From 4e1028e1a1cb343b823b7ff117e6488c821f89e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20K=C3=BChn?= <simon@kuehn.de>
Date: Sat, 2 May 2026 09:53:41 +0200
Subject: [PATCH] Keep screen awake via Wake Lock API while stopwatch is
 running

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 public/app.js | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/public/app.js b/public/app.js
index cd56561..e6991f4 100644
--- a/public/app.js
+++ b/public/app.js
@@ -955,6 +955,18 @@ var sw = (function(){
   var swEl = document.getElementById('sw');
   var state = 0; // 0=stopped, 1=running, 2=paused
   var start = 0, elapsed = 0, raf = null;
+  var wakeLock = null;
+
+  function acquireWakeLock(){
+    if(!('wakeLock' in navigator)) return;
+    navigator.wakeLock.request('screen').then(function(s){ wakeLock = s; }).catch(function(){});
+  }
+  function releaseWakeLock(){
+    if(wakeLock){ wakeLock.release(); wakeLock = null; }
+  }
+  document.addEventListener('visibilitychange', function(){
+    if(document.visibilityState === 'visible' && state === 1) acquireWakeLock();
+  });
 
   function getMs(){ return state === 1 ? elapsed + (Date.now() - start) : elapsed; }
 
@@ -975,18 +987,18 @@ var sw = (function(){
     if(state === 0){
       start = Date.now(); elapsed = 0;
       swEl.classList.add('running');
-      state = 1; tick();
+      state = 1; tick(); acquireWakeLock();
     } else if(state === 1){
       cancelAnimationFrame(raf);
       elapsed += Date.now() - start;
       swEl.textContent = fmt(elapsed);
       swEl.classList.remove('running');
-      state = 2; updateFillBtns();
+      state = 2; updateFillBtns(); releaseWakeLock();
     } else {
       cancelAnimationFrame(raf);
       elapsed = 0; swEl.textContent = '0.00s';
       swEl.classList.remove('running');
-      state = 0; updateFillBtns();
+      state = 0; updateFillBtns(); releaseWakeLock();
     }
   });