ThreadCount Community edition

Uniform stock management for healthcare linen rooms: the coordinator app, the phone counter and the staff app, for your own server. Built from e2d6d42 on 2026-09-13. Licensed under the Functional Source License (FSL-1.1-ALv2).

lib/wakelock.ts

@@ -0,0 +1,45 @@
+"use client";
+/* Keep the screen on while a count is open.
+ *
+ * A shelf count is minutes of handling garments with the phone held low, and Android's display
+ * timeout is often fifteen seconds. Waking the phone, unlocking it and finding your place again
+ * every few garments is the difference between counting a bay and giving up on it.
+ *
+ * This is the Screen Wake Lock API rather than a Capacitor plugin, which means it works the same
+ * in the Android shell and in mobile Chrome, and needs no permission — only a secure context,
+ * which /m always has. Android drops the lock whenever the page is hidden, so it is re-taken on
+ * the way back from a phone call or the app switcher. */
+import { useEffect } from "react";
+
+type Sentinel = { released: boolean; release: () => Promise<void>; addEventListener: (t: string, f: () => void) => void };
+type WakeLockNav = Navigator & { wakeLock?: { request: (type: "screen") => Promise<Sentinel> } };
+
+/** Holds a screen wake lock for as long as `active` is true. A no-op where it isn't supported. */
+export function useKeepAwake(active: boolean) {
+  useEffect(() => {
+    if (!active) return;
+    const nav = navigator as WakeLockNav;
+    if (!nav.wakeLock) return; // older WebView, or an insecure origin
+    let sentinel: Sentinel | null = null;
+    let dropped = false;
+
+    const take = async () => {
+      if (dropped || sentinel || document.visibilityState !== "visible") return;
+      try {
+        sentinel = await nav.wakeLock!.request("screen");
+        // The system releases it on its own terms too; forget the handle when it does.
+        sentinel.addEventListener("release", () => { sentinel = null; });
+      } catch { /* battery saver refuses it — the screen just times out as usual */ }
+    };
+    const onVisible = () => { if (document.visibilityState === "visible") void take(); };
+
+    void take();
+    document.addEventListener("visibilitychange", onVisible);
+    return () => {
+      dropped = true;
+      document.removeEventListener("visibilitychange", onVisible);
+      if (sentinel && !sentinel.released) sentinel.release().catch(() => {});
+      sentinel = null;
+    };
+  }, [active]);
+}