import { ConflictException } from '@nestjs/common';

import { BookingBatchService } from './booking-batch.service';
import { Booking } from '../bookings/entities/booking.entity';

/**
 * Export whole-booking single-train gate: an export booking never splits — it
 * rides one train whole or is rejected. The report must try every fillable
 * train on the day (first full → use the second), and when none fits, say how
 * much space is still bookable so the customer knows what he CAN book.
 */
describe('BookingBatchService — exportSpaceReport (whole-booking, single train)', () => {
  const DAY = new Date('2026-07-20T10:00:00Z');

  const schedule = (id: string) => ({
    id,
    status: 'SCHEDULED',
    direction: 'EXPORT',
    scheduledDepartureDate: DAY,
    bookingWindowStatus: 'OPEN',
    windowPhase: null, // legacy gate: OPEN alone makes it fillable
  });

  const fullGraph = (id: string) => ({
    id,
    originStationId: 'yard-a',
    destinationStationId: 'yard-b',
    routeId: null, // legacy two-stop pseudo-route — no milestone query
    scheduleBookings: [],
    trainSet: {
      locomotive: {
        maxPullWeightTons: 500,
        maxTrainLengthMeters: 140,
        overageToleranceTons: 0,
        overageToleranceMeters: 0,
      },
    },
  });

  const exportBooking = (cargoTons: number) =>
    ({
      id: 'bk-exp',
      freightType: 'BULK',
      tradeDirection: 'EXPORT',
      scheduledDate: DAY,
      originYardId: 'yard-a',
      destinationYardId: 'yard-b',
      cargoTotalWeightVgm: cargoTons,
      bookingContainers: [],
    }) as unknown as Booking;

  // A reserved bulk booking heavy enough to exhaust the 500t pull budget.
  const heavyReserved = {
    id: 'bk-heavy',
    freightType: 'BULK',
    originYardId: 'yard-a',
    destinationYardId: 'yard-b',
    cargoTotalWeightVgm: 476,
    bookingContainers: [],
  } as unknown as Booking;

  let service: BookingBatchService;
  let trainSchedulesRepository: {
    findAll: jest.Mock;
    findByIdWithFullGraph: jest.Mock;
    findById: jest.Mock;
  };
  let bookingsRepository: { findReservedForSchedule: jest.Mock };

  beforeEach(() => {
    trainSchedulesRepository = {
      findAll: jest.fn().mockResolvedValue([]),
      findByIdWithFullGraph: jest
        .fn()
        .mockImplementation(async (id: string) => fullGraph(id)),
      findById: jest.fn(),
    };
    bookingsRepository = { findReservedForSchedule: jest.fn().mockResolvedValue([]) };

    // WagonType.find() → [] so representative default dims apply (bulk 60t
    // payload / 23.4t tare / 14m); RouteMilestone is never queried (routeId null).
    const genericRepo = { find: jest.fn().mockResolvedValue([]) };
    const dataSource = { getRepository: jest.fn().mockReturnValue(genericRepo) };

    service = new BookingBatchService(
      dataSource as never,
      bookingsRepository as never,
      trainSchedulesRepository as never,
      {} as never, // trainScheduleBookingsRepository
      {} as never, // notifier
      {} as never, // scheduler
      {} as never, // trainSchedulingService
      {} as never, // billing
      {} as never, // bookingWindowGateway
      {} as never, // pricingService
    );
  });

  it('uses the other train when the first one is full', async () => {
    trainSchedulesRepository.findAll.mockResolvedValue([
      schedule('train-1'),
      schedule('train-2'),
    ]);
    bookingsRepository.findReservedForSchedule.mockImplementation(
      async (id: string) => (id === 'train-1' ? [heavyReserved] : []),
    );

    const report = await service.exportSpaceReport(exportBooking(60));

    expect(report.scheduleId).toBe('train-2');
  });

  it('rejects a booking no single train fits and reports the bookable space', async () => {
    trainSchedulesRepository.findAll.mockResolvedValue([schedule('train-1')]);

    const report = await service.exportSpaceReport(exportBooking(900));

    expect(report.scheduleId).toBeNull();
    expect(report.bestAvailable).not.toBeNull();
    expect(report.bestAvailable!.cargoTons).toBeGreaterThan(0);
    expect(report.bestAvailable!.cargoTons).toBeLessThan(900);
    expect(report.fullMessage).toMatch(/largest remaining space is about .* tons/);
    expect(report.fullMessage).toMatch(/single train whole/);

    await expect(service.pickExportSchedule(exportBooking(900))).rejects.toThrow(
      ConflictException,
    );
  });

  it('says no train is accepting bookings when the day has none', async () => {
    trainSchedulesRepository.findAll.mockResolvedValue([]);

    const report = await service.exportSpaceReport(exportBooking(60));

    expect(report.scheduleId).toBeNull();
    expect(report.fullMessage).toBe(
      'No export train is accepting bookings for this day',
    );
  });
});