Smooth download speed and time remaining

web/static/js/format.js

@@ -22,14 +22,24 @@ export function formatBytes(bytes) {
   return `${value.toFixed(unitIndex === 0 ? 0 : 1)} ${units[unitIndex]}`;
 }
 
-export function formatDuration(seconds) {
-  const total = Math.max(0, Math.round(seconds));
-  const hours = Math.floor(total / 3600);
-  const minutes = Math.floor((total % 3600) / 60);
-  const remainingSeconds = total % 60;
-  if (hours > 0) return `${hours}h ${minutes}m`;
-  if (minutes > 0) return `${minutes}m ${remainingSeconds}s`;
-  return `${remainingSeconds}s`;
+function roundTo(value, step) {
+  return Math.max(step, Math.round(value / step) * step);
+}
+
+export function formatRemaining(seconds) {
+  if (!Number.isFinite(seconds) || seconds <= 0) return "almost done";
+  if (seconds < 60) return `${roundTo(seconds, 5)}s`;
+  if (seconds < 600) {
+    const rounded = roundTo(seconds, 15);
+    const minutes = Math.floor(rounded / 60);
+    const remainingSeconds = rounded % 60;
+    return remainingSeconds === 0 ? `${minutes}m` : `${minutes}m ${remainingSeconds}s`;
+  }
+  if (seconds < 3600) return `${roundTo(seconds / 60, 1)}m`;
+  const totalMinutes = roundTo(seconds / 60, 5);
+  const hours = Math.floor(totalMinutes / 60);
+  const minutes = totalMinutes % 60;
+  return minutes === 0 ? `${hours}h` : `${hours}h ${minutes}m`;
 }
 
 export function formatDate(value) {