/// أنواع المقاطع المكتشفة تلقائياً
enum SegmentType {
  warmup,   // إحماء - أول 5-10% من المسافة بسرعة منخفضة
  main,     // المرحلة الرئيسية
  cooldown, // تبريد - آخر 5-10% بسرعة متناقصة
  stop,     // نقطة توقف - سرعة < 0.3 m/s لأكثر من 10 ثوان
  sprint,   // تسارع - سرعة > 120% من المتوسط
  uphill,   // صعود - ارتفاع > 3% grade
  downhill, // نزول - انخفاض > 3% grade
}

/// نموذج مقطع من المسار
/// يمثل جزء من التمرين تم تقسيمه بناءً على تغيرات السرعة أو الارتفاع
class WorkoutSegment {
  final int segmentIndex;
  final SegmentType type;
  final double distanceMeters;
  final int durationSeconds;
  final double avgSpeedMps;
  final double maxSpeedMps;
  final double elevationChange; // positive = uphill, negative = downhill
  final int startCoordIndex; // index in coordinates list
  final int endCoordIndex;

  WorkoutSegment({
    required this.segmentIndex,
    required this.type,
    required this.distanceMeters,
    required this.durationSeconds,
    required this.avgSpeedMps,
    this.maxSpeedMps = 0,
    this.elevationChange = 0,
    required this.startCoordIndex,
    required this.endCoordIndex,
  });

  /// Pace in min/km
  double get paceMinKm {
    if (avgSpeedMps <= 0) return 0;
    double kmh = avgSpeedMps * 3.6;
    return kmh > 0 ? 60.0 / kmh : 0;
  }

  /// Gradient percentage (for elevation segments)
  double get gradientPercent {
    if (distanceMeters <= 0) return 0;
    return (elevationChange / distanceMeters) * 100;
  }

  Map<String, dynamic> toMap() {
    return {
      'segment_index': segmentIndex,
      'segment_type': type.name,
      'distance_meters': distanceMeters,
      'duration_seconds': durationSeconds,
      'avg_speed_mps': avgSpeedMps,
      'max_speed_mps': maxSpeedMps,
      'elevation_change': elevationChange,
      'start_coord_index': startCoordIndex,
      'end_coord_index': endCoordIndex,
    };
  }

  factory WorkoutSegment.fromMap(Map<String, dynamic> map) {
    return WorkoutSegment(
      segmentIndex: map['segment_index'] as int,
      type: SegmentType.values.firstWhere(
        (e) => e.name == map['segment_type'],
        orElse: () => SegmentType.main,
      ),
      distanceMeters: (map['distance_meters'] as num).toDouble(),
      durationSeconds: map['duration_seconds'] as int,
      avgSpeedMps: (map['avg_speed_mps'] as num).toDouble(),
      maxSpeedMps: (map['max_speed_mps'] as num?)?.toDouble() ?? 0,
      elevationChange: (map['elevation_change'] as num?)?.toDouble() ?? 0,
      startCoordIndex: map['start_coord_index'] as int,
      endCoordIndex: map['end_coord_index'] as int,
    );
  }

  /// Convert to API-compatible map
  Map<String, dynamic> toApiMap() {
    return {
      'segment_order': segmentIndex,
      'duration_seconds': durationSeconds,
      'distance_meters': distanceMeters.toInt(),
      'index_in_polyline': startCoordIndex,
    };
  }
}