native functionality bridge

backend/mpmediabridge.h

@@ -1,18 +1,46 @@
 /**
  * mpmediabridge.h
  * 
- * This file provides a C bridge to the Objective-C framework for macOS media playback.
+ * This file provides a C bridge to the Objective-C framework for macOS media playback & events.
  * It offers a simplified interface to interact with the MPNowPlayingInfoCenter and other
- * related media playback functionalities in macOS without dealing directly with 
- * Objective-C code.
+ * related media playback functionalities in macOS without dealing directly with Objective-C code.
  */
 
 #include <AppKit/AppKit.h>
 #include <MediaPlayer/MediaPlayer.h>
 
+/**
+* OS remote command enumeration, accepted by 'os_remote_command_callback'.
+*/
+typedef enum {
+    PLAY,
+    PAUSE,
+    STOP,
+    TOGGLE,
+    NEXT_TRACK,
+    PREVIOUS_TRACK
+} Command;
+
+/**
+* registers the 'os_remote_command_callback' to receive OS media commands. 
+*/
+void register_os_remote_commands();
+
+/**
+* Go-backed callback to static function that is called when OS remote commands are received.
+*/
+void os_remote_command_callback(Command command);
+
 /**
  * Updates the "Now Playing" information on macOS for media playback
  * using the MPNowPlayingInfoCenter API to set the metadata 
  * for the currently playing media in the system's "Now Playing" interface.
  */
-void setNowPlayingInfo(const char *title, const char *artist);
+void set_os_now_playing_info(const char *title, const char *artist, const char *coverArtFileURL);
+
+/**
+ * Setter functions for updating the global playback state.
+ */
+void set_os_playback_state_playing();
+void set_os_playback_state_paused();
+void set_os_playback_state_stopped();