refactored timetracking to only use client-supplied times

frontend/src/time.svelte.js

@@ -0,0 +1,34 @@
+export function display(timestamp){
+      const date = new Date(timestamp * 1000);
+      const year = date.getFullYear();
+      const month = String(date.getMonth() + 1).padStart(2, '0');
+      const day = String(date.getDate()).padStart(2, '0');
+      const hours = String(date.getHours()).padStart(2, '0');
+      const minutes = String(date.getMinutes()).padStart(2, '0');
+      return `${year}-${month}-${day} ${hours}:${minutes}`;
+}
+
+function padTo2Digits(num) {
+    return num.toString().padStart(2, '0');
+}
+
+export function msToTime(ms) {
+  const totalSeconds = Math.floor(ms / 1000);
+  const days    = Math.floor(totalSeconds / 86400);
+  const hours   = Math.floor((totalSeconds % 86400) / 3600);
+  const minutes = Math.floor((totalSeconds % 3600)  / 60);
+  const seconds = totalSeconds % 60;
+
+  let timestring = '';
+  if (days)        timestring += days.toString().padStart(2, '0') + ":";
+  if (days||hours) timestring += hours.toString().padStart(2, '0') + ":";
+  return timestring + minutes.toString().padStart(2, '0') + ':' + seconds.toString().padStart(2, '0');
+}
+
+export function now(){
+    return Math.floor(Date.now()/1000);
+}
+
+export function to_secs(datetime){
+    return Math.floor(new Date(datetime).getTime()/1000);
+}