Serverpuls: deutsche Zeitachse und Legende im Diagramm

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/serverpulsFormat.js

@@ -56,3 +56,36 @@ export function formatNumber(v, digits = 2) {
   if (v === null || v === undefined) return '–'
   return nf(digits).format(v)
 }
+
+// --- Zeitachsen (Europe/Berlin, de-DE) ---
+const TZ = 'Europe/Berlin'
+const dtf = (opts) => new Intl.DateTimeFormat('de-DE', { timeZone: TZ, ...opts })
+const F = {
+  time: dtf({ hour: '2-digit', minute: '2-digit', hourCycle: 'h23' }),
+  day: dtf({ day: '2-digit', month: '2-digit' }),
+  month: dtf({ month: 'short', year: 'numeric' }),
+  year: dtf({ year: 'numeric' }),
+  legend: dtf({ day: '2-digit', month: '2-digit', year: 'numeric', hour: '2-digit', minute: '2-digit', hourCycle: 'h23' }),
+}
+
+// Welches Format passt zu einem Tick-Abstand (Sekunden)?
+export function axisTimeKind(incrSec) {
+  if (incrSec < 86400) return 'time'
+  if (incrSec < 86400 * 28) return 'day'
+  if (incrSec < 86400 * 360) return 'month'
+  return 'year'
+}
+
+// Tick (Sekunden) -> Text. Bei Tagesgrenzen innerhalb von Sub-Tages-Achsen das Datum zeigen.
+export function formatAxisTick(sec, incrSec) {
+  const kind = axisTimeKind(incrSec)
+  const d = new Date(sec * 1000)
+  if (kind === 'time' && F.time.format(d) === '00:00') return F.day.format(d)
+  return F[kind].format(d)
+}
+
+// Legende: "30.09.2026, 11:20"
+export function formatLegendTime(sec) {
+  if (sec === null || sec === undefined) return '–'
+  return F.legend.format(new Date(sec * 1000))
+}