import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';
import {
  type LeagueScheduleDTO,
  type LeagueSchedulePreviewDTO,
} from '@gridpilot/racing/application';
import { getPreviewLeagueScheduleUseCase } from '@/lib/di-container';
import { LeagueSchedulePreviewPresenter } from '@/lib/presenters/LeagueSchedulePreviewPresenter';

interface RequestBody {
  seasonStartDate?: string;
  raceStartTime?: string;
  timezoneId?: string;
  recurrenceStrategy?: LeagueScheduleDTO['recurrenceStrategy'];
  intervalWeeks?: number;
  weekdays?: LeagueScheduleDTO['weekdays'];
  monthlyOrdinal?: LeagueScheduleDTO['monthlyOrdinal'];
  monthlyWeekday?: LeagueScheduleDTO['monthlyWeekday'];
  plannedRounds?: number;
}

function toLeagueScheduleDTO(body: RequestBody): LeagueScheduleDTO {
  const {
    seasonStartDate,
    raceStartTime,
    timezoneId,
    recurrenceStrategy,
    intervalWeeks,
    weekdays,
    monthlyOrdinal,
    monthlyWeekday,
    plannedRounds,
  } = body;

  if (
    !seasonStartDate ||
    !raceStartTime ||
    !timezoneId ||
    !recurrenceStrategy ||
    plannedRounds == null
  ) {
    throw new Error(
      'seasonStartDate, raceStartTime, timezoneId, recurrenceStrategy, and plannedRounds are required',
    );
  }

  const dto: LeagueScheduleDTO = {
    seasonStartDate,
    raceStartTime,
    timezoneId,
    recurrenceStrategy,
    plannedRounds,
  };

  if (intervalWeeks != null) {
    dto.intervalWeeks = intervalWeeks;
  }
  if (weekdays && weekdays.length > 0) {
    dto.weekdays = weekdays;
  }
  if (monthlyOrdinal != null) {
    dto.monthlyOrdinal = monthlyOrdinal;
  }
  if (monthlyWeekday != null) {
    dto.monthlyWeekday = monthlyWeekday;
  }

  return dto;
}

export async function POST(request: NextRequest) {
  try {
    const json = (await request.json()) as RequestBody;

    const schedule = toLeagueScheduleDTO(json);

    const presenter = new LeagueSchedulePreviewPresenter();
    const useCase = getPreviewLeagueScheduleUseCase();
    useCase.execute({
      schedule,
      maxRounds: 10,
    });
    const preview = presenter.getData();
    if (!preview) {
      return NextResponse.json({ error: 'Failed to generate preview' }, { status: 500 });
    }

    return NextResponse.json(preview, { status: 200 });
  } catch (error) {
    const message =
      error instanceof Error ? error.message : 'Failed to preview schedule';

    return NextResponse.json(
      {
        error: message,
      },
      { status: 400 },
    );
  }
}