/// Progression d'un lavage en cours.
class WashProgress {
  const WashProgress({
    required this.percent,
    required this.phaseLabel,
    this.phase,
    this.estimatedEndAt,
    this.remainingSeconds,
  });

  final int percent;
  final String phaseLabel;
  final String? phase;
  final DateTime? estimatedEndAt;
  final int? remainingSeconds;

  String get remainingLabel {
    if (remainingSeconds == null) return '';
    final s = remainingSeconds!;
    if (s <= 0) return 'Bientôt terminé';
    if (s < 60) return '$s s restantes';
    final min = (s / 60).ceil();
    return '$min min restantes';
  }

  factory WashProgress.fromJson(Map<String, dynamic>? json) {
    if (json == null) {
      return const WashProgress(percent: 0, phaseLabel: 'En cours');
    }
    return WashProgress(
      percent: json['percent'] as int? ?? 0,
      phase: json['phase'] as String?,
      phaseLabel: json['phase_label'] as String? ?? 'En cours',
      estimatedEndAt: json['estimated_end_at'] != null
          ? DateTime.tryParse(json['estimated_end_at'] as String)
          : null,
      remainingSeconds: json['remaining_seconds'] as int?,
    );
  }

  /// Calcul local si pas de données API (rafraîchissement chaque seconde).
  factory WashProgress.compute({
    required DateTime? startedAt,
    required DateTime? estimatedEndAt,
    required int? durationMinutes,
    required String? machineType,
    required String status,
  }) {
    if (status == 'pending_start') {
      return const WashProgress(percent: 0, phaseLabel: 'En attente de démarrage', phase: 'pending');
    }

    final now = DateTime.now();
    final end = estimatedEndAt ??
        (startedAt != null && durationMinutes != null
            ? startedAt.add(Duration(minutes: durationMinutes))
            : null);

    if (startedAt == null || end == null) {
      return const WashProgress(percent: 5, phaseLabel: 'Démarrage…', phase: 'lock');
    }

    final total = end.difference(startedAt).inSeconds.clamp(1, 999999);
    final elapsed = now.difference(startedAt).inSeconds.clamp(0, total);
    final percent = ((elapsed / total) * 100).round().clamp(0, 99);
    final remaining = end.difference(now).inSeconds.clamp(0, total);

    return WashProgress(
      percent: percent,
      phaseLabel: _phaseLabel(percent, machineType),
      phase: _phase(percent, machineType),
      estimatedEndAt: end,
      remainingSeconds: remaining,
    );
  }

  static String _phase(int percent, String? type) {
    final isDryer = type?.startsWith('dryer') ?? false;
    if (percent < 5) return 'lock';
    if (isDryer) {
      if (percent < 15) return 'heat';
      if (percent < 85) return 'dry';
      return 'finish';
    }
    if (percent < 15) return 'fill';
    if (percent < 55) return 'wash';
    if (percent < 75) return 'rinse';
    if (percent < 90) return 'spin';
    return 'finish';
  }

  static String _phaseLabel(int percent, String? type) {
    switch (_phase(percent, type)) {
      case 'lock':
        return 'Verrouillage';
      case 'heat':
        return 'Préchauffage';
      case 'dry':
        return 'Séchage';
      case 'fill':
        return 'Remplissage';
      case 'wash':
        return 'Lavage';
      case 'rinse':
        return 'Rinçage';
      case 'spin':
        return 'Essorage';
      case 'finish':
        return 'Finition';
      default:
        return 'En cours';
    }
  }
}