feat: add UI toast notification for missing Firefox browser

app/toastNotifier.js

@@ -0,0 +1,22 @@
+const {getMainWindow} = require("./windowManager");
+
+/**
+ * Sends a toast notification to the renderer UI when the main window is ready.
+ *
+ * @param {string} message
+ * @param {"success"|"error"|"warning"|"info"} [type="info"]
+ * @param {number} [duration=4000]
+ * @returns {boolean} Whether the toast was sent.
+ */
+function sendToast(message, type = "info", duration = 4000) {
+    const mainWindow = getMainWindow();
+
+    if (!mainWindow || mainWindow.isDestroyed() || mainWindow.webContents.isDestroyed()) {
+        return false;
+    }
+
+    mainWindow.webContents.send("show-toast", {message, type, duration});
+    return true;
+}
+
+module.exports = {sendToast};

preload.js

@@ -159,6 +159,18 @@ contextBridge.exposeInMainWorld("electronAPI", {
     ipcRenderer.on("update-downloaded", (_, info) => callback(info)),
 
   openReleasePage: () => ipcRenderer.send("open-release-page"),
+
+  /**
+   * Subscribes to toast notifications emitted by the main process.
+   *
+   * @param {Function} callback - Function executed with toast data.
+   * @returns {Function} Removes the listener.
+   */
+  onToast: (callback) => {
+    const listener = (_, toast) => callback(toast);
+    ipcRenderer.on("show-toast", listener);
+    return () => ipcRenderer.removeListener("show-toast", listener);
+  },
 });
 
 /**

public/script/toast.js

@@ -82,4 +82,13 @@ window.showWarning = (message, duration = 4000) =>
  * Shortcut: info toast
  */
 window.showInfo = (message, duration = 4000) =>
-  window.showToast(message, "info", duration);
+  window.showToast(message, "info", duration);
+
+/**
+ * Listens for toast notifications from the main process and displays them in the UI.
+ */
+window.electronAPI?.onToast(({message, type = "info", duration = 4000} = {}) => {
+  if (typeof message === "string") {
+    window.showToast(message, type, duration);
+  }
+});

server/helpers/getBrowser.helpers.js

@@ -2,6 +2,7 @@ const fs = require("fs");
 const os = require("os");
 const notify = require("./notify.helpers");
 const { logger } = require("../logger");
+const {sendToast} = require("../../app/toastNotifier");
 
 /**
  * Detects the first supported browser installed on the system.
@@ -15,6 +16,7 @@ const { logger } = require("../logger");
  * If no supported browser is found:
  * - A warning is logged
  * - A notification is displayed to the user
+ * - An in-app toast is displayed to the user
  * - "firefox" is returned as a fallback to allow yt-dlp to
  *   handle the error gracefully without crashing the application
  *
@@ -51,6 +53,11 @@ function getUserBrowser() {
     // No supported browser found => Notify User
     logger.warn("No supported browser found on the system");
     notify.notifyFirefoxBrowserMissing();
+
+    sendToast(
+        "Firefox was not found on your system. Please install Firefox to import browser cookies.",
+        "error",
+    );
   } else {
     logger.info("Browser found: firefox");
   }

test/unit/toastNotifier.test.js

@@ -0,0 +1,38 @@
+const mockSend = jest.fn();
+const mockGetMainWindow = jest.fn();
+
+jest.mock("../../app/windowManager", () => ({
+    getMainWindow: mockGetMainWindow,
+}));
+
+const {sendToast} = require("../../app/toastNotifier");
+
+describe("toastNotifier", () => {
+    beforeEach(() => {
+        jest.clearAllMocks();
+    });
+
+    test("sends a toast to the active renderer", () => {
+        mockGetMainWindow.mockReturnValue({
+            isDestroyed: () => false,
+            webContents: {
+                isDestroyed: () => false,
+                send: mockSend,
+            },
+        });
+
+        expect(sendToast("Firefox is missing", "error", 5000)).toBe(true);
+        expect(mockSend).toHaveBeenCalledWith("show-toast", {
+            message: "Firefox is missing",
+            type: "error",
+            duration: 5000,
+        });
+    });
+
+    test("does not throw when the renderer is unavailable", () => {
+        mockGetMainWindow.mockReturnValue(null);
+
+        expect(sendToast("Firefox is missing", "error")).toBe(false);
+        expect(mockSend).not.toHaveBeenCalled();
+    });
+});