import 'dart:math';
import '../models/focus_session.dart';
import '../models/user_progress.dart';

/// Service for calculating and managing points
class PointsService {
  /// Calculate points earned from a focus session
  /// Returns a map with breakdown: {basePoints, honestyBonus, total, breakdown}
  Map<String, dynamic> calculateSessionPoints(FocusSession session) {
    // Base points = actual minutes focused
    int basePoints = session.actualMinutes;

    // Honesty bonus: reward for recording distractions (with cap to prevent abuse)
    int honestyBonus = _calculateHonestyBonus(
      session.distractionCount,
      session.actualMinutes,
    );

    int total = basePoints + honestyBonus;

    // Detailed breakdown for UI display
    List<Map<String, dynamic>> breakdown = [
      {
        'label': '专注时长',
        'value': basePoints,
        'description': '每专注1分钟获得1积分',
      },
      {
        'label': '诚实奖励',
        'value': honestyBonus,
        'description': '记录分心情况获得额外积分',
      },
    ];

    return {
      'basePoints': basePoints,
      'honestyBonus': honestyBonus,
      'total': total,
      'breakdown': breakdown,
    };
  }

  /// Calculate honesty bonus with anti-abuse cap
  /// Strategy: Max 1 rewarded distraction per 10 minutes
  int _calculateHonestyBonus(int distractionCount, int minutes) {
    if (distractionCount == 0) return 0;

    // Cap: 1 rewarded distraction per 10 minutes
    // 15 min → max 2 distractions
    // 25 min → max 3 distractions
    // 45 min → max 5 distractions
    int maxBonusDistraction = max(1, (minutes / 10).ceil());
    int rewardedCount = min(distractionCount, maxBonusDistraction);

    return rewardedCount; // 1 point per recorded distraction (up to cap)
  }

  /// Process daily check-in and return points earned with detailed breakdown
  Map<String, dynamic> processCheckIn(UserProgress progress) {
    final now = DateTime.now();

    // Base check-in points
    int points = 5;
    List<Map<String, dynamic>> breakdown = [
      {
        'label': '每日签到',
        'value': 5,
        'description': '每日首次签到获得基础积分',
      },
    ];

    // Update check-in streak
    if (_isConsecutiveDay(progress.lastCheckInDate, now)) {
      progress.consecutiveCheckIns++;
      
      // Bonus for streak milestones
      if (progress.consecutiveCheckIns % 7 == 0) {
        int weeklyBonus = 30;
        points += weeklyBonus;
        breakdown.add({
          'label': '连续签到奖励',
          'value': weeklyBonus,
          'description': '连续签到${progress.consecutiveCheckIns}天',
        });
      } else if (progress.consecutiveCheckIns % 30 == 0) {
        int monthlyBonus = 100;
        points += monthlyBonus;
        breakdown.add({
          'label': '连续签到奖励',
          'value': monthlyBonus,
          'description': '连续签到${progress.consecutiveCheckIns}天',
        });
      }
    } else {
      progress.consecutiveCheckIns = 1;
    }

    // Update last check-in date
    progress.lastCheckInDate = now;

    // Add to check-in history (store date only, not time)
    final dateOnly = DateTime(now.year, now.month, now.day);
    if (!progress.checkInHistory.any((date) =>
        date.year == dateOnly.year &&
        date.month == dateOnly.month &&
        date.day == dateOnly.day)) {
      progress.checkInHistory.add(dateOnly);
    }

    return {
      'points': points,
      'consecutiveDays': progress.consecutiveCheckIns,
      'breakdown': breakdown,
    };
  }

  /// Check if two dates are consecutive days
  bool _isConsecutiveDay(DateTime? lastDate, DateTime currentDate) {
    if (lastDate == null) return false;

    final lastDateOnly = DateTime(lastDate.year, lastDate.month, lastDate.day);
    final currentDateOnly =
        DateTime(currentDate.year, currentDate.month, currentDate.day);

    final diff = currentDateOnly.difference(lastDateOnly).inDays;
    return diff == 1;
  }

  /// Calculate level based on total points
  Map<String, dynamic> calculateLevel(int totalPoints) {
    // Simple level calculation: each level requires 100 points
    int level = (totalPoints / 100).floor() + 1;
    int pointsForCurrentLevel = (level - 1) * 100;
    int pointsForNextLevel = level * 100;
    int pointsInCurrentLevel = totalPoints - pointsForCurrentLevel;
    double progress = pointsInCurrentLevel / 100;

    return {
      'level': level,
      'pointsForCurrentLevel': pointsForCurrentLevel,
      'pointsForNextLevel': pointsForNextLevel,
      'pointsInCurrentLevel': pointsInCurrentLevel,
      'progress': progress,
    };
  }

  /// Get points balance summary
  Map<String, dynamic> getPointsSummary(UserProgress progress) {
    final levelInfo = calculateLevel(progress.totalPoints);
    
    return {
      'currentPoints': progress.currentPoints,
      'totalPoints': progress.totalPoints,
      'level': levelInfo['level'],
      'levelProgress': levelInfo['progress'],
      'consecutiveCheckIns': progress.consecutiveCheckIns,
      'totalCheckIns': progress.checkInHistory.length,
    };
  }
}