AudioServer: Handle multiple audio devices with multiple pins

This makes audio server configurable during runtime!

userspace/libraries/LibAudio/include/LibAudio/Audio.h

@@ -9,8 +9,6 @@
 namespace LibAudio
 {
 
-	static constexpr BAN::StringView s_audio_server_socket = "/tmp/audio-server.socket"_sv;
-
 	struct AudioBuffer
 	{
 		using sample_t = double;

userspace/libraries/LibAudio/include/LibAudio/Protocol.h

@@ -0,0 +1,50 @@
+#pragma once
+
+#include <BAN/StringView.h>
+
+namespace LibAudio
+{
+
+	struct Packet
+	{
+		enum : uint8_t
+		{
+			Notify,         // parameter: ignored
+			                // response: nothing
+			                // server refereshes buffered data
+
+			RegisterBuffer, // paramenter: smo key
+			                // response: nothing
+			                // register audio buffer to server
+
+			QueryDevices,   // parameter: ignored
+			                // response: (uint32_t)
+							// query the number of devices available
+
+			QueryPins,      // parameter: sink number
+			                // response: (uint32_t)
+							// query the number of pins the sink has
+
+			GetDevice,      // parameter: ignored
+			                // reponse: (uint32_t)
+							// get the currently active device
+
+			SetDevice,      // parameter: device number
+			                // reponse: nothing
+							// set the currently active device
+
+			GetPin,         // parameter: ignored
+			                // response: nothing
+							// get the active pin of the current device
+
+			SetPin,         // parameter: pin number
+			                // response: nothing
+							// set the active pin of the current device
+		} type;
+
+		uint64_t parameter;
+	};
+
+	static constexpr BAN::StringView s_audio_server_socket = "/tmp/audio-server.socket"_sv;
+
+}