Fixed timing issue with UTC

2026-05-16 10:28:32 +03:30
parent e4d6246103
commit 2c851725a5
3 changed files with 114 additions and 21 deletions
--- a/src/helpers/iran-datetime.ts
+++ b/src/helpers/iran-datetime.ts
@@ -0,0 +1,82 @@
+/** Iran standard time (Asia/Tehran, UTC+3:30; no DST since 2022). */
+export const IRAN_TIMEZONE = "Asia/Tehran";
+
+const IRAN_UTC_OFFSET = "+03:30";
+
+const DATE_ONLY_RE = /^\d{4}-\d{2}-\d{2}$/;
+const TIME_HM_RE = /^(\d{1,2}):(\d{2})(?::(\d{2}))?$/;
+const NAIVE_ISO_DATETIME_RE =
+  /^(\d{4}-\d{2}-\d{2})[T\s](\d{1,2}:\d{2}(?::\d{2})?)$/;
+
+/**
+ * Gregorian calendar date (`YYYY-MM-DD`) for an instant in Iran.
+ */
+export function gregorianDateInIran(d: Date): string {
+  return new Intl.DateTimeFormat("en-CA", {
+    timeZone: IRAN_TIMEZONE,
+    year: "numeric",
+    month: "2-digit",
+    day: "2-digit",
+  }).format(d);
+}
+
+function normalizeTimeToHms(time: string): string | null {
+  const m = String(time).trim().match(TIME_HM_RE);
+  if (!m) return null;
+  const hh = m[1].padStart(2, "0");
+  const mm = m[2];
+  const ss = m[3] ?? "00";
+  return `${hh}:${mm}:${ss}`;
+}
+
+function parseIranLocalIso(isoDate: string, timeHms: string): Date | null {
+  const d = new Date(`${isoDate}T${timeHms}${IRAN_UTC_OFFSET}`);
+  return Number.isNaN(d.getTime()) ? null : d;
+}
+
+/**
+ * Combines a calendar date and optional `HH:MM` / `HH:MM:SS` as Iran local
+ * time and returns the corresponding UTC instant.
+ */
+export function parseIranLocalDateTime(
+  date: Date | string,
+  time?: string,
+): Date | null {
+  if (date instanceof Date) {
+    if (Number.isNaN(date.getTime())) return null;
+    const cleanTime = (time ?? "").trim();
+    if (!cleanTime) return date;
+    const timeHms = normalizeTimeToHms(cleanTime);
+    if (!timeHms) return null;
+    return parseIranLocalIso(gregorianDateInIran(date), timeHms);
+  }
+
+  const raw = String(date).trim();
+  if (!raw) return null;
+
+  if (/[zZ]|[+-]\d{2}:?\d{2}$/.test(raw)) {
+    const d = new Date(raw);
+    return Number.isNaN(d.getTime()) ? null : d;
+  }
+
+  const naive = raw.match(NAIVE_ISO_DATETIME_RE);
+  if (naive) {
+    const timeHms = normalizeTimeToHms(naive[2]);
+    if (!timeHms) return null;
+    return parseIranLocalIso(naive[1], timeHms);
+  }
+
+  if (DATE_ONLY_RE.test(raw)) {
+    const cleanTime = (time ?? "").trim();
+    if (!cleanTime) {
+      const d = new Date(`${raw}T00:00:00${IRAN_UTC_OFFSET}`);
+      return Number.isNaN(d.getTime()) ? null : d;
+    }
+    const timeHms = normalizeTimeToHms(cleanTime);
+    if (!timeHms) return null;
+    return parseIranLocalIso(raw, timeHms);
+  }
+
+  const d = new Date(raw);
+  return Number.isNaN(d.getTime()) ? null : d;
+}