import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'vehicle_model.dart';
import 'vehicle_api.dart';

class VehicleApplyState {
  final VehicleModel vehicle;
  final bool isSubmitting;
  final bool hasConflict;
  final List<String> passengers;
  const VehicleApplyState({
    required this.vehicle,
    this.isSubmitting = false,
    this.hasConflict = false,
    this.passengers = const [],
  });
  VehicleApplyState copyWith({
    VehicleModel? vehicle,
    bool? isSubmitting,
    bool? hasConflict,
    List<String>? passengers,
  }) =>
      VehicleApplyState(
        vehicle: vehicle ?? this.vehicle,
        isSubmitting: isSubmitting ?? this.isSubmitting,
        hasConflict: hasConflict ?? this.hasConflict,
        passengers: passengers ?? this.passengers,
      );
}

class VehicleApplyController extends StateNotifier<VehicleApplyState> {
  final VehicleApi _api;
  VehicleApplyController(this._api)
    : super(
        VehicleApplyState(
          vehicle: VehicleModel(
            id: '',
            applicationNo: '',
            applicantId: '',
            applicantName: '',
            deptId: '',
            deptName: '',
            purpose: '',
            reason: '',
            origin: '',
            destination: '',
            startTime: DateTime.now(),
            endTime: DateTime.now().add(const Duration(hours: 4)),
            createTime: DateTime.now(),
            updateTime: DateTime.now(),
          ),
        ),
      );

  void updateVehicleId(String v) {
    state = state.copyWith(
      vehicle: state.vehicle.copyWith(vehicleId: v),
    );
    _checkConflict();
  }

  void updatePurpose(String v) =>
      state = state.copyWith(vehicle: state.vehicle.copyWith(purpose: v));

  void updateReason(String v) =>
      state = state.copyWith(vehicle: state.vehicle.copyWith(reason: v));

  void updateOrigin(String v) =>
      state = state.copyWith(vehicle: state.vehicle.copyWith(origin: v));

  void updateOriginCoords(double? lng, double? lat) =>
      state = state.copyWith(
        vehicle: state.vehicle.copyWith(
          originLongitude: lng,
          originLatitude: lat,
        ),
      );

  void updateDestination(String v) =>
      state = state.copyWith(vehicle: state.vehicle.copyWith(destination: v));

  void updateDestCoords(double? lng, double? lat) =>
      state = state.copyWith(
        vehicle: state.vehicle.copyWith(
          destLongitude: lng,
          destLatitude: lat,
        ),
      );

  void updateStartTime(DateTime t) {
    state = state.copyWith(vehicle: state.vehicle.copyWith(startTime: t));
    _checkConflict();
  }

  void updateEndTime(DateTime t) {
    state = state.copyWith(vehicle: state.vehicle.copyWith(endTime: t));
    _checkConflict();
  }

  void updatePassengerCount(int v) => state = state.copyWith(
    vehicle: state.vehicle.copyWith(passengerCount: v < 1 ? 1 : v),
  );

  void addPassenger(String name) {
    if (!state.passengers.contains(name)) {
      state = state.copyWith(passengers: [...state.passengers, name]);
    }
  }

  void removePassenger(String name) {
    state = state.copyWith(
      passengers: state.passengers.where((p) => p != name).toList(),
    );
  }

  /// Mock conflict detection
  void _checkConflict() {
    final vid = state.vehicle.vehicleId;
    if (vid.isEmpty) {
      state = state.copyWith(hasConflict: false);
      return;
    }
    // Mock: 车牌 '京A88888' 在所选时段冲突
    final hasConflict = vid == '京A88888' &&
        state.vehicle.startTime.isBefore(
          DateTime(2026, 6, 4, 12, 0),
        );
    state = state.copyWith(hasConflict: hasConflict);
  }

  bool validate() {
    final v = state.vehicle;
    if (v.vehicleId.isEmpty) return false;
    if (v.reason.trim().isEmpty) return false;
    if (v.purpose.isEmpty) return false;
    if (!v.endTime.isAfter(v.startTime)) return false;
    if (state.hasConflict) return false;
    return true;
  }

  Future<bool> submit() async {
    if (!validate()) return false;
    state = state.copyWith(isSubmitting: true);
    try {
      await _api.submit(state.vehicle.copyWith(status: 'pending'));
      return true;
    } catch (_) {
      return false;
    } finally {
      state = state.copyWith(isSubmitting: false);
    }
  }

  Future<bool> saveDraft() async {
    state = state.copyWith(isSubmitting: true);
    try {
      await _api.saveDraft(state.vehicle);
      return true;
    } catch (_) {
      return false;
    } finally {
      state = state.copyWith(isSubmitting: false);
    }
  }
}

final vehicleApplyProvider = StateNotifierProvider.autoDispose
    .family<VehicleApplyController, VehicleApplyState, String?>((ref, editId) {
      return VehicleApplyController(ref.read(vehicleApiProvider));
    });