/**
 * Copyright 2013 (c) Anna Schumaker.
 */
#ifndef OCARINA_CORE_AUDIO_H
#define OCARINA_CORE_AUDIO_H

#include <core/tags/track.h>
#include <string>
#include <stdint.h>


/**
 * The audio driver class gives us an interface for using multiple
 * audio frameworks for audio playback.
 */
class AudioDriver {
protected:
	void (*on_error) (); /**< Error handling callback function.  */

public:
	AudioDriver();  /**< Default AudioDriver constructor. */
	virtual ~AudioDriver(); /**< AudioDriver destructor.          */


	/**
	 * Loads an audio file for playback.
	 *
	 * @param  track  The Track to load.
	 */
	virtual void load(Track *track) = 0;

	/**
	 * Called to begin playback on the currently loaded track.
	 */
	virtual void play() = 0;

	/**
	 * Called to pause playback on the currently loaded track.
	 */
	virtual void pause() = 0;

	/**
	 * Called to check if the audio library is currently playing a track.
	 *
	 * @return True if audio library is playing, false otherwise.
	 */
	virtual bool is_playing() = 0;


	/**
	 * Seek to a specific position in the current track.
	 *
	 * @param  offset  Position from the beginning of the track where we will seek to, in nanoseconds.
	 */
	virtual void seek_to(int64_t offset) = 0;

	/**
	 * Return the current position of the playback.
	 *
	 * @return The current playback position, in nanoseconds.
	 */
	virtual int64_t position() = 0;

	/**
	 * Return the duration of the currently loaded track.
	 *
	 * @return The duration of the current track, in nanoseconds.
	 */
	virtual int64_t duration() = 0;

	/**
	 * Called to handle reaching the end-of-stream.
	 */
	void eos();
};


/**
 * Namespace for higher-level audio controls.
 */
namespace audio
{

	void init();  /**< Initializes the audio layer. */
	void play();  /**< Begin playback.              */
	void pause(); /**< Pause playback.              */

	/**
	 * Seek to a specific point in the track.
	 *
	 * @param  pos  Offset (in nanoseconds) from the beginning of the track.
	 */
	void seek_to(int64_t);

	/**
	 * Stop playback and seek to the beginning of the track.
	 */
	void stop();

	/**
	 * @return The current position of the audio playback (in nanoseconds).
	 */
	int64_t position();

	/**
	 * @return The duration of the currently loaded track (in nanoseconds).
	 */
	int64_t duration();

	void next(); /**< Find and load the next track that should be played. */
	void prev(); /**< Call the deck :: previous() function and load the result. */

	/**
	 * Load a specific track for playback.
	 *
	 * @param  track  The track that should be loaded.
	 */
	void load_track(Track *track);

	/**
	 * @return A pointer to the currently playing track object.
	 */
	Track *current_track();

	/**
	 * Configure the automatic pausing feature.
	 *
	 * @param  enabled  Set to true to enable pausing, false to disable.
	 * @param  n  Number of tracks to play before pausing.
	 */
	void pause_after(bool, unsigned int);

	/**
	 * Call to find the current automatic pausing state.
	 *
	 * @return True if automatic pausing is enabled, false otherwise.
	 */
	bool pause_enabled();

	/**
	 * Call to find the number of tracks remaining before pausing.
	 *
	 * @return The number of tracks before pausing.
	 */
	unsigned int pause_count();

	/**
	 * Called to access an audio driver.
	 *
	 * @return The current driver used by the application.
	 */
	AudioDriver *get_driver();
};

#endif /* OCARINA_CORE_AUDIO_H */