Export to calendar (Google + Outlook + ICS)

Calendar.php

<?php

namespace App\Utils;

use DateTime;
use App\PostTypes\Event;
use Nette\Utils\Strings;
use Jsvrcek\ICS\CalendarExport;
use Jsvrcek\ICS\CalendarStream;
use Jsvrcek\ICS\Utility\Formatter;
use Jsvrcek\ICS\Model\CalendarEvent;
use Jsvrcek\ICS\Model\Calendar as ICalendar;

/**
 * Create Google and Outlook add-to-calendar links, generated iCal file.
 *
 * @see https://dylanbeattie.net/2021/01/12/adding-events-to-google-calendar-via-a-link.html
 * @see https://stackoverflow.com/questions/50518151/how-to-generate-url-to-add-event-to-outlook-web-client-calendar
 * @see https://github.com/jasvrcek/ICS
 */
class Calendar
{
	/** @var string */
	private const ICS_COMPANY = 'Super duper company';

	/** @var string */
	private const ICS_CALENDAR = 'Calendar of great events';

	/** @var string */
	private const GOOGLE_URL = 'https://calendar.google.com/calendar/u/0/r/eventedit?';

	/** @var string */
	private const OUTLOOK_URL = 'https://outlook.office.com/owa/?path=/calendar/action/compose&rruaddevent&';

	public function __construct(
		private string $id,
		private DateTime $start,
		private DateTime $end,
		private string $name,
		private string $description = '',
		private string $location = '',
		private string $url = ''
	) { }

	// Factory from WP post type
	public static function fromEvent(Event $event): self
	{
		return new self(
			sha1($event->ID),
			$event->getStart(),
			$event->getEnd(),
			$event->post_title,
			nl2br($event->getSchedule()),
			$event->getAddress(),
			get_permalink($event->ID)
		);
	}

	public function googleUrl(): string
	{
		$googleParams = array_filter([
			'text' => $this->name,
			'dates' => $this->start->format('Ymd\THisp') . '/' . $this->end->format('Ymd\THisp'),
			'location' => $this->location,
			'details' => $this->getDetails()
		]);
		return self::GOOGLE_URL . http_build_query($googleParams);
	}

	public function outlookUrl(): string
	{
		$outlookParams = array_filter([
			'allDay' => $this->isAllDay() ? 'true' : 'false',
			'startdt' => $this->start->format('Y-m-d\TH:i:s'),
			'enddt' => $this->end->format('Y-m-d\TH:i:s'),
			'subject' => $this->name,
			'location' => $this->location,
			'body' => $this->getDetails()
		]);
		return self::OUTLOOK_URL . http_build_query($outlookParams);
	}

	// WP-relevant method
	public function iCalUrl(Event $event): string
	{
		return get_bloginfo('url') . '/?ical=' . $event->ID;
	}

	public function getICal(): ICalendar
	{
		$event = new CalendarEvent();
		$event
			->setUid($this->id)
			->setStart($this->start)
			->setEnd($this->end)
			->setAllDay($this->isAllDay())
			->setSummary($this->name);
		if ($this->description) $event->setDescription($this->description);
		if ($this->url) $event->setUrl($this->url);

		$calendar = new ICalendar();
		$calendar->setProdId('-//' . self::ICS_COMPANY . '//' . self::ICS_CALENDAR . '//EN')
			->addEvent($event);

		return $calendar;
	}

	private function isAllDay(): bool
	{
		$day = 24 * 60 * 60;
		return $this->end->getTimestamp() - $this->start->getTimestamp() > $day;
	}

	private function getDetails(): string
	{
		$details = $this->description;
		if ($this->url) $details .= ($details ? PHP_EOL . PHP_EOL : '') . $this->url;
		return $details;
	}
}

// For Wordpress
add_action('wp', function() {
	if (!isset($_GET['ical']) || !is_numeric($_GET['ical'])) return;
	$event = new Event($_GET['ical']);

	$calendar = Calendar::fromEvent($event)->getICal();
	$calendarExport = new CalendarExport(new CalendarStream, new Formatter());
	$calendarExport->addCalendar($calendar);

	$filename = Strings::webalize($event->post_title);
	header('Content-type: text/calendar; charset=utf-8');
	header('Content-Disposition: attachment; filename=' . $filename . '.ics');
	echo $calendarExport->getStream();
	exit();
});