//     ____                _       __               
//    / __ )____  _____   | |     / /___ ___________
//   / __  / __ \/ ___/   | | /| / / __ `/ ___/ ___/
//  / /_/ / /_/ (__  )    | |/ |/ / /_/ / /  (__  ) 
// /_____/\____/____/     |__/|__/\__,_/_/  /____/  
//                                              
//       A futuristic real-time strategy game.
//          This file is part of Bos Wars.
//
/**@name sound_server.cpp - The sound server (hardware layer and so on) */
//
//      (c) Copyright 1998-2008 by Lutz Sammer, Fabrice Rossi, and
//                                 Jimmy Salmon
//
//      This program is free software; you can redistribute it and/or modify
//      it under the terms of the GNU General Public License as published by
//      the Free Software Foundation; only version 2 of the License.
//
//      This program is distributed in the hope that it will be useful,
//      but WITHOUT ANY WARRANTY; without even the implied warranty of
//      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//      GNU General Public License for more details.
//
//      You should have received a copy of the GNU General Public License
//      along with this program; if not, write to the Free Software
//      Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
//      02111-1307, USA.
//


//@{

/*----------------------------------------------------------------------------
--  Includes
----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "stratagus.h"

#include "SDL.h"

#include "sound_server.h"
#include "iolib.h"
#include "iocompat.h"


/*----------------------------------------------------------------------------
--  Variables
----------------------------------------------------------------------------*/

static bool SoundInitialized;    /// is sound initialized
static bool MusicPlaying;        /// flag true if playing music

static int EffectsVolume = 128;  /// effects sound volume
static int MusicVolume = 128;    /// music volume

static bool MusicEnabled = true;
static bool EffectsEnabled = true;

	/// Channels for sound effects and unit speach
struct SoundChannel {
	CSample *Sample;       /// sample to play
	unsigned char Volume;  /// Volume of this channel
	signed char Stereo;    /// stereo location of sound (-128 left, 0 center, 127 right)

	bool Playing;          /// channel is currently playing
	int Point;             /// point in sample if playing or next free channel

	void (*FinishedCallback)(int channel); /// Callback for when a sample finishes playing
};

#define MaxChannels 32     /// How many channels are supported

static SoundChannel Channels[MaxChannels];
static int NextFreeChannel;

static struct {
	CSample *Sample;       /// Music sample
	void (*FinishedCallback)(); /// Callback for when music finishes playing
} MusicChannel;

static void ChannelFinished(int channel);

static int *MixerBuffer;
static int MixerBufferSize;


/*----------------------------------------------------------------------------
--  Mixers
----------------------------------------------------------------------------*/

/**
**  Convert RAW sound data to 44100 hz, Stereo, 16 bits per channel
**
**  @param src        Source buffer
**  @param dest       Destination buffer
**  @param frequency  Frequency of source
**  @param chansize   Bitrate in bytes per channel of source
**  @param channels   Number of channels of source
**  @param bytes      Number of compressed bytes to read
**
**  @return           Number of bytes written in 'dest'
*/
static int ConvertToStereo32(const char *src, char *dest, int frequency,
	int chansize, int channels, int bytes)
{
	SDL_AudioCVT acvt;
	Uint16 format;

	if (chansize == 1) {
		format = AUDIO_U8;
	} else {
		format = AUDIO_S16SYS;
	}
	SDL_BuildAudioCVT(&acvt, format, channels, frequency, AUDIO_S16SYS, 2, 44100);

	acvt.buf = (Uint8 *)dest;
	memcpy(dest, src, bytes);
	acvt.len = bytes;

	SDL_ConvertAudio(&acvt);

	return acvt.len_mult * bytes;
}

/**
**  Mix music to stereo 32 bit.
**
**  @param buffer  Buffer for mixed samples.
**  @param size    Number of samples that fits into buffer.
**
**  @todo this functions can be called from inside the SDL audio callback,
**  which is bad, the buffer should be precalculated.
*/
static void MixMusicToStereo32(int *buffer, int size)
{
	int i;
	int n;
	int len;
	short *buf;
	char *tmp;
	int div;

	if (MusicPlaying) {
		Assert(MusicChannel.Sample);

		len = size * sizeof(*buf);
		tmp = new char[len];
		buf = new short[len];

		div = 176400 / (MusicChannel.Sample->Frequency * (MusicChannel.Sample->SampleSize / 8)
				* MusicChannel.Sample->Channels);

		size = MusicChannel.Sample->Read(tmp, len / div);

		n = ConvertToStereo32((char *)(tmp), (char *)buf, MusicChannel.Sample->Frequency,
			MusicChannel.Sample->SampleSize / 8, MusicChannel.Sample->Channels, size);

		for (i = 0; i < n / (int)sizeof(*buf); ++i) {
			// Add to our samples
			// FIXME: why taking out '/ 2' leads to distortion
			buffer[i] += buf[i] * MusicVolume / MaxVolume / 2;
		}

		delete[] tmp;
		delete[] buf;

		if (n < len) { // End reached
			MusicPlaying = false;
			delete MusicChannel.Sample;
			MusicChannel.Sample = NULL;

			if (MusicChannel.FinishedCallback) {
				MusicChannel.FinishedCallback();
			}
		}
	}
}

/**
**  Mix sample to buffer.
**
**  The input samples are adjusted by the local volume and resampled
**  to the output frequence.
**
**  @param sample  Input sample
**  @param index   Position into input sample
**  @param volume  Volume of the input sample
**  @param stereo  Stereo (left/right) position of sample
**  @param buffer  Output buffer
**  @param size    Size of output buffer (in samples per channel)
**
**  @return        The number of bytes used to fill buffer
**
**  @todo          Can mix faster if signed 8 bit buffers are used.
*/
static int MixSampleToStereo32(CSample *sample, int index, unsigned char volume,
	char stereo, int *buffer, int size)
{
	int local_volume;
	unsigned char left;
	unsigned char right;
	int i;
	static int buf[SOUND_BUFFER_SIZE / 2];
	int div;

	div = 176400 / (sample->Frequency * (sample->SampleSize / 8)
			* sample->Channels);

	local_volume = (int)volume * EffectsVolume / MaxVolume;

	if (stereo < 0) {
		left = 128;
		right = 128 + stereo;
	} else {
		left = 128 - stereo;
		right = 128;
	}

	Assert(!(index & 1));

	if (size >= (sample->Len - index) * div / 2) {
		size = (sample->Len - index) * div / 2;
	}

	size = ConvertToStereo32((char *)(sample->Buffer + index), (char *)buf, sample->Frequency,
			sample->SampleSize / 8, sample->Channels,
			size * 2 / div);

	size /= 2;
	for (i = 0; i < size; i += 2) {
		// FIXME: why taking out '/ 2' leads to distortion
		buffer[i] += ((short *)buf)[i] * local_volume * left / 128 / MaxVolume / 2;
		buffer[i + 1] += ((short *)buf)[i + 1] * local_volume * right / 128 / MaxVolume / 2;
	}

	return 2 * size / div;
}

/**
**  Mix channels to stereo 32 bit.
**
**  @param buffer  Buffer for mixed samples.
**  @param size    Number of samples that fits into buffer.
**
**  @return        How many channels become free after mixing them.
*/
static int MixChannelsToStereo32(int *buffer, int size)
{
	int channel;
	int i;
	int new_free_channels;

	new_free_channels = 0;
	for (channel = 0; channel < MaxChannels; ++channel) {
		if (Channels[channel].Playing && Channels[channel].Sample) {
			i = MixSampleToStereo32(Channels[channel].Sample,
				Channels[channel].Point, Channels[channel].Volume,
				Channels[channel].Stereo, buffer, size);
			Channels[channel].Point += i;
			Assert(Channels[channel].Point <= Channels[channel].Sample->Len);

			if (Channels[channel].Point == Channels[channel].Sample->Len) {
				ChannelFinished(channel);
				++new_free_channels;
			}
		}
	}

	return new_free_channels;
}

/**
**  Clip mix to output stereo 16 signed bit.
**
**  @param mix     signed 32 bit input.
**  @param size    number of samples in input.
**  @param output  clipped 16 signed bit output buffer.
*/
static void ClipMixToStereo16(const int *mix, int size, short *output)
{
	int s;
	const int *end;

	end = mix + size;
	while (mix < end) {
		s = (*mix++);
		if (s > SHRT_MAX) {
			*output++ = SHRT_MAX;
		} else if (s < SHRT_MIN) {
			*output++ = SHRT_MIN;
		} else {
			*output++ = s;
		}
	}
}

/**
**  Mix into buffer.
**
**  @param buffer   Buffer to be filled with samples. Buffer must be big enough.
**  @param samples  Number of samples.
*/
static void MixIntoBuffer(void *buffer, int samples)
{
	if (samples > MixerBufferSize) {
		delete[] MixerBuffer;
		MixerBuffer = new int[samples];
		MixerBufferSize = samples;
	}

	// FIXME: can save the memset here, if first channel sets the values
	memset(MixerBuffer, 0, samples * sizeof(*MixerBuffer));

	if (EffectsEnabled) {
		// Add channels to mixer buffer
		MixChannelsToStereo32(MixerBuffer, samples);
	}
	if (MusicEnabled) {
		// Add music to mixer buffer
		MixMusicToStereo32(MixerBuffer, samples);
	}

	ClipMixToStereo16(MixerBuffer, samples, (short *)buffer);
}

/**
**  Fill buffer for the sound card.
**
**  @see SDL_OpenAudio
**
**  @param udata   the pointer stored in userdata field of SDL_AudioSpec.
**  @param stream  pointer to buffer you want to fill with information.
**  @param len     is length of audio buffer in bytes.
*/
static void FillAudio(void *udata, Uint8 *stream, int len)
{
	len >>= 1;
	MixIntoBuffer(stream, len);
}

/*----------------------------------------------------------------------------
--  Effects
----------------------------------------------------------------------------*/

/**
**  A channel is finished playing
*/
static void ChannelFinished(int channel)
{
	if (Channels[channel].FinishedCallback) {
		Channels[channel].FinishedCallback(channel);
	}

	Channels[channel].Playing = false;
	Channels[channel].Point = NextFreeChannel;
	NextFreeChannel = channel;
}

/**
**  Put a sound request in the next free channel.
*/
static int FillChannel(CSample *sample, unsigned char volume, char stereo)
{
	Assert(NextFreeChannel < MaxChannels);

	int old_free = NextFreeChannel;
	int next_free = Channels[NextFreeChannel].Point;

	Channels[NextFreeChannel].Volume = volume;
	Channels[NextFreeChannel].Point = 0;
	Channels[NextFreeChannel].Playing = true;
	Channels[NextFreeChannel].Sample = sample;
	Channels[NextFreeChannel].Stereo = stereo;
	Channels[NextFreeChannel].FinishedCallback = NULL;

	NextFreeChannel = next_free;

	return old_free;
}

/**
**  Set the channel volume
**
**  @param channel  Channel to set
**  @param volume   New volume, <0 will not set the volume
**
**  @return         Current volume of the channel, -1 for error
*/
int SetChannelVolume(int channel, int volume)
{
	if (channel < 0 || channel >= MaxChannels) {
		return -1;
	}

	if (volume < 0) {
		volume = Channels[channel].Volume;
	} else {
		SDL_LockAudio();

		if (volume > MaxVolume) {
			volume = MaxVolume;
		}
		Channels[channel].Volume = volume;

		SDL_UnlockAudio();
	}

	return volume;
}

/**
**  Set the channel stereo
**
**  @param channel  Channel to set
**  @param stereo   -128 to 127, out of range will not set the stereo
**
**  @return         Current stereo of the channel, -1 for error
*/
int SetChannelStereo(int channel, int stereo)
{
	if (channel < 0 || channel >= MaxChannels) {
		return -1;
	}

	if (stereo < -128 || stereo > 127) {
		stereo = Channels[channel].Stereo;
	} else {
		SDL_LockAudio();

		if (stereo > 127) {
			stereo = 127;
		} else if (stereo < -128) {
			stereo = -128;
		}
		Channels[channel].Stereo = stereo;

		SDL_UnlockAudio();
	}

	return stereo;
}

/**
**  Set the channel's callback for when a sound finishes playing
**
**  @param channel   Channel to set
**  @param callback  Callback to call when the sound finishes
*/
void SetChannelFinishedCallback(int channel, void (*callback)(int channel))
{
	if (channel < 0 || channel >= MaxChannels) {
		return;
	}

	Channels[channel].FinishedCallback = callback;
}

/**
**  Get the sample playing on a channel
*/
CSample *GetChannelSample(int channel)
{
	if (channel < 0 || channel >= MaxChannels) {
		return NULL;
	}

	return Channels[channel].Sample;
}

/**
**  Stop a channel
**
**  @param channel  Channel to stop
*/
void StopChannel(int channel)
{
	SDL_LockAudio();

	if (channel >= 0 && channel < MaxChannels) {
		if (Channels[channel].Playing) {
			ChannelFinished(channel);
		}
	}

	SDL_UnlockAudio();
}

/**
**  Stop all channels
*/
void StopAllChannels()
{
	SDL_LockAudio();

	for (int i = 0; i < MaxChannels; ++i) {
		if (Channels[i].Playing) {
			ChannelFinished(i);
		}
	}

	SDL_UnlockAudio();
}

/**
**  Load a sample
**
**  @param name  File name of sample (short version).
**
**  @return      General sample loaded from file into memory.
**
**  @todo  Add streaming, caching support.
*/
CSample *LoadSample(const std::string &name)
{
	CSample *sample;
	char buf[PATH_MAX];

	LibraryFileName(name.c_str(), buf, sizeof(buf));

	if ((sample = LoadWav(buf, PlayAudioLoadInMemory))) {
		return sample;
	}
#ifdef USE_VORBIS
	if ((sample = LoadVorbis(buf, PlayAudioLoadInMemory))) {
		return sample;
	}
#endif

	fprintf(stderr, "Can't load the sound `%s'\n", name.c_str());

	return sample;
}

/**
**  Play a sound sample
**
**  @param sample  Sample to play
**
**  @return        Channel number, -1 for error
*/
int PlaySample(CSample *sample)
{
	int channel = -1;

	SDL_LockAudio();

	if (SoundEnabled() && EffectsEnabled && sample &&
			NextFreeChannel != MaxChannels) {
		channel = FillChannel(sample, EffectsVolume, 0);
	}

	SDL_UnlockAudio();

	return channel;
}

/**
**  Play a sound file
**
**  @param name  Filename of a sound to play
**
**  @return      Channel number the sound is playing on, -1 for error
*/
int PlaySoundFile(const std::string &name)
{
	CSample *sample = LoadSample(name);
	if (sample) {
		return PlaySample(sample);
	}
	return -1;
}

/**
**  Set the global sound volume.
**
**  @param volume  the sound volume 0-255
*/
void SetEffectsVolume(int volume)
{
	if (volume < 0) {
		EffectsVolume = 0;
	} else if (volume > MaxVolume) {
		EffectsVolume = MaxVolume;
	} else {
		EffectsVolume = volume;
	}
}

/**
**  Get effects volume
*/
int GetEffectsVolume(void)
{
	return EffectsVolume;
}

/**
**  Set effects enabled
*/
void SetEffectsEnabled(bool enabled)
{
	EffectsEnabled = enabled;
}

/**
**  Check if effects are enabled
*/
bool IsEffectsEnabled(void)
{
	return EffectsEnabled;
}

/*----------------------------------------------------------------------------
--  Music
----------------------------------------------------------------------------*/

/**
**  Set the music finished callback
*/
void SetMusicFinishedCallback(void (*callback)(void))
{
	MusicChannel.FinishedCallback = callback;
}

/**
**  Play a music file.
**
**  @param sample  Music sample.
**
**  @return        0 if music is playing, -1 if not.
*/
int PlayMusic(CSample *sample)
{
	if (sample) {
		StopMusic();
		MusicChannel.Sample = sample;
		MusicPlaying = true;
		return 0;
	} else {
		DebugPrint("Could not play sample\n");
		return -1;
	}
}

/**
**  Play a music file.
**
**  @param file  Name of music file, format is automatically detected.
**
**  @return      0 if music is playing, -1 if not.
*/
int PlayMusic(const std::string &file)
{
	char name[PATH_MAX];
	CSample *sample;

	if (!SoundEnabled() || !IsMusicEnabled()) {
		return -1;
	}

	LibraryFileName(file.c_str(), name, sizeof(name));

	DebugPrint("play music %s\n" _C_ name);

	sample = LoadWav(name, PlayAudioStream);

#ifdef USE_VORBIS
	if (!sample) {
		sample = LoadVorbis(name, PlayAudioStream);
	}
#endif

	if (sample) {
		StopMusic();
		MusicChannel.Sample = sample;
		MusicPlaying = true;
		return 0;
	} else {
		DebugPrint("Could not play %s\n" _C_ file.c_str());
		return -1;
	}
}

/**
**  Stop the current playing music.
*/
void StopMusic(void)
{
	if (MusicPlaying) {
		MusicPlaying = false;
		if (MusicChannel.Sample) {
			SDL_LockAudio();
			delete MusicChannel.Sample;
			MusicChannel.Sample = NULL;
			SDL_UnlockAudio();
		}
	}
}

/**
**  Set the music volume.
**
**  @param volume  the music volume 0-255
*/
void SetMusicVolume(int volume)
{
	if (volume < 0) {
		MusicVolume = 0;
	} else if (volume > MaxVolume) {
		MusicVolume = MaxVolume;
	} else {
		MusicVolume = volume;
	}
}

/**
**  Get music volume
*/
int GetMusicVolume(void)
{
	return MusicVolume;
}

/**
**  Set music enabled
*/
void SetMusicEnabled(bool enabled)
{
	if (enabled) {
		MusicEnabled = true;
	} else {
		MusicEnabled = false;
		StopMusic();
	}
}

/**
**  Check if music is enabled
*/
bool IsMusicEnabled(void)
{
	return MusicEnabled;
}

/**
**  Check if music is playing
*/
bool IsMusicPlaying(void)
{
	return MusicPlaying;
}

/*----------------------------------------------------------------------------
--  Init
----------------------------------------------------------------------------*/

/**
**  Check if sound is enabled
*/
bool SoundEnabled(void)
{
	return SoundInitialized;
}

/**
**  Initialize sound card hardware part with SDL.
**
**  @param freq  Sample frequency (44100,22050,11025 hz).
**  @param size  Sample size (8bit, 16bit)
**
**  @return      True if failure, false if everything ok.
*/
static int InitSdlSound(int freq, int size)
{
	SDL_AudioSpec wanted;

	wanted.freq = freq;
	if (size == 8) {
		wanted.format = AUDIO_U8;
	} else if (size == 16) {
		wanted.format = AUDIO_S16SYS;
	} else {
		DebugPrint("Unexpected sample size %d\n" _C_ size);
		wanted.format = AUDIO_S16SYS;
	}
	wanted.channels = 2;
	wanted.samples = 4096;
	wanted.callback = FillAudio;
	wanted.userdata = NULL;

	//  Open the audio device, forcing the desired format
	if (SDL_OpenAudio(&wanted, NULL) < 0) {
		fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
		return -1;
	}
	SDL_PauseAudio(0);

	return 0;
}

/**
**  Initialize sound card.
**
**  @return  True if failure, false if everything ok.
*/
int InitSound(void)
{
	//
	// Open sound device, 8bit samples, stereo.
	//
	if (InitSdlSound(44100, 16)) {
		SoundInitialized = false;
		return 1;
	}
	SoundInitialized = true;

	// ARI: The following must be done here to allow sound to work in
	// pre-start menus!
	// initialize channels
	for (int i = 0; i < MaxChannels; ++i) {
		Channels[i].Point = i + 1;
	}

	return 0;
}

/**
**  Cleanup sound server.
*/
void QuitSound(void)
{
	SDL_CloseAudio();
	SoundInitialized = false;
	delete[] MixerBuffer;
	MixerBuffer = NULL;
}

//@}