/*
Copyright (C) 1996-1997 Id Software, Inc.

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.

*/
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/shm.h>
#include <sys/wait.h>
#include <stdio.h>
#include <sys/audioio.h>
#include <errno.h>
#include "quakedef.h"

int audio_fd;
int snd_inited;

static int bufpos;
static int wbufp;
static audio_info_t info;

#define BUFFER_SIZE   8192

unsigned char dma_buffer[BUFFER_SIZE];
unsigned char pend_buffer[BUFFER_SIZE];
int pending;

static int lastwrite = 0;

qboolean SNDDMA_Init(void)
{
  int rc;
  int fmt;
  int tmp;
  int i;
  char *s;
  int caps;

  if (snd_inited) {
    printf("Sound already init'd\n");
    return;
  }

  shm = &sn;
  shm->splitbuffer = 0;

  audio_fd = open("/dev/audio", O_WRONLY|O_NDELAY);

  if (audio_fd < 0) {
    if (errno == EBUSY) {
      Con_Printf("Audio device is being used by another process\n");
    }
    perror("/dev/audio");
    Con_Printf("Could not open /dev/audio\n");
    return (0);
  }

  if (ioctl(audio_fd, AUDIO_GETINFO, &info) < 0) {
    perror("/dev/audio");
    Con_Printf("Could not communicate with audio device.\n");
    close(audio_fd);
    return 0;
  }

  //
  // set to nonblock
  //
  if (fcntl(audio_fd, F_SETFL, O_NONBLOCK) < 0) {
    perror("/dev/audio");
    close(audio_fd);
    return 0;
  }

  AUDIO_INITINFO(&info);

  shm->speed = 11025;

  // try 16 bit stereo
  info.play.encoding = AUDIO_ENCODING_LINEAR;
  info.play.sample_rate = 11025;
  info.play.channels = 2;
  info.play.precision = 16;

  if (ioctl(audio_fd, AUDIO_SETINFO, &info) < 0) {
    info.play.encoding = AUDIO_ENCODING_LINEAR;
    info.play.sample_rate = 11025;
    info.play.channels = 1;
    info.play.precision = 16;
    if (ioctl(audio_fd, AUDIO_SETINFO, &info) < 0) {
      Con_Printf("Incapable sound hardware.\n");
      close(audio_fd);
      return 0;
    }
    Con_Printf("16 bit mono sound initialized\n");
    shm->samplebits = 16;
    shm->channels = 1;
  } else { // 16 bit stereo
    Con_Printf("16 bit stereo sound initialized\n");
    shm->samplebits = 16;
    shm->channels = 2;
  }

  shm->soundalive = true;
  shm->samples = sizeof(dma_buffer) / (shm->samplebits/8);
  shm->samplepos = 0;
  shm->submission_chunk = 1;
  shm->buffer = (unsigned char *)dma_buffer;

  snd_inited = 1;

  return 1;
}

int SNDDMA_GetDMAPos(void)
{
  if (!snd_inited)
    return (0);

  if (ioctl(audio_fd, AUDIO_GETINFO, &info) < 0) {
    perror("/dev/audio");
    Con_Printf("Could not communicate with audio device.\n");
    close(audio_fd);
    snd_inited = 0;
    return (0);
  }

  return ((info.play.samples*shm->channels) % shm->samples);
}

int SNDDMA_GetSamples(void)
{
  if (!snd_inited)
    return (0);

  if (ioctl(audio_fd, AUDIO_GETINFO, &info) < 0) {
    perror("/dev/audio");
    Con_Printf("Could not communicate with audio device.\n");
    close(audio_fd);
    snd_inited = 0;
    return (0);
  }

  return info.play.samples;
}

void SNDDMA_Shutdown(void)
{
  if (snd_inited) {
    close(audio_fd);
    snd_inited = 0;
  }
}

/*
==============
SNDDMA_Submit

Send sound to device if buffer isn't really the dma buffer
===============
*/
void SNDDMA_Submit(void)
{
  int samps;
  int bsize;
  int bytes, b;
  static unsigned char writebuf[1024];
  unsigned char *p;
  int idx;
  int stop = paintedtime;
  extern int soundtime;

  if (paintedtime < wbufp)
    wbufp = 0; // reset

  bsize = shm->channels * (shm->samplebits/8);
  bytes = (paintedtime - wbufp) * bsize;

  if (!bytes)
    return;

  if (bytes > sizeof(writebuf)) {
    bytes = sizeof(writebuf);
    stop = wbufp + bytes/bsize;
  }

  p = writebuf;
  idx = (wbufp*bsize) & (BUFFER_SIZE - 1);

  for (b = bytes; b; b--) {
    *p++ = dma_buffer[idx];
    idx = (idx + 1) & (BUFFER_SIZE - 1);
  }

  wbufp = stop;

  if (write(audio_fd, writebuf, bytes) < bytes)
    printf("audio can't keep up!\n");

}