/*
* 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; either version 2 of the License, or
*(at your option) any later version.
*
* 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
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <alsa/asoundlib.h>

#include "../client/client.h"
#include "../client/snd_loc.h"

#define BUFFER_SAMPLES 4096
#define SUBMISSION_CHUNK BUFFER_SAMPLES / 2

static snd_pcm_t *pcm_handle;
static snd_pcm_hw_params_t *hw_params;

static struct sndinfo * si;

static int sample_bytes;
static int buffer_bytes;

cvar_t *sndbits;
cvar_t *sndspeed;
cvar_t *sndchannels;
cvar_t *snddevice;


/*
*  The sample rates which will be attempted.
*/
static int RATES[] = {
	44100, 22050, 11025, 8000
};

/*
*  Initialize ALSA pcm device, and bind it to sndinfo.
*/
qboolean SNDDMA_Init(void){
	int i, err, dir;
	unsigned int r;
	snd_pcm_uframes_t p;

	
	if (!snddevice)
	  {
	    sndbits = Cvar_Get("sndbits", "16", CVAR_ARCHIVE);
	    sndspeed = Cvar_Get("sndspeed", "0", CVAR_ARCHIVE);
	    sndchannels = Cvar_Get("sndchannels", "2", CVAR_ARCHIVE);
	    snddevice = Cvar_Get("snddevice", "/dev/dsp", CVAR_ARCHIVE);
	  }
	
	if(!strcmp(snddevice->string, "/dev/dsp"))  //silly oss default
	  snddevice->string = "default";
	
	if((err = snd_pcm_open(&pcm_handle, snddevice->string,
			       SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0)
	  {
	    Com_Printf("ALSA: cannot open device %s(%s)\n",
		       snddevice->string, snd_strerror(err));
	    return false;
	  }
	
	if((err = snd_pcm_hw_params_malloc(&hw_params)) < 0){
	  Com_Printf("ALSA: cannot allocate hw params(%s)\n",
		     snd_strerror(err));
	  return false;
	}
	
	if((err = snd_pcm_hw_params_any(pcm_handle, hw_params)) < 0){
	  Com_Printf("ALSA: cannot init hw params(%s)\n", snd_strerror(err));
	  snd_pcm_hw_params_free(hw_params);
	  return false;
	}
	
	if((err = snd_pcm_hw_params_set_access
	    (pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
	  {
	    Com_Printf("ALSA: cannot set access(%s)\n", snd_strerror(err));
	    snd_pcm_hw_params_free(hw_params);
	    return false;
	  }
	
	dma.samplebits = (int)sndbits->value;
	if(dma.samplebits != 8){  //try 16 by default
	  dma.samplebits = 16;  //ensure this is set for other calculations
	  
	  if((err = snd_pcm_hw_params_set_format(pcm_handle, hw_params,
						 SND_PCM_FORMAT_S16)) < 0){
	    Com_Printf("ALSA: 16 bit not supported, trying 8\n");
	    dma.samplebits = 8;
	  }
	}
	if(dma.samplebits == 8){  //or 8 if specifically asked to
	  if((err = snd_pcm_hw_params_set_format(pcm_handle, hw_params,
						 SND_PCM_FORMAT_U8)) < 0){
	    Com_Printf("ALSA: cannot set format(%s)\n", snd_strerror(err));
	    snd_pcm_hw_params_free(hw_params);
	    return false;
	  }
	}
	
	dma.speed = (int)sndspeed->value;
	if(dma.speed){  //try specified rate
	  r = dma.speed;
		
	  if((err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, &r, &dir)) < 0)
	    Com_Printf("ALSA: cannot set rate %d(%s)\n", r, snd_strerror(err));
	  else {  //rate succeeded, but is perhaps slightly different
	    if(dir != 0) 
	      Com_Printf("ALSA: rate %d not supported, using %d\n", sndspeed->value, r);
	    dma.speed = r;
	  }
	}
	if(!dma.speed){  //or all available ones
	  for(i = 0; i < sizeof(RATES); i++){
	    r = RATES[i];
	    dir = 0;
	    
	    if((err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, &r, &dir)) < 0)
	      Com_Printf("ALSA: cannot set rate %d(%s)\n", r, snd_strerror(err));
	    else {  //rate succeeded, but is perhaps slightly different
	      dma.speed = r;
	      if(dir != 0) 
		Com_Printf("ALSA: rate %d not supported, using %d\n", RATES[i], r);
	      break;
	    }
	  }
	}
	if(!dma.speed){  //failed
	  Com_Printf("ALSA: cannot set rate\n");
	  snd_pcm_hw_params_free(hw_params);
	  return false;
	}
	
	dma.channels = sndchannels->value;
	if(dma.channels < 1 || dma.channels > 2)
	  dma.channels = 2;  //ensure either stereo or mono
	
	
	
	if((err = snd_pcm_hw_params_set_channels(pcm_handle, hw_params, 
						 dma.channels)) < 0)
	  {
	    Com_Printf("ALSA: cannot set channels %d(%s)\n",
		       sndchannels->value, snd_strerror(err));
	    snd_pcm_hw_params_free(hw_params);
	    return false;
	  }
	
	p = BUFFER_SAMPLES / dma.channels;
	if((err = snd_pcm_hw_params_set_period_size_near(pcm_handle, hw_params,
							 &p, &dir)) < 0){
	  Com_Printf("ALSA: cannot set period size (%s)\n", snd_strerror(err));
	  snd_pcm_hw_params_free(hw_params);
	  return false;
	}
	else {  //rate succeeded, but is perhaps slightly different
	  if(dir != 0) 
	    Com_Printf("ALSA: period %d not supported, using %d\n", (BUFFER_SAMPLES/dma.channels), p);
	}
	
	if((err = snd_pcm_hw_params(pcm_handle, hw_params)) < 0){  //set params
	  Com_Printf("ALSA: cannot set params(%s)\n", snd_strerror(err));
	  snd_pcm_hw_params_free(hw_params);
	  return false;
	}
	
	sample_bytes = dma.samplebits / 8;
	buffer_bytes = BUFFER_SAMPLES * sample_bytes;
	
	dma.buffer = malloc(buffer_bytes);  //allocate pcm frame buffer
	memset(dma.buffer, 0, buffer_bytes);
	
	dma.samplepos = 0;
	
	dma.samples = BUFFER_SAMPLES;
	dma.submission_chunk = SUBMISSION_CHUNK;
	
	snd_pcm_prepare(pcm_handle);
	
	return true;
}

/*
*  Returns the current sample position, if sound is running.
*/
int SNDDMA_GetDMAPos(void){
	
	if(dma.buffer)
	  return dma.samplepos;
	
	Com_Printf("Sound not inizialized\n");
	return 0;
}

/*
*  Closes the ALSA pcm device and frees the dma buffer.
*/
void SNDDMA_Shutdown(void){
	
	if(dma.buffer){
	  snd_pcm_drop(pcm_handle);
	  snd_pcm_close(pcm_handle);
	}
	
	free(dma.buffer);
	dma.buffer = 0;
}

/*
*  Writes the dma buffer to the ALSA pcm device.
*/
void SNDDMA_Submit(void){
	int s, w, frames;
	void *start;
	
	if(!dma.buffer)
	  return;
	
	s = dma.samplepos * sample_bytes;
	start = (void *)&dma.buffer[s];
	
	frames = dma.submission_chunk / dma.channels;
	
	if((w = snd_pcm_writei(pcm_handle, start, frames)) < 0){  //write to card
		snd_pcm_prepare(pcm_handle);  //xrun occured
		return;
	}
	
	dma.samplepos += w * dma.channels;  //mark progress
	
	if(dma.samplepos >= dma.samples)
	  dma.samplepos = 0;  //wrap buffer
}

/*
*  Callback provided by the engine in case we need it.  We don't.
*/
void SNDDMA_BeginPainting(void){}