Post a system message when deleting a message

Signed-off-by: Joas Schilling <coding@schilljs.com>

4 files changed, 61 insertions, 8 deletions

diff --git a/docs/chat.md b/docs/chat.md
index f9b336ff6..78a2840aa 100644
--- a/docs/chat.md
+++ b/docs/chat.md
@@ -44,7 +44,7 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
         `actorDisplayName` | string | Display name of the message author
         `timestamp` | int | Timestamp in seconds and UTC time zone
         `systemMessage` | string | empty for normal chat message or the type of the system message (untranslated)
-        `messageType` | string | Currently known types are `comment`, `system` and `command`
+        `messageType` | string | Currently known types are `comment`, `comment_deleted`, `system` and `command`
         `isReplyable` | bool | True if the user can post a reply to this message (only available with `chat-replies` capability)
         `referenceId` | string | A reference string that was given while posting the message to be able to identify a sent message again (only available with `chat-reference-id` capability)
         `message` | string | Message string with placeholders (see [Rich Object String](https://github.com/nextcloud/server/issues/1706))
@@ -177,3 +177,4 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
 * `moderator_demoted` - {actor} demoted {user} from moderator
 * `guest_moderator_promoted` - {actor} promoted {user} to moderator
 * `guest_moderator_demoted` - {actor} demoted {user} from moderator
+* `message_deleted` - Message deleted by {actor} (Should not be shown to the user)
diff --git a/lib/Chat/ChatManager.php b/lib/Chat/ChatManager.php
index b63fa0f79..4202a3a46 100644
--- a/lib/Chat/ChatManager.php
+++ b/lib/Chat/ChatManager.php
@@ -106,15 +106,28 @@ class ChatManager {
 	 * @param \DateTime $creationDateTime
 	 * @param bool $sendNotifications
 	 * @param string|null $referenceId
+	 * @param int|null $parentId
 	 * @return IComment
 	 */
-	public function addSystemMessage(Room $chat, string $actorType, string $actorId, string $message, \DateTime $creationDateTime, bool $sendNotifications, ?string $referenceId = null): IComment {
+	public function addSystemMessage(
+		Room $chat,
+		string $actorType,
+		string $actorId,
+		string $message,
+		\DateTime $creationDateTime,
+		bool $sendNotifications,
+		?string $referenceId = null,
+		?int $parentId = null
+	): IComment {
 		$comment = $this->commentsManager->create($actorType, $actorId, 'chat', (string) $chat->getId());
 		$comment->setMessage($message, self::MAX_CHAT_LENGTH);
 		$comment->setCreationDateTime($creationDateTime);
 		if ($referenceId !== null) {
 			$comment->setReferenceId($referenceId);
 		}
+		if ($parentId !== null) {
+			$comment->setParentId((string) $parentId);
+		}
 		$comment->setVerb('system');
 
 		$event = new ChatEvent($chat, $comment);
@@ -231,6 +244,30 @@ class ChatManager {
 		return $comment;
 	}
 
+	public function deleteMessage(Room $chat, int $messageId, string $actorType, string $actorId, \DateTime $deletionTime): IComment {
+		$comment = $this->getComment($chat, (string) $messageId);
+		$comment->setMessage(
+			json_encode([
+				'deleted_by_type' => $actorType,
+				'deleted_by_id' => $actorId,
+				'deleted_on' => $deletionTime->getTimestamp(),
+			])
+		);
+		$comment->setVerb('comment_deleted');
+		$this->commentsManager->save($comment);
+
+		return $this->addSystemMessage(
+			$chat,
+			$actorType,
+			$actorId,
+			json_encode(['message' => 'message_deleted', 'parameters' => ['message' => $messageId]]),
+			$this->timeFactory->getDateTime(),
+			false,
+			null,
+			$messageId
+		);
+	}
+
 	/**
 	 * @param Room $chat
 	 * @param string $parentId
diff --git a/lib/Controller/ChatController.php b/lib/Controller/ChatController.php
index 3516388da..bc0dcb277 100644
--- a/lib/Controller/ChatController.php
+++ b/lib/Controller/ChatController.php
@@ -484,16 +484,25 @@ class ChatController extends AEnvironmentAwareController {
 			return new DataResponse([], Http::STATUS_FORBIDDEN);
 		}
 
-		$this->chatManager->addSystemMessage(
+		$systemMessageComment = $this->chatManager->deleteMessage(
 			$this->room,
+			$messageId,
 			$attendee->getActorType(),
 			$attendee->getActorId(),
-			json_encode(['message' => 'message_deleted', 'parameters' => ['message' => $messageId]]),
-			$this->timeFactory->getDateTime(),
-			false
+			$this->timeFactory->getDateTime()
 		);
 
-		return new DataResponse();
+		$systemMessage = $this->messageParser->createMessage($this->room, $this->participant, $systemMessageComment, $this->l);
+		$this->messageParser->parseMessage($systemMessage);
+
+		$comment = $this->chatManager->getComment($this->room, (string) $messageId);
+		$message = $this->messageParser->createMessage($this->room, $this->participant, $comment, $this->l);
+		$this->messageParser->parseMessage($message);
+
+		$data = $systemMessage->toArray();
+		$data['parent'] = $message->toArray();
+
+		return new DataResponse($data);
 	}
 
 	/**
diff --git a/lib/Model/Message.php b/lib/Model/Message.php
index 97d578c18..97e63e8de 100644
--- a/lib/Model/Message.php
+++ b/lib/Model/Message.php
@@ -162,7 +162,7 @@ class Message {
 	}
 
 	public function toArray(): array {
-		return [
+		$data = [
 			'id' => (int) $this->getComment()->getId(),
 			'token' => $this->getRoom()->getToken(),
 			'actorType' => $this->getActorType(),
@@ -176,5 +176,11 @@ class Message {
 			'isReplyable' => $this->isReplyable(),
 			'referenceId' => (string) $this->getComment()->getReferenceId(),
 		];
+
+		if ($this->getMessageType() === 'comment_deleted') {
+			$data['deleted'] = true;
+		}
+
+		return $data;
 	}
 }