Timestamp and registration checking

src/lib/format.ts

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+/**
+ * Locale-aware date/time formatting helpers.
+ *
+ * Built on top of next-intl's format API, which wraps Intl.DateTimeFormat /
+ * Intl.RelativeTimeFormat using the active request locale. These helpers add
+ * three things on top of raw next-intl:
+ *
+ *   1. Tolerant input — accepts string | Date | null | undefined and returns
+ *      a stable em-dash for missing values, so call sites don't need to
+ *      conditionally render.
+ *   2. Two presets used everywhere in the portal (`dateTime`, `dateOnly`)
+ *      so the four locales render consistently. German/French/Italian use
+ *      24h DD.MM.YYYY HH:mm; English uses 12h MMM D, YYYY h:mm a.
+ *   3. A `relative` helper that auto-picks the right unit (minute/hour/day/
+ *      week/month) based on the elapsed delta.
+ *
+ * Usage in client components:
+ *
+ *   import { useFormatter } from "next-intl";
+ *   import { formatDateTime, formatRelative } from "@/lib/format";
+ *
+ *   const f = useFormatter();
+ *   <span>{formatDateTime(req.createdAt, f)}</span>
+ *   <span title={formatDateTime(req.createdAt, f)}>
+ *     {formatRelative(req.createdAt, f)}
+ *   </span>
+ *
+ * Usage in server components:
+ *
+ *   import { getFormatter } from "next-intl/server";
+ *   const f = await getFormatter();
+ *   ...same calls...
+ */
+
+// next-intl's `useFormatter()` (client) and `getFormatter()` (server) return
+// the same shape. We derive the type from useFormatter's return so we stay
+// in sync with next-intl version bumps without hand-maintaining a mirror.
+import type { useFormatter } from "next-intl";
+type Formatter = ReturnType<typeof useFormatter>;
+
+const FALLBACK = "—";
+
+function toDate(value: string | Date | null | undefined): Date | null {
+  if (!value) return null;
+  if (value instanceof Date) return Number.isNaN(value.getTime()) ? null : value;
+  const d = new Date(value);
+  return Number.isNaN(d.getTime()) ? null : d;
+}
+
+/**
+ * Full date+time, locale-formatted. Returns "—" if the value is missing.
+ *
+ *   de: 25.04.2026, 14:30
+ *   en: Apr 25, 2026, 2:30 PM
+ *   fr: 25 avr. 2026, 14:30
+ *   it: 25 apr 2026, 14:30
+ */
+export function formatDateTime(
+  value: string | Date | null | undefined,
+  formatter: Formatter
+): string {
+  const d = toDate(value);
+  if (!d) return FALLBACK;
+  return formatter.dateTime(d, {
+    year: "numeric",
+    month: "short",
+    day: "numeric",
+    hour: "2-digit",
+    minute: "2-digit",
+  });
+}
+
+/**
+ * Date only, locale-formatted. Use in dense table cells.
+ */
+export function formatDateOnly(
+  value: string | Date | null | undefined,
+  formatter: Formatter
+): string {
+  const d = toDate(value);
+  if (!d) return FALLBACK;
+  return formatter.dateTime(d, {
+    year: "numeric",
+    month: "short",
+    day: "numeric",
+  });
+}
+
+/**
+ * Relative time ("2 hours ago", "vor 2 Stunden", etc.).
+ * Picks the unit automatically based on the magnitude of the delta.
+ * Returns "—" if the value is missing.
+ *
+ * Anchors against `now` (defaults to current time) so SSR and client
+ * render the same string when called within a single request.
+ */
+export function formatRelative(
+  value: string | Date | null | undefined,
+  formatter: Formatter,
+  now: Date = new Date()
+): string {
+  const d = toDate(value);
+  if (!d) return FALLBACK;
+
+  const diffMs = d.getTime() - now.getTime();
+  const absSeconds = Math.abs(diffMs) / 1000;
+
+  let unit: Intl.RelativeTimeFormatUnit;
+  if (absSeconds < 60) unit = "second";
+  else if (absSeconds < 3_600) unit = "minute";
+  else if (absSeconds < 86_400) unit = "hour";
+  else if (absSeconds < 604_800) unit = "day";
+  else if (absSeconds < 2_592_000) unit = "week";
+  else if (absSeconds < 31_536_000) unit = "month";
+  else unit = "year";
+
+  return formatter.relativeTime(d, { now, unit });
+}