

    // 按分类聚合
    final categoryTime = <String, int>{};
    int totalTime = 0;
    int appSwitchCount = 0;

    for (final usage in appUsages) {
      categoryTime[usage.category] = (categoryTime[usage.category] ?? 0) + usage.duration;
      totalTime += usage.duration;
      appSwitchCount += usage.deviceUnlockCount;
    }

    // 计算效率评分
    final efficiencyScore = _calculateEfficiencyScore(categoryTime, totalTime);

    // 计算专注度评分
    final focusScore = _calculateFocusScore(appSwitchCount, totalTime);

    return DailyStats(
      date: startOfDay,
      totalTime: totalTime,
      workTime: categoryTime['work'] ?? 0,
      studyTime: categoryTime['study'] ?? 0,
      entertainmentTime: categoryTime['entertainment'] ?? 0,
      socialTime: categoryTime['social'] ?? 0,
      toolTime: categoryTime['tool'] ?? 0,
      efficiencyScore: efficiencyScore,
      focusScore: focusScore,
      appSwitchCount: appSwitchCount,
      createdAt: DateTime.now(),
      updatedAt: DateTime.now(),
    );
  }

  // 计算效率评分
  int _calculateEfficiencyScore(Map<String, int> categoryTime, int totalTime) {
    if (totalTime == 0) return 0;

    // 工作时间占比（40%）
    final workRatio = (categoryTime['work'] ?? 0) / totalTime;
    final workScore = workRatio * 40;

    // 学习时间占比（30%）
    final studyRatio = (categoryTime['study'] ?? 0) / totalTime;
    final studyScore = studyRatio * 30;

    // 娱乐时间占比（越低越好，30%）
    final entertainmentRatio = (categoryTime['entertainment'] ?? 0) / totalTime;
    final entertainmentScore = (1 - entertainmentRatio) * 30;

    return (workScore + studyScore + entertainmentScore).round();
  }

  // 计算专注度评分
  int _calculateFocusScore(int appSwitchCount, int totalTime) {
    if (totalTime == 0) return 0;

    // 平均每小时切换次数
    final switchesPerHour = (appSwitchCount / (totalTime / 3600));
    
    // 理想情况：每小时切换 < 10 次 = 100分
    // 每小时切换 > 50 次 = 0分
    final score = 100 - (switchesPerHour * 2).clamp(0, 100);
    
    return score.round();
  }

  // 获取本周统计
  Future<List<DailyStats>> getWeekStats() async {
    // Web 平台返回测试数据
    if (kIsWeb) {
      return MockDataService.generateWeekStats();
    }

    final stats = await _dailyStatsDao.getWeekStats();
    
    // 如果数据不完整，计算缺失的日期
    final now = DateTime.now();
    final startOfWeek = now.subtract(Duration(days: now.weekday - 1));
    
    final result = <DailyStats>[];
    for (int i = 0; i < 7; i++) {
      final date = startOfWeek.add(Duration(days: i));
      final existing = stats.firstWhere(
        (s) => s.date.year == date.year && 
               s.date.month == date.month && 
               s.date.day == date.day,
        orElse: () => DailyStats(
          date: date,
          totalTime: 0,
          createdAt: DateTime.now(),
          updatedAt: DateTime.now(),
        ),
      );
      result.add(existing);
    }
    
    return result;
  }

  // 获取本月统计
  Future<List<DailyStats>> getMonthStats() async {
    return await _dailyStatsDao.getMonthStats();
  }

  // 刷新今日统计（重新计算）
  Future<DailyStats> refreshTodayStats() async {
    final today = DateTime.now();
    final stats = await _calculateDailyStats(today);
    
    if (stats != null) {
      await _dailyStatsDao.upsertDailyStats(stats);
      return stats;
    } else {
      final emptyStats = DailyStats(
        date: today,
        totalTime: 0,
        createdAt: DateTime.now(),
        updatedAt: DateTime.now(),
      );
      await _dailyStatsDao.upsertDailyStats(emptyStats);
      return emptyStats;
    }
  }

  // 获取 Top 应用
  Future<List<AppUsage>> getTopApps({
    required DateTime startTime,
    required DateTime endTime,
    int limit = 10,
  }) async {
    // Web 平台返回测试数据
    if (kIsWeb) {
      return MockDataService.generateTopApps().take(limit).toList();
    }

    return await _appUsageDao.getTopApps(
      startTime: startTime,
      endTime: endTime,
      limit: limit,
    );
  }
}