import { findBestMatchingTitle } from "~/libs/findBestMatchingTitle";
import { sleep } from "~/libs/sleep";
import { Episode, type EpisodesResponse } from "~/types/episode";

export async function getEpisodesFromAniwatch(
  aniListId: number,
  shouldRetry: boolean = false,
): Promise<EpisodesResponse | null> {
  try {
    const animeTitle = await import("~/libs/anilist/getTitle")
      .then(({ fetchTitleFromAnilist }) =>
        fetchTitleFromAnilist(aniListId, undefined),
      )
      .then((title) => ({
        english: title?.title?.english,
        userPreferred: title?.title?.userPreferred,
      }));

    if (!animeTitle.english && !animeTitle.userPreferred) {
      return null;
    }

    const aniwatchId = await getAniwatchId(animeTitle);
    if (!aniwatchId) {
      return null;
    }

    const episodes: Episode[] | null = await fetchEpisodes(
      aniwatchId,
      aniListId,
    );
    if (!episodes || episodes.length === 0) {
      return null;
    }

    // Tower of God S2
    if (aniListId == 153406) {
      const aniwatchId = await getAniwatchId({
        english: "Tower of God Season 2: Workshop Battle",
      });
      if (aniwatchId) {
        const lastEpisodeOfPreviousTitle = episodes.at(-1)!!.number;
        return {
          providerId: "aniwatch",
          episodes: await fetchEpisodes(aniwatchId, aniListId).then(
            (extraEpisodes) =>
              episodes.concat(
                extraEpisodes?.map(({ number, ...episode }) => ({
                  ...episode,
                  number: number + lastEpisodeOfPreviousTitle,
                })) ?? [],
              ),
          ),
        };
      }
    }

    return { providerId: "aniwatch", episodes };
  } catch (error) {
    if (shouldRetry && "response" in error && error.response.status === 429) {
      console.log(
        "429, retrying in",
        error.response.headers.get("Retry-After"),
      );
      return sleep(
        Number(error.response.headers.get("Retry-After")!) * 1000,
      ).then(() => getEpisodesFromAniwatch(aniListId));
    }

    console.error(
      new Error(
        `Error trying to load episodes from aniwatch; aniListId: ${aniListId}`,
        { cause: error },
      ),
    );
  }

  return null;
}

async function fetchEpisodes(
  aniwatchId: string,
  aniListId: number,
): Promise<
  | {
      number: number;
      id: string;
      updatedAt: number;
      description?: string | null | undefined;
      title?: string | null | undefined;
      img?: string | null | undefined;
      rating?: number | null | undefined;
    }[]
  | null
> {
  return await fetch(
    `https://aniwatch.up.railway.app/api/v2/hianime/anime/${aniwatchId}/episodes`,
  )
    .then(
      (res) =>
        res.json() as Promise<{
          success: boolean;
          data: AniwatchEpisodesResponse;
        }>,
    )
    .then(({ success, data }) => {
      if (!success || data.totalEpisodes === 0) {
        console.error(
          `Error trying to load episodes from aniwatch; aniListId: ${aniListId}, totalEpisodes: ${totalEpisodes}`,
        );
        return null;
      }
      const { totalEpisodes, episodes } = data;

      return episodes.map<Episode>(({ episodeId, number, title }) => ({
        id: episodeId,
        number,
        title,
        updatedAt: 0,
      }));
    });
}

function getAniwatchId(
  animeTitle: Partial<{ english: string; userPreferred: string }>,
): Promise<string | undefined> {
  return fetch(
    `https://aniwatch.up.railway.app/api/v2/hianime/search?q=${encodeURIComponent(animeTitle.english ?? animeTitle.userPreferred!)}`,
  )
    .then(
      (res) =>
        res.json() as Promise<{
          success: boolean;
          data: AniwatchSearchResponse;
        }>,
    )
    .then(({ success, data: { animes } }) => {
      if (!success) {
        return;
      }

      const bestMatchingTitle = findBestMatchingTitle(
        animeTitle,
        animes.map((anime) => ({
          english: anime.name,
          userPreferred: anime.jname,
        })),
      );
      return animes.find(
        (anime) =>
          anime.name === bestMatchingTitle || anime.jname === bestMatchingTitle,
      )?.id;
    });
}

export interface AniwatchEpisodesResponse {
  totalEpisodes: number;
  episodes: AniwatchEpisode[];
}

export interface AniwatchEpisode {
  title: string;
  episodeId: string;
  number: number;
  isFiller: boolean;
}

export interface AniwatchSearchResponse {
  animes: Anime[];
  currentPage: number;
  hasNextPage: boolean;
  totalPages: number;
}

interface Anime {
  id: string;
  name: string;
  jname: string;
  poster: string;
  duration: string;
  type: Type;
  rating: null | string;
  episodes: Episodes;
}

interface Episodes {
  sub: number | null;
  dub: number | null;
}

enum Type {
  Movie = "Movie",
  Ona = "ONA",
  Ova = "OVA",
  Special = "Special",
  Tv = "TV",
}