Instead of the offset based use lastKnownMessageId as for message

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

docs/chat.md

@@ -163,7 +163,7 @@ See [OCP\RichObjectStrings\Definitions](https://github.com/nextcloud/server/blob
 
   field | type | Description
   ---|---|---
-  `offset` | int | Offset parameter to get another chunk of chat messages
+  `lastKnownMessageId` | int | Serves as an offset for the query. The lastKnownMessageId for the next page is available in the `X-Chat-Last-Given` header.
   `limit` | int | Number of chat messages with shares you want to get
 
 * Response:
@@ -173,6 +173,12 @@ See [OCP\RichObjectStrings\Definitions](https://github.com/nextcloud/server/blob
         + `404 Not Found` When the conversation could not be found for the participant
         + `412 Precondition Failed` When the lobby is active and the user is not a moderator
 
+    - Header:
+
+      field | type | Description
+      ---|---|---
+      `X-Chat-Last-Given` | int | Offset (lastKnownMessageId) for the next page.
+
     - Data:
       Array of messages as defined in [Receive chat messages of a conversation](#receive-chat-messages-of-a-conversation)
 

lib/Chat/ChatManager.php

@@ -564,6 +564,25 @@ class ChatManager {
 		$this->notifier->removePendingNotificationsForRoom($chat);
 	}
 
+	/**
+	 * Search for comments with a given content
+	 *
+	 * @param Room $chat
+	 * @param int $offset
+	 * @param int $limit
+	 * @return IComment[]
+	 */
+	public function getSharedObjectMessages(Room $chat, int $offset, int $limit): array {
+		return $this->commentsManager->getCommentsWithVerbForObjectSinceComment(
+			'chat',
+			(string) $chat->getId(),
+			['object_shared'],
+			$offset,
+			'desc',
+			$limit
+		);
+	}
+
 	/**
 	 * Search for comments with a given content
 	 *

lib/Controller/ChatController.php

@@ -706,15 +706,15 @@ class ChatController extends AEnvironmentAwareController {
 	 * @RequireReadWriteConversation
 	 * @RequireModeratorOrNoLobby
 	 *
-	 * @param int $offset
+	 * @param int $lastKnownMessageId
 	 * @param int $limit
 	 * @return DataResponse
 	 */
-	public function getObjectsSharedInRoom(int $offset = 0, int $limit = 50): DataResponse {
+	public function getObjectsSharedInRoom(int $lastKnownMessageId = 0, int $limit = 100): DataResponse {
-		$offset = max(0, $offset);
+		$offset = max(0, $lastKnownMessageId);
 		$limit = min(200, $limit);
 
-		$comments = $this->chatManager->searchForObjects('', [$this->room->getId()], 'object_shared', $offset, $limit);
+		$comments = $this->chatManager->getSharedObjectMessages($this->room, $offset, $limit);
 
 		$messages = [];
 		foreach ($comments as $comment) {
@@ -728,7 +728,14 @@ class ChatController extends AEnvironmentAwareController {
 			$messages[] = $message->toArray();
 		}
 
-		return new DataResponse($messages);
+		$response = new DataResponse($messages, Http::STATUS_OK);
+
+		$newLastKnown = end($comments);
+		if ($newLastKnown instanceof IComment) {
+			$response->addHeader('X-Chat-Last-Given', $newLastKnown->getId());
+		}
+
+		return $response;
 	}
 
 	/**

tests/integration/features/bootstrap/FeatureContext.php

@@ -1561,7 +1561,7 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 	 * @param string $statusCode
 	 * @param string $apiVersion
 	 */
-	public function userSeesTheFollowingSharedMediaInRoom($user, $identifier, $statusCode, $apiVersion = 'v1', TableNode $formData = null) {
+	public function userSeesTheFollowingSharedMediaInRoom($user, $identifier, $statusCode, $apiVersion = 'v1', TableNode $formData = null): void {
 		$this->setCurrentUser($user);
 		$this->sendRequest('GET', '/apps/spreed/api/' . $apiVersion . '/chat/' . self::$identifierToToken[$identifier] . '/share');
 		$this->assertStatusCode($this->response, $statusCode);