/* Sound device access
 *
 * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
 * All Rights Reserved
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdint.h>
#include <math.h>
#include <alsa/asoundlib.h>
#include "../libsample/sample.h"
#include "../liblogging/logging.h"
#ifdef HAVE_MOBILE
#include "../libmobile/sender.h"
#else
#include "sound.h"
#endif

static int KEEP_FRAMES=8;		/* minimum frames not to read, to prevent reading from buffer before data has been received (seems to be a bug in ALSA) */

typedef struct sound {
	enum sound_direction direction;
	snd_pcm_t *phandle, *chandle;
	int pchannels, cchannels;
	int channels;			/* required number of channels */
	int samplerate;			/* required sample rate */
	char *caudiodev, *paudiodev;	/* required device */
	double spl_deviation;		/* how much deviation is one sample step */
#ifdef HAVE_MOBILE
	double paging_phaseshift;	/* phase to shift every sample */
	double paging_phase;	 	/* current phase */
	double rx_frequency[2];		/* rx frequency of radio connected to channel */
	dispmeasparam_t *dmp[2];
#endif
} sound_t;

static int set_hw_params(snd_pcm_t *handle, int samplerate, int *channels)
{
	snd_pcm_hw_params_t *hw_params = NULL;
	int rc;
	unsigned int rrate;

	rc = snd_pcm_hw_params_malloc(&hw_params);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "Failed to allocate hw_params! (%s)\n", snd_strerror(rc));
		goto error;
	}

	rc = snd_pcm_hw_params_any(handle, hw_params);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot initialize hardware parameter structure (%s)\n", snd_strerror(rc));
		goto error;
	}

	rc = snd_pcm_hw_params_set_rate_resample(handle, hw_params, 0);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot set real hardware rate (%s)\n", snd_strerror(rc));
		goto error;
	}

	rc = snd_pcm_hw_params_set_access (handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot set access to interleaved (%s)\n", snd_strerror(rc));
		goto error;
	}

	rc = snd_pcm_hw_params_set_format(handle, hw_params, SND_PCM_FORMAT_S16);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot set sample format (%s)\n", snd_strerror(rc));
		goto error;
	}

	rrate = samplerate;
	rc = snd_pcm_hw_params_set_rate_near(handle, hw_params, &rrate, 0);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot set sample rate (%s)\n", snd_strerror(rc));
		goto error;
	}
	if ((int)rrate != samplerate) {
		LOGP(DSOUND, LOGL_ERROR, "Rate doesn't match (requested %dHz, get %dHz)\n", samplerate, rrate);
		rc = -EIO;
		goto error;
	}

	*channels = 1;
	rc = snd_pcm_hw_params_set_channels(handle, hw_params, *channels);
	if (rc < 0) {
		*channels = 2;
		rc = snd_pcm_hw_params_set_channels(handle, hw_params, *channels);
		if (rc < 0) {
			LOGP(DSOUND, LOGL_ERROR, "cannot set channel count to 1 nor 2 (%s)\n", snd_strerror(rc));
			goto error;
		}
	}

	rc = snd_pcm_hw_params(handle, hw_params);
	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "cannot set parameters (%s)\n", snd_strerror(rc));
		goto error;
	}

	snd_pcm_hw_params_free(hw_params);

	return 0;

error:
	if (hw_params) {
		snd_pcm_hw_params_free(hw_params);
	}

	return rc;
}

static int dev_open(sound_t *sound)
{
	int rc, rc_rec = 0, rc_play = 0;

	if (sound->direction == SOUND_DIR_PLAY || sound->direction == SOUND_DIR_DUPLEX) {
		rc_play = snd_pcm_open(&sound->phandle, sound->paudiodev, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
		if (rc_play < 0)
			LOGP(DSOUND, LOGL_ERROR, "Failed to open '%s' for playback! (%s) Please select a device that supports playing audio.\n", sound->paudiodev, snd_strerror(rc_play));
	}
	if (sound->direction == SOUND_DIR_REC || sound->direction == SOUND_DIR_DUPLEX) {
		rc_rec = snd_pcm_open(&sound->chandle, sound->caudiodev, SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK);
		if (rc_rec < 0)
			LOGP(DSOUND, LOGL_ERROR, "Failed to open '%s' for capture! (%s) Please select a device that supports capturing audio.\n", sound->caudiodev, snd_strerror(rc_rec));
	}
	if (rc_play < 0 || rc_rec < 0)
		return (rc_play < 0) ? rc_play : rc_rec;

	if (sound->direction == SOUND_DIR_PLAY || sound->direction == SOUND_DIR_DUPLEX) {
		rc = set_hw_params(sound->phandle, sound->samplerate, &sound->pchannels);
		if (rc < 0) {
			LOGP(DSOUND, LOGL_ERROR, "Failed to set playback hw params\n");
			return rc;
		}
		if (sound->pchannels < sound->channels) {
			LOGP(DSOUND, LOGL_ERROR, "Sound card only supports %d channel for playback.\n", sound->pchannels);
			return rc;
		}
		LOGP(DSOUND, LOGL_DEBUG, "Playback with %d channels.\n", sound->pchannels);

		rc = snd_pcm_prepare(sound->phandle);
		if (rc < 0) {
			LOGP(DSOUND, LOGL_ERROR, "cannot prepare audio interface for use (%s)\n", snd_strerror(rc));
			return rc;
		}
	}

	if (sound->direction == SOUND_DIR_REC || sound->direction == SOUND_DIR_DUPLEX) {
		rc = set_hw_params(sound->chandle, sound->samplerate, &sound->cchannels);
		if (rc < 0) {
			LOGP(DSOUND, LOGL_ERROR, "Failed to set capture hw params\n");
			return rc;
		}
		if (sound->cchannels < sound->channels) {
			LOGP(DSOUND, LOGL_ERROR, "Sound card only supports %d channel for capture.\n", sound->cchannels);
			return -EIO;
		}
		LOGP(DSOUND, LOGL_DEBUG, "Capture with %d channels.\n", sound->cchannels);

		rc = snd_pcm_prepare(sound->chandle);
		if (rc < 0) {
			LOGP(DSOUND, LOGL_ERROR, "cannot prepare audio interface for use (%s)\n", snd_strerror(rc));
			return rc;
		}
	}

	return 0;
}

static void dev_close(sound_t *sound)
{
	if (sound->phandle != NULL)
		snd_pcm_close(sound->phandle);
	if (sound->chandle != NULL)
		snd_pcm_close(sound->chandle);
}

void *sound_open(int direction, const char *audiodev, double __attribute__((unused)) *tx_frequency, double __attribute__((unused)) *rx_frequency, int __attribute__((unused)) *am, int channels, double __attribute__((unused)) paging_frequency, int samplerate, int __attribute((unused)) buffer_size, double __attribute__((unused)) interval, double max_deviation, double __attribute__((unused)) max_modulation, double __attribute__((unused)) modulation_index)
{
	sound_t *sound;
	const char *env;
	char *p;
	int rc;

	if (channels < 1 || channels > 2) {
		LOGP(DSOUND, LOGL_ERROR, "Cannot use more than two channels with the same sound card!\n");
		return NULL;
	}

	sound = calloc(1, sizeof(sound_t));
	if (!sound) {
		LOGP(DSOUND, LOGL_ERROR, "Failed to alloc memory!\n");
		return NULL;
	}

	sound->paudiodev = strdup(audiodev); // is feed when closed
	if ((p = strchr(sound->paudiodev, '/'))) {
		*p++ = '\0';
		sound->caudiodev = p;
	} else {
		sound->caudiodev = sound->paudiodev;
	}
	sound->direction = direction;
	sound->channels = channels;
	sound->samplerate = samplerate;
	sound->spl_deviation = max_deviation / 32767.0;
#ifdef HAVE_MOBILE
	sound->paging_phaseshift = 1.0 / ((double)samplerate / 1000.0);
#endif

	rc = dev_open(sound);
	if (rc < 0)
		goto error;

#ifdef HAVE_MOBILE
	if (rx_frequency) {
		sender_t *sender;
		int i;
		for (i = 0; i < channels; i++) {
			sound->rx_frequency[i] = rx_frequency[i];
			sender = get_sender_by_empfangsfrequenz(sound->rx_frequency[i]);
			if (!sender)
				continue;
			sound->dmp[i] = display_measurements_add(&sender->dispmeas, "RX Level", "%.1f dB", DISPLAY_MEAS_PEAK, DISPLAY_MEAS_LEFT, -96.0, 0.0, -INFINITY);
		}
	}
#endif

	if ((env = getenv("KEEP_FRAMES"))) {
		KEEP_FRAMES = atoi(env);
		LOGP(DSOUND, LOGL_NOTICE, "KEEP %d samples in RX buffer, to prevent corrupt read.\n", KEEP_FRAMES);
	}

	return sound;

error:
	sound_close(sound);
	return NULL;
}

/* start streaming */
int sound_start(void *inst)
{
	sound_t *sound = (sound_t *)inst;
	int16_t buff[2];

	if (sound->direction != SOUND_DIR_REC && sound->direction != SOUND_DIR_DUPLEX)
		return -EINVAL;

	/* trigger capturing */
	snd_pcm_readi(sound->chandle, buff, 1);

	return 0;
}

void sound_close(void *inst)
{
	sound_t *sound = (sound_t *)inst;

	dev_close(sound);
	free(sound->paudiodev);
	free(sound);
}

#ifdef HAVE_MOBILE
static void gen_paging_tone(sound_t *sound, int16_t *samples, int length, enum paging_signal paging_signal, int on)
{
	double phaseshift, phase;
	int i;

	switch (paging_signal) {
	case PAGING_SIGNAL_NOTONE:
		/* no tone if paging signal is on */
		on = !on;
		/* FALLTHRU */
	case PAGING_SIGNAL_TONE:
		/* tone if paging signal is on */
		if (on) {
			phaseshift = sound->paging_phaseshift;
			phase = sound->paging_phase;
			for (i = 0; i < length; i++) {
				if (phase < 0.5)
					*samples++ = 30000;
				else
					*samples++ = -30000;
				phase += phaseshift;
				if (phase >= 1.0)
					phase -= 1.0;
			}
			sound->paging_phase = phase;
		} else
			memset(samples, 0, length << 1);
		break;
	case PAGING_SIGNAL_NEGATIVE:
		/* negative signal if paging signal is on */
		on = !on;
		/* FALLTHRU */
	case PAGING_SIGNAL_POSITIVE:
		/* positive signal if paging signal is on */
		if (on)
			memset(samples, 127, length << 1);
		else
			memset(samples, 128, length << 1);
		break;
	case PAGING_SIGNAL_NONE:
		break;
	}
}
#endif

int sound_write(void *inst, sample_t **samples, uint8_t __attribute__((unused)) **power, int num, enum paging_signal __attribute__((unused)) *paging_signal, int __attribute__((unused)) *on, int channels)
{
	sound_t *sound = (sound_t *)inst;
	double spl_deviation = sound->spl_deviation;
	int32_t value;
	int16_t buff[num << 1];
	int rc;
	int i, ii;

	if (sound->direction != SOUND_DIR_PLAY && sound->direction != SOUND_DIR_DUPLEX)
		return -EINVAL;

	if (sound->pchannels == 2) {
		/* two channels */
#ifdef HAVE_MOBILE
		if (paging_signal && on && paging_signal[0] != PAGING_SIGNAL_NONE) {
			int16_t paging[num << 1];
			gen_paging_tone(sound, paging, num, paging_signal[0], on[0]);
			for (i = 0, ii = 0; i < num; i++) {
				value = samples[0][i] / spl_deviation;
				if (value > 32767)
					value = 32767;
				else if (value < -32767)
					value = -32767;
				buff[ii++] = value;
				buff[ii++] = paging[i];
			}
		} else
#endif
		if (channels == 2) {
			for (i = 0, ii = 0; i < num; i++) {
				value = samples[0][i] / spl_deviation;
				if (value > 32767)
					value = 32767;
				else if (value < -32767)
					value = -32767;
				buff[ii++] = value;
				value = samples[1][i] / spl_deviation;
				if (value > 32767)
					value = 32767;
				else if (value < -32767)
					value = -32767;
				buff[ii++] = value;
			}
		} else {
			for (i = 0, ii = 0; i < num; i++) {
				value = samples[0][i] / spl_deviation;
				if (value > 32767)
					value = 32767;
				else if (value < -32767)
					value = -32767;
				buff[ii++] = value;
				buff[ii++] = value;
			}
		}
	} else {
		/* one channel */
		for (i = 0, ii = 0; i < num; i++) {
			value = samples[0][i] / spl_deviation;
			if (value > 32767)
				value = 32767;
			else if (value < -32767)
				value = -32767;
			buff[ii++] = value;
		}
	}
	rc = snd_pcm_writei(sound->phandle, buff, num);

	if (rc < 0) {
		LOGP(DSOUND, LOGL_ERROR, "failed to write audio to interface (%s)\n", snd_strerror(rc));
		if (rc == -EPIPE) {
			dev_close(sound);
			rc = dev_open(sound);
			if (rc < 0)
				return rc;
			sound_start(sound);
			return -EPIPE; /* indicate what happened */
		}
		return rc;
	}

	if (rc != num)
		LOGP(DSOUND, LOGL_ERROR, "short write to audio interface, written %d bytes, got %d bytes\n", num, rc);

	return rc;
}

int sound_read(void *inst, sample_t **samples, int num, int channels, double *rf_level_db)
{
	sound_t *sound = (sound_t *)inst;
	double spl_deviation = sound->spl_deviation;
	int16_t buff[num << 1];
	int32_t spl;
	int32_t max[2], a;
	int in, rc;
	int i, ii;

	if (sound->direction != SOUND_DIR_REC && sound->direction != SOUND_DIR_DUPLEX)
		return -EINVAL;

	/* get samples in rx buffer */
	in = snd_pcm_avail(sound->chandle);
	/* if not more than KEEP_FRAMES frames available, try next time */
	if (in <= KEEP_FRAMES)
		return 0;
	/* read some frames less than in buffer, because snd_pcm_readi() seems
	 * to corrupt last frames */
	in -= KEEP_FRAMES;
	if (in > num)
		in = num;

	/* make valgrind happy, because snd_pcm_readi() does not seem to initially fill buffer with values */
	memset(buff, 0, sizeof(*buff) * sound->cchannels * in);

	rc = snd_pcm_readi(sound->chandle, buff, in);
	if (rc < 0) {
		if (errno == EAGAIN)
			return 0;
		LOGP(DSOUND, LOGL_ERROR, "failed to read audio from interface (%s)\n", snd_strerror(rc));
		/* recover read */
		if (rc == -EPIPE) {
			dev_close(sound);
			rc = dev_open(sound);
			if (rc < 0)
				return rc;
			sound_start(sound);
			return -EPIPE; /* indicate what happened */
		}
		return rc;
	}
	if (rc == 0)
		return rc;
	if (sound->cchannels == 2) {
		if (channels < 2) {
			for (i = 0, ii = 0; i < rc; i++) {
				spl = buff[ii++];
				spl += buff[ii++];
				a = (spl >= 0) ? spl : -spl;
				if (i == 0 || a > max[0])
					max[0] = a;
				samples[0][i] = (double)spl * spl_deviation;
			}
		} else {
			for (i = 0, ii = 0; i < rc; i++) {
				spl = buff[ii++];
				a = (spl >= 0) ? spl : -spl;
				if (i == 0 || a > max[0])
					max[0] = a;
				samples[0][i] = (double)spl * spl_deviation;
				spl = buff[ii++];
				a = (spl >= 0) ? spl : -spl;
				if (i == 0 || a > max[1])
					max[1] = a;
				samples[1][i] = (double)spl * spl_deviation;
			}
		}
	} else {
		for (i = 0, ii = 0; i < rc; i++) {
			spl = buff[ii++];
			a = (spl >= 0) ? spl : -spl;
			if (i == 0 || a > max[0])
				max[0] = a;
			samples[0][i] = (double)spl * spl_deviation;
		}
	}

#ifdef HAVE_MOBILE
	sender_t *sender;
	for (i = 0; i < channels; i++) {
		if (rf_level_db)
			rf_level_db[i] = NAN;
		sender = get_sender_by_empfangsfrequenz(sound->rx_frequency[i]);
		if (!sender)
			continue;
		display_measurements_update(sound->dmp[i], log10((double)max[i] / 32768.0) * 20, 0.0);
	}
#else
	for (i = 0; i < channels; i++) {
		if (rf_level_db)
			rf_level_db[i] = NAN;
	}
#endif

	return rc;
}

/* 
 * get playback buffer space
 *
 * return number of samples to be sent */
int sound_get_tosend(void *inst, int buffer_size)
{
	sound_t *sound = (sound_t *)inst;
	int rc;
	snd_pcm_sframes_t delay;
	int tosend;

	if (sound->direction != SOUND_DIR_PLAY && sound->direction != SOUND_DIR_DUPLEX)
		return -EINVAL;

	rc = snd_pcm_delay(sound->phandle, &delay);
	if (rc < 0) {
		if (rc == -32)
			LOGP(DSOUND, LOGL_ERROR, "Buffer underrun: Please use higher buffer and enable real time scheduling\n");
		else
			LOGP(DSOUND, LOGL_ERROR, "failed to get delay from interface (%s)\n", snd_strerror(rc));
		if (rc == -EPIPE) {
			dev_close(sound);
			rc = dev_open(sound);
			if (rc < 0)
				return rc;
			sound_start(sound);
			return -EPIPE; /* indicate what happened */
		}
		return rc;
	}

	tosend = buffer_size - delay;
	if (tosend < 0)
		tosend = 0;
	return tosend;
}

int sound_is_stereo_capture(void *inst)
{
	sound_t *sound = (sound_t *)inst;

	if (sound->cchannels == 2)
		return 1;
	return 0;
}

int sound_is_stereo_playback(void *inst)
{
	sound_t *sound = (sound_t *)inst;

	if (sound->pchannels == 2)
		return 1;
	return 0;
}