feat(comments): Use activity tab to mount comments sidebar section if available

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

10 files changed, 386 insertions, 98 deletions

diff --git a/apps/comments/lib/Listener/LoadSidebarScripts.php b/apps/comments/lib/Listener/LoadSidebarScripts.php
index a77cd4e0af3..39c81c03ad1 100644
--- a/apps/comments/lib/Listener/LoadSidebarScripts.php
+++ b/apps/comments/lib/Listener/LoadSidebarScripts.php
@@ -28,6 +28,8 @@ namespace OCA\Comments\Listener;
 
 use OCA\Comments\AppInfo\Application;
 use OCA\Files\Event\LoadSidebar;
+use OCP\App\IAppManager;
+use OCP\AppFramework\Services\IInitialState;
 use OCP\Comments\ICommentsManager;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
@@ -36,6 +38,8 @@ use OCP\Util;
 class LoadSidebarScripts implements IEventListener {
 	public function __construct(
 		private ICommentsManager $commentsManager,
+		private IInitialState $initialState,
+		private IAppManager $appManager,
 	) {
 	}
 
@@ -46,6 +50,8 @@ class LoadSidebarScripts implements IEventListener {
 
 		$this->commentsManager->load();
 
+		$this->initialState->provideInitialState('activityEnabled', $this->appManager->isEnabledForUser('activity'));
+
 		// TODO: make sure to only include the sidebar script when
 		// we properly split it between files list and sidebar
 		Util::addScript(Application::APP_ID, 'comments');
diff --git a/apps/comments/src/comments-activity-tab.ts b/apps/comments/src/comments-activity-tab.ts
new file mode 100644
index 00000000000..30c1e38d8e7
--- /dev/null
+++ b/apps/comments/src/comments-activity-tab.ts
@@ -0,0 +1,85 @@
+/**
+ * @copyright Copyright (c) 2023 Ferdinand Thiessen <opensource@fthiessen.de>
+ *
+ * @author Ferdinand Thiessen <opensource@fthiessen.de>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+import moment from '@nextcloud/moment'
+import Vue from 'vue'
+import logger from './logger.js'
+import { getComments } from './services/GetComments.js'
+
+let ActivityTabPluginView
+let ActivityTabPluginInstance
+
+/**
+ * Register the comments plugins for the Activity sidebar
+ */
+export function registerCommentsPlugins() {
+	window.OCA.Activity.registerSidebarAction({
+		mount: async (el, { context, fileInfo, reload }) => {
+			if (!ActivityTabPluginView) {
+				const { default: ActivityCommmentAction } = await import('./views/ActivityCommentAction.vue')
+				ActivityTabPluginView = Vue.extend(ActivityCommmentAction)
+			}
+			ActivityTabPluginInstance = new ActivityTabPluginView({
+				parent: context,
+				propsData: {
+					reloadCallback: reload,
+					ressourceId: fileInfo.id,
+				},
+			})
+			ActivityTabPluginInstance.$mount(el)
+			logger.info('Comments plugin mounted in Activity sidebar action', { fileInfo })
+		},
+		unmount: () => {
+			// destroy previous instance if available
+			if (ActivityTabPluginInstance) {
+				ActivityTabPluginInstance.$destroy()
+			}
+		},
+	})
+
+	window.OCA.Activity.registerSidebarEntries(async ({ fileInfo, limit, offset }) => {
+		const { data: comments } = await getComments({ commentsType: 'files', ressourceId: fileInfo.id }, { limit, offset })
+		logger.debug('Loaded comments', { fileInfo, comments })
+		const { default: CommentView } = await import('./views/ActivityCommentEntry.vue')
+		const CommentsViewObject = Vue.extend(CommentView)
+
+		return comments.map((comment) => ({
+			timestamp: moment(comment.props.creationDateTime).toDate().getTime(),
+			mount(element, { context, reload }) {
+				this._CommentsViewInstance = new CommentsViewObject({
+					parent: context,
+					propsData: {
+						comment,
+						ressourceId: fileInfo.id,
+						reloadCallback: reload,
+					},
+				})
+				this._CommentsViewInstance.$mount(element)
+			},
+			unmount() {
+				this._CommentsViewInstance.$destroy()
+			},
+		}))
+	})
+
+	window.OCA.Activity.registerSidebarFilter((activity) => activity.type !== 'comments')
+	logger.info('Comments plugin registered for Activity sidebar action')
+}
diff --git a/apps/comments/src/comments-tab.js b/apps/comments/src/comments-tab.js
index 121b8d686f4..1a367cc18ee 100644
--- a/apps/comments/src/comments-tab.js
+++ b/apps/comments/src/comments-tab.js
@@ -22,40 +22,53 @@
 
 // eslint-disable-next-line n/no-missing-import, import/no-unresolved
 import MessageReplyText from '@mdi/svg/svg/message-reply-text.svg?raw'
+import { getRequestToken } from '@nextcloud/auth'
+import { loadState } from '@nextcloud/initial-state'
+import { registerCommentsPlugins } from './comments-activity-tab.ts'
 
-// Init Comments tab component
-let TabInstance = null
-const commentTab = new OCA.Files.Sidebar.Tab({
-	id: 'comments',
-	name: t('comments', 'Comments'),
-	iconSvg: MessageReplyText,
+// @ts-expect-error __webpack_nonce__ is injected by webpack
+__webpack_nonce__ = btoa(getRequestToken())
 
-	async mount(el, fileInfo, context) {
-		if (TabInstance) {
+if (loadState('comments', 'activityEnabled', false) && OCA?.Activity?.registerSidebarAction !== undefined) {
+	// Do not mount own tab but mount into activity
+	window.addEventListener('DOMContentLoaded', function() {
+		registerCommentsPlugins()
+	})
+} else {
+	// Init Comments tab component
+	let TabInstance = null
+	const commentTab = new OCA.Files.Sidebar.Tab({
+		id: 'comments',
+		name: t('comments', 'Comments'),
+		iconSvg: MessageReplyText,
+
+		async mount(el, fileInfo, context) {
+			if (TabInstance) {
+				TabInstance.$destroy()
+			}
+			TabInstance = new OCA.Comments.View('files', {
+				// Better integration with vue parent component
+				parent: context,
+			})
+			// Only mount after we have all the info we need
+			await TabInstance.update(fileInfo.id)
+			TabInstance.$mount(el)
+		},
+		update(fileInfo) {
+			TabInstance.update(fileInfo.id)
+		},
+		destroy() {
 			TabInstance.$destroy()
-		}
-		TabInstance = new OCA.Comments.View('files', {
-			// Better integration with vue parent component
-			parent: context,
-		})
-		// Only mount after we have all the info we need
-		await TabInstance.update(fileInfo.id)
-		TabInstance.$mount(el)
-	},
-	update(fileInfo) {
-		TabInstance.update(fileInfo.id)
-	},
-	destroy() {
-		TabInstance.$destroy()
-		TabInstance = null
-	},
-	scrollBottomReached() {
-		TabInstance.onScrollBottomReached()
-	},
-})
+			TabInstance = null
+		},
+		scrollBottomReached() {
+			TabInstance.onScrollBottomReached()
+		},
+	})
 
-window.addEventListener('DOMContentLoaded', function() {
-	if (OCA.Files && OCA.Files.Sidebar) {
-		OCA.Files.Sidebar.registerTab(commentTab)
-	}
-})
+	window.addEventListener('DOMContentLoaded', function() {
+		if (OCA.Files && OCA.Files.Sidebar) {
+			OCA.Files.Sidebar.registerTab(commentTab)
+		}
+	})
+}
diff --git a/apps/comments/src/components/Comment.vue b/apps/comments/src/components/Comment.vue
index e8ae9a88e77..a5b72efb74b 100644
--- a/apps/comments/src/components/Comment.vue
+++ b/apps/comments/src/components/Comment.vue
@@ -111,6 +111,7 @@
 
 <script>
 import { getCurrentUser } from '@nextcloud/auth'
+import { translate as t } from '@nextcloud/l10n'
 import moment from '@nextcloud/moment'
 
 import NcActionButton from '@nextcloud/vue/dist/Components/NcActionButton.js'
@@ -235,6 +236,8 @@ export default {
 	},
 
 	methods: {
+		t,
+
 		/**
 		 * Update local Message on outer change
 		 *
@@ -279,7 +282,7 @@ $comment-padding: 10px;
 
 .comment {
 	display: flex;
-	gap: 16px;
+	gap: 8px;
 	padding: 5px $comment-padding;
 
 	&__side {
diff --git a/apps/comments/src/mixins/CommentMixin.js b/apps/comments/src/mixins/CommentMixin.js
index 545625ab97e..bcb72af2315 100644
--- a/apps/comments/src/mixins/CommentMixin.js
+++ b/apps/comments/src/mixins/CommentMixin.js
@@ -20,10 +20,11 @@
  *
  */
 
+import { showError, showUndo, TOAST_UNDO_TIMEOUT } from '@nextcloud/dialogs'
 import NewComment from '../services/NewComment.js'
 import DeleteComment from '../services/DeleteComment.js'
 import EditComment from '../services/EditComment.js'
-import { showError, showUndo, TOAST_UNDO_TIMEOUT } from '@nextcloud/dialogs'
+import logger from '../logger.js'
 
 export default {
 	props: {
@@ -46,6 +47,7 @@ export default {
 			deleted: false,
 			editing: false,
 			loading: false,
+			commentsType: 'files',
 		}
 	},
 
@@ -63,7 +65,7 @@ export default {
 			this.loading = true
 			try {
 				await EditComment(this.commentsType, this.ressourceId, this.id, message)
-				this.logger.debug('Comment edited', { commentsType: this.commentsType, ressourceId: this.ressourceId, id: this.id, message })
+				logger.debug('Comment edited', { commentsType: this.commentsType, ressourceId: this.ressourceId, id: this.id, message })
 				this.$emit('update:message', message)
 				this.editing = false
 			} catch (error) {
@@ -86,7 +88,7 @@ export default {
 		async onDelete() {
 			try {
 				await DeleteComment(this.commentsType, this.ressourceId, this.id)
-				this.logger.debug('Comment deleted', { commentsType: this.commentsType, ressourceId: this.ressourceId, id: this.id })
+				logger.debug('Comment deleted', { commentsType: this.commentsType, ressourceId: this.ressourceId, id: this.id })
 				this.$emit('delete', this.id)
 			} catch (error) {
 				showError(t('comments', 'An error occurred while trying to delete the comment'))
@@ -100,7 +102,7 @@ export default {
 			this.loading = true
 			try {
 				const newComment = await NewComment(this.commentsType, this.ressourceId, message)
-				this.logger.debug('New comment posted', { commentsType: this.commentsType, ressourceId: this.ressourceId, newComment })
+				logger.debug('New comment posted', { commentsType: this.commentsType, ressourceId: this.ressourceId, newComment })
 				this.$emit('new', newComment)
 
 				// Clear old content
diff --git a/apps/comments/src/mixins/CommentView.ts b/apps/comments/src/mixins/CommentView.ts
new file mode 100644
index 00000000000..9cd14904875
--- /dev/null
+++ b/apps/comments/src/mixins/CommentView.ts
@@ -0,0 +1,68 @@
+import axios from '@nextcloud/axios'
+import { getCurrentUser } from '@nextcloud/auth'
+import { loadState } from '@nextcloud/initial-state'
+import { generateOcsUrl } from '@nextcloud/router'
+import { defineComponent } from 'vue'
+
+export default defineComponent({
+	props: {
+		ressourceId: {
+			type: Number,
+			required: true,
+		},
+	},
+	data() {
+		return {
+			editorData: {
+				actorDisplayName: getCurrentUser()!.displayName as string,
+				actorId: getCurrentUser()!.uid as string,
+				key: 'editor',
+			},
+			userData: {},
+		}
+	},
+	methods: {
+		/**
+		 * Autocomplete @mentions
+		 *
+		 * @param {string} search the query
+		 * @param {Function} callback the callback to process the results with
+		 */
+		async autoComplete(search, callback) {
+			const { data } = await axios.get(generateOcsUrl('core/autocomplete/get'), {
+				params: {
+					search,
+					itemType: 'files',
+					itemId: this.ressourceId,
+					sorter: 'commenters|share-recipients',
+					limit: loadState('comments', 'maxAutoCompleteResults'),
+				},
+			})
+			// Save user data so it can be used by the editor to replace mentions
+			data.ocs.data.forEach(user => { this.userData[user.id] = user })
+			return callback(Object.values(this.userData))
+		},
+
+		/**
+		 * Make sure we have all mentions as Array of objects
+		 *
+		 * @param mentions the mentions list
+		 */
+		// eslint-disable-next-line @typescript-eslint/no-explicit-any
+		genMentionsData(mentions: any[]): Record<string, object> {
+			Object.values(mentions)
+				.flat()
+				.forEach(mention => {
+					this.userData[mention.mentionId] = {
+						// TODO: support groups
+						icon: 'icon-user',
+						id: mention.mentionId,
+						label: mention.mentionDisplayName,
+						source: 'users',
+						primary: getCurrentUser()?.uid === mention.mentionId,
+					}
+				})
+			return this.userData
+		},
+	},
+})
diff --git a/apps/comments/src/services/GetComments.ts b/apps/comments/src/services/GetComments.ts
index d74e92bce68..2ca725c2ae6 100644
--- a/apps/comments/src/services/GetComments.ts
+++ b/apps/comments/src/services/GetComments.ts
@@ -20,7 +20,7 @@
  *
  */
 
-import { parseXML, type DAVResult, type FileStat } from 'webdav'
+import { parseXML, type DAVResult, type FileStat, type ResponseDataDetailed } from 'webdav'
 
 // https://github.com/perry-mitchell/webdav-client/issues/339
 import { processResponsePayload } from '../../../../node_modules/webdav/dist/node/response.js'
@@ -37,11 +37,13 @@ export const DEFAULT_LIMIT = 20
  * @param {number} data.ressourceId the ressource ID
  * @param {object} [options] optional options for axios
  * @param {number} [options.offset] the pagination offset
- * @return {object[]} the comments list
+ * @param {number} [options.limit] the pagination limit, defaults to 20
+ * @param {Date} [options.datetime] optional date to query
+ * @return {{data: object[]}} the comments list
  */
-export const getComments = async function({ commentsType, ressourceId }, options: { offset: number }) {
+export const getComments = async function({ commentsType, ressourceId }, options: { offset: number, limit?: number, datetime?: Date }) {
 	const ressourcePath = ['', commentsType, ressourceId].join('/')
-
+	const datetime = options.datetime ? `<oc:datetime>${options.datetime.toISOString()}</oc:datetime>` : ''
 	const response = await client.customRequest(ressourcePath, Object.assign({
 		method: 'REPORT',
 		data: `<?xml version="1.0"?>
@@ -50,15 +52,16 @@ export const getComments = async function({ commentsType, ressourceId }, options
 				xmlns:oc="http://owncloud.org/ns"
 				xmlns:nc="http://nextcloud.org/ns"
 				xmlns:ocs="http://open-collaboration-services.org/ns">
-				<oc:limit>${DEFAULT_LIMIT}</oc:limit>
+				<oc:limit>${options.limit ?? DEFAULT_LIMIT}</oc:limit>
 				<oc:offset>${options.offset || 0}</oc:offset>
+				${datetime}
 			</oc:filter-comments>`,
 	}, options))
 
 	const responseData = await response.text()
 	const result = await parseXML(responseData)
 	const stat = getDirectoryFiles(result, true)
-	return processResponsePayload(response, stat, true)
+	return processResponsePayload(response, stat, true) as ResponseDataDetailed<FileStat[]>
 }
 
 // https://github.com/perry-mitchell/webdav-client/blob/8d9694613c978ce7404e26a401c39a41f125f87f/source/operations/directoryContents.ts
diff --git a/apps/comments/src/views/ActivityCommentAction.vue b/apps/comments/src/views/ActivityCommentAction.vue
new file mode 100644
index 00000000000..96edaf6d46f
--- /dev/null
+++ b/apps/comments/src/views/ActivityCommentAction.vue
@@ -0,0 +1,70 @@
+<!--
+  - @copyright Copyright (c) 2023 Ferdinand Thiessen <opensource@fthiessen.de>
+  -
+  - @author Ferdinand Thiessen <opensource@fthiessen.de>
+  -
+  - @license AGPL-3.0-or-later
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program. If not, see <http://www.gnu.org/licenses/>.
+  -
+  -->
+
+<template>
+	<Comment v-bind="editorData"
+		:auto-complete="autoComplete"
+		:user-data="userData"
+		:editor="true"
+		:ressource-id="ressourceId"
+		class="comments-action"
+		@new="onNewComment" />
+</template>
+
+<script lang="ts">
+import { defineComponent } from 'vue'
+import Comment from '../components/Comment.vue'
+import CommentView from '../mixins/CommentView.js'
+import logger from '../logger'
+import { showError } from '@nextcloud/dialogs'
+import { translate as t } from '@nextcloud/l10n'
+
+export default defineComponent({
+	components: {
+		Comment,
+	},
+	mixins: [CommentView],
+	props: {
+		reloadCallback: {
+			type: Function,
+			required: true,
+		},
+	},
+	methods: {
+		onNewComment() {
+			try {
+				// just force reload
+				this.reloadCallback()
+			} catch (e) {
+				showError(t('comments', 'Could not reload comments'))
+				logger.debug(e)
+			}
+		},
+	},
+})
+</script>
+
+<style scoped>
+.comments-action {
+	padding: 0;
+}
+</style>
diff --git a/apps/comments/src/views/ActivityCommentEntry.vue b/apps/comments/src/views/ActivityCommentEntry.vue
new file mode 100644
index 00000000000..21c600dcddb
--- /dev/null
+++ b/apps/comments/src/views/ActivityCommentEntry.vue
@@ -0,0 +1,86 @@
+<!--
+  - @copyright Copyright (c) 2023 Ferdinand Thiessen <opensource@fthiessen.de>
+  -
+  - @author Ferdinand Thiessen <opensource@fthiessen.de>
+  -
+  - @license AGPL-3.0-or-later
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program. If not, see <http://www.gnu.org/licenses/>.
+  -
+  -->
+
+<template>
+	<Comment ref="comment"
+		tag="li"
+		v-bind="comment.props"
+		:auto-complete="autoComplete"
+		:message="commentMessage"
+		:ressource-id="ressourceId"
+		:user-data="genMentionsData(comment.props.mentions)"
+		class="comments-activity"
+		@delete="reloadCallback()" />
+</template>
+
+<script lang="ts">
+import { translate as t } from '@nextcloud/l10n'
+
+import Comment from '../components/Comment.vue'
+import CommentView from '../mixins/CommentView'
+
+export default {
+	name: 'ActivityCommentEntry',
+
+	components: {
+		Comment,
+	},
+
+	mixins: [CommentView],
+	props: {
+		comment: {
+			type: Object,
+			required: true,
+		},
+		reloadCallback: {
+			type: Function,
+			required: true,
+		},
+	},
+
+	data() {
+		return {
+			commentMessage: '',
+		}
+	},
+
+	watch: {
+		comment() {
+			this.commentMessage = this.comment.props.message
+		},
+	},
+
+	mounted() {
+		this.commentMessage = this.comment.props.message
+	},
+
+	methods: {
+		t,
+	},
+}
+</script>
+
+<style scoped>
+.comments-activity {
+	padding: 0;
+}
+</style>
diff --git a/apps/comments/src/views/Comments.vue b/apps/comments/src/views/Comments.vue
index 93e9031df5a..7a36823299e 100644
--- a/apps/comments/src/views/Comments.vue
+++ b/apps/comments/src/views/Comments.vue
@@ -82,11 +82,8 @@
 </template>
 
 <script>
-import { generateOcsUrl } from '@nextcloud/router'
-import { getCurrentUser } from '@nextcloud/auth'
-import { loadState } from '@nextcloud/initial-state'
 import { showError } from '@nextcloud/dialogs'
-import axios from '@nextcloud/axios'
+import { translate as t } from '@nextcloud/l10n'
 import VTooltip from 'v-tooltip'
 import Vue from 'vue'
 import VueObserveVisibility from 'vue-observe-visibility'
@@ -101,6 +98,7 @@ import Comment from '../components/Comment.vue'
 import { getComments, DEFAULT_LIMIT } from '../services/GetComments.ts'
 import cancelableRequest from '../utils/cancelableRequest.js'
 import { markCommentsAsRead } from '../services/ReadComments.ts'
+import CommentView from '../mixins/CommentView'
 
 Vue.use(VTooltip)
 Vue.use(VueObserveVisibility)
@@ -109,7 +107,6 @@ export default {
 	name: 'Comments',
 
 	components: {
-		// Avatar,
 		Comment,
 		NcEmptyContent,
 		NcButton,
@@ -118,6 +115,8 @@ export default {
 		AlertCircleOutlineIcon,
 	},
 
+	mixins: [CommentView],
+
 	data() {
 		return {
 			error: '',
@@ -130,12 +129,6 @@ export default {
 
 			cancelRequest: () => {},
 
-			editorData: {
-				actorDisplayName: getCurrentUser().displayName,
-				actorId: getCurrentUser().uid,
-				key: 'editor',
-			},
-
 			Comment,
 			userData: {},
 		}
@@ -151,6 +144,8 @@ export default {
 	},
 
 	methods: {
+		t,
+
 		async onVisibilityChange(isVisible) {
 			if (isVisible) {
 				try {
@@ -189,28 +184,6 @@ export default {
 		},
 
 		/**
-		 * Make sure we have all mentions as Array of objects
-		 *
-		 * @param {any[]} mentions the mentions list
-		 * @return {Record<string, object>}
-		 */
-		genMentionsData(mentions) {
-			Object.values(mentions)
-				.flat()
-				.forEach(mention => {
-					this.userData[mention.mentionId] = {
-						// TODO: support groups
-						icon: 'icon-user',
-						id: mention.mentionId,
-						label: mention.mentionDisplayName,
-						source: 'users',
-						primary: getCurrentUser().uid === mention.mentionId,
-					}
-				})
-			return this.userData
-		},
-
-		/**
 		 * Get the existing shares infos
 		 */
 		async getComments() {
@@ -256,27 +229,6 @@ export default {
 		},
 
 		/**
-		 * Autocomplete @mentions
-		 *
-		 * @param {string} search the query
-		 * @param {Function} callback the callback to process the results with
-		 */
-		async autoComplete(search, callback) {
-			const results = await axios.get(generateOcsUrl('core/autocomplete/get'), {
-				params: {
-					search,
-					itemType: 'files',
-					itemId: this.ressourceId,
-					sorter: 'commenters|share-recipients',
-					limit: loadState('comments', 'maxAutoCompleteResults'),
-				},
-			})
-			// Save user data so it can be used by the editor to replace mentions
-			results.data.ocs.data.forEach(user => { this.userData[user.id] = user })
-			return callback(Object.values(this.userData))
-		},
-
-		/**
 		 * Add newly created comment to the list
 		 *
 		 * @param {object} comment the new comment