/*
	snd_alsa_0_9.c

	Support for ALSA 0.9 sound driver (cvs development version)

	Copyright (C) 1999,2000  contributors of the QuakeForge project
	Please see the file "AUTHORS" for a list of contributors

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

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

#include <stdio.h>

#include <sys/asoundlib.h>

#include "QF/qtypes.h"
#include "QF/sound.h"
#include "QF/qargs.h"
#include "QF/console.h"

static int  snd_inited;

static snd_pcm_t *pcm;
static const snd_pcm_channel_area_t *mmap_areas;
static char *pcmname = NULL;
size_t      buffer_size;

qboolean
SNDDMA_Init (void)
{
	int         err;
	int         rate = -1, bps = -1, stereo = -1, frag_size;
	snd_pcm_hw_params_t *hw;
	snd_pcm_sw_params_t *sw;

	snd_pcm_hw_params_alloca (&hw);
	snd_pcm_sw_params_alloca (&sw);

	if (snd_device->string[0])
		pcmname = snd_device->string;
	if (snd_bits->int_val) {
		bps = snd_bits->int_val;
		if (bps != 16 && bps != 8) {
			Con_Printf ("Error: invalid sample bits: %d\n", bps);
			return 0;
		}
	}
	if (snd_rate->int_val) {
		rate = snd_rate->int_val;
		if (rate != 44100 && rate != 22050 && rate != 11025) {
			Con_Printf ("Error: invalid sample rate: %d\n", rate);
			return 0;
		}
	}
	stereo = snd_stereo->int_val;
	if (!pcmname)
		pcmname = "plug:0,0";
	if ((err = snd_pcm_open (&pcm, pcmname,
							 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0) {
		Con_Printf ("Error: audio open error: %s\n", snd_strerror (err));
		return 0;
	}

	Con_Printf ("Using PCM %s.\n", pcmname);
	snd_pcm_hw_params_any (pcm, hw);


	switch (rate) {
		case -1:
			if (snd_pcm_hw_params_set_rate_near (pcm, hw, 44100, 0) >= 0) {
				frag_size = 256;		/* assuming stereo 8 bit */
				rate = 44100;
			} else if (snd_pcm_hw_params_set_rate_near (pcm, hw, 22050, 0) >= 0) {
				frag_size = 128;		/* assuming stereo 8 bit */
				rate = 22050;
			} else if (snd_pcm_hw_params_set_rate_near (pcm, hw, 11025, 0) >= 0) {
				frag_size = 64;			/* assuming stereo 8 bit */
				rate = 11025;
			} else {
				Con_Printf ("ALSA: no useable rates\n");
				goto error;
			}
			break;
		case 11025:
		case 22050:
		case 44100:
			if (snd_pcm_hw_params_set_rate_near (pcm, hw, rate, 0) >= 0) {
				frag_size = 64 * rate / 11025;	/* assuming stereo 8 bit */
				break;
			}
			/* Fall through */
		default:
			Con_Printf ("ALSA: desired rate not supported\n");
			goto error;
	}

	switch (bps) {
		case -1:
			if (snd_pcm_hw_params_set_format (pcm, hw, SND_PCM_FORMAT_S16_LE) >=
				0) {
				bps = 16;
			} else if (snd_pcm_hw_params_set_format (pcm, hw, SND_PCM_FORMAT_U8)
					   >= 0) {
				bps = 8;
			} else {
				Con_Printf ("ALSA: no useable formats\n");
				goto error;
			}
			break;
		case 8:
		case 16:
			if (snd_pcm_hw_params_set_format (pcm, hw,
											  bps == 8 ? SND_PCM_FORMAT_U8 :
											  SND_PCM_FORMAT_S16) >= 0) {
				break;
			}
			/* Fall through */
		default:
			Con_Printf ("ALSA: desired format not supported\n");
			goto error;
	}

	if (snd_pcm_hw_params_set_access (pcm, hw,
									  SND_PCM_ACCESS_MMAP_INTERLEAVED) < 0) {
		Con_Printf ("ALSA: interleaved is not supported\n");
		goto error;
	}

	switch (stereo) {
		case -1:
			if (snd_pcm_hw_params_set_channels (pcm, hw, 2) >= 0) {
				stereo = 1;
			} else if (snd_pcm_hw_params_set_channels (pcm, hw, 1) >= 0) {
				stereo = 0;
			} else {
				Con_Printf ("ALSA: no useable channels\n");
				goto error;
			}
			break;
		case 0:
		case 1:
			if (snd_pcm_hw_params_set_channels (pcm, hw, stereo ? 2 : 1) >= 0)
				break;
			/* Fall through */
		default:
			Con_Printf ("ALSA: desired channels not supported\n");
			goto error;
	}

	snd_pcm_hw_params_set_period_size_near (pcm, hw, frag_size, 0);

	err = snd_pcm_hw_params (pcm, hw);
	if (err < 0) {
		Con_Printf ("ALSA: unable to install hw params\n");
		goto error;
	}

	snd_pcm_sw_params_current (pcm, sw);
	snd_pcm_sw_params_set_start_mode (pcm, sw, SND_PCM_START_EXPLICIT);
	snd_pcm_sw_params_set_xrun_mode (pcm, sw, SND_PCM_XRUN_NONE);

	err = snd_pcm_sw_params (pcm, sw);
	if (err < 0) {
		Con_Printf ("ALSA: unable to install sw params\n");
		goto error;
	}

	mmap_areas = snd_pcm_mmap_running_areas (pcm);

	shm = &sn;
	memset ((dma_t *) shm, 0, sizeof (*shm));
	shm->splitbuffer = 0;
	shm->channels = stereo + 1;
	shm->submission_chunk = snd_pcm_hw_params_get_period_size (hw, 0);	// don't 
																		// mix 
																		// less 
																		// than 
																		// this 
																		// #
	shm->samplepos = 0;					// in mono samples
	shm->samplebits = bps;
	buffer_size = snd_pcm_hw_params_get_buffer_size (hw);
	shm->samples = buffer_size * shm->channels;	// mono samples in buffer
	shm->speed = rate;
	shm->buffer = (unsigned char *) mmap_areas->addr;
	Con_Printf ("%5d stereo\n", shm->channels - 1);
	Con_Printf ("%5d samples\n", shm->samples);
	Con_Printf ("%5d samplepos\n", shm->samplepos);
	Con_Printf ("%5d samplebits\n", shm->samplebits);
	Con_Printf ("%5d submission_chunk\n", shm->submission_chunk);
	Con_Printf ("%5d speed\n", shm->speed);
	Con_Printf ("0x%x dma buffer\n", (int) shm->buffer);
	Con_Printf ("%5d total_channels\n", total_channels);

	snd_inited = 1;
	return 1;
  error:
	snd_pcm_close (pcm);
	return 0;
}

static inline int
get_hw_ptr ()
{
	size_t      app_ptr;
	snd_pcm_sframes_t delay;
	int         hw_ptr;

	if (snd_pcm_state (pcm) != SND_PCM_STATE_RUNNING)
		return 0;
	app_ptr = snd_pcm_mmap_offset (pcm);
	snd_pcm_delay (pcm, &delay);
	hw_ptr = app_ptr - delay;
	if (hw_ptr < 0)
		hw_ptr += buffer_size;
	return hw_ptr;
}

int
SNDDMA_GetDMAPos (void)
{
	int         hw_ptr;

	if (!snd_inited)
		return 0;

	hw_ptr = get_hw_ptr ();
	hw_ptr *= shm->channels;
	shm->samplepos = hw_ptr;
	return shm->samplepos;
}

void
SNDDMA_Shutdown (void)
{
	if (snd_inited) {
		snd_pcm_close (pcm);
		snd_inited = 0;
	}
}

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

Send sound to device if buffer isn't really the dma buffer
===============
*/
void
SNDDMA_Submit (void)
{
	int         count = paintedtime - soundtime;
	int         avail;
	int         missed;
	int         state;
	int         hw_ptr;
	int         offset;

	state = snd_pcm_state (pcm);

	switch (state) {
		case SND_PCM_STATE_PREPARED:
			snd_pcm_mmap_forward (pcm, count);
			snd_pcm_start (pcm);
			break;
		case SND_PCM_STATE_RUNNING:
			hw_ptr = get_hw_ptr ();
			missed = hw_ptr - shm->samplepos / shm->channels;
			if (missed < 0)
				missed += buffer_size;
			count -= missed;
			offset = snd_pcm_mmap_offset (pcm);
			if (offset > hw_ptr)
				count -= (offset - hw_ptr);
			else
				count -= (buffer_size - hw_ptr + offset);
			if (count < 0) {
				snd_pcm_rewind (pcm, -count);
			} else {
				avail = snd_pcm_avail_update (pcm);
				if (avail < 0)
					avail = buffer_size;
				if (count > avail)
					count = avail;
				snd_pcm_mmap_forward (pcm, count);
			}
			break;
		default:
			break;
	}
}