struct MidiEvent {
	uint32 delta;
	uint32 event;
};

/* Lowlevel Abstract Midi Driver Class */
class MidiDriver {
	
public:
	/* called whenever the midi driver is in streaming mode,
	 * and more midi commands need to be generated
	 * return 0 to tell the mididriver that the end of stream was reached
	 */
	typedef int StreamCallback(void *param, MidiEvent *ev, int num);
	

	/* open modes, pass one of those to open() */
	enum {
		MO_SIMPLE = 1,
		MO_STREAMING = 2,
	};

	/* Special events that can be inserted in a MidiEvent.
	 * event = (ME_xxx<<24) | <24-bit data associated with event>
	 */
	enum {
		ME_NONE  = 0,
		ME_TEMPO = 1,
	};

	/* error codes returned by open.
	 * can be converted to a string with get_error_name()
	 */
	enum {
		MERR_CANNOT_CONNECT = 1,
		MERR_STREAMING_NOT_AVAILABLE = 2,
		MERR_DEVICE_NOT_AVAILABLE = 3,
		MERR_ALREADY_OPEN = 4,
	};

	enum {
		PROP_TIMEDIV = 1,
	};

	
	/* destroy the midi object */
	virtual void destroy() = 0;

	/* open the midi driver.
	 * returns 0 if successful.
	 * otherwise an error code. */
	virtual int open(int mode) = 0;

	/* close the midi driver */
	virtual void close() = 0;

	/* output a packed midi command to the midi stream
	 * valid only if mode is MO_SIMPLE
	 */
	virtual void send(uint32 b) = 0;

	/* set callback when more streams need to be generated.
	 * valid only when mode==MO_STREAMING
	 */
	virtual void set_stream_callback(void *param, StreamCallback *sc) = 0;

	/* Pause or resume streaming MIDI */
	virtual void pause(bool pause) = 0;


	/* Get or set a property */
	virtual uint32 property(int prop, uint32 param) = 0;

	/* retrieve a string representation of an error code */
	static const char *get_error_name(int error_code);
};



/* driver types */
enum {
	MD_AUTO = 0,
	MD_NULL = 1,
	MD_WINDOWS = 2,
	MD_TIMIDITY = 3,
	MD_SEQ = 4,
	MD_QTMUSIC = 5,
	MD_AMIDI = 6,
};


/* Factory functions => no need to include the specific classes
 * in this header => faster compile */
MidiDriver *MidiDriver_NULL_create();
MidiDriver *MidiDriver_WIN_create();
MidiDriver *MidiDriver_TIMIDITY_create();
MidiDriver *MidiDriver_SEQ_create();
MidiDriver *MidiDriver_QT_create();
MidiDriver *MidiDriver_AMIDI_create();