feat: add calendar event normalization and sanitization functions with tests

lib/calendar-event-normalization.ts

@@ -0,0 +1,101 @@
+import { parseISO } from 'date-fns';
+import type { CalendarEvent } from '@/lib/jmap/types';
+
+const DURATION_RE = /^P(?:(\d+)W)?(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?$/;
+
+function isDateOnlyValue(value: string): boolean {
+  return /^\d{4}-\d{2}-\d{2}$/.test(value);
+}
+
+function isMidnightValue(value: string): boolean {
+  if (isDateOnlyValue(value)) {
+    return true;
+  }
+
+  const match = value.match(/T(\d{2}):(\d{2})(?::(\d{2})(?:\.\d+)?)?(?:Z|[+-]\d{2}:\d{2})?$/);
+  if (!match) {
+    return false;
+  }
+
+  return match[1] === '00' && match[2] === '00' && (match[3] ?? '00') === '00';
+}
+
+function parseDurationSeconds(duration: string | undefined): number | null {
+  if (!duration) {
+    return null;
+  }
+
+  const match = DURATION_RE.exec(duration);
+  if (!match) {
+    return null;
+  }
+
+  const weeks = parseInt(match[1] || '0', 10);
+  const days = parseInt(match[2] || '0', 10);
+  const hours = parseInt(match[3] || '0', 10);
+  const minutes = parseInt(match[4] || '0', 10);
+  const seconds = parseInt(match[5] || '0', 10);
+
+  return (((weeks * 7 + days) * 24 + hours) * 60 + minutes) * 60 + seconds;
+}
+
+export function normalizeAllDayDurationValue(duration: string | undefined): string | undefined {
+  const totalSeconds = parseDurationSeconds(duration);
+  if (totalSeconds === null || totalSeconds < 86400 || totalSeconds % 86400 !== 0) {
+    return duration;
+  }
+
+  return `P${totalSeconds / 86400}D`;
+}
+
+export function isAllDayEventLike(event: Pick<Partial<CalendarEvent>, 'start' | 'duration' | 'showWithoutTime'>): boolean {
+  if (event.showWithoutTime) {
+    return true;
+  }
+
+  if (!event.start || !event.duration || !isMidnightValue(event.start)) {
+    return false;
+  }
+
+  const totalSeconds = parseDurationSeconds(event.duration);
+  if (totalSeconds === null || totalSeconds < 86400 || totalSeconds % 86400 !== 0) {
+    return false;
+  }
+
+  const start = parseISO(event.start);
+  if (Number.isNaN(start.getTime())) {
+    return false;
+  }
+
+  const end = new Date(start.getTime() + totalSeconds * 1000);
+  return end.getHours() === 0
+    && end.getMinutes() === 0
+    && end.getSeconds() === 0
+    && end.getMilliseconds() === 0;
+}
+
+export function normalizeCalendarEventLike<T extends Partial<CalendarEvent>>(event: T): T {
+  if (!isAllDayEventLike(event)) {
+    return event;
+  }
+
+  return {
+    ...event,
+    showWithoutTime: true,
+    duration: normalizeAllDayDurationValue(event.duration),
+  } as T;
+}
+
+export function sanitizeOutgoingCalendarEventData<T extends Partial<CalendarEvent>>(event: T): T {
+  const normalized = normalizeCalendarEventLike(event);
+  if (!normalized.showWithoutTime) {
+    return normalized;
+  }
+
+  return {
+    ...normalized,
+    start: normalized.start ? normalized.start.slice(0, 10) : normalized.start,
+    duration: normalizeAllDayDurationValue(normalized.duration),
+    timeZone: null,
+  } as T;
+}