1 files changed, 147 insertions, 0 deletions
diff --git a/lib/private/Calendar/CalendarEventBuilder.php b/lib/private/Calendar/CalendarEventBuilder.php
new file mode 100644
index 00000000000..1aa11c2436d
--- /dev/null
+++ b/lib/private/Calendar/CalendarEventBuilder.php
@@ -0,0 +1,147 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\Calendar;
+
+use DateTimeInterface;
+use InvalidArgumentException;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Calendar\CalendarEventStatus;
+use OCP\Calendar\ICalendarEventBuilder;
+use OCP\Calendar\ICreateFromString;
+use Sabre\VObject\Component\VCalendar;
+use Sabre\VObject\Component\VEvent;
+
+class CalendarEventBuilder implements ICalendarEventBuilder {
+	private ?DateTimeInterface $startDate = null;
+	private ?DateTimeInterface $endDate = null;
+	private ?string $summary = null;
+	private ?string $description = null;
+	private ?string $location = null;
+	private ?CalendarEventStatus $status = null;
+	private ?array $organizer = null;
+	private array $attendees = [];
+
+	public function __construct(
+		private readonly string $uid,
+		private readonly ITimeFactory $timeFactory,
+	) {
+	}
+
+	public function setStartDate(DateTimeInterface $start): ICalendarEventBuilder {
+		$this->startDate = $start;
+		return $this;
+	}
+
+	public function setEndDate(DateTimeInterface $end): ICalendarEventBuilder {
+		$this->endDate = $end;
+		return $this;
+	}
+
+	public function setSummary(string $summary): ICalendarEventBuilder {
+		$this->summary = $summary;
+		return $this;
+	}
+
+	public function setDescription(string $description): ICalendarEventBuilder {
+		$this->description = $description;
+		return $this;
+	}
+
+	public function setLocation(string $location): ICalendarEventBuilder {
+		$this->location = $location;
+		return $this;
+	}
+
+	public function setStatus(CalendarEventStatus $status): static {
+		$this->status = $status;
+		return $this;
+	}
+
+	public function setOrganizer(string $email, ?string $commonName = null): ICalendarEventBuilder {
+		$this->organizer = [$email, $commonName];
+		return $this;
+	}
+
+	public function addAttendee(string $email, ?string $commonName = null): ICalendarEventBuilder {
+		$this->attendees[] = [$email, $commonName];
+		return $this;
+	}
+
+	public function toIcs(): string {
+		if ($this->startDate === null) {
+			throw new InvalidArgumentException('Event is missing a start date');
+		}
+
+		if ($this->endDate === null) {
+			throw new InvalidArgumentException('Event is missing an end date');
+		}
+
+		if ($this->summary === null) {
+			throw new InvalidArgumentException('Event is missing a summary');
+		}
+
+		if ($this->organizer === null && $this->attendees !== []) {
+			throw new InvalidArgumentException('Event has attendees but is missing an organizer');
+		}
+
+		$vcalendar = new VCalendar();
+		$props = [
+			'UID' => $this->uid,
+			'DTSTAMP' => $this->timeFactory->now(),
+			'SUMMARY' => $this->summary,
+			'DTSTART' => $this->startDate,
+			'DTEND' => $this->endDate,
+			'STATUS' => $this->status->value,
+		];
+		if ($this->description !== null) {
+			$props['DESCRIPTION'] = $this->description;
+		}
+		if ($this->location !== null) {
+			$props['LOCATION'] = $this->location;
+		}
+		/** @var VEvent $vevent */
+		$vevent = $vcalendar->add('VEVENT', $props);
+		if ($this->organizer !== null) {
+			self::addAttendeeToVEvent($vevent, 'ORGANIZER', $this->organizer);
+		}
+		foreach ($this->attendees as $attendee) {
+			self::addAttendeeToVEvent($vevent, 'ATTENDEE', $attendee);
+		}
+		return $vcalendar->serialize();
+	}
+
+	public function createInCalendar(ICreateFromString $calendar): string {
+		$fileName = $this->uid . '.ics';
+		$calendar->createFromString($fileName, $this->toIcs());
+		return $fileName;
+	}
+
+	/**
+	 * @param array{0: string, 1: ?string} $tuple A tuple of [$email, $commonName] where $commonName may be null.
+	 */
+	private static function addAttendeeToVEvent(VEvent $vevent, string $name, array $tuple): void {
+		[$email, $cn] = $tuple;
+		if (!str_starts_with($email, 'mailto:')) {
+			$email = "mailto:$email";
+		}
+		$params = [];
+		if ($cn !== null) {
+			$params['CN'] = $cn;
+			if ($name === 'ORGANIZER') {
+				$params['ROLE'] = 'CHAIR';
+				$params['PARTSTAT'] = 'ACCEPTED';
+			} else {
+				$params['ROLE'] = 'REQ-PARTICIPANT';
+				$params['PARTSTAT'] = 'NEEDS-ACTION';
+			}
+		}
+		$vevent->add($name, $email, $params);
+	}
+}