#ifndef _AUDIO_SDL_H
#define _AUDIO_SDL_H

extern "C" {
#include <SDL_audio.h>
};
#include "proAudio.h"
#include <map>

/** @file proAudioSdl.h
 \brief SDL backend of proteaAudio
 \author  Gerald Franz, www.viremo.de
 \version 2.0
*/

//--- class DeviceAudioSdl -----------------------------------------

/// internal class to manage sample data
class _AudioTrack;

/// SDL based stereo audio mixer/playback device
class DeviceAudioSdl : public DeviceAudio {
public:
    ///creates audio device
    /** Use this method instead of a constructor.
     \param nTracks (optional) the maximum number of sounds that are played parallely. Computation time is linearly correlated to this factor.
     \param frequency (optional) sample frequency of the playback in Hz. 22050 corresponds to FM radio 44100 is CD quality. Computation time is linearly correlated to this factor.
     \param chunkSize (optional) the number of bytes that are sent to the sound card at once. Low numbers lead to smaller latencies but need more computation time (thread switches). If a too small number is chosen, the sounds might not be played continuously. The default value 512 guarantees a good latency below 40 ms at 22050 Hz sample frequency.
     \return a pointer to an audio device object in case of success
     Note that the parameters are only handled when calling for the first time. Afterwards always the same object is returned until an explicit destroy() is called.
     */
    static DeviceAudio* create(unsigned int nTracks=8, unsigned int frequency=22050, unsigned int chunkSize=1024);

    /// converts a sound sample to internal audio format, returns handle
    virtual uint64_t sampleFromMemory(const AudioSample & sample, float volume=1.0f);
    /// deletes a previously created sound sample resource identified by its handle
    virtual bool sampleDestroy(uint64_t sample);

    /// plays a specified sample once and sets its parameters
    /** \param sample a sample handle returned by a previous load() call
     \param volumeL (optional) left volume
     \param volumeR (optional) right volume
     \param disparity (optional) time difference between left and right channel in seconds. Use negative values to specify a delay for the left channel, positive for the right.
     \param pitch (optional) pitch factor for playback. 0.5 corresponds to one octave below, 2.0 to one above the original sample.
     \return a handle to the currently played sound or 0 in case of error */
    virtual uint64_t soundPlay(uint64_t sample, float volumeL=1.0f, float volumeR=1.0f, float disparity=0.0f, float pitch=1.0f );
    /** plays a specified sample continuously and sets its parameters
     \param sample a sample handle returned by a previous load() call
     \param volumeL (optional) left volume
     \param volumeR (optional) right volume
     \param disparity (optional) time difference between left and right channel in seconds. Use negative values to specify a delay for the left channel, positive for the right.
     \param pitch (optional) pitch factor for playback. 0.5 corresponds to one octave below, 2.0 to one above the original sample.
     \return a handle to the currently played sound or 0 in case of error */
    virtual uint64_t soundLoop(uint64_t sample, float volumeL=1.0f, float volumeR=1.0f, float disparity=0.0f, float pitch=1.0f );
    /// plays a specified sample once on a specific channel and sets its parameters
    /** \param i a channel number with the first channel starting at 0 
     \param sample a sample handle returned by a previous load() call
     \param volumeL (optional) left volume
     \param volumeR (optional) right volume
     \param disparity (optional) time difference between left and right channel in seconds. Use negative values to specify a delay for the left channel, positive for the right.
     \param pitch (optional) pitch factor for playback. 0.5 corresponds to one octave below, 2.0 to one above the original sample.
     \return a handle to the currently played sound or 0 in case of error */
    virtual uint64_t soundPlayOn(unsigned int i, uint64_t sample, float volumeL=1.0f, float volumeR=1.0f, float disparity=0.0f, float pitch=1.0f );
    /// plays a specified sample continuously on a specific channel and sets its parameters
    /** \param i a channel number with the first channel starting at 0 
     \param sample a sample handle returned by a previous load() call
     \param volumeL (optional) left volume
     \param volumeR (optional) right volume
     \param disparity (optional) time difference between left and right channel in seconds. Use negative values to specify a delay for the left channel, positive for the right.
     \param pitch (optional) pitch factor for playback. 0.5 corresponds to one octave below, 2.0 to one above the original sample.
     \return a handle to the currently played sound or 0 in case of error */
    virtual uint64_t soundLoopOn(unsigned int i, uint64_t sample, float volumeL=1.0f, float volumeR=1.0f, float disparity=0.0f, float pitch=1.0f );
    /// updates parameters of a specified sound
     /** \param sound  handle of a currently active sound
     \param volumeL left volume
     \param volumeR right volume
     \param disparity (optional) time difference between left and right channel in seconds. Use negative values to specify a delay for the left channel, positive for the right.
     \param pitch (optional) pitch factor for playback. 0.5 corresponds to one octave below, 2.0 to one above the original sample.
     \return true in case the parameters have been updated successfully */
    virtual bool soundUpdate(uint64_t sound, float volumeL, float volumeR, float disparity=0.0f, float pitch=1.0f );
    /// stops a specified sound immediately
    virtual bool soundStop(uint64_t sound);
    /// stops all sounds immediately
    virtual void soundStop();
    /// returns number of currently active sounds
    virtual unsigned int soundActive() const;
    /// check if a specified sound is active
    virtual bool soundActive(uint64_t sound);
protected:
    /// constructor. Use the create() method instead
    DeviceAudioSdl(unsigned int nTracks, unsigned int frequency, unsigned int chunkSize);
    /// destructor. Use the destroy() method instead
    virtual ~DeviceAudioSdl();
    /// stores audio specification
    SDL_AudioSpec m_spec;
    /// stores loaded sound samples
    std::map<uint64_t, _AudioTrack> mm_sample;
    /// counter for unique sample and sound id's
    uint64_t m_uniqueCounter;
    /// stores whether obtained audio format corresponds to expectations
    bool m_isDesiredFormat;

    /// stores sounds to be mixed
    _AudioTrack * ma_sound;
    /// stores number of parallel tracks
    unsigned int m_nSound;

    /// output callback
    static void cbOutput(void *userData, Uint8 *stream, int len);
    /// advanced mixer method
    void mixOutputFloat(signed short *outputBuffer, unsigned int nFrames);
    /// fallback mixer method
    void mixOutputSInt(Uint8 *stream, int len);
};

#endif // _AUDIO_SDL_H