/**
 * @file vumeter.c  VU-meter
 *
 * Copyright (C) 2010 Creytiv.com
 */
#include <string.h>
#include <stdlib.h>
#include <re.h>
#include <baresip.h>


/**
 * @defgroup vumeter vumeter
 *
 * Simple ASCII VU-meter for the audio-signal.
 *
 * The Volume unit (VU) meter module takes the audio-signal as input
 * and prints a simple ASCII-art bar for the recording and playback levels.
 * It is using the aufilt API to get the audio samples.
 */


struct vumeter_enc {
	struct aufilt_enc_st af;  /* inheritance */
	struct tmr tmr;
	int16_t avg_rec;
	volatile bool started;
};

struct vumeter_dec {
	struct aufilt_dec_st af;  /* inheritance */
	struct tmr tmr;
	int16_t avg_play;
	volatile bool started;
};


static void enc_destructor(void *arg)
{
	struct vumeter_enc *st = arg;

	list_unlink(&st->af.le);
	tmr_cancel(&st->tmr);
}


static void dec_destructor(void *arg)
{
	struct vumeter_dec *st = arg;

	list_unlink(&st->af.le);
	tmr_cancel(&st->tmr);
}


static int16_t calc_avg_s16(const int16_t *sampv, size_t sampc)
{
	int32_t v = 0;
	size_t i;

	if (!sampv || !sampc)
		return 0;

	for (i=0; i<sampc; i++)
		v += abs(sampv[i]);

	return v/sampc;
}


static int audio_print_vu(struct re_printf *pf, int16_t *avg)
{
	char buf[16];
	size_t res;

	res = min(2 * sizeof(buf) * (*avg)/0x8000,
		  sizeof(buf)-1);

	memset(buf, '=', res);
	buf[res] = '\0';

	return re_hprintf(pf, "[%-16s]", buf);
}


static void print_vumeter(int pos, int color, int value)
{
	/* move cursor to a fixed position */
	re_fprintf(stderr, "\x1b[%dG", pos);

	/* print VU-meter in Nice colors */
	re_fprintf(stderr, " \x1b[%dm%H\x1b[;m\r",
		   color, audio_print_vu, &value);
}


static void enc_tmr_handler(void *arg)
{
	struct vumeter_enc *st = arg;

	tmr_start(&st->tmr, 100, enc_tmr_handler, st);

	if (st->started)
		print_vumeter(60, 31, st->avg_rec);
}


static void dec_tmr_handler(void *arg)
{
	struct vumeter_dec *st = arg;

	tmr_start(&st->tmr, 100, dec_tmr_handler, st);

	if (st->started)
		print_vumeter(80, 32, st->avg_play);
}


static int encode_update(struct aufilt_enc_st **stp, void **ctx,
			 const struct aufilt *af, struct aufilt_prm *prm)
{
	struct vumeter_enc *st;
	(void)ctx;
	(void)prm;

	if (!stp || !af)
		return EINVAL;

	if (*stp)
		return 0;

	st = mem_zalloc(sizeof(*st), enc_destructor);
	if (!st)
		return ENOMEM;

	tmr_start(&st->tmr, 100, enc_tmr_handler, st);

	*stp = (struct aufilt_enc_st *)st;

	return 0;
}


static int decode_update(struct aufilt_dec_st **stp, void **ctx,
			 const struct aufilt *af, struct aufilt_prm *prm)
{
	struct vumeter_dec *st;
	(void)ctx;
	(void)prm;

	if (!stp || !af)
		return EINVAL;

	if (*stp)
		return 0;

	st = mem_zalloc(sizeof(*st), dec_destructor);
	if (!st)
		return ENOMEM;

	tmr_start(&st->tmr, 100, dec_tmr_handler, st);

	*stp = (struct aufilt_dec_st *)st;

	return 0;
}


static int encode(struct aufilt_enc_st *st, int16_t *sampv, size_t *sampc)
{
	struct vumeter_enc *vu = (void *)st;

	vu->avg_rec = calc_avg_s16(sampv, *sampc);
	vu->started = true;

	return 0;
}


static int decode(struct aufilt_dec_st *st, int16_t *sampv, size_t *sampc)
{
	struct vumeter_dec *vu = (void *)st;

	vu->avg_play = calc_avg_s16(sampv, *sampc);
	vu->started = true;

	return 0;
}


static struct aufilt vumeter = {
	LE_INIT, "vumeter", encode_update, encode, decode_update, decode
};


static int module_init(void)
{
	aufilt_register(&vumeter);
	return 0;
}


static int module_close(void)
{
	aufilt_unregister(&vumeter);
	return 0;
}


EXPORT_SYM const struct mod_export DECL_EXPORTS(vumeter) = {
	"vumeter",
	"filter",
	module_init,
	module_close
};