From e406f778e2be40d2d042970d326c155f40e9eb61 Mon Sep 17 00:00:00 2001
From: Jonas <jonas@freesources.org>
Date: Sat, 7 Mar 2026 00:58:39 +0100
Subject: [PATCH 1/2] feat: add event reference provider and widget

Fixes: #7104

Signed-off-by: Jonas <jonas@freesources.org>
---
 lib/AppInfo/Application.php              |   3 +
 lib/Reference/EventReferenceProvider.php | 207 +++++++++++++++++++++++
 psalm.xml                                |   2 +
 src/reference.js                         |  13 ++
 src/views/EventReferenceWidget.vue       | 163 ++++++++++++++++++
 5 files changed, 388 insertions(+)
 create mode 100644 lib/Reference/EventReferenceProvider.php
 create mode 100644 src/views/EventReferenceWidget.vue

diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index b0409bc4c7..082a84949d 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -15,6 +15,7 @@
 use OCA\Calendar\Listener\UserDeletedListener;
 use OCA\Calendar\Notification\Notifier;
 use OCA\Calendar\Profile\AppointmentsAction;
+use OCA\Calendar\Reference\EventReferenceProvider;
 use OCA\Calendar\Reference\ReferenceProvider;
 use OCA\Calendar\UserMigration\Migrator;
 use OCP\AppFramework\App;
@@ -52,6 +53,8 @@ public function register(IRegistrationContext $context): void {
 
 		$context->registerProfileLinkAction(AppointmentsAction::class);
 
+		$context->registerReferenceProvider(EventReferenceProvider::class);
+
 		$context->registerReferenceProvider(ReferenceProvider::class);
 
 		$context->registerEventListener(BeforeAppointmentBookedEvent::class, AppointmentBookedListener::class);
diff --git a/lib/Reference/EventReferenceProvider.php b/lib/Reference/EventReferenceProvider.php
new file mode 100644
index 0000000000..d5d32d164f
--- /dev/null
+++ b/lib/Reference/EventReferenceProvider.php
@@ -0,0 +1,207 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Calendar\Reference;
+
+use OCA\Calendar\AppInfo\Application;
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\Calendar\IManager;
+use OCP\Collaboration\Reference\ADiscoverableReferenceProvider;
+use OCP\Collaboration\Reference\IReference;
+use OCP\Collaboration\Reference\Reference;
+use OCP\IDateTimeFormatter;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use Sabre\VObject\Reader;
+
+class EventReferenceProvider extends ADiscoverableReferenceProvider {
+	public function __construct(
+		private readonly IL10N $l10n,
+		private readonly IURLGenerator $urlGenerator,
+		private readonly IManager $calendarManager,
+		private CalDavBackend $calDavBackend,
+		private readonly IDateTimeFormatter $dateTimeFormatter,
+		private readonly ?string $userId,
+	) {
+	}
+
+	#[\Override]
+	public function getId(): string {
+		return 'calendar-event';
+	}
+
+	#[\Override]
+	public function getTitle(): string {
+		return $this->l10n->t('Calendar event');
+	}
+
+	#[\Override]
+	public function getOrder(): int {
+		return 21;
+	}
+
+	#[\Override]
+	public function getIconUrl(): string {
+		return $this->urlGenerator->getAbsoluteURL(
+			$this->urlGenerator->imagePath(Application::APP_ID, 'calendar-dark.svg')
+		);
+	}
+
+	#[\Override]
+	public function matchReference(string $referenceText): bool {
+		$start = $this->urlGenerator->getAbsoluteURL('/apps/' . Application::APP_ID);
+		$startIndex = $this->urlGenerator->getAbsoluteURL('/index.php/apps/' . Application::APP_ID);
+
+		foreach ([$start, $startIndex] as $base) {
+			$quoted = preg_quote($base, '/');
+
+			// URL pattern 1: .../apps/calendar/edit/{objectId}
+			// URL pattern 2: .../apps/calendar/edit/{objectId}/{recurrenceId}
+			if (preg_match('/^' . $quoted . '\/edit\/[^\/?#]+$/i', $referenceText) === 1) {
+				return true;
+			}
+
+			// URL pattern 3: .../apps/calender/{view}/{timeRange}/edit/{mode}/{objectId}/{recurrenceId}
+			$views = 'timeGridDay|timeGridWeek|dayGridMonth|multiMonthYear|listMonth';
+			if (preg_match('/^' . $quoted . '\/(?:' . $views . ')\/[^\/]+\/edit\/(?:popover|full)\/[^\/?#]+/i', $referenceText) === 1) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	#[\Override]
+	public function resolveReference(string $referenceText): ?IReference {
+		if ($this->userId === null || !$this->matchReference($referenceText)) {
+			return null;
+		}
+
+		$objectId = $this->getObjectIdFromUrl($referenceText);
+		if ($objectId === null) {
+			return null;
+		}
+
+		// objectId is base64(davUrl)
+		$davUrl = base64_decode($objectId, true);
+		if ($davUrl === false) {
+			return null;
+		}
+
+		// DAV URL format: /remote.php/dav/calendars/{userid}/{calendarUri}/{eventFile}.ics
+		$parts = explode('/', trim($davUrl, '/'));
+		if (count($parts) < 2) {
+			return null;
+		}
+		$eventFile = array_pop($parts); // e.g. 'event.ics'
+		$calendarUri = array_pop($parts); // e.g. 'personal'
+		if (empty($calendarUri) || empty($eventFile)) {
+			return null;
+		}
+
+		$calendar = $this->getCalendar($calendarUri);
+		if ($calendar === null) {
+			return null;
+		}
+
+		$eventData = $this->getEventData($calendar['id'], $eventFile);
+		if ($eventData === null) {
+			return null;
+		}
+
+		$reference = new Reference($referenceText);
+		$reference->setTitle($eventData['title']);
+		$reference->setDescription($eventData['date'] ?? $calendar['{DAV:}displayname'] ?? '');
+		$reference->setRichObject(
+			'calendar_event',
+			[
+				'title' => $eventData['title'],
+				'calendarName' => $calendar['{DAV:}displayname'] ?? '',
+				'calendarColor' => $calendar['{http://apple.com/ns/ical/}calendar-color'] ?? null,
+				'date' => $eventData['date'],
+				'startTimestamp' => $eventData['startTimestamp'],
+				'endTimestamp' => $eventData['endTimestamp'],
+				'url' => $referenceText,
+			]
+		);
+		return $reference;
+	}
+
+	private function getObjectIdFromUrl(string $url): ?string {
+		// URL pattern 1+2: .../apps/calendar/edit/{objectId}[/{recurrenceId}]
+		if (preg_match('/\/edit\/([^\/?#]+)/i', $url, $matches) === 1) {
+			if (in_array($matches[1], ['popover', 'full'], true)) {
+				// URL pattern 3: .../apps/calender/{view}/{timeRange}/edit/{mode}/{objectId}/{recurrenceId}
+				if (preg_match('/\/edit\/(?:popover|full)\/([^\/?#]+)/i', $url, $m2)) {
+					return $m2[1];
+				}
+				return null;
+			}
+			return $matches[1];
+		}
+		return null;
+	}
+
+	private function getCalendar(string $calendarUri): ?array {
+		$principalUri = 'principals/users/' . $this->userId;
+		$calendar = $this->calDavBackend->getCalendarByUri($principalUri, $calendarUri);
+		if ($calendar === null || $calendar['{http://nextcloud.com/ns}deleted_at'] !== null) {
+			return null;
+		}
+		return $calendar;
+	}
+
+	private function getEventData(int $calendarId, string $eventFile): ?array {
+		$object = $this->calDavBackend->getCalendarObject($calendarId, $eventFile);
+		if ($object === null) {
+			return null;
+		}
+
+		$vObject = Reader::read($object['calendardata']);
+		$vEvent = $vObject->VEVENT ?? null;
+		if ($vEvent === null) {
+			return null;
+		}
+
+		$date = null;
+		$startTimestamp = null;
+		if (isset($vEvent->DTSTART)) {
+			$dt = $vEvent->DTSTART->getDateTime();
+			$date = $this->dateTimeFormatter->formatTimeSpan(\DateTime::createFromInterface($dt));
+			$startTimestamp = $dt->getTimestamp();
+		}
+
+		$endTimestamp = null;
+		if (isset($vEvent->DTEND)) {
+			$dt = $vEvent->DTEND->getDateTime();
+			$endTimestamp = $dt->getTimestamp();
+		} elseif (isset($vEvent->DURATION) && $startTimestamp !== null) {
+			$duration = $vEvent->DURATION->getDateInterval();
+			$endTimestamp = (new \DateTime())->setTimestamp($startTimestamp)->add($duration)->getTimestamp();
+		}
+
+		return [
+			'title' => isset($vEvent->SUMMARY) ? (string)$vEvent->SUMMARY : $this->l10n->t('Untitled event'),
+			'date' => $date,
+			'startTimestamp' => $startTimestamp,
+			'endTimestamp' => $endTimestamp,
+			'location' => isset($vEvent->LOCATION) ? (string)$vEvent->LOCATION : null,
+		];
+	}
+
+	#[\Override]
+	public function getCachePrefix(string $referenceId): string {
+		return $this->userId ?? '';
+	}
+
+	#[\Override]
+	public function getCacheKey(string $referenceId): string {
+		return $referenceId;
+	}
+}
diff --git a/psalm.xml b/psalm.xml
index 5080548c66..ec0ab1de0b 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -37,6 +37,7 @@
 				<referencedClass name="OCA\Circles\Api\v1\Circles" />
 				<referencedClass name="OCA\Circles\Exceptions\CircleNotFoundException" />
 				<referencedClass name="OCA\Calendar\Controller\Exception" />
+				<referencedClass name="OCA\DAV\CalDAV\CalDavBackend" />
 				<referencedClass name="OCA\DAV\CalDAV\Calendar" />
 				<referencedClass name="OCA\DAV\CalDAV\CalendarHome" />
 				<referencedClass name="OCA\DAV\CalDAV\InvitationResponse\InvitationResponseServer" />
@@ -45,6 +46,7 @@
 				<referencedClass name="Sabre\VObject\Component\VCalendar" />
 				<referencedClass name="Sabre\VObject\Component\VEvent" />
 				<referencedClass name="Sabre\VObject\Component\VTimezone" />
+				<referencedClass name="Sabre\VObject\Reader" />
 				<referencedClass name="Sabre\VObject\TimeZoneUtil" />
 				<referencedClass name="Symfony\Component\HttpFoundation\IpUtils" />
 				<referencedClass name="Symfony\Component\Console\Command\Command" />
diff --git a/src/reference.js b/src/reference.js
index 23b70af59c..be8fcf1715 100644
--- a/src/reference.js
+++ b/src/reference.js
@@ -39,3 +39,16 @@ registerWidget('calendar_widget', async (el, { richObjectType, richObject, acces
 }, (el, renderResult) => {
 	renderResult.object.$destroy()
 }, true)
+
+registerWidget('calendar_event', async (el, { richObject }) => {
+	const { createApp } = await import('vue')
+	const { default: EventReferenceWidget } = await import('./views/EventReferenceWidget.vue')
+
+	const app = createApp(EventReferenceWidget, {
+		richObject,
+	})
+	app.mount(el)
+	return new NcCustomPickerRenderResult(el, app)
+}, (el, renderResult) => {
+	renderResult.object.$destroy()
+})
diff --git a/src/views/EventReferenceWidget.vue b/src/views/EventReferenceWidget.vue
new file mode 100644
index 0000000000..f4876185ae
--- /dev/null
+++ b/src/views/EventReferenceWidget.vue
@@ -0,0 +1,163 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<template>
+	<a
+		:href="richObject.url"
+		class="event"
+		target="_blank">
+		<div class="event__image">
+			<CalendarIcon :size="50" />
+		</div>
+
+		<div class="event__content">
+			<div class="line-one">
+				<strong class="title">{{ richObject.title }}</strong>
+				<span class="separator">•</span>
+				<span class="calendar-prefix">{{ t('calendar', 'In calendar') }}</span>
+				<span v-if="calendarColor" class="color" :style="{ backgroundColor: calendarColor }" />
+				<span class="name">{{ richObject.calendarName }}</span>
+			</div>
+			<div class="line-two" :title="dateTitle">
+				{{ t('calendar', 'Start: {date}', { date: richObject.date }) }}
+				<span v-if="duration" class="duration">
+					<span class="separator">•</span>
+					<span>{{ duration }}</span>
+				</span>
+			</div>
+		</div>
+	</a>
+</template>
+
+<script lang="ts">
+import { n, t } from '@nextcloud/l10n'
+import moment from '@nextcloud/moment'
+import { defineComponent } from 'vue'
+import CalendarIcon from 'vue-material-design-icons/Calendar.vue'
+
+export default defineComponent({
+	name: 'EventReferenceWidget',
+
+	components: {
+		CalendarIcon,
+	},
+
+	props: {
+		richObject: {
+			type: Object,
+			default: null,
+		},
+	},
+
+	computed: {
+		calendarColor(): string | null {
+			return this.richObject?.calendarColor || null
+		},
+
+		dateTitle(): string | undefined {
+			if (!this.richObject.startTimestamp) {
+				return undefined
+			}
+
+			return moment(this.richObject.startTimestamp * 1000).format('LLLL')
+		},
+
+		duration(): string | null {
+			const start: number | undefined = this.richObject.startTimestamp
+			const end: number | undefined = this.richObject.endTimestamp
+			if (!start || !end || end <= start) {
+				return null
+			}
+
+			const dur = moment.duration(end - start, 'seconds')
+			const days = Math.floor(dur.asDays())
+			const hours = dur.hours()
+			const minutes = dur.minutes()
+
+			const parts: string[] = []
+			if (days > 0) {
+				parts.push(n('calendar', '%n day', '%n days', days))
+			}
+			if (hours > 0) {
+				parts.push(n('calendar', '%n hour', '%n hours', hours))
+			}
+			if (minutes > 0) {
+				parts.push(n('calendar', '%n minute', '%n minutes', minutes))
+			}
+
+			return parts.length > 0 ? parts.join(' ') : null
+		},
+	},
+
+	methods: {
+		t,
+	},
+})
+</script>
+
+<style lang="scss" scoped>
+.event {
+	width: 100%;
+	padding-inline: calc(var(--default-grid-baseline) * 3);
+	display: flex;
+	gap: var(--default-grid-baseline);
+	text-decoration: none;
+	color: var(--color-main-text);
+
+	&__image {
+		margin-inline-end: calc(var(--default-grid-baseline) * 3);
+		display: flex;
+		align-items: center;
+	}
+
+	&__content {
+		display: flex;
+		flex-direction: column;
+		flex: 1;
+		min-width: 0;
+
+		.separator {
+			padding-inline: var(--default-grid-baseline);
+			flex-shrink: 0;
+		}
+
+		.line-one {
+			display: flex;
+			align-items: center;
+
+			.title {
+				overflow: hidden;
+				white-space: nowrap;
+				text-overflow: ellipsis;
+			}
+
+			.calendar-prefix {
+				white-space: nowrap;
+			}
+
+			.color {
+				display: inline-block;
+				width: calc(var(--default-grid-baseline) * 4);
+				height: calc(var(--default-grid-baseline) * 4);
+				border-radius: 50%;
+				flex-shrink: 0;
+				margin-inline-start: var(--default-grid-baseline);
+			}
+
+			.name {
+				white-space: nowrap;
+				margin-inline-start: var(--default-grid-baseline);
+			}
+		}
+
+		.line-two {
+			display: flex;
+			align-items: center;
+			font-size: 0.9em;
+			color: var(--color-text-maxcontrast);
+		}
+	}
+}
+</style>

From fc255c2aa6609eba04fe85b8c1f97935f9453fc3 Mon Sep 17 00:00:00 2001
From: Jonas <jonas@freesources.org>
Date: Thu, 19 Mar 2026 18:50:13 +0100
Subject: [PATCH 2/2] chore(EventReferenceProvider): use IManager instead of
 CalDavBackend

Signed-off-by: Jonas <jonas@freesources.org>
---
 lib/Reference/EventReferenceProvider.php | 69 +++++++++++++-----------
 1 file changed, 37 insertions(+), 32 deletions(-)

diff --git a/lib/Reference/EventReferenceProvider.php b/lib/Reference/EventReferenceProvider.php
index d5d32d164f..ba2b96fb81 100644
--- a/lib/Reference/EventReferenceProvider.php
+++ b/lib/Reference/EventReferenceProvider.php
@@ -10,7 +10,7 @@
 namespace OCA\Calendar\Reference;
 
 use OCA\Calendar\AppInfo\Application;
-use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\Calendar\ICalendar;
 use OCP\Calendar\IManager;
 use OCP\Collaboration\Reference\ADiscoverableReferenceProvider;
 use OCP\Collaboration\Reference\IReference;
@@ -18,14 +18,12 @@
 use OCP\IDateTimeFormatter;
 use OCP\IL10N;
 use OCP\IURLGenerator;
-use Sabre\VObject\Reader;
 
 class EventReferenceProvider extends ADiscoverableReferenceProvider {
 	public function __construct(
 		private readonly IL10N $l10n,
 		private readonly IURLGenerator $urlGenerator,
 		private readonly IManager $calendarManager,
-		private CalDavBackend $calDavBackend,
 		private readonly IDateTimeFormatter $dateTimeFormatter,
 		private readonly ?string $userId,
 	) {
@@ -106,24 +104,24 @@ public function resolveReference(string $referenceText): ?IReference {
 		}
 
 		$calendar = $this->getCalendar($calendarUri);
-		if ($calendar === null) {
+		if ($calendar->isDeleted()) {
 			return null;
 		}
 
-		$eventData = $this->getEventData($calendar['id'], $eventFile);
+		$eventData = $this->getEventData($calendar, $eventFile);
 		if ($eventData === null) {
 			return null;
 		}
 
 		$reference = new Reference($referenceText);
 		$reference->setTitle($eventData['title']);
-		$reference->setDescription($eventData['date'] ?? $calendar['{DAV:}displayname'] ?? '');
+		$reference->setDescription($eventData['date'] ?? $calendar->getDisplayName());
 		$reference->setRichObject(
 			'calendar_event',
 			[
 				'title' => $eventData['title'],
-				'calendarName' => $calendar['{DAV:}displayname'] ?? '',
-				'calendarColor' => $calendar['{http://apple.com/ns/ical/}calendar-color'] ?? null,
+				'calendarName' => $calendar->getDisplayName(),
+				'calendarColor' => $calendar->getDisplayColor(),
 				'date' => $eventData['date'],
 				'startTimestamp' => $eventData['startTimestamp'],
 				'endTimestamp' => $eventData['endTimestamp'],
@@ -148,50 +146,57 @@ private function getObjectIdFromUrl(string $url): ?string {
 		return null;
 	}
 
-	private function getCalendar(string $calendarUri): ?array {
+	private function getCalendar(string $calendarUri): ICalendar {
 		$principalUri = 'principals/users/' . $this->userId;
-		$calendar = $this->calDavBackend->getCalendarByUri($principalUri, $calendarUri);
-		if ($calendar === null || $calendar['{http://nextcloud.com/ns}deleted_at'] !== null) {
-			return null;
-		}
-		return $calendar;
+		$calendars = $this->calendarManager->getCalendarsForPrincipal($principalUri, [$calendarUri]);
+		return $calendars[0];
 	}
 
-	private function getEventData(int $calendarId, string $eventFile): ?array {
-		$object = $this->calDavBackend->getCalendarObject($calendarId, $eventFile);
-		if ($object === null) {
+	private function getEventData(ICalendar $calendar, string $eventFile): ?array {
+		$event = null;
+		foreach ($calendar->search('') as $result) {
+			if (($result['uri'] ?? null) === $eventFile) {
+				$event = $result;
+				break;
+			}
+		}
+		if ($event === null) {
 			return null;
 		}
 
-		$vObject = Reader::read($object['calendardata']);
-		$vEvent = $vObject->VEVENT ?? null;
-		if ($vEvent === null) {
+		$object = $event['objects'][0] ?? null;
+		if ($object === null) {
 			return null;
+
 		}
 
 		$date = null;
 		$startTimestamp = null;
-		if (isset($vEvent->DTSTART)) {
-			$dt = $vEvent->DTSTART->getDateTime();
-			$date = $this->dateTimeFormatter->formatTimeSpan(\DateTime::createFromInterface($dt));
-			$startTimestamp = $dt->getTimestamp();
+		/** @var \DateTimeInterface|null $dtStart */
+		$dtStart = $object['DTSTART'][0] ?? null;
+		if ($dtStart instanceof \DateTimeInterface) {
+			$date = $this->dateTimeFormatter->formatTimeSpan(\DateTime::createFromInterface($dtStart));
+			$startTimestamp = $dtStart->getTimestamp();
 		}
 
 		$endTimestamp = null;
-		if (isset($vEvent->DTEND)) {
-			$dt = $vEvent->DTEND->getDateTime();
-			$endTimestamp = $dt->getTimestamp();
-		} elseif (isset($vEvent->DURATION) && $startTimestamp !== null) {
-			$duration = $vEvent->DURATION->getDateInterval();
-			$endTimestamp = (new \DateTime())->setTimestamp($startTimestamp)->add($duration)->getTimestamp();
+		/** @var \DateTimeInterface|null $dtEnd */
+		$dtEnd = $object['DTEND'][0] ?? null;
+		if ($dtEnd instanceof \DateTimeInterface) {
+			$endTimestamp = $dtEnd->getTimestamp();
+		} elseif ($startTimestamp !== null) {
+			$duration = $object['DURATION'][0] ?? null;
+			if ($duration instanceof \DateInterval) {
+				$endTimestamp = (new \DateTime())->setTimestamp($startTimestamp)->add($duration)->getTimestamp();
+			}
 		}
 
 		return [
-			'title' => isset($vEvent->SUMMARY) ? (string)$vEvent->SUMMARY : $this->l10n->t('Untitled event'),
+			'title' => $object['SUMMARY'][0] ?? $this->l10n->t('Untitled event'),
 			'date' => $date,
 			'startTimestamp' => $startTimestamp,
 			'endTimestamp' => $endTimestamp,
-			'location' => isset($vEvent->LOCATION) ? (string)$vEvent->LOCATION : null,
+			'location' => $object['LOCATION'][0] ?? null,
 		];
 	}