fixed the issue to accept 0 and null and changed the default text value to remaining downloads

lib/Controller/ApiController.php

@@ -73,12 +73,13 @@ public function __construct(IRequest $request,
 	 *
 	 * Set the download limit for a given link share
 	 */
-	public function setDownloadLimit(string $token, int $limit): Response {
+	public function setDownloadLimit(string $token, $limit): Response {
 		$this->validateToken($token);
+		$limit = trim($limit);
 
-		// Count needs to be at least 1
-		if ($limit < 1) {
-			throw new OCSBadRequestException('Limit needs to be greater or equal than 1');
+		// Count needs to be at least 0 or null
+		if (!is_numeric($limit) && $limit !== '') {
+			throw new OCSBadRequestException('Limit must be greater than or equal to 0 or null');
 		}
 
 		// Getting existing limit and init if unset
@@ -93,10 +94,18 @@ public function setDownloadLimit(string $token, int $limit): Response {
 
 		// Update DB
 		$shareLimit->setLimit($limit);
-		if ($insert) {
-			$this->mapper->insert($shareLimit);
+		if($limit == 0 || $limit == ''){
+			$this->mapper->delete($shareLimit);
 		} else {
-			$this->mapper->update($shareLimit);
+			if($limit < 0) {
+				throw new OCSBadRequestException('Limit must be greater than or equal to 0 or null');
+			} else {
+				if ($insert) {
+					$this->mapper->insert($shareLimit);
+				} else {
+					$this->mapper->update($shareLimit);
+				}
+			}
 		}
 
 		return new DataResponse();

src/models/DownloadLimitAction.js

@@ -48,8 +48,8 @@ export default class DownloadLimitAction {
 			icon: 'icon-download',
 			is: this._store.enabled ? ActionInput : null,
 			text: t('files_downloadlimit', 'Download limit'),
-			title: t('files_downloadlimit', 'Download count: {count}', this._store),
-			value: this._store.limit,
+			title: t('files_downloadlimit', 'Downloads: {count}', this._store),
+			value: this._store.limit ? this._store.limit - this._store.count : this._store.limit,
 		}
 	}