/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
Copyright (C) 2006 Robert Beckebans <trebor_7@users.sourceforge.net>

This file is part of XreaL source code.

XreaL source code 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.

XreaL source code 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 XreaL source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  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>
#ifdef __linux__				// rb0101023 - guard this
#include <linux/soundcard.h>
#endif
#ifdef __FreeBSD__				// rb0101023 - added
#include <sys/soundcard.h>
#endif
#include <stdio.h>

#include "../common/shared.h"
#include "../sound/snd_local.h"

int             audio_fd;
int             snd_inited = 0;

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

cvar_t         *snddevice;

/* Some devices may work only with 48000 */
static int      tryrates[] = { 22050, 11025, 44100, 48000, 8000 };

static qboolean use_custom_memset = qfalse;

// https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=371 
void Snd_Memset(void *dest, const int val, const size_t count)
{
	int            *pDest;
	int             i, iterate;

	if(!use_custom_memset)
	{
		memset(dest, val, count);
		return;
	}
	iterate = count / sizeof(int);
	pDest = (int *)dest;
	for(i = 0; i < iterate; i++)
	{
		pDest[i] = val;
	}
}

qboolean SNDDMA_Init(void)
{
	int             rc;
	int             fmt;
	int             tmp;
	int             i;

	// char *s; // bk001204 - unused
	struct audio_buf_info info;
	int             caps;
	extern uid_t    saved_euid;

	if(snd_inited)
		return 1;

	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);
	}

	// open /dev/dsp, confirm capability to mmap, and get size of dma buffer
	if(!audio_fd)
	{
		seteuid(saved_euid);

		audio_fd = open(snddevice->string, O_RDWR);

		seteuid(getuid());

		if(audio_fd < 0)
		{
			perror(snddevice->string);
			Com_Printf("Could not open %s\n", snddevice->string);
			return 0;
		}
	}

	if(ioctl(audio_fd, SNDCTL_DSP_GETCAPS, &caps) == -1)
	{
		perror(snddevice->string);
		Com_Printf("Sound driver too old\n");
		close(audio_fd);
		return 0;
	}

	if(!(caps & DSP_CAP_TRIGGER) || !(caps & DSP_CAP_MMAP))
	{
		Com_Printf("Sorry but your soundcard can't do this\n");
		close(audio_fd);
		return 0;
	}


	/* SNDCTL_DSP_GETOSPACE moved to be called later */

	// set sample bits & speed
	dma.samplebits = (int)sndbits->value;
	if(dma.samplebits != 16 && dma.samplebits != 8)
	{
		ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &fmt);
		if(fmt & AFMT_S16_LE)
			dma.samplebits = 16;
		else if(fmt & AFMT_U8)
			dma.samplebits = 8;
	}

	dma.speed = (int)sndspeed->value;
	if(!dma.speed)
	{
		for(i = 0; i < sizeof(tryrates) / 4; i++)
			if(!ioctl(audio_fd, SNDCTL_DSP_SPEED, &tryrates[i]))
				break;
		dma.speed = tryrates[i];
	}

	dma.channels = (int)sndchannels->value;
	if(dma.channels < 1 || dma.channels > 2)
		dma.channels = 2;

/*  mmap() call moved forward */

	tmp = 0;
	if(dma.channels == 2)
		tmp = 1;
	rc = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
	if(rc < 0)
	{
		perror(snddevice->string);
		Com_Printf("Could not set %s to stereo=%d", snddevice->string, dma.channels);
		close(audio_fd);
		return 0;
	}

	if(tmp)
		dma.channels = 2;
	else
		dma.channels = 1;

	rc = ioctl(audio_fd, SNDCTL_DSP_SPEED, &dma.speed);
	if(rc < 0)
	{
		perror(snddevice->string);
		Com_Printf("Could not set %s speed to %d", snddevice->string, dma.speed);
		close(audio_fd);
		return 0;
	}

	if(dma.samplebits == 16)
	{
		rc = AFMT_S16_LE;
		rc = ioctl(audio_fd, SNDCTL_DSP_SETFMT, &rc);
		if(rc < 0)
		{
			perror(snddevice->string);
			Com_Printf("Could not support 16-bit data.  Try 8-bit.\n");
			close(audio_fd);
			return 0;
		}
	}
	else if(dma.samplebits == 8)
	{
		rc = AFMT_U8;
		rc = ioctl(audio_fd, SNDCTL_DSP_SETFMT, &rc);
		if(rc < 0)
		{
			perror(snddevice->string);
			Com_Printf("Could not support 8-bit data.\n");
			close(audio_fd);
			return 0;
		}
	}
	else
	{
		perror(snddevice->string);
		Com_Printf("%d-bit sound not supported.", dma.samplebits);
		close(audio_fd);
		return 0;
	}

	if(ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) == -1)
	{
		perror("GETOSPACE");
		Com_Printf("Um, can't do GETOSPACE?\n");
		close(audio_fd);
		return 0;
	}

	dma.samples = info.fragstotal * info.fragsize / (dma.samplebits / 8);
	dma.submission_chunk = 1;

	// memory map the dma buffer

	// TTimo 2001/10/08 added PROT_READ to the mmap
	// https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=371
	// checking Alsa bug, doesn't allow dma alloc with PROT_READ?

	if(!dma.buffer)
		dma.buffer = (unsigned char *)mmap(NULL, info.fragstotal
										   * info.fragsize, PROT_WRITE | PROT_READ, MAP_FILE | MAP_SHARED, audio_fd, 0);

	if(dma.buffer == MAP_FAILED)
	{
		Com_Printf("Could not mmap dma buffer PROT_WRITE|PROT_READ\n");
		Com_Printf("trying mmap PROT_WRITE (with associated better compatibility / less performance code)\n");
		dma.buffer = (unsigned char *)mmap(NULL, info.fragstotal * info.fragsize, PROT_WRITE, MAP_FILE | MAP_SHARED, audio_fd, 0);
		// NOTE TTimo could add a variable to force using regular memset on systems that are known to be safe
		use_custom_memset = qtrue;
	}

	if(dma.buffer == MAP_FAILED)
	{
		perror(snddevice->string);
		Com_Printf("Could not mmap %s\n", snddevice->string);
		close(audio_fd);
		return 0;
	}

	// toggle the trigger & start her up

	tmp = 0;
	rc = ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &tmp);
	if(rc < 0)
	{
		perror(snddevice->string);
		Com_Printf("Could not toggle.\n");
		close(audio_fd);
		return 0;
	}

	tmp = PCM_ENABLE_OUTPUT;
	rc = ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &tmp);
	if(rc < 0)
	{
		perror(snddevice->string);
		Com_Printf("Could not toggle.\n");
		close(audio_fd);

		return 0;
	}

	snd_inited = 1;
	return 1;
}

int SNDDMA_GetDMAPos(void)
{
	struct count_info count;

	if(!snd_inited)
		return 0;

	if(ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &count) == -1)
	{
		perror(snddevice->string);
		Com_Printf("Uh, sound dead.\n");
		close(audio_fd);
		snd_inited = 0;
		return 0;
	}
	return count.ptr / (dma.samplebits / 8);
}

void SNDDMA_Shutdown(void)
{
}

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

Send sound to device if buffer isn't really the dma buffer
===============
*/
void SNDDMA_Submit(void)
{
}

void SNDDMA_BeginPainting(void)
{
}
