Subsonic: Provide a non-dummy implementation for getNowPlaying

Replace the empty/dummy implementation added in b23a56a with a one returning
some valid data. As usual, we don't provide other users' data even though
that's how the endpoint is specified because we don't want to leak any user
data without an explicit consent. The song shown in the response is based on
the scrobbling messages from the clients.

Author: paulijar

CHANGELOG.md

@@ -19,6 +19,8 @@
   * Limit also album art search to the path provided with argument `--folder`
 - Identify playlist-type radio streams from the Content-Type header instead of the URL, hopefully making the logic more robust
 - Updated the getID3 library to the release version 1.9.24-202509040923
+- Subsonic API:
+  * Non-dummy implementation for the endpoint `getNowPlaying`
 - OpenSubsonic API: 
   * Add property `mediaType` to the result type `Child`
   * Add properties `genres` and `artists` to the album results

lib/Controller/SubsonicController.php

@@ -1164,8 +1164,20 @@ protected function getScanStatus() : array {
 	 * @SubsonicAPI
 	 */
 	protected function getNowPlaying() : array {
-		// TODO: not supported yet
-		return ['nowPlaying' => ['entry' => []]];
+		// Note: This is documented to return latest play of all users on the server but we don't want to
+		// provide access to other people's data => Always return just this user's data.
+		$recent = $this->trackBusinessLayer->findRecentPlay($this->user(), 1);
+
+		if (!empty($recent)) {
+			$playTime = new \DateTime($recent[0]->getLastPlayed());
+			$now = new \DateTime();
+			$recent = $this->tracksToApi($recent);
+			$recent[0]['username'] = $this->user();
+			$recent[0]['minutesAgo'] = (int)(($now->getTimestamp() - $playTime->getTimestamp()) / 60);
+			$recent[0]['playerId'] = 0; // dummy
+		}
+
+		return ['nowPlaying' => ['entry' => $recent]];
 	}
 
 	/**