feat(events): add calendar email support

Help registrants add events to their calendars and keep waitlisted places distinct from confirmed attendance.
2026-09-27 15:57:43 +02:00
parent 8e502b4a01
commit 5310272715
6 changed files with 388 additions and 18 deletions
@@ -0,0 +1,111 @@
+const CRLF = '\r\n';
+const MAX_OCTETS = 75;
+const CONTROL_CHARS = /[\u0000-\u0008\u000B\u000C\u000E-\u001F\u007F]/g;
+
+export type CalendarEvent = {
+  uid: string;
+  start: string | Date;
+  end?: string | Date | null;
+  allDay?: boolean;
+  summary: string;
+  description?: string;
+  location?: string;
+  url?: string;
+  status?: 'CONFIRMED' | 'TENTATIVE' | 'CANCELLED';
+};
+
+function escapeText(value: string): string {
+  return value
+    .replace(/\\/g, '\\\\')
+    .replace(/;/g, '\\;')
+    .replace(/,/g, '\\,')
+    .replace(/\r\n|\r|\n/g, '\\n')
+    .replace(CONTROL_CHARS, '');
+}
+
+function foldLine(line: string): string {
+  if (Buffer.byteLength(line, 'utf8') <= MAX_OCTETS) return line;
+
+  const folded: string[] = [];
+  let current = '';
+  let octets = 0;
+
+  for (const character of line) {
+    const size = Buffer.byteLength(character, 'utf8');
+    if (octets + size > MAX_OCTETS) {
+      folded.push(current);
+      current = ' ';
+      octets = 1;
+    }
+    current += character;
+    octets += size;
+  }
+
+  folded.push(current);
+  return folded.join(CRLF);
+}
+
+function property(name: string, value: string): string {
+  return foldLine(`${name}:${value}`);
+}
+
+function parseDate(value: string | Date | null | undefined): Date | undefined {
+  if (!value) return undefined;
+  const date = value instanceof Date ? value : new Date(value);
+  return Number.isNaN(date.getTime()) ? undefined : date;
+}
+
+function toUtcStamp(date: Date): string {
+  return date.toISOString().replace(/[-:]/g, '').replace(/\.\d{3}/, '');
+}
+
+function toDateValue(date: Date): string {
+  return date.toISOString().slice(0, 10).replace(/-/g, '');
+}
+
+export function buildEventCalendar(event: CalendarEvent): string {
+  const start = parseDate(event.start);
+  const end = parseDate(event.end);
+  const lines = [
+    'BEGIN:VCALENDAR',
+    'VERSION:2.0',
+    property('PRODID', '-//SHARP-ER//Events Calendar//EN'),
+    'CALSCALE:GREGORIAN',
+    'METHOD:PUBLISH',
+    property('X-WR-CALNAME', 'SHARP-ER'),
+  ];
+
+  if (start) {
+    lines.push('BEGIN:VEVENT');
+    lines.push(property('UID', escapeText(event.uid)));
+    lines.push(property('DTSTAMP', toUtcStamp(new Date())));
+
+    if (event.allDay) {
+      lines.push(`DTSTART;VALUE=DATE:${toDateValue(start)}`);
+      const exclusiveEnd = new Date((end ?? start).getTime() + 86_400_000);
+      lines.push(`DTEND;VALUE=DATE:${toDateValue(exclusiveEnd)}`);
+    } else {
+      lines.push(property('DTSTART', toUtcStamp(start)));
+      if (end && end.getTime() > start.getTime()) {
+        lines.push(property('DTEND', toUtcStamp(end)));
+      }
+    }
+
+    lines.push(property('SUMMARY', escapeText(event.summary)));
+    if (event.description) {
+      lines.push(property('DESCRIPTION', escapeText(event.description)));
+    }
+    if (event.location) {
+      lines.push(property('LOCATION', escapeText(event.location)));
+    }
+    if (event.url && /^https?:\/\//i.test(event.url)) {
+      lines.push(property('URL', event.url));
+    }
+
+    lines.push(property('STATUS', event.status ?? 'CONFIRMED'));
+    lines.push('END:VEVENT');
+  }
+
+  lines.push('END:VCALENDAR');
+  return `${lines.join(CRLF)}${CRLF}`;
+}