feat(pwa): add useInstallPrompt hook with tests

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

apps/main/src/hooks/useInstallPrompt.test.ts

@@ -0,0 +1,60 @@
+import { act, renderHook } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { useInstallPrompt } from "./useInstallPrompt";
+
+const DISMISSED_KEY = "pwa-install-dismissed";
+
+describe("useInstallPrompt", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("starts with canInstall false and isStandalone false", () => {
+    const { result } = renderHook(() => useInstallPrompt());
+    expect(result.current.canInstall).toBe(false);
+    expect(result.current.isStandalone).toBe(false);
+    expect(result.current.isDismissed).toBe(false);
+  });
+
+  it("captures beforeinstallprompt event and sets canInstall to true", () => {
+    const { result } = renderHook(() => useInstallPrompt());
+
+    const event = new Event("beforeinstallprompt");
+    Object.assign(event, { preventDefault: vi.fn(), prompt: vi.fn() });
+
+    act(() => {
+      window.dispatchEvent(event);
+    });
+
+    expect(result.current.canInstall).toBe(true);
+  });
+
+  it("dismiss persists to localStorage and sets isDismissed", () => {
+    const { result } = renderHook(() => useInstallPrompt());
+
+    act(() => {
+      result.current.dismiss();
+    });
+
+    expect(result.current.isDismissed).toBe(true);
+    expect(localStorage.getItem(DISMISSED_KEY)).toBe("true");
+  });
+
+  it("reads dismissed state from localStorage on mount", () => {
+    localStorage.setItem(DISMISSED_KEY, "true");
+    const { result } = renderHook(() => useInstallPrompt());
+    expect(result.current.isDismissed).toBe(true);
+  });
+
+  it("detects iOS Safari", () => {
+    vi.spyOn(navigator, "userAgent", "get").mockReturnValue(
+      "Mozilla/5.0 (iPhone; CPU iPhone OS 17_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1"
+    );
+    const { result } = renderHook(() => useInstallPrompt());
+    expect(result.current.isIOS).toBe(true);
+  });
+});

apps/main/src/hooks/useInstallPrompt.ts

@@ -0,0 +1,50 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+
+const DISMISSED_KEY = "pwa-install-dismissed";
+
+interface BeforeInstallPromptEvent extends Event {
+  prompt(): Promise<{ outcome: "accepted" | "dismissed" }>;
+}
+
+export function useInstallPrompt() {
+  const deferredPrompt = useRef<BeforeInstallPromptEvent | null>(null);
+  const [canInstall, setCanInstall] = useState(false);
+  const [isDismissed, setIsDismissed] = useState(
+    () => localStorage.getItem(DISMISSED_KEY) === "true"
+  );
+
+  const isStandalone =
+    typeof window !== "undefined" &&
+    typeof window.matchMedia === "function" &&
+    (window.matchMedia("(display-mode: standalone)")?.matches ?? false);
+
+  const isIOS =
+    typeof navigator !== "undefined" &&
+    /iPad|iPhone|iPod/.test(navigator.userAgent);
+
+  useEffect(() => {
+    const handler = (e: Event) => {
+      e.preventDefault();
+      deferredPrompt.current = e as BeforeInstallPromptEvent;
+      setCanInstall(true);
+    };
+    window.addEventListener("beforeinstallprompt", handler);
+    return () => window.removeEventListener("beforeinstallprompt", handler);
+  }, []);
+
+  const promptInstall = useCallback(async () => {
+    if (!deferredPrompt.current) return;
+    const result = await deferredPrompt.current.prompt();
+    if (result.outcome === "accepted") {
+      deferredPrompt.current = null;
+      setCanInstall(false);
+    }
+  }, []);
+
+  const dismiss = useCallback(() => {
+    setIsDismissed(true);
+    localStorage.setItem(DISMISSED_KEY, "true");
+  }, []);
+
+  return { canInstall, isStandalone, isIOS, isDismissed, promptInstall, dismiss };
+}