Prevent Lyrics from opening up Spotify if it is closed

We don't want that so we check with macOS first to see if we should even talk to Spotify (which implies starting it if it wasn't running).

README.md

@@ -24,10 +24,6 @@ The video needs to be recorded based on an automated script to be reproducible.
 I will use faked synchronized lyrics for it so that I don't need to connect to
 Spotify from the agent.
 
-### Prevent the app from re-opening Spotify if not open or closed while it runs
-
-It seems to be reviving it.
-
 ### Integrate the Electron auto-update service once GitHub Actions is set up
 
 So I do not need to replace the app but can rely on it to auto-update on start
@@ -130,3 +126,4 @@ Also consider saving the changes to manually synchronized lyrics for reuse.
 - Removed no longer used stuff now that the app uses the user's Home directory
 - Worked around the ghosting issue and capture a repro repository for it:
   https://github.com/TomasHubelbauer/electron-lingering-shadow-repro
+- Fixed the Lyrics app opening up Spotify unintentionally if it was closed

askSpotify.js

@@ -1,16 +1,8 @@
-import child_process from 'child_process';
-import util from 'util';
-
-const exec = util.promisify(child_process.exec);
+import runAppleScript from './runAppleScript.js';
 
 export default async function askSpotify(
   /** @type {string} */
   query
 ) {
-  const { stdout, stderr } = await exec(`osascript -e 'tell application "Spotify" to ${query}'`);
-  if (stderr) {
-    throw new Error(stderr);
-  }
-
-  return stdout.trimEnd();
+  return await runAppleScript(`tell application "Spotify" to ${query}`);
 }

index.js

@@ -3,6 +3,7 @@ import timers from 'timers/promises';
 import fs from 'fs';
 import askSpotify from './askSpotify.js';
 import promptAuthorization from './promptAuthorization.js';
+import runAppleScript from './runAppleScript.js';
 
 // Set working directory for the production builds
 process.chdir(electron.app.getPath('home'));
@@ -98,6 +99,8 @@ electron.app.on('ready', async () => {
       }
 
       if (!lyrics || ('error' in lyrics) || state !== 'playing') {
+        // Clear the last line in case Spotify got paused or stopped
+        await window.webContents.executeJavaScript(`document.body.dataset.lyric = '';`);
         return;
       }
 
@@ -166,9 +169,15 @@ electron.app.on('ready', async () => {
 
   // Check artist, song and time and fetch and update lyrics on slow interval
   while (true) {
-    // Wait for 5 seconds between Spotify checks unless it is the first loop run
-    if (lyrics) {
-      await timers.setTimeout(5000);
+    // Wait a bit seconds between AppleScript Spotify checks to not be spammy
+    await timers.setTimeout(2000);
+
+    // Determine if Spotify is running to avoid starting it unintentionally
+    if (!+await runAppleScript('tell application "System Events" to count (every process whose name is "Spotify")')) {
+      // Reset the lyris so we don't get stuck on the last line
+      lyrics = undefined;
+
+      continue;
     }
 
     /** @type {string} */
@@ -264,7 +273,7 @@ electron.app.on('ready', async () => {
 
     try {
       const _state = await askSpotify('player state');
-      if (_state !== 'playing' && _state !== 'paused') {
+      if (_state !== 'playing' && _state !== 'paused' && _state !== 'stopped') {
         throw new Error(`Unexpected player state '${_state}'!`);
       }
 

runAppleScript.js

@@ -0,0 +1,20 @@
+import child_process from 'child_process';
+import util from 'util';
+
+const exec = util.promisify(child_process.exec);
+
+export default async function runAppleScript(
+  /** @type {string} */
+  query
+) {
+  if (query.includes('\'')) {
+    throw new Error('The query cannot contain single quotes');
+  }
+
+  const { stdout, stderr } = await exec(`osascript -e '${query}'`);
+  if (stderr) {
+    throw new Error(stderr);
+  }
+
+  return stdout.trimEnd();
+}