import 'package:equatable/equatable.dart';

import 'package:uto_manager/domain/entities/authorized_rank.dart';
import 'package:uto_manager/domain/value_objects/duty_mos.dart';

/// Represents the readiness state of a soldier.
enum ReadinessState {
  /// Fully mission-capable; no limiting factors.
  fullyMissionCapable,

  /// Partially mission-capable; some limiting factors present.
  partiallyMissionCapable,

  /// Not mission-capable; significant limiting factors.
  notMissionCapable,

  /// Status unknown or not yet assessed.
  unknown;

  /// Returns a human-readable display name.
  String get displayName {
    switch (this) {
      case ReadinessState.fullyMissionCapable:
        return 'FMC';
      case ReadinessState.partiallyMissionCapable:
        return 'PMC';
      case ReadinessState.notMissionCapable:
        return 'NMC';
      case ReadinessState.unknown:
        return 'Unknown';
    }
  }
}

/// Represents a soldier's personnel record in the UTO system.
///
/// Contains identifying information, MOS qualifications, pay grade,
/// and current readiness state.
///
/// [name] is optional. When omitted the soldier is identified by
/// [positionTitle] (e.g. "Team Leader", "Rifleman").
class PersonnelRecord extends Equatable {
  const PersonnelRecord({
    required this.soldierId,
    required this.primaryMos,
    required this.payGrade,
    required this.readinessState,
    this.name,
    this.positionTitle,
    this.qualifications = const [],
    this.assignedSlotId,
  });

  /// Unique identifier for this soldier (UUID v4).
  final String soldierId;

  /// The soldier's full name (Last, First MI format), or null if unnamed.
  final String? name;

  /// The soldier's duty position title (e.g. "Team Leader", "Rifleman").
  ///
  /// Used as the display label when [name] is null.
  final String? positionTitle;

  /// The soldier's primary Military Occupational Specialty.
  final DutyMos primaryMos;

  /// The soldier's current pay grade.
  final AuthorizedRank payGrade;

  /// Additional MOS qualifications and special skills.
  final List<String> qualifications;

  /// The current readiness state of this soldier.
  final ReadinessState readinessState;

  /// The ID of the position slot this soldier is assigned to, or null.
  final String? assignedSlotId;

  /// Returns the best available display label for this soldier.
  ///
  /// Prefers [name]; falls back to [positionTitle]; then a generic label.
  String get displayLabel {
    if (name != null && name!.isNotEmpty) return name!;
    if (positionTitle != null && positionTitle!.isNotEmpty) return positionTitle!;
    return '(Unnamed Soldier)';
  }

  /// Returns true if this soldier is currently assigned to a position.
  bool get isAssigned => assignedSlotId != null;

  /// Returns true if this soldier is available for assignment.
  bool get isUnassigned => assignedSlotId == null;

  /// Returns true if this soldier is fully mission capable.
  bool get isFmc => readinessState == ReadinessState.fullyMissionCapable;

  /// Returns a copy of this [PersonnelRecord] with the given fields replaced.
  PersonnelRecord copyWith({
    String? soldierId,
    String? name,
    bool clearName = false,
    String? positionTitle,
    bool clearPositionTitle = false,
    DutyMos? primaryMos,
    AuthorizedRank? payGrade,
    List<String>? qualifications,
    ReadinessState? readinessState,
    String? assignedSlotId,
    bool clearAssignment = false,
  }) {
    return PersonnelRecord(
      soldierId: soldierId ?? this.soldierId,
      name: clearName ? null : (name ?? this.name),
      positionTitle: clearPositionTitle ? null : (positionTitle ?? this.positionTitle),
      primaryMos: primaryMos ?? this.primaryMos,
      payGrade: payGrade ?? this.payGrade,
      qualifications: qualifications ?? this.qualifications,
      readinessState: readinessState ?? this.readinessState,
      assignedSlotId: clearAssignment ? null : (assignedSlotId ?? this.assignedSlotId),
    );
  }

  @override
  List<Object?> get props => [
        soldierId,
        name,
        positionTitle,
        primaryMos,
        payGrade,
        qualifications,
        readinessState,
        assignedSlotId,
      ];

  @override
  String toString() => 'PersonnelRecord(id: $soldierId, label: $displayLabel, '
      'mos: ${primaryMos.code}, grade: ${payGrade.payGrade}, '
      'readiness: ${readinessState.displayName})';
}