/*

	alsa: sound output with Advanced Linux Sound Architecture 1.x API

	copyright 2006-2016 by the mpg123 project - free software under the terms of the LGPL 2.1

	see COPYING and AUTHORS files in distribution or http://mpg123.org

	initially written by Clemens Ladisch <clemens@ladisch.de>

*/

/* ALSA headers define struct timeval if no POSIX macro is set,

   nicely in conflict with definitions in system headers. They had

   a discussion about that a long time ago:

     http://mailman.alsa-project.org/pipermail/alsa-devel/2007-June/001684.html

   ... seems like the conclusion was not carried through.

 */

#define _POSIX_SOURCE

/* Things are still missing if _DEFAULT_SOURCE is not defined (for recent

   glibc, I presume. */

#define _DEFAULT_SOURCE

#include "out123_int.h"

#include <errno.h>

/* make ALSA 0.9.x compatible to the 1.0.x API */

#define ALSA_PCM_NEW_HW_PARAMS_API

#define ALSA_PCM_NEW_SW_PARAMS_API

#include <alloca.h> /* GCC complains about missing declaration of alloca. */

#include <alsa/asoundlib.h>

#include "debug.h"

/* Total buffer size in seconds, 0.2 is more true to what ALSA maximally uses

   here (8192 samples). The earlier default of 0.5 was never true. */

#define BUFFER_LENGTH (ao->device_buffer > 0. ? ao->device_buffer : 0.2)

static const struct {

	snd_pcm_format_t alsa;

	int mpg123;

} format_map[] = {

	{ SND_PCM_FORMAT_S16,    MPG123_ENC_SIGNED_16   },

	{ SND_PCM_FORMAT_U16,    MPG123_ENC_UNSIGNED_16 },

	{ SND_PCM_FORMAT_U8,     MPG123_ENC_UNSIGNED_8  },

	{ SND_PCM_FORMAT_S8,     MPG123_ENC_SIGNED_8    },

	{ SND_PCM_FORMAT_A_LAW,  MPG123_ENC_ALAW_8      },

	{ SND_PCM_FORMAT_MU_LAW, MPG123_ENC_ULAW_8      },

	{ SND_PCM_FORMAT_S32,    MPG123_ENC_SIGNED_32   },

	{ SND_PCM_FORMAT_U32,    MPG123_ENC_UNSIGNED_32 },

#ifdef WORDS_BIGENDIAN

	{ SND_PCM_FORMAT_S24_3BE, MPG123_ENC_SIGNED_24   },

	{ SND_PCM_FORMAT_U24_3BE, MPG123_ENC_UNSIGNED_24 },

#else

	{ SND_PCM_FORMAT_S24_3LE, MPG123_ENC_SIGNED_24   },

	{ SND_PCM_FORMAT_U24_3LE, MPG123_ENC_UNSIGNED_24 },

#endif

	{ SND_PCM_FORMAT_FLOAT,  MPG123_ENC_FLOAT_32    },

	{ SND_PCM_FORMAT_FLOAT64, MPG123_ENC_FLOAT_64   }

};

#define NUM_FORMATS (sizeof format_map / sizeof format_map[0])

static int rates_match(long int desired, unsigned int actual)

{

	return actual * 100 > desired * (100 - AUDIO_RATE_TOLERANCE) &&

	       actual * 100 < desired * (100 + AUDIO_RATE_TOLERANCE);

}

static int initialize_device(out123_handle *ao)

{

	snd_pcm_hw_params_t *hw=NULL;

	snd_pcm_sw_params_t *sw=NULL;

	snd_pcm_uframes_t buffer_size;

	snd_pcm_uframes_t period_size;

	snd_pcm_format_t format;

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	unsigned int rate;

	int i;

	snd_pcm_hw_params_alloca(&hw;; /* Ignore GCC warning here... alsa-lib>=1.0.16 doesn't trigger that anymore, too. */

	if (snd_pcm_hw_params_any(pcm, hw) < 0) {

		if(!AOQUIET) error("initialize_device(): no configuration available");

		return -1;

	}

	if (snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {

		if(!AOQUIET) error("initialize_device(): device does not support interleaved access");

		return -1;

	}

	format = SND_PCM_FORMAT_UNKNOWN;

	for (i = 0; i < NUM_FORMATS; ++i) {

		if (ao->format == format_map[i].mpg123) {

			format = format_map[i].alsa;

			break;

		}

	}

	if (format == SND_PCM_FORMAT_UNKNOWN) {

		if(!AOQUIET) error1("initialize_device(): invalid sample format %d", ao->format);

		errno = EINVAL;

		return -1;

	}

	if (snd_pcm_hw_params_set_format(pcm, hw, format) < 0) {

		if(!AOQUIET) error1("initialize_device(): cannot set format %s", snd_pcm_format_name(format));

		return -1;

	}

	if (snd_pcm_hw_params_set_channels(pcm, hw, ao->channels) < 0) {

		if(!AOQUIET) error1("initialize_device(): cannot set %d channels", ao->channels);

		return -1;

	}

	rate = ao->rate;

	if (snd_pcm_hw_params_set_rate_near(pcm, hw, &rate, NULL) < 0) {

		if(!AOQUIET) error1("initialize_device(): cannot set rate %u", rate);

		return -1;

	}

	if (!rates_match(ao->rate, rate)) {

		if(!AOQUIET) error2("initialize_device(): rate %ld not available, using %u", ao->rate, rate);

		/* return -1; */

	}

	buffer_size = rate * BUFFER_LENGTH;

	if (snd_pcm_hw_params_set_buffer_size_near(pcm, hw, &buffer_size) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set buffer size");

		return -1;

	}

	debug1("buffer_size=%lu", (unsigned long)buffer_size);

	period_size = buffer_size / 3; /* 3 periods is so much more common. */

	if (snd_pcm_hw_params_set_period_size_near(pcm, hw, &period_size, NULL) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set period size");

		return -1;

	}

	debug1("period_size=%lu", (unsigned long)period_size);

	if (snd_pcm_hw_params(pcm, hw) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set hw params");

		return -1;

	}

	snd_pcm_sw_params_alloca(&sw);

	if (snd_pcm_sw_params_current(pcm, sw) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot get sw params");

		return -1;

	}

	/* start playing right away */

	if (snd_pcm_sw_params_set_start_threshold(pcm, sw, 1) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set start threshold");

		return -1;

	}

	/* wake up on every interrupt */

	if (snd_pcm_sw_params_set_avail_min(pcm, sw, 1) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set min available");

		return -1;

	}

#if SND_LIB_VERSION < ((1<<16)|16)

	/* Always write as many frames as possible (deprecated since alsa-lib 1.0.16) */

	if (snd_pcm_sw_params_set_xfer_align(pcm, sw, 1) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set transfer alignment");

		return -1;

	}

#endif

	if (snd_pcm_sw_params(pcm, sw) < 0) {

		if(!AOQUIET) error("initialize_device(): cannot set sw params");

		return -1;

	}

	return 0;

}

#ifndef DEBUG

static void error_ignorer(const char *file, int line, const char *function, int err, const char *fmt,...)

{

	/* I can make ALSA silent. */

}

#endif

static int open_alsa(out123_handle *ao)

{

	const char *pcm_name;

	snd_pcm_t *pcm=NULL;

	debug1("open_alsa with %p", ao->userptr);

#ifndef DEBUG

	if(AOQUIET) snd_lib_error_set_handler(error_ignorer);

#endif

	pcm_name = ao->device ? ao->device : "default";

	if (snd_pcm_open(&pcm, pcm_name, SND_PCM_STREAM_PLAYBACK, 0) < 0) {

		if(!AOQUIET) error1("cannot open device %s", pcm_name);

		return -1;

	}

	ao->userptr = pcm;

	if (ao->format != -1) {

		/* we're going to play: initalize sample format */

		return initialize_device(ao);

	} else {

		/* query mode; sample format will be set for each query */

		return 0;

	}

}

static int get_formats_alsa(out123_handle *ao)

{

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	snd_pcm_hw_params_t *hw;

	unsigned int rate;

	int supported_formats, i;

	snd_pcm_hw_params_alloca(&hw;;

	if (snd_pcm_hw_params_any(pcm, hw) < 0) {

		if(!AOQUIET) error("get_formats_alsa(): no configuration available");

		return -1;

	}

	if (snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED) < 0)

		return -1;

	if (snd_pcm_hw_params_set_channels(pcm, hw, ao->channels) < 0)

		return 0;

	rate = ao->rate;

	if (snd_pcm_hw_params_set_rate_near(pcm, hw, &rate, NULL) < 0)

		return -1;

	if (!rates_match(ao->rate, rate))

		return 0;

	supported_formats = 0;

	for (i = 0; i < NUM_FORMATS; ++i) {

		if (snd_pcm_hw_params_test_format(pcm, hw, format_map[i].alsa) == 0)

			supported_formats |= format_map[i].mpg123;

	}

	return supported_formats;

}

static int write_alsa(out123_handle *ao, unsigned char *buf, int bytes)

{

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	snd_pcm_uframes_t frames;

	snd_pcm_sframes_t written;

	frames = snd_pcm_bytes_to_frames(pcm, bytes);

	while

	( /* Try to write, recover if error, try again if recovery successful. */

		(written = snd_pcm_writei(pcm, buf, frames)) < 0

		&& snd_pcm_recover(pcm, (int)written, 0) == 0

	)

	{

		debug2("recovered from alsa issue %i while trying to write %lu frames", (int)written, (unsigned long)frames);

	}

	if(written < 0)

	{

		error1("Fatal problem with alsa output, error %i.", (int)written);

		return -1;

	}

	else return snd_pcm_frames_to_bytes(pcm, written);

}

static void flush_alsa(out123_handle *ao)

{

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	/* is this the optimal solution? - we should figure out what we really whant from this function */

debug("alsa drop");

	snd_pcm_drop(pcm);

debug("alsa prepare");

	snd_pcm_prepare(pcm);

debug("alsa flush done");

}

static void drain_alsa(out123_handle *ao)

{

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	debug1("drain_alsa with %p", ao->userptr);

	snd_pcm_drain(pcm);

}

static int close_alsa(out123_handle *ao)

{

	snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

	debug1("close_alsa with %p", ao->userptr);

	if(pcm != NULL) /* be really generous for being called without any device opening */

	{

		ao->userptr = NULL; /* Should alsa do this or the module wrapper? */

		return snd_pcm_close(pcm);

	}

	else return 0;

}

static int init_alsa(out123_handle* ao)

{

	if (ao==NULL) return -1;

	/* Set callbacks */

	ao->open = open_alsa;

	ao->flush = flush_alsa;

	ao->drain = drain_alsa;

	ao->write = write_alsa;

	ao->get_formats = get_formats_alsa;

	ao->close = close_alsa;

	/* Success */

	return 0;

}

/* 

	Module information data structure

*/

mpg123_module_t mpg123_output_module_info = {

	/* api_version */	MPG123_MODULE_API_VERSION,

	/* name */			"alsa",						

	/* description */	"Output audio using Advanced Linux Sound Architecture (ALSA).",

	/* revision */		"$Rev:$",						

	/* handle */		NULL,

	/* init_output */	init_alsa,						

};