import type { Media, MediaTitle } from './media';

interface SchedulePage {
  data: {
    Page: {
      media: {
        title: MediaTitle;
        synonyms: string[];
        id: number;
        idMal: number;
        episodes: number;
        nextAiringEpisode?: {
          episode: number;
          airingAt?: number;
        };
        coverImage: {
          extraLarge: string;
          medium: string;
        };
      }[];
      pageInfo: {
        hasNextPage: boolean;
      };
    };
  };
}

const schedulePage = async (
  page: number,
  year: number,
  season: 'WINTER' | 'SPRING' | 'SUMMER' | 'FALL'
): Promise<SchedulePage> =>
  await (
    await fetch('https://graphql.anilist.co', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Accept: 'application/json'
      },
      body: JSON.stringify({
        query: `{
  Page(page: ${page}) {
    pageInfo {
      hasNextPage
    }
    media(season: ${season}, seasonYear: ${year}) {
      id idMal episodes synonyms
      title { english romaji native }
			nextAiringEpisode { episode airingAt }
      coverImage { extraLarge medium }
    }
  }
}`
      })
    })
  ).json();

type Season = 'WINTER' | 'SPRING' | 'SUMMER' | 'FALL';

export const scheduleMediaListCollection = async (
  year: number,
  season: Season,
  includeLastSeason = false
) => {
  const scheduledMedia = [];
  let page = 1;
  let currentPage = await schedulePage(page, year, season);

  for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);

  while (currentPage['data']['Page']['pageInfo']['hasNextPage']) {
    for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);

    page += 1;
    currentPage = await schedulePage(page, year, season);
  }

  for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);

  if (includeLastSeason) {
    const lastSeason = {
      WINTER: 'FALL',
      SPRING: 'WINTER',
      SUMMER: 'SPRING',
      FALL: 'SUMMER'
    }[season];

    const lastSeasonYear = season === 'WINTER' ? year - 1 : year;

    let page = 1;
    let currentPage = await schedulePage(page, lastSeasonYear, lastSeason as Season);

    for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);

    while (currentPage['data']['Page']['pageInfo']['hasNextPage']) {
      for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);

      page += 1;
      currentPage = await schedulePage(page, lastSeasonYear, lastSeason as Season);
    }

    for (const candidate of currentPage.data.Page.media) scheduledMedia.push(candidate);
  }

  return scheduledMedia as Partial<Media[]>;
};