import 'package:flutter_test/flutter_test.dart';
import 'package:uto_manager/domain/entities/authorized_rank.dart';
import 'package:uto_manager/domain/entities/doctrinal_branch.dart';
import 'package:uto_manager/domain/entities/echelon.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/value_objects/duty_mos.dart';
import 'package:uto_manager/infrastructure/codecs/unit_tree_codec.dart';

void main() {
  const codec = UnitTreeCodec();

  // ---------------------------------------------------------------------------
  // Fixtures
  // ---------------------------------------------------------------------------

  const brigade = UnitNode(
    unitId: 'bde-1',
    echelon: Echelon.brigade,
    branch: DoctrinalBranch.infantry,
    name: 'Test Brigade',
    isKeyLeader: false,
  );

  const battalion = UnitNode(
    unitId: 'bn-1',
    echelon: Echelon.battalion,
    branch: DoctrinalBranch.infantry,
    parentUnitId: 'bde-1',
    name: 'Test Battalion',
    isKeyLeader: false,
  );

  final slot = PositionSlot(
    slotId: 'slot-1',
    unitId: 'bde-1',
    positionTitle: 'Brigade Commander',
    dutyMos: DutyMos.unvalidated('11A'),
    authorizedRank: AuthorizedRank.o6,
    isKeyLeader: true,
  );

  final soldier = PersonnelRecord(
    soldierId: 'p-1',
    name: 'COL Test',
    primaryMos: DutyMos.unvalidated('11A'),
    payGrade: AuthorizedRank.o6,
    readinessState: ReadinessState.fullyMissionCapable,
    assignedSlotId: 'slot-1',
  );

  // ---------------------------------------------------------------------------
  // encode / decode round-trip
  // ---------------------------------------------------------------------------

  group('encode / decode round-trip', () {
    test('empty snapshot round-trips correctly', () {
      final json = codec.encode(units: [], slots: [], personnel: []);
      final snapshot = codec.decode(json);

      expect(snapshot.units, isEmpty);
      expect(snapshot.slots, isEmpty);
      expect(snapshot.personnel, isEmpty);
    });

    test('units round-trip with all fields preserved', () {
      final json = codec.encode(
        units: [brigade, battalion],
        slots: [],
        personnel: [],
      );
      final snapshot = codec.decode(json);

      expect(snapshot.units.length, 2);

      final decodedBde = snapshot.units.firstWhere((u) => u.unitId == 'bde-1');
      expect(decodedBde.name, brigade.name);
      expect(decodedBde.echelon, brigade.echelon);
      expect(decodedBde.branch, brigade.branch);
      expect(decodedBde.parentUnitId, isNull);
      expect(decodedBde.isKeyLeader, brigade.isKeyLeader);

      final decodedBn = snapshot.units.firstWhere((u) => u.unitId == 'bn-1');
      expect(decodedBn.parentUnitId, 'bde-1');
    });

    test('slots round-trip with all fields preserved', () {
      final json = codec.encode(
        units: [brigade],
        slots: [slot],
        personnel: [],
      );
      final snapshot = codec.decode(json);

      expect(snapshot.slots.length, 1);
      final decodedSlot = snapshot.slots.first;
      expect(decodedSlot.slotId, slot.slotId);
      expect(decodedSlot.unitId, slot.unitId);
      expect(decodedSlot.positionTitle, slot.positionTitle);
      expect(decodedSlot.dutyMos.code, slot.dutyMos.code);
      expect(decodedSlot.authorizedRank, slot.authorizedRank);
      expect(decodedSlot.isKeyLeader, slot.isKeyLeader);
      expect(decodedSlot.assignedPersonnelId, isNull);
    });

    test('personnel round-trip with all fields preserved', () {
      final json = codec.encode(
        units: [],
        slots: [],
        personnel: [soldier],
      );
      final snapshot = codec.decode(json);

      expect(snapshot.personnel.length, 1);
      final decoded = snapshot.personnel.first;
      expect(decoded.soldierId, soldier.soldierId);
      expect(decoded.name, soldier.name);
      expect(decoded.primaryMos.code, soldier.primaryMos.code);
      expect(decoded.payGrade, soldier.payGrade);
      expect(decoded.readinessState, soldier.readinessState);
      expect(decoded.assignedSlotId, soldier.assignedSlotId);
    });

    test('full snapshot round-trips correctly', () {
      final json = codec.encode(
        units: [brigade, battalion],
        slots: [slot],
        personnel: [soldier],
      );
      final snapshot = codec.decode(json);

      expect(snapshot.units.length, 2);
      expect(snapshot.slots.length, 1);
      expect(snapshot.personnel.length, 1);
    });

    test('encodeToMap / decodeFromMap round-trip', () {
      final map = codec.encodeToMap(
        units: [brigade],
        slots: [slot],
        personnel: [],
      );
      final snapshot = codec.decodeFromMap(map);

      expect(snapshot.units.length, 1);
      expect(snapshot.slots.length, 1);
    });
  });

  // ---------------------------------------------------------------------------
  // Schema version
  // ---------------------------------------------------------------------------

  group('schema version', () {
    test('encoded JSON contains version field', () {
      final json = codec.encode(units: [], slots: [], personnel: []);
      expect(json, contains('"version"'));
      expect(json, contains('"exportedAt"'));
    });

    test('throws FormatException for wrong schema version', () {
      final map = codec.encodeToMap(units: [], slots: [], personnel: []);
      map['version'] = 99;

      expect(
        () => codec.decodeFromMap(map),
        throwsA(isA<FormatException>()),
      );
    });

    test('throws FormatException for missing version', () {
      final map = codec.encodeToMap(units: [], slots: [], personnel: [])..remove('version');

      expect(
        () => codec.decodeFromMap(map),
        throwsA(isA<FormatException>()),
      );
    });

    test('throws FormatException for non-object JSON root', () {
      expect(
        () => codec.decode('[1, 2, 3]'),
        throwsA(isA<FormatException>()),
      );
    });
  });

  // ---------------------------------------------------------------------------
  // Null / optional fields
  // ---------------------------------------------------------------------------

  group('optional fields', () {
    test('null parentUnitId is preserved through round-trip', () {
      final json = codec.encode(units: [brigade], slots: [], personnel: []);
      final snapshot = codec.decode(json);
      expect(snapshot.units.first.parentUnitId, isNull);
    });

    test('null assignedPersonnelId is preserved through round-trip', () {
      final json = codec.encode(units: [], slots: [slot], personnel: []);
      final snapshot = codec.decode(json);
      expect(snapshot.slots.first.assignedPersonnelId, isNull);
    });

    test('null assignedSlotId is preserved through round-trip', () {
      final unassigned = PersonnelRecord(
        soldierId: 'p-2',
        name: 'SGT Free',
        primaryMos: DutyMos.unvalidated('11B'),
        payGrade: AuthorizedRank.e5,
        readinessState: ReadinessState.unknown,
      );
      final json = codec.encode(units: [], slots: [], personnel: [unassigned]);
      final snapshot = codec.decode(json);
      expect(snapshot.personnel.first.assignedSlotId, isNull);
    });

    test('qualifications list round-trips correctly', () {
      final soldierWithQuals = PersonnelRecord(
        soldierId: 'p-3',
        name: 'SGT Qualified',
        primaryMos: DutyMos.unvalidated('11B'),
        payGrade: AuthorizedRank.e5,
        readinessState: ReadinessState.fullyMissionCapable,
        qualifications: const ['Airborne', 'Ranger', 'SERE'],
      );
      final json = codec.encode(
        units: [],
        slots: [],
        personnel: [soldierWithQuals],
      );
      final snapshot = codec.decode(json);
      expect(
        snapshot.personnel.first.qualifications,
        containsAll(['Airborne', 'Ranger', 'SERE']),
      );
    });
  });
}