Add YT Music preload scraper that emits wtm:state IPC

desktop-client/yt-scraper.js

@@ -0,0 +1,61 @@
+const { ipcRenderer } = require('electron');
+
+const POLL_INTERVAL_MS = 3000;
+let lastSent = null;
+
+function scrapeNowPlaying() {
+  const titleEl =
+    document.querySelector('ytmusic-player-bar .title') ||
+    document.querySelector('.ytmusic-player-bar .title');
+  const title = titleEl ? titleEl.textContent.trim() : null;
+
+  const bylineEl =
+    document.querySelector('ytmusic-player-bar .byline') ||
+    document.querySelector('.ytmusic-player-bar .byline');
+  const artist = bylineEl ? bylineEl.textContent.trim() : null;
+
+  const artImg =
+    document.querySelector('ytmusic-player-bar .middle-controls .thumbnail-image-wrapper img') ||
+    document.querySelector('ytmusic-player-bar .image img') ||
+    document.querySelector('ytmusic-player-bar img.image');
+  const albumArt = artImg ? artImg.src : null;
+
+  // The play/pause button's title indicates state: when music is playing the
+  // button's action is "Pause", and vice versa.
+  const playPauseBtn = document.querySelector('#play-pause-button');
+  let isPlaying = false;
+  if (playPauseBtn) {
+    const btnTitle = (
+      playPauseBtn.getAttribute('title') ||
+      playPauseBtn.getAttribute('aria-label') ||
+      ''
+    ).toLowerCase();
+    isPlaying = btnTitle.includes('pause');
+  }
+
+  if (!title) return null;
+  return { title, artist, albumArt, isPlaying };
+}
+
+function changed(a, b) {
+  if (a === null && b === null) return false;
+  if (a === null || b === null) return true;
+  return (
+    a.title !== b.title ||
+    a.artist !== b.artist ||
+    a.albumArt !== b.albumArt ||
+    a.isPlaying !== b.isPlaying
+  );
+}
+
+function poll() {
+  const data = scrapeNowPlaying();
+  if (!changed(data, lastSent)) return;
+  lastSent = data;
+  ipcRenderer.send('wtm:state', data || { isPlaying: false });
+}
+
+setInterval(poll, POLL_INTERVAL_MS);
+poll();
+
+console.log('[wtm] yt-scraper preload loaded');