Add new protocol registration to app

Author: teonbrooks

package.json

@@ -48,6 +48,12 @@
     "productName": "BrainWaves",
     "appId": "com.electron.brainwaves",
     "asar": true,
+    "protocols": [
+      {
+        "name": "BrainWaves",
+        "schemes": ["brainwaves"]
+      }
+    ],
     "files": [
       "out/**/*",
       "node_modules/**/*",

src/main/index.ts

@@ -24,6 +24,45 @@ app.commandLine.appendSwitch(
   'true'
 );
 
+// Enforce a single app instance — required so the second-instance event fires
+// on Windows/Linux when the OS re-launches the app to deliver an OAuth callback.
+if (!app.requestSingleInstanceLock()) {
+  app.quit();
+}
+
+// Register brainwaves:// as the OS-level deep-link scheme.
+// Redirect URI for OAuth: brainwaves://oauth/callback
+app.setAsDefaultProtocolClient('brainwaves');
+
+// Buffer an OAuth callback URL that arrives before the window is ready
+// (e.g. the app is cold-launched by the OS to handle the redirect).
+let pendingOAuthUrl: string | null = null;
+
+const handleOAuthCallback = (url: string) => {
+  if (mainWindow) {
+    mainWindow.webContents.send('oauth:callback', url);
+  } else {
+    pendingOAuthUrl = url;
+  }
+};
+
+// macOS: OS fires open-url when a brainwaves:// link is opened.
+app.on('open-url', (event, url) => {
+  event.preventDefault();
+  handleOAuthCallback(url);
+});
+
+// Windows / Linux: OS relaunches the app with the URL as a CLI argument.
+// requestSingleInstanceLock() above ensures the existing instance gets this event.
+app.on('second-instance', (_event, argv) => {
+  const url = argv.find((arg) => arg.startsWith('brainwaves://'));
+  if (url) handleOAuthCallback(url);
+  if (mainWindow) {
+    if (mainWindow.isMinimized()) mainWindow.restore();
+    mainWindow.focus();
+  }
+});
+
 // Register pyodide:// as a privileged custom scheme so web workers can
 // fetch() package .whl files from it. Must be called before app.whenReady().
 protocol.registerSchemesAsPrivileged([
@@ -460,6 +499,10 @@ const createWindow = async () => {
     if (is.dev || process.env.DEBUG_PROD === 'true') {
       mainWindow.webContents.openDevTools();
     }
+    if (pendingOAuthUrl) {
+      mainWindow.webContents.send('oauth:callback', pendingOAuthUrl);
+      pendingOAuthUrl = null;
+    }
   });
 
   mainWindow.on('closed', () => {

src/preload/index.ts

@@ -153,4 +153,14 @@ contextBridge.exposeInMainWorld('electronAPI', {
   getResourcePath: (): Promise<string> => ipcRenderer.invoke('getResourcePath'),
 
   getViewerUrl: (): Promise<string> => ipcRenderer.invoke('getViewerUrl'),
+
+  // ------------------------------------------------------------------
+  // OAuth deep-link callback
+  // ------------------------------------------------------------------
+  onOAuthCallback: (callback: (url: string) => void) => {
+    const handler = (_event: Electron.IpcRendererEvent, url: string) =>
+      callback(url);
+    ipcRenderer.on('oauth:callback', handler);
+    return () => ipcRenderer.removeListener('oauth:callback', handler);
+  },
 });