/*
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)
{
	if (snd_inited) {
		printf("Sound already init'd\n");
		return 0;
	}

	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");

}