/// Metadata for a single recorded ECU datalog session.
class DatalogSession {
  final int? id;
  final String ecuType;
  final DateTime startTime;
  final DateTime? endTime;
  final int frameCount;

  const DatalogSession({
    this.id,
    required this.ecuType,
    required this.startTime,
    this.endTime,
    this.frameCount = 0,
  });

  Duration get duration {
    final end = endTime ?? DateTime.now();
    return end.difference(startTime);
  }

  String get durationLabel {
    final d = duration;
    final m = d.inMinutes.remainder(60).toString().padLeft(2, '0');
    final s = d.inSeconds.remainder(60).toString().padLeft(2, '0');
    return '$m:$s';
  }

  DatalogSession copyWith({
    int? id,
    String? ecuType,
    DateTime? startTime,
    DateTime? endTime,
    int? frameCount,
  }) =>
      DatalogSession(
        id: id ?? this.id,
        ecuType: ecuType ?? this.ecuType,
        startTime: startTime ?? this.startTime,
        endTime: endTime ?? this.endTime,
        frameCount: frameCount ?? this.frameCount,
      );

  Map<String, dynamic> toMap() => {
        'id': id,
        'ecu_type': ecuType,
        'start_time': startTime.millisecondsSinceEpoch,
        'end_time': endTime?.millisecondsSinceEpoch,
        'frame_count': frameCount,
      };

  factory DatalogSession.fromMap(Map<String, dynamic> m) => DatalogSession(
        id: m['id'] as int?,
        ecuType: m['ecu_type'] as String,
        startTime:
            DateTime.fromMillisecondsSinceEpoch(m['start_time'] as int),
        endTime: m['end_time'] == null
            ? null
            : DateTime.fromMillisecondsSinceEpoch(m['end_time'] as int),
        frameCount: m['frame_count'] as int? ?? 0,
      );
}