Implement hashtag url storage for easy retry

web/app.js

@@ -21,6 +21,43 @@ let jobCompleted = false;
 let abortRequested = false;
 let syncRunning = false;
 
+function normalizedShareUrl(value) {
+  try {
+    const url = new URL(value.trim());
+    if (!['http:', 'https:'].includes(url.protocol) || !url.hostname || url.username || url.password) return undefined;
+    const marker = url.pathname.lastIndexOf('/share/');
+    if (marker < 0) return undefined;
+    const credential = url.pathname.slice(marker + 7).replace(/\/+$/, '');
+    if (!credential || credential.includes('/')) return undefined;
+    url.search = '';
+    url.hash = '';
+    return url.toString();
+  } catch {
+    return undefined;
+  }
+}
+
+function updateShareFragment() {
+  const left = normalizedShareUrl($('#leftUrl').value);
+  const right = normalizedShareUrl($('#rightUrl').value);
+  if (!left || !right) {
+    if (location.hash) history.replaceState(null, '', `${location.pathname}${location.search}`);
+    return;
+  }
+  const fragment = new URLSearchParams({ left, right });
+  history.replaceState(null, '', `${location.pathname}${location.search}#${fragment}`);
+}
+
+function restoreShareFragment() {
+  const fragment = new URLSearchParams(location.hash.slice(1));
+  const left = normalizedShareUrl(fragment.get('left') || '');
+  const right = normalizedShareUrl(fragment.get('right') || '');
+  if (!left || !right) return false;
+  $('#leftUrl').value = left;
+  $('#rightUrl').value = right;
+  return true;
+}
+
 function openJob(request) {
   if (socket && socket.readyState !== WebSocket.CLOSED) {
     ui.message.textContent = 'Please wait for the current job to finish.';
@@ -34,6 +71,7 @@ function openJob(request) {
   jobCompleted = false;
   abortRequested = false;
   ui.inspect.disabled = true;
+  updateShareFragment();
   setConnection('connecting', 'Connecting');
 
   jobSocket.addEventListener('open', () => {
@@ -242,6 +280,7 @@ function handle(message) {
 }
 
 ui.inspect.addEventListener('click', inspect);
+for (const input of [$('#leftUrl'), $('#rightUrl')]) input.addEventListener('input', updateShareFragment);
 for (const input of $$('input')) input.addEventListener('keydown', (event) => {
   if (event.key === 'Enter') inspect();
 });
@@ -254,3 +293,4 @@ ui.abort.addEventListener('click', () => {
 });
 
 setConnection('idle', 'Idle');
+if (restoreShareFragment()) inspect();