import 'package:equatable/equatable.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:uto_manager/domain/entities/personnel_record.dart';
import 'package:uto_manager/domain/entities/position_slot.dart';
import 'package:uto_manager/domain/entities/unit_node.dart';
import 'package:uto_manager/domain/services/mtoe_validation_engine.dart';

// ---------------------------------------------------------------------------
// State
// ---------------------------------------------------------------------------

/// State for the validation cubit.
sealed class ValidationState extends Equatable {
  const ValidationState();
}

/// No validation has been run yet.
class ValidationInitial extends ValidationState {
  const ValidationInitial();

  @override
  List<Object?> get props => [];
}

/// Validation is in progress.
class ValidationRunning extends ValidationState {
  const ValidationRunning();

  @override
  List<Object?> get props => [];
}

/// Validation completed with a (possibly empty) list of findings.
class ValidationComplete extends ValidationState {
  const ValidationComplete(this.findings);

  final List<ValidationFinding> findings;

  /// All critical findings.
  List<ValidationFinding> get critical =>
      findings.where((f) => f.severity == FindingSeverity.critical).toList();

  /// All warning findings.
  List<ValidationFinding> get warnings =>
      findings.where((f) => f.severity == FindingSeverity.warning).toList();

  /// All advisory findings.
  List<ValidationFinding> get advisories =>
      findings.where((f) => f.severity == FindingSeverity.advisory).toList();

  /// Returns findings for a specific [unitId].
  List<ValidationFinding> findingsForUnit(String unitId) =>
      findings.where((f) => f.unitId == unitId).toList();

  /// True if there are no findings.
  bool get isClean => findings.isEmpty;

  @override
  List<Object?> get props => [findings];
}

// ---------------------------------------------------------------------------
// Cubit
// ---------------------------------------------------------------------------

/// Runs the [MtoeValidationEngine] against the current unit tree snapshot
/// and exposes the resulting [ValidationFinding]s to the UI.
///
/// Call [validate] whenever the unit tree, slots, or personnel change.
class ValidationCubit extends Cubit<ValidationState> {
  ValidationCubit() : super(const ValidationInitial());

  final _engine = const MtoeValidationEngine();

  /// Runs all MTOE validation rules against the provided snapshot.
  ///
  /// Emits [ValidationRunning] while computing, then [ValidationComplete]
  /// with the results.
  void validate({
    required List<UnitNode> units,
    required List<PositionSlot> slots,
    required List<PersonnelRecord> personnel,
  }) {
    emit(const ValidationRunning());
    final findings = _engine.validate(
      units: units,
      slots: slots,
      personnel: personnel,
    );
    emit(ValidationComplete(findings));
  }

  /// Clears all findings and resets to the initial state.
  void clear() => emit(const ValidationInitial());
}