/// Rotation configuration for the duty schedule generator.
///
/// Stored in `app_settings` with key `rotation_config`. Contains:
/// - Ordered list of IT Staff IDs for general rotation
/// - Ordered list of non-Islam IT Staff IDs for Friday AM rotation
/// - Set of excluded IT Staff IDs
/// - Initial AM and PM duty assignments for the next generated schedule
class RotationConfig {
  RotationConfig({
    List<String>? rotationOrder,
    List<String>? fridayAmOrder,
    List<String>? excludedStaffIds,
    this.initialAmStaffId,
    this.initialPmStaffId,
  }) : rotationOrder = rotationOrder ?? [],
       fridayAmOrder = fridayAmOrder ?? [],
       excludedStaffIds = excludedStaffIds ?? [];

  /// Ordered IDs for standard AM/PM rotation.
  final List<String> rotationOrder;

  /// Ordered IDs for Friday AM duty (non-Islam staff only).
  final List<String> fridayAmOrder;

  /// Staff IDs excluded from all rotation.
  final List<String> excludedStaffIds;

  /// The staff member that should take AM duty on the first day of the next
  /// generated schedule. `null` means "continue from last week".
  final String? initialAmStaffId;

  /// The staff member that should take PM duty on the first day of the next
  /// generated schedule. `null` means "continue from last week".
  final String? initialPmStaffId;

  factory RotationConfig.fromJson(Map<String, dynamic> json) {
    return RotationConfig(
      rotationOrder: _toStringList(json['rotation_order']),
      fridayAmOrder: _toStringList(json['friday_am_order']),
      excludedStaffIds: _toStringList(json['excluded_staff_ids']),
      initialAmStaffId: json['initial_am_staff_id'] as String?,
      initialPmStaffId: json['initial_pm_staff_id'] as String?,
    );
  }

  Map<String, dynamic> toJson() => {
    'rotation_order': rotationOrder,
    'friday_am_order': fridayAmOrder,
    'excluded_staff_ids': excludedStaffIds,
    'initial_am_staff_id': initialAmStaffId,
    'initial_pm_staff_id': initialPmStaffId,
  };

  RotationConfig copyWith({
    List<String>? rotationOrder,
    List<String>? fridayAmOrder,
    List<String>? excludedStaffIds,
    String? initialAmStaffId,
    String? initialPmStaffId,
    bool clearInitialAm = false,
    bool clearInitialPm = false,
  }) {
    return RotationConfig(
      rotationOrder: rotationOrder ?? this.rotationOrder,
      fridayAmOrder: fridayAmOrder ?? this.fridayAmOrder,
      excludedStaffIds: excludedStaffIds ?? this.excludedStaffIds,
      initialAmStaffId: clearInitialAm
          ? null
          : (initialAmStaffId ?? this.initialAmStaffId),
      initialPmStaffId: clearInitialPm
          ? null
          : (initialPmStaffId ?? this.initialPmStaffId),
    );
  }

  static List<String> _toStringList(dynamic value) {
    if (value is List) return value.map((e) => e.toString()).toList();
    return [];
  }
}