feat: migration to TypeScript part 3

Co-authored-by: Su-Yong <simssy2205@gmail.com>

plugins/last-fm/back.ts

@@ -0,0 +1,191 @@
+import { BrowserWindow, net, shell } from 'electron';
+import md5 from 'md5';
+
+import { setOptions } from '../../config/plugins';
+import registerCallback, { SongInfo } from '../../providers/song-info';
+import defaultConfig from '../../config/defaults';
+import config from '../../config';
+
+const LastFMOptionsObj = config.get('plugins.last-fm');
+type LastFMOptions = typeof LastFMOptionsObj;
+
+interface LastFmData {
+  method: string,
+  timestamp?: number,
+}
+
+const createFormData = (parameters: Record<string, unknown>) => {
+  // Creates the body for in the post request
+  const formData = new URLSearchParams();
+  for (const key in parameters) {
+    formData.append(key, String(parameters[key]));
+  }
+
+  return formData;
+};
+
+const createQueryString = (parameters: Record<string, unknown>, apiSignature: string) => {
+  // Creates a querystring
+  const queryData = [];
+  parameters.api_sig = apiSignature;
+  for (const key in parameters) {
+    queryData.push(`${encodeURIComponent(key)}=${encodeURIComponent(String(parameters[key]))}`);
+  }
+
+  return '?' + queryData.join('&');
+};
+
+const createApiSig = (parameters: Record<string, unknown>, secret: string) => {
+  // This function creates the api signature, see: https://www.last.fm/api/authspec
+  const keys = [];
+  for (const key in parameters) {
+    keys.push(key);
+  }
+
+  keys.sort();
+  let sig = '';
+  for (const key of keys) {
+    if (String(key) === 'format') {
+      continue;
+    }
+
+    sig += `${key}${String(parameters[key])}`;
+  }
+
+  sig += secret;
+  sig = md5(sig);
+  return sig;
+};
+
+const createToken = async ({ api_key: apiKey, api_root: apiRoot, secret }: LastFMOptions) => {
+  // Creates and stores the auth token
+  const data = {
+    method: 'auth.gettoken',
+    apiKey,
+    format: 'json',
+  };
+  const apiSigature = createApiSig(data, secret);
+  const response = await net.fetch(`${apiRoot}${createQueryString(data, apiSigature)}`);
+  const json = await response.json() as Record<string, string>;
+  return json?.token;
+};
+
+const authenticateAndGetToken = async (config: LastFMOptions) => {
+  // Asks the user for authentication
+  await shell.openExternal(`https://www.last.fm/api/auth/?api_key=${config.api_key}&token=${config.token}`);
+  return await createToken(config);
+};
+
+const getAndSetSessionKey = async (config: LastFMOptions) => {
+  // Get and store the session key
+  const data = {
+    api_key: config.api_key,
+    format: 'json',
+    method: 'auth.getsession',
+    token: config.token,
+  };
+  const apiSignature = createApiSig(data, config.secret);
+  const response = await net.fetch(`${config.api_root}${createQueryString(data, apiSignature)}`);
+  const json = await response.json() as {
+    error?: string,
+      session?: {
+        key: string,
+      }
+  };
+  if (json.error) {
+    config.token = await authenticateAndGetToken(config);
+    setOptions('last-fm', config);
+  }
+  if (json.session) {
+    config.session_key = json?.session?.key;
+    setOptions('last-fm', config);
+  }
+  return config;
+};
+
+const postSongDataToAPI = async (songInfo: SongInfo, config: LastFMOptions, data: LastFmData) => {
+  // This sends a post request to the api, and adds the common data
+  if (!config.session_key) {
+    await getAndSetSessionKey(config);
+  }
+
+  const postData = {
+    track: songInfo.title,
+    duration: songInfo.songDuration,
+    artist: songInfo.artist,
+    ...(songInfo.album ? { album: songInfo.album } : undefined), // Will be undefined if current song is a video
+    api_key: config.api_key,
+    api_sig: '',
+    sk: config.session_key,
+    format: 'json',
+    ...data,
+  };
+
+  postData.api_sig = createApiSig(postData, config.secret);
+  net.fetch('https://ws.audioscrobbler.com/2.0/', { method: 'POST', body: createFormData(postData) })
+    .catch(async (error: {
+      response?: {
+        data?: {
+          error: number,
+        }
+      }
+    }) => {
+      if (error?.response?.data?.error === 9) {
+        // Session key is invalid, so remove it from the config and reauthenticate
+        config.session_key = undefined;
+        config.token = await authenticateAndGetToken(config);
+        setOptions('last-fm', config);
+      }
+    });
+};
+
+const addScrobble = (songInfo: SongInfo, config: LastFMOptions) => {
+  // This adds one scrobbled song to last.fm
+  const data = {
+    method: 'track.scrobble',
+    timestamp: Math.trunc((Date.now() - (songInfo.elapsedSeconds ?? 0)) / 1000),
+  };
+  postSongDataToAPI(songInfo, config, data);
+};
+
+const setNowPlaying = (songInfo: SongInfo, config: LastFMOptions) => {
+  // This sets the now playing status in last.fm
+  const data = {
+    method: 'track.updateNowPlaying',
+  };
+  postSongDataToAPI(songInfo, config, data);
+};
+
+// This will store the timeout that will trigger addScrobble
+let scrobbleTimer: NodeJS.Timeout | undefined;
+
+const lastfm = async (_win: BrowserWindow, config: LastFMOptions) => {
+  if (!config.api_root) {
+    // Settings are not present, creating them with the default values
+    config = defaultConfig.plugins['last-fm'];
+    config.enabled = true;
+    setOptions('last-fm', config);
+  }
+
+  if (!config.session_key) {
+    // Not authenticated
+    config = await getAndSetSessionKey(config);
+  }
+
+  registerCallback((songInfo) => {
+    // Set remove the old scrobble timer
+    clearTimeout(scrobbleTimer);
+    if (!songInfo.isPaused) {
+      setNowPlaying(songInfo, config);
+      // Scrobble when the song is halfway through, or has passed the 4-minute mark
+      const scrobbleTime = Math.min(Math.ceil(songInfo.songDuration / 2), 4 * 60);
+      if (scrobbleTime > (songInfo.elapsedSeconds ?? 0)) {
+        // Scrobble still needs to happen
+        const timeToWait = (scrobbleTime - (songInfo.elapsedSeconds ?? 0)) * 1000;
+        scrobbleTimer = setTimeout(addScrobble, timeToWait, songInfo, config);
+      }
+    }
+  });
+};
+
+module.exports = lastfm;