import { hostname, userInfo } from 'node:os';
import { Readable } from 'stream';

interface AuthInfo {
  token: string;
  userId: string;
  authHeaderValue: string;
}

export interface ServerCreds {
  server: string;
  user: string;
  password: string;
}

interface View {
  Id: string;
  CollectionType: string;
}

export interface Playlist {
  Name: string;
  Id: string;
  MediaType: string;
  songlist: SongMeta[];
}

export interface SongMeta {
  Id: string;
  Name: string;
  Path: string;
}

let tokenPromise: Promise<AuthInfo> | undefined = undefined;

const getAuthHeaderValue = (token?: string) => {
  let val = `MediaBrowser Client="JF-to-M3U",Device="CLI",DeviceId="${
    userInfo().username
  }-${hostname()}",Version="0.0.1"`;

  if (token) {
    val += `,Token="${token}"`;
  }
  return val;
};

const getAuthInfo = async ({ server, user, password }: ServerCreds) => {
  if (!tokenPromise) {
    const url = `${server}/Users/authenticatebyname`;
    console.log('URL: ', url);
    const response = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: getAuthHeaderValue(),
      },
      body: JSON.stringify({
        Username: user,
        Pw: password,
      }),
    });
    if (!response.ok) {
      console.error('Error authenticating to server: ', await response.text());
      console.log('Exiting due unrecoverable error');
      process.exit();
    }
    const authInfo = await response.json();
    const token = authInfo.AccessToken;
    const userId = authInfo.User.Id;
    const authHeaderValue = getAuthHeaderValue(token);
    tokenPromise = Promise.resolve({ token, authHeaderValue, userId });
  }
  return tokenPromise as Promise<AuthInfo>;
};

export const getAllViews = async (creds: ServerCreds): Promise<View[]> => {
  const auth = await getAuthInfo(creds);
  const url = `${creds.server}/UserViews?userId=${auth.userId}`;

  const response = await fetch(url, { headers: { Authorization: auth.authHeaderValue } });
  return (await response.json()).Items as View[];
};

export const getItemsByParent = async (creds: ServerCreds, parentId: string) => {
  const auth = await getAuthInfo(creds);
  const url = `${creds.server}/Items?userId=${auth.userId}&parentId=${parentId}`;

  const response = await fetch(url, { headers: { Authorization: auth.authHeaderValue } });
  return (await response.json()).Items;
};

export const getAllPlaylists = async (creds: ServerCreds): Promise<Playlist[]> => {
  const auth = await getAuthInfo(creds);
  const views = await getAllViews(creds);
  const musicViews = views.filter(c => c.CollectionType === 'music');
  const playlistViews = views.filter(c => c.CollectionType === 'playlists');
  const playlists: Playlist[] = (
    await Promise.all(playlistViews.map(c => getItemsByParent(creds, c.Id)))
  ).flat(Infinity);
  return playlists.filter(p => p.MediaType === 'Audio');
};

export const getSonglistForPlaylist = async (creds: ServerCreds, id: string) => {
  const auth = await getAuthInfo(creds);
  const response = await fetch(
    `${creds.server}/Playlists/${id}/Items?userId=${auth.userId}&fields=Path`,
    {
      headers: { Authorization: auth.authHeaderValue },
    },
  );
  return (await response.json()).Items as SongMeta[];
};

export const getSongFileBuffer = async (creds: ServerCreds, id: string) => {
  const auth = await getAuthInfo(creds);
  const response = await fetch(`${creds.server}/Items/${id}/File?userId=${auth.userId}`, {
    headers: { Authorization: auth.authHeaderValue },
  });
  return Readable.fromWeb(response.body);
};