From 3fa4240a2411143facb244e274c39f10994997fb Mon Sep 17 00:00:00 2001
From: Grigory Vodyanov <scratchx@gmx.com>
Date: Thu, 12 Mar 2026 10:25:01 +0100
Subject: [PATCH] feat: add calendar delegation feature

Signed-off-by: Grigory Vodyanov <scratchx@gmx.com>
Signed-off-by: Hamza <hamzamahjoubi221@gmail.com>

Assisted-by: claude:Opus 4.7 (1M context)
---
 src/components/AppNavigation/CalendarList.vue |  56 ++-
 .../CalendarList/CalendarListItem.vue         |  61 ++-
 src/components/AppNavigation/Settings.vue     |  13 +
 .../Settings/SettingsDelegationSection.vue    | 440 ++++++++++++++++++
 .../AppointmentConfigModal/DurationInput.vue  |   2 +-
 .../Editor/CalendarPickerHeader.vue           | 171 ++++++-
 src/components/Shared/CalendarPicker.vue      |   4 +
 .../Shared/CalendarPickerOption.vue           |  45 +-
 src/models/calendar.js                        |   5 +
 src/services/caldavService.js                 |  14 +
 src/store/delegation.ts                       | 231 +++++++++
 src/store/principals.js                       |  12 +-
 src/views/Calendar.vue                        |   9 +
 tests/javascript/unit/models/calendar.test.js |  26 ++
 14 files changed, 1073 insertions(+), 16 deletions(-)
 create mode 100644 src/components/AppNavigation/Settings/SettingsDelegationSection.vue
 create mode 100644 src/store/delegation.ts

diff --git a/src/components/AppNavigation/CalendarList.vue b/src/components/AppNavigation/CalendarList.vue
index 7e32e374dc..ed37317380 100644
--- a/src/components/AppNavigation/CalendarList.vue
+++ b/src/components/AppNavigation/CalendarList.vue
@@ -101,6 +101,19 @@
 				:calendar="calendar" />
 		</template>
 
+		<template v-if="!isPublic && isDelegationSupported && sortedCalendars.delegated.length">
+			<template v-for="group in delegatedGroups" :key="group.delegatorUrl">
+				<NcAppNavigationCaption
+					:name="group.readOnly
+						? $t('calendar', 'Delegated by {name} (read-only)', { name: group.displayname })
+						: $t('calendar', 'Delegated by {name}', { name: group.displayname })" />
+				<CalendarListItem
+					v-for="calendar in group.calendars"
+					:key="calendar.id"
+					:calendar="calendar" />
+			</template>
+		</template>
+
 		<NcAppNavigationSpacer />
 
 		<!-- The header slot must be placed here, otherwise vuedraggable adds undefined as item to the array -->
@@ -122,6 +135,9 @@ import CalendarListItemLoadingPlaceholder from './CalendarList/CalendarListItemL
 import CalendarListNew from './CalendarList/CalendarListNew.vue'
 import PublicCalendarListItem from './CalendarList/PublicCalendarListItem.vue'
 import useCalendarsStore from '../../store/calendars.js'
+import useDelegationStore from '../../store/delegation.ts'
+import usePrincipalsStore from '../../store/principals.js'
+import { isAfterVersion } from '../../utils/nextcloudVersion.ts'
 
 const limit = pLimit(1)
 
@@ -153,13 +169,14 @@ export default {
 		return {
 			calendars: [],
 			/**
-			 * Calendars sorted by personal, shared, deck, and tasks
+			 * Calendars sorted by personal, shared, deck, and delegated
 			 */
 			sortedCalendars: {
 				personal: [],
 				shared: [],
 				deck: [],
 				tasks: [],
+				delegated: [],
 			},
 
 			disableDragging: false,
@@ -168,7 +185,7 @@ export default {
 	},
 
 	computed: {
-		...mapStores(useCalendarsStore),
+		...mapStores(useCalendarsStore, useDelegationStore, usePrincipalsStore),
 		...mapState(useCalendarsStore, {
 			serverCalendars: 'sortedCalendarsSubscriptions',
 		}),
@@ -176,6 +193,35 @@ export default {
 		loadingKeyCalendars() {
 			return this._uid + '-loading-placeholder-calendars'
 		},
+
+		isDelegationSupported() {
+			return isAfterVersion(34)
+		},
+
+		/**
+		 * Delegated calendars grouped by the delegator (the user who granted
+		 * proxy access), which may differ from each calendar's owner when the
+		 * delegator only has access via a regular share.
+		 *
+		 * @return {Array<{delegatorUrl: string, displayname: string, calendars: object[]}>}
+		 */
+		delegatedGroups() {
+			const groups = new Map()
+			for (const calendar of this.sortedCalendars.delegated) {
+				const delegatorUrl = calendar.delegatorUrl || calendar.owner || ''
+				if (!groups.has(delegatorUrl)) {
+					const principal = this.principalsStore.getPrincipalByUrl(delegatorUrl)
+					groups.set(delegatorUrl, {
+						delegatorUrl,
+						displayname: principal?.displayname || principal?.userId || '',
+						readOnly: !!calendar.readOnly,
+						calendars: [],
+					})
+				}
+				groups.get(delegatorUrl).calendars.push(calendar)
+			}
+			return Array.from(groups.values())
+		},
 	},
 
 	watch: {
@@ -208,9 +254,15 @@ export default {
 				shared: [],
 				deck: [],
 				tasks: [],
+				delegated: [],
 			}
 
 			this.calendars.forEach((calendar) => {
+				if (calendar.isDelegated) {
+					this.sortedCalendars.delegated.push(calendar)
+					return
+				}
+
 				if (calendar.isSharedWithMe) {
 					this.sortedCalendars.shared.push(calendar)
 					return
diff --git a/src/components/AppNavigation/CalendarList/CalendarListItem.vue b/src/components/AppNavigation/CalendarList/CalendarListItem.vue
index b8cc504872..c2501a76ea 100644
--- a/src/components/AppNavigation/CalendarList/CalendarListItem.vue
+++ b/src/components/AppNavigation/CalendarList/CalendarListItem.vue
@@ -26,16 +26,36 @@
 
 		<template #counter>
 			<LinkVariant v-if="isSharedByMe" :size="20" />
+			<NcAvatar
+				v-else-if="isDelegated && loadedDelegatorPrincipal && !actionsMenuOpen"
+				:user="delegatorUserId"
+				:displayName="delegatorDisplayname"
+				:title="delegatorDisplayname"
+				:hideStatus="true"
+				:size="20"
+				class="delegated-counter-avatar" />
 			<NcAvatar
 				v-else-if="isSharedWithMe && loadedOwnerPrincipal && !actionsMenuOpen"
 				:user="ownerUserId"
 				:displayName="ownerDisplayname" />
-			<div v-else-if="isSharedWithMe && !loadedOwnerPrincipal" class="icon icon-loading" />
+			<div v-else-if="(isSharedWithMe && !loadedOwnerPrincipal) || (isDelegated && !loadedDelegatorPrincipal)" class="icon icon-loading" />
 		</template>
 
 		<template #actions>
 			<template v-if="!isBeingDeleted">
-				<template v-if="isSharedWithMe">
+				<template v-if="isDelegated">
+					<NcActionCaption :name="$t('calendar', 'Delegated to you by')" />
+					<NcActionText class="delegated-action-text">
+						<template #icon>
+							<div class="actions-icon-avatar">
+								<NcAvatar :user="delegatorUserId" :displayName="delegatorDisplayname" :size="30" />
+							</div>
+						</template>
+						{{ delegatorDisplayname }}
+					</NcActionText>
+					<NcActionSeparator />
+				</template>
+				<template v-else-if="isSharedWithMe">
 					<NcActionCaption :name="$t('calendar', 'Shared with you by')" />
 					<NcActionText>
 						<template #icon>
@@ -143,7 +163,7 @@ export default {
 		canBeShared() {
 			// The backend falsely reports incoming editable shares as being shareable
 			// Ref https://github.com/nextcloud/calendar/issues/5755
-			if (this.calendar.isSharedWithMe) {
+			if (this.calendar.isSharedWithMe || this.calendar.isDelegated) {
 				return false
 			}
 
@@ -165,7 +185,16 @@ export default {
 		 * @return {boolean}
 		 */
 		isSharedWithMe() {
-			return this.calendar.isSharedWithMe
+			return this.calendar.isSharedWithMe && !this.calendar.isDelegated
+		},
+
+		/**
+		 * Is the calendar delegated to me by another user?
+		 *
+		 * @return {boolean}
+		 */
+		isDelegated() {
+			return !!this.calendar.isDelegated
 		},
 
 		/**
@@ -186,6 +215,10 @@ export default {
 			return this.principalsStore.getPrincipalByUrl(this.calendar.owner) !== undefined
 		},
 
+		loadedDelegatorPrincipal() {
+			return this.principalsStore.getPrincipalByUrl(this.calendar.delegatorUrl) !== undefined
+		},
+
 		ownerUserId() {
 			const principal = this.principalsStore.getPrincipalByUrl(this.calendar.owner)
 			if (principal) {
@@ -204,6 +237,16 @@ export default {
 			return ''
 		},
 
+		delegatorUserId() {
+			const principal = this.principalsStore.getPrincipalByUrl(this.calendar.delegatorUrl)
+			return principal?.userId || ''
+		},
+
+		delegatorDisplayname() {
+			const principal = this.principalsStore.getPrincipalByUrl(this.calendar.delegatorUrl)
+			return principal?.displayname || principal?.userId || ''
+		},
+
 		/**
 		 * compute aria-description for AppNavigationItem link
 		 *
@@ -308,6 +351,16 @@ export default {
 		height: 44px;
 	}
 
+	// Size and position the delegated avatar in the counter slot to match icon buttons
+	.delegated-counter-avatar {
+		margin-inline-start: auto;
+	}
+
+	// Vertically align the owner name with the avatar in the "Delegated to you by" row
+	:deep(.action-text__text) {
+		align-self: center ;
+	}
+
 	// Hide avatars if list item is hovered
 	:deep(.app-navigation-entry:hover .app-navigation-entry__counter-wrapper) {
 		display: none;
diff --git a/src/components/AppNavigation/Settings.vue b/src/components/AppNavigation/Settings.vue
index e71b95ccf8..a70a5a5413 100644
--- a/src/components/AppNavigation/Settings.vue
+++ b/src/components/AppNavigation/Settings.vue
@@ -135,6 +135,12 @@
 						<SettingsAttachmentsFolder />
 					</NcFormGroup>
 				</NcAppSettingsSection>
+				<NcAppSettingsSection
+					v-if="isDelegationSupported"
+					id="settings-modal-delegation"
+					:name="t('calendar', 'Delegation')">
+					<SettingsDelegationSection />
+				</NcAppSettingsSection>
 				<EventLegend />
 				<ShortcutOverview />
 			</NcAppSettingsDialog>
@@ -167,6 +173,7 @@ import CogIcon from 'vue-material-design-icons/CogOutline.vue'
 import CalendarPicker from '../Shared/CalendarPicker.vue'
 import EventLegend from './Settings/EventLegend.vue'
 import SettingsAttachmentsFolder from './Settings/SettingsAttachmentsFolder.vue'
+import SettingsDelegationSection from './Settings/SettingsDelegationSection.vue'
 import SettingsImportSection from './Settings/SettingsImportSection.vue'
 import SettingsTimezoneSelect from './Settings/SettingsTimezoneSelect.vue'
 import ShortcutOverview from './Settings/ShortcutOverview.vue'
@@ -187,6 +194,7 @@ import {
 	getAmountHoursMinutesAndUnitForAllDayEvents,
 } from '../../utils/alarms.js'
 import logger from '../../utils/logger.js'
+import { isAfterVersion } from '../../utils/nextcloudVersion.ts'
 
 export default {
 	name: 'Settings',
@@ -199,6 +207,7 @@ export default {
 		SettingsImportSection,
 		SettingsTimezoneSelect,
 		SettingsAttachmentsFolder,
+		SettingsDelegationSection,
 		ShortcutOverview,
 		CogIcon,
 		NcFormBox,
@@ -264,6 +273,10 @@ export default {
 			return this.savingBirthdayCalendar || this.loadingCalendars
 		},
 
+		isDelegationSupported() {
+			return isAfterVersion(34)
+		},
+
 		files() {
 			return this.importFilesStore.importFiles
 		},
diff --git a/src/components/AppNavigation/Settings/SettingsDelegationSection.vue b/src/components/AppNavigation/Settings/SettingsDelegationSection.vue
new file mode 100644
index 0000000000..11c74a04ae
--- /dev/null
+++ b/src/components/AppNavigation/Settings/SettingsDelegationSection.vue
@@ -0,0 +1,440 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<template>
+	<div class="delegation-settings">
+		<NcNoteCard v-if="loadError" type="error">
+			{{ t('calendar', 'Could not load delegates.') }}
+		</NcNoteCard>
+
+		<NcFormGroup
+			:label="t('calendar', 'Delegates')"
+			:description="t('calendar', 'Allow users to manage your calendar events and invitations on your behalf.')">
+			<NcEmptyContent
+				v-if="loading"
+				icon="icon-loading"
+				class="delegation-settings__loading"
+				:description="t('calendar', 'Loading delegates\u2026')" />
+			<ul v-else class="delegation-settings__list">
+				<NcListItem
+					v-for="delegate in delegationStore.delegates"
+					:key="delegate.url ?? ''"
+					:name="delegate.displayname || delegate.principalId || ''"
+					:compact="true">
+					<template #subname>
+						{{ delegateSubname(delegate) }}
+					</template>
+					<template #actions>
+						<NcActionButton
+							:aria-label="t('calendar', 'Revoke access')"
+							@click="onRevokeClick(delegate)">
+							<template #icon>
+								<CloseIcon :size="20" />
+							</template>
+							{{ t('calendar', 'Revoke access') }}
+						</NcActionButton>
+					</template>
+				</NcListItem>
+			</ul>
+
+			<p v-if="!loading && delegationStore.delegates.length === 0" class="delegation-settings__empty">
+				{{ t('calendar', 'No delegates yet.') }}
+			</p>
+
+			<NcButton
+				class="delegation-settings__add-button"
+				variant="secondary"
+				:wide="true"
+				@click="openAddDelegate">
+				<template #icon>
+					<PlusIcon :size="20" />
+				</template>
+				{{ t('calendar', 'Add delegate') }}
+			</NcButton>
+		</NcFormGroup>
+
+		<!-- Revoke Confirmation Dialog -->
+		<NcDialog
+			v-if="revokeTarget"
+			:open="!!revokeTarget"
+			:name="t('calendar', 'Revoke access?')"
+			:message="revokeMessage"
+			:buttons="revokeButtons"
+			@update:open="onRevokeDialogClose" />
+
+		<!-- Add Delegate Dialog -->
+		<NcDialog
+			v-if="showAddDelegate"
+			:open="showAddDelegate"
+			:name="t('calendar', 'Add delegate')"
+			@update:open="onAddDelegateDialogClose">
+			<div class="delegation-add">
+				<NcSelect
+					v-model="selectedUser"
+					class="delegation-add__select"
+					:options="searchResults"
+					:searchable="true"
+					:internalSearch="false"
+					:loading="searchLoading"
+					:max-height="300"
+					:placeholder="t('calendar', 'Search for a user\u2026')"
+					:clearable="true"
+					:filterBy="filterSearchResults"
+					openDirection="below"
+					trackBy="url"
+					label="displayname"
+					@search="onSearch">
+					<template #no-options>
+						<span>{{ t('calendar', 'No users found') }}</span>
+					</template>
+					<template #option="user">
+						<div class="delegation-add__option">
+							<NcAvatar :user="user.principalId" :displayName="user.displayname" />
+							<div class="delegation-add__option-label">
+								<span>{{ user.displayname }}</span>
+								<span class="delegation-add__option-email">{{ user.emailAddress }}</span>
+							</div>
+						</div>
+					</template>
+				</NcSelect>
+				<p class="delegation-add__description">
+					{{ t('calendar', 'Choose whether they can view and edit events, or only view them.') }}
+				</p>
+			</div>
+			<template #actions>
+				<NcButton variant="secondary" @click="showAddDelegate = false">
+					{{ t('calendar', 'Cancel') }}
+				</NcButton>
+				<NcButton
+					variant="secondary"
+					:disabled="!selectedUser || addLoading"
+					@click="confirmAddDelegate('read')">
+					{{ t('calendar', 'Add as viewer') }}
+				</NcButton>
+				<NcButton
+					variant="primary"
+					:disabled="!selectedUser || addLoading"
+					@click="confirmAddDelegate('write')">
+					{{ t('calendar', 'Add as editor') }}
+				</NcButton>
+			</template>
+		</NcDialog>
+	</div>
+</template>
+
+<script setup lang="ts">
+import type { DelegatePrincipal } from '@/store/delegation.ts'
+
+import { showError, showSuccess } from '@nextcloud/dialogs'
+import { translate as t } from '@nextcloud/l10n'
+import {
+	NcActionButton,
+	NcAvatar,
+	NcButton,
+	NcDialog,
+	NcEmptyContent,
+	NcFormGroup,
+	NcListItem,
+	NcNoteCard,
+	NcSelect,
+} from '@nextcloud/vue'
+import debounce from 'debounce'
+import { computed, onMounted, ref } from 'vue'
+import CloseIcon from 'vue-material-design-icons/Close.vue'
+import { principalPropertySearchByDisplaynameOrEmail } from '@/services/caldavService.js'
+import useDelegationStore from '@/store/delegation.ts'
+import usePrincipalsStore from '@/store/principals.js'
+import logger from '@/utils/logger.js'
+
+interface SearchUser {
+	url: string
+	displayname: string | null
+	emailAddress: string | null
+	principalId: string | null
+}
+
+const delegationStore = useDelegationStore()
+const principalsStore = usePrincipalsStore()
+
+/** Whether the data is being loaded */
+const loading = ref(false)
+/** Whether there was an error loading delegates */
+const loadError = ref(false)
+/** The delegate object pending revocation, or null */
+const revokeTarget = ref<DelegatePrincipal | null>(null)
+/** Whether the add-delegate dialog is open */
+const showAddDelegate = ref(false)
+/** Currently selected user in the add-delegate dialog */
+const selectedUser = ref<SearchUser | null>(null)
+/** Search results for user lookup */
+const searchResults = ref<SearchUser[]>([])
+/** Whether user search is in progress */
+const searchLoading = ref(false)
+/** Whether an add-delegate operation is in progress */
+const addLoading = ref(false)
+
+/**
+ * Confirmation message for the revoke dialog.
+ */
+const revokeMessage = computed((): string => {
+	if (!revokeTarget.value) {
+		return ''
+	}
+	const email = revokeTarget.value.emailAddress
+		|| revokeTarget.value.displayname
+		|| revokeTarget.value.principalId
+	return t('calendar', '{email} will no longer be able to act on your behalf.', { email: email ?? '' })
+})
+
+/**
+ * Buttons for the revoke confirmation dialog.
+ */
+const revokeButtons = computed(() => [
+	{
+		label: t('calendar', 'Cancel'),
+		callback: () => { revokeTarget.value = null },
+	},
+	{
+		label: t('calendar', 'Revoke'),
+		variant: 'error' as const,
+		callback: confirmRevoke,
+	},
+])
+
+onMounted(async () => {
+	loadError.value = false
+	loading.value = true
+	try {
+		await delegationStore.fetchDelegates()
+	} catch (error) {
+		logger.error('Failed to load delegates', { error })
+		loadError.value = true
+	} finally {
+		loading.value = false
+	}
+})
+
+/**
+ * Returns a descriptive subname for a delegate list item
+ * showing their permission level and optionally their email.
+ *
+ * @param delegate - The delegate principal object
+ */
+function delegateSubname(delegate: DelegatePrincipal): string {
+	const permissionLabel = delegate.permission === 'read'
+		? t('calendar', 'Viewer')
+		: t('calendar', 'Editor')
+	if (delegate.emailAddress) {
+		return `${permissionLabel} · ${delegate.emailAddress}`
+	}
+	return permissionLabel
+}
+
+/**
+ * Open the revoke confirmation dialog for a specific delegate.
+ *
+ * @param delegate - The delegate principal object
+ */
+function onRevokeClick(delegate: DelegatePrincipal): void {
+	revokeTarget.value = delegate
+}
+
+/**
+ * Handle the revoke dialog close event.
+ *
+ * @param open - New open state
+ */
+function onRevokeDialogClose(open: boolean): void {
+	if (!open) {
+		revokeTarget.value = null
+	}
+}
+
+/**
+ * Execute the revoke operation after user confirmation.
+ */
+async function confirmRevoke(): Promise<void> {
+	if (!revokeTarget.value) {
+		return
+	}
+	const delegate = revokeTarget.value
+	revokeTarget.value = null
+	try {
+		const url = delegate.url
+		if (!url) {
+			showError(t('calendar', 'Could not revoke access.'))
+			logger.error('Failed to revoke delegate access, no delegate url')
+			return
+		}
+		await delegationStore.removeDelegate({ principalUrl: url })
+		showSuccess(t('calendar', 'Access revoked successfully.'))
+	} catch (error) {
+		logger.error('Failed to revoke delegate access', { error })
+		showError(t('calendar', 'Could not revoke access.'))
+	}
+}
+
+/**
+ * Open the add-delegate dialog.
+ */
+function openAddDelegate(): void {
+	selectedUser.value = null
+	searchResults.value = []
+	showAddDelegate.value = true
+}
+
+/**
+ * Handle the add-delegate dialog close event.
+ *
+ * @param open - New open state
+ */
+function onAddDelegateDialogClose(open: boolean): void {
+	if (!open) {
+		showAddDelegate.value = false
+	}
+}
+
+/**
+ * Execute the add-delegate operation.
+ *
+ * @param permission - The permission level to grant
+ */
+async function confirmAddDelegate(permission: 'write' | 'read'): Promise<void> {
+	if (!selectedUser.value) {
+		return
+	}
+	addLoading.value = true
+	const user = selectedUser.value
+	showAddDelegate.value = false
+	try {
+		await delegationStore.addDelegate({ principalUrl: user.url, permission })
+		const label = permission === 'read'
+			? t('calendar', '{name} can now view your calendars.', { name: user.displayname || user.principalId || '' })
+			: t('calendar', '{name} can now act on your behalf.', { name: user.displayname || user.principalId || '' })
+		showSuccess(label)
+	} catch (error) {
+		logger.error('Failed to add delegate', { error })
+		showError(t('calendar', 'Could not add delegate.'))
+	} finally {
+		addLoading.value = false
+		selectedUser.value = null
+	}
+}
+
+/**
+ * Filter function for NcSelect to match against displayname, email, or principalId.
+ *
+ * @param option - The option object
+ * @param label - The label value
+ * @param search - The current search term
+ */
+function filterSearchResults(option: SearchUser, label: string, search: string): boolean {
+	if (!search) {
+		return true
+	}
+	const term = search.toLowerCase()
+	return (!!label && label.toLowerCase().includes(term))
+		|| (!!option.emailAddress && option.emailAddress.toLowerCase().includes(term))
+		|| (!!option.principalId && option.principalId.toLowerCase().includes(term))
+}
+
+/**
+ * Search for users by display name or email.
+ */
+const onSearch = debounce(async (query: string): Promise<void> => {
+	if (!query) {
+		searchResults.value = []
+		return
+	}
+
+	searchLoading.value = true
+	try {
+		const results = await principalPropertySearchByDisplaynameOrEmail(query)
+		const currentUser = principalsStore.getCurrentUserPrincipal
+		const existingDelegateUrls = delegationStore.delegates.map((d) => d.url)
+
+		searchResults.value = results
+			.filter((result: Record<string, unknown>) => {
+				// Only include individual users (not rooms/resources/groups)
+				if (result.calendarUserType !== 'INDIVIDUAL') {
+					return false
+				}
+				// Exclude the current user
+				if (currentUser && result.principalUrl === currentUser.url) {
+					return false
+				}
+				// Exclude already-existing delegates (both editors and viewers)
+				if (existingDelegateUrls.includes(result.principalUrl as string)) {
+					return false
+				}
+				return true
+			})
+			.map((result: Record<string, unknown>) => ({
+				url: result.principalUrl as string,
+				displayname: result.displayname as string | null,
+				emailAddress: result.email as string | null,
+				principalId: result.userId as string | null,
+			}))
+	} catch (error) {
+		logger.error('User search failed', { error })
+		searchResults.value = []
+	} finally {
+		searchLoading.value = false
+	}
+}, 300)
+</script>
+
+<style lang="scss" scoped>
+.delegation-settings {
+	&__loading {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+	}
+
+	&__list {
+		list-style: none;
+		padding: 0;
+		margin: 0 0 calc(var(--default-grid-baseline) * 2);
+	}
+
+	&__empty {
+		color: var(--color-text-maxcontrast);
+		font-style: italic;
+		margin: calc(var(--default-grid-baseline) * 2) 0;
+	}
+
+	&__add-button {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+	}
+}
+
+.delegation-add {
+	padding: var(--default-grid-baseline) 0;
+
+	&__select {
+		width: 100%;
+	}
+
+	&__description {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+		color: var(--color-text-maxcontrast);
+	}
+
+	&__option {
+		display: flex;
+		align-items: center;
+		gap: calc(var(--default-grid-baseline) * 2);
+		width: 100%;
+	}
+
+	&__option-label {
+		display: flex;
+		flex-direction: column;
+	}
+
+	&__option-email {
+		color: var(--color-text-lighter);
+	}
+}
+</style>
diff --git a/src/components/AppointmentConfigModal/DurationInput.vue b/src/components/AppointmentConfigModal/DurationInput.vue
index 59a528f890..8e0e8af3a7 100644
--- a/src/components/AppointmentConfigModal/DurationInput.vue
+++ b/src/components/AppointmentConfigModal/DurationInput.vue
@@ -85,7 +85,7 @@ export default {
 			}
 
 			// Emit value in seconds
-			// eslint-disable-next-line vue/require-explicit-emits
+
 			this.$emit('update:modelValue', this.parsedInternalValue * 60)
 		},
 
diff --git a/src/components/Editor/CalendarPickerHeader.vue b/src/components/Editor/CalendarPickerHeader.vue
index 494287d10d..99e76a7e47 100644
--- a/src/components/Editor/CalendarPickerHeader.vue
+++ b/src/components/Editor/CalendarPickerHeader.vue
@@ -15,7 +15,7 @@
 			:class="{
 				'calendar-picker-header__picker--has-menu': !isReadOnly && calendars.length > 1,
 			}"
-			:menuName="value.displayName"
+			:menuName="getOptionLabel(value)"
 			:forceName="true"
 			:disabled="isDisabled">
 			<template #icon>
@@ -34,26 +34,68 @@
 					@click="$emit('update:value', calendar)">
 					<template #icon>
 						<div class="calendar-picker-header__icon">
+							<NcAvatar
+								v-if="calendar.isDelegated"
+								class="calendar-picker-header__picker__option__avatar"
+								:title="getDelegatorDisplayName(calendar)"
+								:disableMenu="true"
+								:disableTooltip="true"
+								:hideStatus="true"
+								:user="getDelegatorUserId(calendar)"
+								:displayName="getDelegatorDisplayName(calendar)"
+								:size="20" />
+							<NcAvatar
+								v-else-if="calendar.isSharedWithMe"
+								class="calendar-picker-header__picker__option__avatar"
+								:title="getOwnerDisplayName(calendar)"
+								:disableMenu="true"
+								:disableTooltip="true"
+								:hideStatus="true"
+								:user="getOwnerUserId(calendar)"
+								:displayName="getOwnerDisplayName(calendar)"
+								:size="20" />
 							<div
+								v-else
 								class="calendar-picker-header__icon__dot"
 								:style="{ 'background-color': calendar.color }" />
 						</div>
 					</template>
-					{{ calendar.displayName }}
+					{{ getOptionLabel(calendar) }}
 				</NcActionButton>
 			</template>
 		</NcActions>
+		<NcAvatar
+			v-if="value.isDelegated"
+			class="calendar-picker-header__avatar"
+			:disableMenu="true"
+			:title="delegatorDisplayName"
+			:disableTooltip="true"
+			:user="delegatorUserId"
+			:displayName="delegatorDisplayName"
+			:size="24" />
+		<NcAvatar
+			v-else-if="value.isSharedWithMe"
+			class="calendar-picker-header__avatar"
+			:disableMenu="true"
+			:title="ownerDisplayName"
+			:disableTooltip="true"
+			:user="ownerUserId"
+			:displayName="ownerDisplayName"
+			:size="24" />
 	</div>
 </template>
 
 <script>
-import { NcActionButton, NcActions } from '@nextcloud/vue'
+import { NcActionButton, NcActions, NcAvatar } from '@nextcloud/vue'
+import { mapStores } from 'pinia'
+import usePrincipalsStore from '../../store/principals.js'
 
 export default {
 	name: 'CalendarPickerHeader',
 	components: {
 		NcActions,
 		NcActionButton,
+		NcAvatar,
 	},
 
 	props: {
@@ -79,12 +121,55 @@ export default {
 	},
 
 	computed: {
+		...mapStores(usePrincipalsStore),
 		/**
 		 * @return {boolean}
 		 */
 		isDisabled() {
 			return this.isReadOnly || this.calendars.length < 2
 		},
+
+		/**
+		 * Get the principal object of the calendar's owner
+		 *
+		 * @return {null | object}
+		 */
+		ownerPrincipal() {
+			return this.principalsStore.getPrincipalByUrl(this.value.owner)
+		},
+
+		/**
+		 * Gets the user-id of the calendar's owner
+		 *
+		 * @return {null | string}
+		 */
+		ownerUserId() {
+			return this.ownerPrincipal?.userId ?? null
+		},
+
+		/**
+		 * Gets the display name of the calendar's owner
+		 *
+		 * @return {null | string}
+		 */
+		ownerDisplayName() {
+			return this.ownerPrincipal?.displayname ?? null
+		},
+
+		delegatorPrincipal() {
+			if (!this.value.delegatorUrl) {
+				return null
+			}
+			return this.principalsStore.getPrincipalByUrl(this.value.delegatorUrl) ?? null
+		},
+
+		delegatorUserId() {
+			return this.delegatorPrincipal?.userId ?? null
+		},
+
+		delegatorDisplayName() {
+			return this.delegatorPrincipal?.displayname ?? this.delegatorPrincipal?.userId ?? null
+		},
 	},
 
 	mounted() {
@@ -93,6 +178,76 @@ export default {
 		const menuDownIconUrl = 'url(data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAyNCAyNCI+PHBhdGggZD0iTTcsMTBMMTIsMTVMMTcsMTBIN1oiIC8+PC9zdmc+)'
 		this.$el.style.setProperty('--mdi-menu-down', menuDownIconUrl)
 	},
+
+	methods: {
+		/**
+		 * Gets the user-id of the given calendar's owner
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getOwnerUserId(calendar) {
+			return this.principalsStore.getPrincipalByUrl(calendar.owner)?.userId ?? null
+		},
+
+		/**
+		 * Gets the display name of the given calendar's owner
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getOwnerDisplayName(calendar) {
+			return this.principalsStore.getPrincipalByUrl(calendar.owner)?.displayname ?? null
+		},
+
+		/**
+		 * Gets the user-id of the given delegated calendar's delegator
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getDelegatorUserId(calendar) {
+			if (!calendar.delegatorUrl) {
+				return null
+			}
+			return this.principalsStore.getPrincipalByUrl(calendar.delegatorUrl)?.userId ?? null
+		},
+
+		/**
+		 * Gets the display name of the given delegated calendar's delegator
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getDelegatorDisplayName(calendar) {
+			if (!calendar.delegatorUrl) {
+				return null
+			}
+			const principal = this.principalsStore.getPrincipalByUrl(calendar.delegatorUrl)
+			return principal?.displayname ?? principal?.userId ?? null
+		},
+
+		/**
+		 * Builds the option label including the "(delegated by X)" suffix
+		 * when applicable. NcActionButton only renders the first text node of
+		 * its default slot, so the suffix must be part of the same string.
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {string}
+		 */
+		getOptionLabel(calendar) {
+			if (calendar.isDelegated) {
+				const delegator = this.getDelegatorDisplayName(calendar)
+				if (delegator) {
+					return this.$t('calendar', '{name} (delegated by {delegator})', {
+						name: calendar.displayName,
+						delegator,
+					})
+				}
+			}
+			return calendar.displayName
+		},
+	},
 }
 </script>
 
@@ -142,6 +297,10 @@ export default {
 			:deep(button) {
 				align-items: center !important;
 			}
+
+			&__avatar {
+				margin: auto;
+			}
 		}
 
 		// Fix long calendar name ellipsis
@@ -162,6 +321,12 @@ export default {
 		}
 	}
 
+	&__avatar {
+		flex-shrink: 0;
+		align-self: center;
+		margin-inline-start: var(--default-grid-baseline);
+	}
+
 	&__icon {
 		display: flex;
 		align-items: center;
diff --git a/src/components/Shared/CalendarPicker.vue b/src/components/Shared/CalendarPicker.vue
index 91faa0ceea..2c428ccd78 100644
--- a/src/components/Shared/CalendarPicker.vue
+++ b/src/components/Shared/CalendarPicker.vue
@@ -21,6 +21,8 @@
 				:color="getCalendarById(id).color"
 				:displayName="getCalendarById(id).displayName"
 				:isSharedWithMe="getCalendarById(id).isSharedWithMe"
+				:isDelegated="getCalendarById(id).isDelegated"
+				:delegatorUrl="getCalendarById(id).delegatorUrl"
 				:owner="getCalendarById(id).owner" />
 		</template>
 		<template #selected-option="{ id }">
@@ -28,6 +30,8 @@
 				:color="getCalendarById(id).color"
 				:displayName="getCalendarById(id).displayName"
 				:isSharedWithMe="getCalendarById(id).isSharedWithMe"
+				:isDelegated="getCalendarById(id).isDelegated"
+				:delegatorUrl="getCalendarById(id).delegatorUrl"
 				:owner="getCalendarById(id).owner" />
 		</template>
 	</NcSelect>
diff --git a/src/components/Shared/CalendarPickerOption.vue b/src/components/Shared/CalendarPickerOption.vue
index 1c528f6fe8..f5123579ab 100644
--- a/src/components/Shared/CalendarPickerOption.vue
+++ b/src/components/Shared/CalendarPickerOption.vue
@@ -11,10 +11,21 @@
 
 		<span class="calendar-picker-option__label">
 			{{ displayName }}
+			<span v-if="isDelegated && delegatorDisplayName" class="calendar-picker-option__delegation">
+				{{ $t('calendar', '(delegated by {name})', { name: delegatorDisplayName }) }}
+			</span>
 		</span>
 
 		<Avatar
-			v-if="isSharedWithMe"
+			v-if="isDelegated"
+			class="calendar-picker-option__avatar"
+			:disableMenu="true"
+			:disableTooltip="true"
+			:user="delegatorUserId"
+			:displayName="delegatorDisplayName"
+			:size="18" />
+		<Avatar
+			v-else-if="isSharedWithMe"
 			class="calendar-picker-option__avatar"
 			:disableMenu="true"
 			:disableTooltip="true"
@@ -55,6 +66,16 @@ export default {
 			type: Boolean,
 			required: true,
 		},
+
+		isDelegated: {
+			type: Boolean,
+			default: false,
+		},
+
+		delegatorUrl: {
+			type: String,
+			default: '',
+		},
 	},
 
 	computed: {
@@ -93,6 +114,28 @@ export default {
 
 			return null
 		},
+
+		delegatorPrincipal() {
+			if (!this.delegatorUrl) {
+				return null
+			}
+			return this.principalsStore.getPrincipalByUrl(this.delegatorUrl) || null
+		},
+
+		delegatorUserId() {
+			return this.delegatorPrincipal?.userId || null
+		},
+
+		delegatorDisplayName() {
+			return this.delegatorPrincipal?.displayname || this.delegatorPrincipal?.userId || ''
+		},
 	},
 }
 </script>
+
+<style lang="scss" scoped>
+.calendar-picker-option__delegation {
+	color: var(--color-text-maxcontrast);
+	margin-inline-start: 4px;
+}
+</style>
diff --git a/src/models/calendar.js b/src/models/calendar.js
index 8b478bf474..3617bc502f 100644
--- a/src/models/calendar.js
+++ b/src/models/calendar.js
@@ -45,6 +45,11 @@ function getDefaultCalendarObject(props = {}) {
 		order: 0,
 		// Whether or not the calendar is shared with me
 		isSharedWithMe: false,
+		// Whether or not the calendar belongs to a user who delegated to me
+		isDelegated: false,
+		// Principal URL of the delegator whose home this calendar was fetched from
+		// (may differ from `owner` when the delegator only has access via a share)
+		delegatorUrl: '',
 		// Whether or not the calendar can be shared by me
 		canBeShared: false,
 		// Whether or not the calendar can be published by me
diff --git a/src/services/caldavService.js b/src/services/caldavService.js
index 851cebb78d..a61defe695 100644
--- a/src/services/caldavService.js
+++ b/src/services/caldavService.js
@@ -250,6 +250,18 @@ async function findPrincipalsInCollection(url, options = {}) {
 	return getClient().findPrincipalsInCollection(url, options)
 }
 
+/**
+ * Fetches all calendars from a calendar home at an arbitrary URL.
+ * Used to load calendars from another user's calendar home when acting as their proxy.
+ *
+ * @param {string} calendarHomeUrl Absolute URL of the calendar home to fetch from
+ * @return {Promise<Calendar[]>} Raw cdav-library Calendar objects
+ */
+async function findCalendarsAtUrl(calendarHomeUrl) {
+	const calendarHome = getClient().getCalendarHomeForUrl(calendarHomeUrl)
+	return calendarHome.findAllCalendars()
+}
+
 export {
 	advancedPrincipalPropertySearch,
 	createCalendar,
@@ -258,12 +270,14 @@ export {
 	findAll,
 	findAllCalendars,
 	findAllDeletedCalendars,
+	findCalendarsAtUrl,
 	findPrincipalByUrl,
 	findPrincipalsInCollection,
 	findPublicCalendarsByTokens,
 	findSchedulingInbox,
 	findSchedulingOutbox,
 	getBirthdayCalendar,
+	getClient,
 	getCurrentUserPrincipal,
 	initializeClientForPublicView,
 	initializeClientForUserView,
diff --git a/src/store/delegation.ts b/src/store/delegation.ts
new file mode 100644
index 0000000000..0035378257
--- /dev/null
+++ b/src/store/delegation.ts
@@ -0,0 +1,231 @@
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+import { showError } from '@nextcloud/dialogs'
+import { translate as t } from '@nextcloud/l10n'
+import { defineStore } from 'pinia'
+import { computed, ref } from 'vue'
+import useCalendarsStore from './calendars.js'
+import usePrincipalsStore from './principals.js'
+import { mapDavCollectionToCalendar } from '@/models/calendar.js'
+import { mapDavToPrincipal } from '@/models/principal.js'
+import { findCalendarsAtUrl, findPrincipalByUrl, getClient } from '@/services/caldavService.js'
+import logger from '@/utils/logger.js'
+
+export interface DelegatePrincipal {
+	id: string | null
+	calendarUserType: string
+	emailAddress: string | null
+	displayname: string | null
+	principalScheme: string | null
+	userId: string | null
+	url: string | null
+	dav: unknown
+	isCircle: boolean
+	isUser: boolean
+	isGroup: boolean
+	isCalendarResource: boolean
+	isCalendarRoom: boolean
+	principalId: string | null
+	scheduleDefaultCalendarUrl: string | null
+	permission: 'write' | 'read'
+}
+
+export interface Delegator {
+	principalUrl: string
+	permission: 'write' | 'read'
+}
+
+export default defineStore('delegation', () => {
+	/**
+	 * List of principal objects that the current user has delegated to.
+	 * Each entry has the principal fields plus a `permission` field ('write'|'read').
+	 */
+	const delegates = ref<DelegatePrincipal[]>([])
+
+	/**
+	 * Users who have granted the current user proxy access, with permission level.
+	 */
+	const delegators = ref<Delegator[]>([])
+
+	/**
+	 * Whether any delegated calendars exist (i.e. the current user is a delegate for someone).
+	 */
+	const hasDelegatedCalendars = computed(() => delegators.value.length > 0)
+
+	/**
+	 * Fetch the current user's delegates (members of their calendar-proxy-write
+	 * and calendar-proxy-read groups) and resolve their principal details.
+	 */
+	async function fetchDelegates(): Promise<void> {
+		const principalsStore = usePrincipalsStore()
+		const currentUser = principalsStore.getCurrentUserPrincipal
+		if (!currentUser?.url) {
+			return
+		}
+
+		let writeUrls: string[] = []
+		let readUrls: string[] = []
+		try {
+			const delegateUrls = await getClient().getDelegatesForPrincipal(currentUser.url)
+			writeUrls = delegateUrls.write
+			readUrls = delegateUrls.read
+		} catch (error) {
+			logger.error('Could not fetch delegate URLs', { error })
+			return
+		}
+
+		const result: DelegatePrincipal[] = []
+
+		for (const url of writeUrls) {
+			try {
+				const dav = await findPrincipalByUrl(url)
+				if (dav) {
+					result.push({ ...mapDavToPrincipal(dav), permission: 'write' })
+				}
+			} catch (error) {
+				logger.error('Could not resolve write delegate principal', { url, error })
+			}
+		}
+
+		for (const url of readUrls) {
+			try {
+				const dav = await findPrincipalByUrl(url)
+				if (dav) {
+					result.push({ ...mapDavToPrincipal(dav), permission: 'read' })
+				}
+			} catch (error) {
+				logger.error('Could not resolve read delegate principal', { url, error })
+			}
+		}
+
+		delegates.value = result
+		logger.debug('Fetched delegates', { delegates: delegates.value })
+	}
+
+	/**
+	 * Fetch the principal URLs and permission level of users who have granted
+	 * the current user proxy access (both read and write).
+	 */
+	async function fetchDelegators(): Promise<void> {
+		const principalsStore = usePrincipalsStore()
+		const currentUser = principalsStore.getCurrentUserPrincipal
+		if (!currentUser?.url) {
+			return
+		}
+
+		try {
+			delegators.value = await getClient().getDelegatorsWithPermission(currentUser.url)
+			logger.debug('Fetched delegators', { delegators: delegators.value })
+		} catch (error) {
+			logger.error('Could not fetch delegator information', { error })
+		}
+	}
+
+	/**
+	 * Add a user as a delegate with the given permission level.
+	 *
+	 * @param principalUrl - Absolute URL of the principal to add
+	 * @param permission - The permission level to grant
+	 */
+	async function addDelegate({ principalUrl, permission = 'write' as 'write' | 'read' }): Promise<void> {
+		const principalsStore = usePrincipalsStore()
+		const currentUser = principalsStore.getCurrentUserPrincipal
+		if (!currentUser?.url) {
+			return
+		}
+
+		await getClient().addDelegate(currentUser.url, principalUrl, permission)
+		await fetchDelegates()
+	}
+
+	/**
+	 * Remove a delegate from whichever proxy group(s) they are in.
+	 *
+	 * @param principalUrl - Absolute URL of the principal to remove
+	 */
+	async function removeDelegate({ principalUrl }: { principalUrl: string }): Promise<void> {
+		const principalsStore = usePrincipalsStore()
+		const currentUser = principalsStore.getCurrentUserPrincipal
+		if (!currentUser?.url) {
+			return
+		}
+
+		// Find the delegate's current permission so we remove from the right group.
+		const existing = delegates.value.find((d) => d.url === principalUrl)
+		const permission = existing?.permission ?? 'write'
+
+		await getClient().removeDelegate(currentUser.url, principalUrl, permission)
+		delegates.value = delegates.value.filter((d) => d.url !== principalUrl)
+	}
+
+	/**
+	 * Fetch all calendars from delegators' calendar homes and add them to the
+	 * calendars store so they participate in normal event fetching and rendering.
+	 * The calendars are tagged with isDelegated=true so CalendarList can show them
+	 * in their own section.
+	 *
+	 * Read-only delegators' calendars are additionally marked readOnly=true so they
+	 * are excluded from the calendar picker (which only lists writable calendars).
+	 */
+	async function fetchDelegatedCalendars(): Promise<void> {
+		if (!delegators.value.length) {
+			return
+		}
+
+		const principalsStore = usePrincipalsStore()
+		const calendarsStore = useCalendarsStore()
+		const currentUser = principalsStore.getCurrentUserPrincipal
+
+		for (const { principalUrl: delegatorPrincipalUrl, permission } of delegators.value) {
+			const calendarHomeUrl = await getClient().getCalendarHomeUrlForPrincipal(delegatorPrincipalUrl)
+			if (!calendarHomeUrl) {
+				logger.warn('Could not determine calendar home URL for delegator', { delegatorPrincipalUrl })
+				showError(t('calendar', 'Could not load delegated calendars. Make sure the server supports calendar delegation.'))
+				continue
+			}
+
+			try {
+				const delegatorPrincipal = await principalsStore.fetchPrincipalByUrl({ url: delegatorPrincipalUrl })
+				const canonicalDelegatorUrl = delegatorPrincipal?.url || delegatorPrincipalUrl
+
+				const rawCalendars = await findCalendarsAtUrl(calendarHomeUrl)
+				const mappedCalendars = rawCalendars
+					.map((cal: unknown) => mapDavCollectionToCalendar(cal, currentUser))
+					.map((cal: Record<string, unknown>) => ({
+						...cal,
+						isDelegated: true,
+						delegatorUrl: canonicalDelegatorUrl,
+						// Read-only proxy access: prevent editing and hide from calendar picker
+						...(permission === 'read' ? { readOnly: true } : {}),
+					}))
+
+				for (const calendar of mappedCalendars) {
+					if (!calendarsStore.getCalendarById(calendar.id)) {
+						calendarsStore.addCalendarMutation({ calendar })
+					}
+				}
+
+				const ownerUrls = [...new Set(mappedCalendars.map((cal: Record<string, unknown>) => cal.owner).filter(Boolean))] as string[]
+				await Promise.all(ownerUrls.map((url) => principalsStore.fetchPrincipalByUrl({ url })))
+
+				logger.debug('Fetched delegated calendars from', { calendarHomeUrl, permission, count: mappedCalendars.length })
+			} catch (error) {
+				logger.error('Could not fetch calendars for delegator', { delegatorPrincipalUrl, error })
+				showError(t('calendar', 'Could not load delegated calendars. Make sure the server supports calendar delegation.'))
+			}
+		}
+	}
+
+	return {
+		delegates,
+		delegators,
+		hasDelegatedCalendars,
+		fetchDelegates,
+		fetchDelegators,
+		addDelegate,
+		removeDelegate,
+		fetchDelegatedCalendars,
+	}
+})
diff --git a/src/store/principals.js b/src/store/principals.js
index b6506738aa..40e6482e54 100644
--- a/src/store/principals.js
+++ b/src/store/principals.js
@@ -80,18 +80,20 @@ export default defineStore('principals', {
 		 * @return {Promise<void>}
 		 */
 		async fetchPrincipalByUrl({ url }) {
-			// Don't refetch principals we already have
-			if (this.getPrincipalByUrl(url)) {
-				return
+			const existing = this.getPrincipalByUrl(url)
+			if (existing) {
+				return existing
 			}
 
 			const principal = await findPrincipalByUrl(url)
 			if (!principal) {
 				// TODO - handle error
-				return
+				return undefined
 			}
 
-			this.addPrincipalMutation({ principal: mapDavToPrincipal(principal) })
+			const mapped = mapDavToPrincipal(principal)
+			this.addPrincipalMutation({ principal: mapped })
+			return this.getPrincipalById(mapped.id)
 		},
 
 		/**
diff --git a/src/views/Calendar.vue b/src/views/Calendar.vue
index 078bd11d82..52e7722466 100644
--- a/src/views/Calendar.vue
+++ b/src/views/Calendar.vue
@@ -134,6 +134,7 @@ import { isNotifyPushAvailable, registerNotifyPushSyncListener } from '../servic
 import getTimezoneManager from '../services/timezoneDataProviderService.js'
 import useCalendarObjectsStore from '../store/calendarObjects.js'
 import useCalendarsStore from '../store/calendars.js'
+import useDelegationStore from '../store/delegation.ts'
 import useFetchedTimeRangesStore from '../store/fetchedTimeRanges.js'
 import usePrincipalsStore from '../store/principals.js'
 import useSettingsStore from '../store/settings.js'
@@ -147,6 +148,7 @@ import {
 } from '../utils/date.js'
 import logger from '../utils/logger.js'
 import loadMomentLocalization from '../utils/moment.js'
+import { isAfterVersion } from '../utils/nextcloudVersion.ts'
 
 import '@nextcloud/dialogs/style.css'
 
@@ -220,6 +222,7 @@ export default {
 			usePrincipalsStore,
 			useSettingsStore,
 			useWidgetStore,
+			useDelegationStore,
 		),
 
 		...mapState(useSettingsStore, {
@@ -386,6 +389,12 @@ export default {
 				})
 			}
 
+			// Load delegation info: who has delegated their calendars to the current user
+			if (isAfterVersion(34)) {
+				await this.delegationStore.fetchDelegators()
+				await this.delegationStore.fetchDelegatedCalendars()
+			}
+
 			this.loadingCalendars = false
 		}
 	},
diff --git a/tests/javascript/unit/models/calendar.test.js b/tests/javascript/unit/models/calendar.test.js
index 951784053d..20fee7366e 100644
--- a/tests/javascript/unit/models/calendar.test.js
+++ b/tests/javascript/unit/models/calendar.test.js
@@ -32,6 +32,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			url: '',
 			readOnly: false,
 			order: 0,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canBeShared: false,
 			canBePublished: false,
@@ -44,6 +45,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			transparency: 'opaque',
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 	})
 
@@ -68,6 +70,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			url: '',
 			readOnly: false,
 			order: 0,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canBeShared: false,
 			canBePublished: false,
@@ -80,6 +83,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			transparency: 'opaque',
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 	})
 
@@ -119,6 +123,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -131,6 +136,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -172,6 +178,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -184,6 +191,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -223,6 +231,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -235,6 +244,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -274,6 +284,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: true,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -286,6 +297,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -325,6 +337,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -337,6 +350,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -376,6 +390,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -388,6 +403,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -427,6 +443,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -439,6 +456,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -478,6 +496,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -490,6 +509,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -585,6 +605,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -597,6 +618,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(4)
@@ -708,6 +730,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: true,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -720,6 +743,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 
 		expect(mapDavShareeToCalendarShareObject).toHaveBeenCalledTimes(0)
@@ -760,6 +784,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -772,6 +797,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			loading: false,
 			defaultAlarmFullDay: null,
 			defaultAlarmPartDay: null,
+			delegatorUrl: '',
 		})
 	})