feat: complete AI analytics experience

src/lib/growth-coach-schedule.ts

@@ -0,0 +1,34 @@
+const tehranParts = new Intl.DateTimeFormat('en-CA', {
+  timeZone: 'Asia/Tehran',
+  year: 'numeric',
+  month: '2-digit',
+  day: '2-digit',
+  hour: '2-digit',
+  minute: '2-digit',
+  second: '2-digit',
+  hourCycle: 'h23',
+});
+
+function parts(value: Date) {
+  return Object.fromEntries(
+    tehranParts
+      .formatToParts(value)
+      .filter((part) => part.type !== 'literal')
+      .map((part) => [part.type, Number(part.value)]),
+  );
+}
+
+function tehranOffset(value: Date) {
+  const local = parts(value);
+  return (
+    Date.UTC(local.year, local.month - 1, local.day, local.hour, local.minute, local.second) - value.getTime()
+  );
+}
+
+export function millisecondsUntilTehranMidnight(now = new Date()): number {
+  const local = parts(now);
+  const targetAsUTC = Date.UTC(local.year, local.month - 1, local.day + 1);
+  let target = new Date(targetAsUTC - tehranOffset(now));
+  target = new Date(targetAsUTC - tehranOffset(target));
+  return Math.max(0, target.getTime() - now.getTime());
+}