import { env } from '../env';
import { HttpError, fetchJson } from '../lib/http';
import { ProviderAuthError, type PollingProvider } from './types';

interface LastfmTrack {
  name: string;
  artist: { '#text': string };
  album: { '#text': string };
  image: { size: string; '#text': string }[];
  '@attr'?: { nowplaying?: string };
}

const api = (params: Record<string, string>) =>
  `https://ws.audioscrobbler.com/2.0/?${new URLSearchParams({ ...params, api_key: env.LASTFM_API_KEY!, format: 'json' })}`;

export async function lastfmUserExists(username: string): Promise<{ name: string } | null> {
  try {
    const res = await fetchJson<{ user: { name: string } }>(api({ method: 'user.getinfo', user: username }));
    return res ? { name: res.user.name } : null;
  } catch (e) {
    if (e instanceof HttpError && e.status === 404) return null;
    throw e;
  }
}

export const lastfmProvider: PollingProvider = {
  id: 'lastfm',
  async poll(conn) {
    let res;
    try {
      res = await fetchJson<{ recenttracks: { track: LastfmTrack[] | LastfmTrack } }>(
        api({ method: 'user.getrecenttracks', user: conn.externalUserId, limit: '1' }),
      );
    } catch (e) {
      if (e instanceof HttpError && e.status === 404) throw new ProviderAuthError('last.fm user not found');
      throw e;
    }
    const raw = res?.recenttracks.track;
    const first = Array.isArray(raw) ? raw[0] : raw;
    if (!first || first['@attr']?.nowplaying !== 'true') return null;
    const art = first.image.find((i) => i.size === 'extralarge')?.['#text'] || null;
    return {
      track: {
        title: first.name,
        artist: first.artist['#text'],
        album: first.album['#text'] || null,
        // Last.fm serves a grey star placeholder when it has no art
        artworkUrl: art && !art.includes('2a96cbd8b46e442fc41c2b86b821562f') ? art : null,
      },
      isPlaying: true,
      progressMs: null,
    };
  },
};