feat: Add 'copy direct link' action to message menu

Implements a UI button in the MenuEnvelope to generate and copy a direct link to the message using the new deep link route. Utilizes the standard Nextcloud clipboard fallback via window.prompt for non-secure contexts.

Signed-off-by: SoleroTG <github-29h@solero.quietmail.eu>

Author: SoleroTG

src/components/MenuEnvelope.vue

@@ -1,5 +1,5 @@
 <!--
-  - SPDX-FileCopyrightText: 2021 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-FileCopyrightText: 2021-2026 Nextcloud GmbH and Nextcloud contributors
   - SPDX-License-Identifier: AGPL-3.0-or-later
 -->
 <!-- Standard Actions menu for Envelopes -->
@@ -29,6 +29,21 @@
 				</template>
 				{{ t('mail', 'Forward') }}
 			</ActionButton>
+			<ActionButton
+				:close-after-click="false"
+				:description="t('mail', 'Only for message recipients')"
+				@click.prevent="onCopyMessageLink">
+				<template #icon>
+					<CheckIcon
+						v-if="copied"
+						:size="20" />
+					<ContentCopyIcon
+						v-else
+						:title="t('mail', 'Copy direct link')"
+						:size="20" />
+				</template>
+				{{ copied ? t('mail', 'Link copied') : t('mail', 'Copy direct link') }}
+			</ActionButton>
 			<ActionButton
 				v-if="hasWriteAcl"
 				:close-after-click="true"
@@ -277,6 +292,7 @@ import CalendarClock from 'vue-material-design-icons/CalendarClockOutline.vue'
 import CheckIcon from 'vue-material-design-icons/Check.vue'
 import TaskIcon from 'vue-material-design-icons/CheckboxMarkedCirclePlusOutline.vue'
 import ChevronLeft from 'vue-material-design-icons/ChevronLeft.vue'
+import ContentCopyIcon from 'vue-material-design-icons/ContentCopy.vue'
 import DotsHorizontalIcon from 'vue-material-design-icons/DotsHorizontal.vue'
 import FilterIcon from 'vue-material-design-icons/FilterOutline.vue'
 import InformationIcon from 'vue-material-design-icons/InformationOutline.vue'
@@ -321,6 +337,7 @@ export default {
 		AlarmIcon,
 		PrinterIcon,
 		FilterIcon,
+		ContentCopyIcon,
 	},
 
 	props: {
@@ -367,6 +384,8 @@ export default {
 			snoozeActionsOpen: false,
 			forwardMessages: this.envelope.databaseId,
 			customSnoozeDateTime: new Date(moment().add(2, 'hours').minute(0).second(0).valueOf()),
+			copied: false,
+			copyResetTimer: null,
 		}
 	},
 
@@ -634,6 +653,35 @@ export default {
 			this.$emit('print')
 		},
 
+		async onCopyMessageLink() {
+			if (this.copyResetTimer) {
+				clearTimeout(this.copyResetTimer)
+			}
+
+			if (!this.envelope || typeof this.envelope.messageId !== 'string' || !this.envelope.messageId.trim()) {
+				showError(t('mail', 'Could not generate direct link: Message ID is missing'))
+				return
+			}
+
+			const trimmedMessageId = this.envelope.messageId.trim().replace(/^<|>$/g, '')
+			const url = window.location.origin + generateUrl('/apps/mail/open/' + encodeURIComponent(trimmedMessageId))
+
+			try {
+				await navigator.clipboard.writeText(url)
+				this.copied = true
+				showSuccess(t('mail', 'Direct link copied to clipboard'))
+			} catch (error) {
+				// Fallback for cases where clipboard API is not available (e.g. non-HTTPS localhost)
+				// or permission is denied. This exactly matches Nextcloud's useCopy composable behavior.
+				window.prompt(t('mail', 'Copy direct link'), url)
+			} finally {
+				this.copyResetTimer = setTimeout(() => {
+					this.copied = false
+					this.localMoreActionsOpen = false
+				}, 2000)
+			}
+		},
+
 		isSieveEnabled() {
 			return this.account.sieveEnabled
 		},