From 5ff0635aa585a8c9cedf585853cd378827bf33ff Mon Sep 17 00:00:00 2001
From: Claus Lohmar <claus.lohmar@lohmar.co.uk>
Date: Tue, 21 Jul 2026 19:43:04 +0000
Subject: [PATCH] fix: show upload phase immediately + fallback for
 non-computable progress

Added loadstart handler to show 'Uploading...' spinner as soon as
upload begins, plus fallback label when lengthComputable is false
(shows bytes uploaded even without percentage).
---
 frontend/templates/index.html | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/frontend/templates/index.html b/frontend/templates/index.html
index a22d8ec..5e41565 100644
--- a/frontend/templates/index.html
+++ b/frontend/templates/index.html
@@ -128,17 +128,31 @@ async function startSession(e) {
   }
   btn.disabled = false;
 }
-
 async function handleUpload(formData) {
   return new Promise((resolve) => {
     const xhr = new XMLHttpRequest();
     xhr.open('POST', '/session/upload');
+    xhr.timeout = 7200000;  // 2 hour timeout for very large uploads
+
     xhr.upload.addEventListener('progress', (e) => {
       if (e.lengthComputable) {
         const pct = Math.round((e.loaded / e.total) * 100);
         setPhase('Uploading source file... ' + (e.loaded / (1024**3)).toFixed(1) + ' GiB', pct, false);
+      } else {
+        // Fallback: show bytes uploaded even without total
+        setPhase('Uploading source file... ' + (e.loaded / (1024**3)).toFixed(1) + ' GiB', 0, true);
       }
     });
+
+    xhr.addEventListener('loadstart', () => {
+      setPhase('Uploading source file...', 0, true);
+    });
+
+    xhr.addEventListener('timeout', () => {
+      setPhase('Upload timed out', 0, false);
+      showError('Upload timed out after 2 hours. The file may be too large for your connection speed. Try downloading the file directly on the server instead.');
+      resolve();
+    });
     xhr.addEventListener('load', async () => {
       if (xhr.status === 200) {
         const data = JSON.parse(xhr.responseText);