/*
 * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
 * Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
 * Copyright (C) 2012 by Hoernchen <la@tfc-server.de>
 * Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com>
 * Copyright (C) 2013 by Elias Oenal <EliasOenal@gmail.com>
 * Copyright (C) 2014 by Kyle Keen <keenerd@gmail.com>
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <signal.h>
#include <pthread.h>
#include <unistd.h>
#include <queue>
#include <rtl-sdr.h>
#include "dsd.h"

#define DEFAULT_SAMPLE_RATE		48000
#define DEFAULT_BUF_LENGTH		(1 * 16384)
#define MAXIMUM_OVERSAMPLE		16
#define MAXIMUM_BUF_LENGTH		(MAXIMUM_OVERSAMPLE * DEFAULT_BUF_LENGTH)
#define AUTO_GAIN			-100
#define BUFFER_DUMP		4096

#define FREQUENCIES_LIMIT		  1000

static int lcm_post[17] = {1,1,1,3,1,5,3,7,1,9,5,11,3,13,7,15,1};
static int ACTUAL_BUF_LENGTH;

static int *atan_lut = NULL;
static int atan_lut_size = 131072; /* 512 KB */
static int atan_lut_coef = 8;

//UDP -- keep for compatibility reasons
#include <netinet/in.h>
#include <arpa/inet.h>
static pthread_t socket_freq;

int rtl_bandwidth;
int bandwidth_multiplier;
int bandwidth_divisor = 48000; //divide bandwidth by this to get multiplier for the for j loop to queue.push

short int volume_multiplier;
short int port;

struct dongle_state
{
	int      exit_flag;
	pthread_t thread;
	rtlsdr_dev_t *dev;
	int      dev_index;
	uint32_t freq;
	uint32_t rate;
	int      gain;
	uint16_t buf16[MAXIMUM_BUF_LENGTH];
	uint32_t buf_len;
	int      ppm_error;
	int      offset_tuning;
	int      direct_sampling;
	int      mute;
	struct demod_state *demod_target;
};

struct demod_state
{
	int      exit_flag;
	pthread_t thread;
	int16_t  lowpassed[MAXIMUM_BUF_LENGTH];
	int      lp_len;
	int16_t  lp_i_hist[10][6];
	int16_t  lp_q_hist[10][6];
	int16_t  result[MAXIMUM_BUF_LENGTH];
	int16_t  droop_i_hist[9];
	int16_t  droop_q_hist[9];
	int      result_len;
	int      rate_in;
	int      rate_out;
	int      rate_out2;
	int      now_r, now_j;
	int      pre_r, pre_j;
	int      prev_index;
	int      downsample;    /* min 1, max 256 */
	int      post_downsample;
	int      output_scale;
	int      squelch_level, conseq_squelch, squelch_hits, terminate_on_squelch;
	int      downsample_passes;
	int      comp_fir_size;
	int      custom_atan;
	int      deemph, deemph_a;
	int      now_lpr;
	int      prev_lpr_index;
	int      dc_block, dc_avg;
	void     (*mode_demod)(struct demod_state*);
	pthread_rwlock_t rw;
	pthread_cond_t ready;
	pthread_mutex_t ready_m;
	struct output_state *output_target;
};

struct output_state
{
	int      rate;
	std::queue<int16_t> queue;
	pthread_rwlock_t rw;
	pthread_cond_t ready;
	pthread_mutex_t ready_m;
};

struct controller_state
{
	int      exit_flag;
	pthread_t thread;
	uint32_t freqs[FREQUENCIES_LIMIT];
	int      freq_len;
	int      freq_now;
	int      edge;
	int      wb_mode;
	pthread_cond_t hop;
	pthread_mutex_t hop_m;
};

struct dongle_state dongle;
struct demod_state demod;
struct output_state output;
struct controller_state controller;

#define safe_cond_signal(n, m) pthread_mutex_lock(m); pthread_cond_signal(n); pthread_mutex_unlock(m)
#define safe_cond_wait(n, m) pthread_mutex_lock(m); pthread_cond_wait(n, m); pthread_mutex_unlock(m)

/* {length, coef, coef, coef}  and scaled by 2^15
   for now, only length 9, optimal way to get +85% bandwidth */
#define CIC_TABLE_MAX 10
int cic_9_tables[][10] = {
	{0,},
	{9, -156,  -97, 2798, -15489, 61019, -15489, 2798,  -97, -156},
	{9, -128, -568, 5593, -24125, 74126, -24125, 5593, -568, -128},
	{9, -129, -639, 6187, -26281, 77511, -26281, 6187, -639, -129},
	{9, -122, -612, 6082, -26353, 77818, -26353, 6082, -612, -122},
	{9, -120, -602, 6015, -26269, 77757, -26269, 6015, -602, -120},
	{9, -120, -582, 5951, -26128, 77542, -26128, 5951, -582, -120},
	{9, -119, -580, 5931, -26094, 77505, -26094, 5931, -580, -119},
	{9, -119, -578, 5921, -26077, 77484, -26077, 5921, -578, -119},
	{9, -119, -577, 5917, -26067, 77473, -26067, 5917, -577, -119},
	{9, -199, -362, 5303, -25505, 77489, -25505, 5303, -362, -199},
};

void rotate_90(unsigned char *buf, uint32_t len)
/* 90 rotation is 1+0j, 0+1j, -1+0j, 0-1j
   or [0, 1, -3, 2, -4, -5, 7, -6] */
{
	uint32_t i;
	unsigned char tmp;
	for (i=0; i<len; i+=8) {
		/* uint8_t negation = 255 - x */
		tmp = 255 - buf[i+3];
		buf[i+3] = buf[i+2];
		buf[i+2] = tmp;

		buf[i+4] = 255 - buf[i+4];
		buf[i+5] = 255 - buf[i+5];

		tmp = 255 - buf[i+6];
		buf[i+6] = buf[i+7];
		buf[i+7] = tmp;
	}
}

void low_pass(struct demod_state *d)
/* simple square window FIR */
{
	int i=0, i2=0;
	while (i < d->lp_len) {
		d->now_r += d->lowpassed[i];
		d->now_j += d->lowpassed[i+1];
		i += 2;
		d->prev_index++;
		if (d->prev_index < d->downsample) {
			continue;
		}
		d->lowpassed[i2]   = d->now_r; // * d->output_scale;
		d->lowpassed[i2+1] = d->now_j; // * d->output_scale;
		d->prev_index = 0;
		d->now_r = 0;
		d->now_j = 0;
		i2 += 2;
	}
	d->lp_len = i2;
}

int low_pass_simple(int16_t *signal2, int len, int step)
// no wrap around, length must be multiple of step
{
	int i, i2, sum;
	for(i=0; i < len; i+=step) {
		sum = 0;
		for(i2=0; i2<step; i2++) {
			sum += (int)signal2[i + i2];
		}
		//signal2[i/step] = (int16_t)(sum / step);
		signal2[i/step] = (int16_t)(sum);
	}
	signal2[i/step + 1] = signal2[i/step];
	return len / step;
}

void low_pass_real(struct demod_state *s)
/* simple square window FIR */
// add support for upsampling?
{
	int i=0, i2=0;
	int fast = (int)s->rate_out;
	int slow = s->rate_out2;
	while (i < s->result_len) {
		s->now_lpr += s->result[i];
		i++;
		s->prev_lpr_index += slow;
		if (s->prev_lpr_index < fast) {
			continue;
		}
		s->result[i2] = (int16_t)(s->now_lpr / (fast/slow));
		s->prev_lpr_index -= fast;
		s->now_lpr = 0;
		i2 += 1;
	}
	s->result_len = i2;
}

void fifth_order(int16_t *data, int length, int16_t *hist)
/* for half of interleaved data */
{
	int i;
	int16_t a, b, c, d, e, f;
	a = hist[1];
	b = hist[2];
	c = hist[3];
	d = hist[4];
	e = hist[5];
	f = data[0];
	/* a downsample should improve resolution, so don't fully shift */
	data[0] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
	for (i=4; i<length; i+=4) {
		a = c;
		b = d;
		c = e;
		d = f;
		e = data[i-2];
		f = data[i];
		data[i/2] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
	}
	/* archive */
	hist[0] = a;
	hist[1] = b;
	hist[2] = c;
	hist[3] = d;
	hist[4] = e;
	hist[5] = f;
}

void generic_fir(int16_t *data, int length, int *fir, int16_t *hist)
/* Okay, not at all generic.  Assumes length 9, fix that eventually. */
{
	int d, temp, sum;
	for (d=0; d<length; d+=2) {
		temp = data[d];
		sum = 0;
		sum += (hist[0] + hist[8]) * fir[1];
		sum += (hist[1] + hist[7]) * fir[2];
		sum += (hist[2] + hist[6]) * fir[3];
		sum += (hist[3] + hist[5]) * fir[4];
		sum +=            hist[4]  * fir[5];
		data[d] = sum >> 15 ;
		hist[0] = hist[1];
		hist[1] = hist[2];
		hist[2] = hist[3];
		hist[3] = hist[4];
		hist[4] = hist[5];
		hist[5] = hist[6];
		hist[6] = hist[7];
		hist[7] = hist[8];
		hist[8] = temp;
	}
}

// define our own complex math ops because ARMv5 has no hardware float
void multiply(int ar, int aj, int br, int bj, int *cr, int *cj)
{
	*cr = ar*br - aj*bj;
	*cj = aj*br + ar*bj;
}

int polar_discriminant(int ar, int aj, int br, int bj)
{
	int cr, cj;
	double angle;
	multiply(ar, aj, br, -bj, &cr, &cj);
	angle = atan2((double)cj, (double)cr);
	return (int)(angle / 3.14159 * (1<<14));
}

int fast_atan2(int y, int x)
/* pre scaled for int16 */
{
	int yabs, angle;
	int pi4=(1<<12), pi34=3*(1<<12);  // note pi = 1<<14
	if (x==0 && y==0) {
		return 0;
	}
	yabs = y;
	if (yabs < 0) {
		yabs = -yabs;
	}
	if (x >= 0) {
		angle = pi4  - pi4 * (x-yabs) / (x+yabs);
	} else {
		angle = pi34 - pi4 * (x+yabs) / (yabs-x);
	}
	if (y < 0) {
		return -angle;
	}
	return angle;
}

int polar_disc_fast(int ar, int aj, int br, int bj)
{
	int cr, cj;
	multiply(ar, aj, br, -bj, &cr, &cj);
	return fast_atan2(cj, cr);
}

int atan_lut_init(void)
{
	int i = 0;

	atan_lut = static_cast<int*>(malloc(atan_lut_size * sizeof(int)));

	for (i = 0; i < atan_lut_size; i++) {
		atan_lut[i] = (int) (atan((double) i / (1<<atan_lut_coef)) / 3.14159 * (1<<14));
	}

	return 0;
}

int polar_disc_lut(int ar, int aj, int br, int bj)
{
	int cr, cj, x, x_abs;

	multiply(ar, aj, br, -bj, &cr, &cj);

	/* special cases */
	if (cr == 0 || cj == 0) {
		if (cr == 0 && cj == 0)
			{return 0;}
		if (cr == 0 && cj > 0)
			{return 1 << 13;}
		if (cr == 0 && cj < 0)
			{return -(1 << 13);}
		if (cj == 0 && cr > 0)
			{return 0;}
		if (cj == 0 && cr < 0)
			{return 1 << 14;}
	}

	/* real range -32768 - 32768 use 64x range -> absolute maximum: 2097152 */
	x = (cj << atan_lut_coef) / cr;
	x_abs = abs(x);

	if (x_abs >= atan_lut_size) {
		/* we can use linear range, but it is not necessary */
		return (cj > 0) ? 1<<13 : -(1<<13);
	}

	if (x > 0) {
		return (cj > 0) ? atan_lut[x] : atan_lut[x] - (1<<14);
	} else {
		return (cj > 0) ? (1<<14) - atan_lut[-x] : -atan_lut[-x];
	}

	return 0;
}

void fm_demod(struct demod_state *fm)
{
	int i, pcm;
	int16_t *lp = fm->lowpassed;
	pcm = polar_discriminant(lp[0], lp[1],
		fm->pre_r, fm->pre_j);
	fm->result[0] = (int16_t)pcm;
	for (i = 2; i < (fm->lp_len-1); i += 2) {
		switch (fm->custom_atan) {
		case 0:
			pcm = polar_discriminant(lp[i], lp[i+1],
				lp[i-2], lp[i-1]);
			break;
		case 1:
			pcm = polar_disc_fast(lp[i], lp[i+1],
				lp[i-2], lp[i-1]);
			break;
		case 2:
			pcm = polar_disc_lut(lp[i], lp[i+1],
				lp[i-2], lp[i-1]);
			break;
		}
		fm->result[i/2] = (int16_t)pcm;
	}
	fm->pre_r = lp[fm->lp_len - 2];
	fm->pre_j = lp[fm->lp_len - 1];
	fm->result_len = fm->lp_len/2;
}

void raw_demod(struct demod_state *fm)
{
	int i;
	for (i = 0; i < fm->lp_len; i++) {
		fm->result[i] = (int16_t)fm->lowpassed[i];
	}
	fm->result_len = fm->lp_len;
}

void deemph_filter(struct demod_state *fm)
{
	static int avg;  // cheating...
	int i, d;
	// de-emph IIR
	// avg = avg * (1 - alpha) + sample * alpha;
	for (i = 0; i < fm->result_len; i++) {
		d = fm->result[i] - avg;
		if (d > 0) {
			avg += (d + fm->deemph_a/2) / fm->deemph_a;
		} else {
			avg += (d - fm->deemph_a/2) / fm->deemph_a;
		}
		fm->result[i] = (int16_t)avg;
	}
}

void dc_block_filter(struct demod_state *fm)
{
	int i, avg;
	int64_t sum = 0;
	for (i=0; i < fm->result_len; i++) {
		sum += fm->result[i];
	}
	avg = sum / fm->result_len;
	avg = (avg + fm->dc_avg * 9) / 10;
	for (i=0; i < fm->result_len; i++) {
		fm->result[i] -= avg;
	}
	fm->dc_avg = avg;
}

long int rms(int16_t *samples, int len, int step)
{
	int i;
	long int rms_val;
	int64_t p = 0, t = 0;
	int64_t s;

	for (i = 0; i < len; i += step) {
		s = samples[i];
		t += s;
		p += s * s;
	}

	double dc = (double)(t * (int64_t)step) / (double)len;
	double err = (double)t * 2.0 * dc - dc * dc * (double)len;

	double val = ((double)p - err) / (double)len;
	if (val < 0.0) val = 0.0;

	rms_val = (long int)sqrt(val);
	if (rms_val < 0) rms_val = 999;
	return rms_val;
}

void full_demod(struct demod_state *d)
{
	int i, ds_p;
	int sr = 0;
	ds_p = d->downsample_passes;
	if (ds_p) {
		for (i=0; i < ds_p; i++) {
			fifth_order(d->lowpassed,   (d->lp_len >> i), d->lp_i_hist[i]);
			fifth_order(d->lowpassed+1, (d->lp_len >> i) - 1, d->lp_q_hist[i]);
		}
		d->lp_len = d->lp_len >> ds_p;
		/* droop compensation */
		if (d->comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) {
			generic_fir(d->lowpassed, d->lp_len,
				cic_9_tables[ds_p], d->droop_i_hist);
			generic_fir(d->lowpassed+1, d->lp_len-1,
				cic_9_tables[ds_p], d->droop_q_hist);
		}
	} else {
		low_pass(d);
	}
	/* power squelch */
	if (d->squelch_level) {
		sr = rms(d->lowpassed, d->lp_len, 1);
		if (sr < d->squelch_level) {
			d->squelch_hits++;
			for (i=0; i<d->lp_len; i++) {
				d->lowpassed[i] = 0;
			}
		} else {
			d->squelch_hits = 0;}
	}
	d->mode_demod(d);  /* lowpassed -> result */
	if (d->mode_demod == &raw_demod) {
		return;
	}
	/* todo, fm noise squelch */
	// use nicer filter here too?
	if (d->post_downsample > 1) {
		d->result_len = low_pass_simple(d->result, d->result_len, d->post_downsample);}
	if (d->deemph) {
		deemph_filter(d);}
	if (d->dc_block) {
		dc_block_filter(d);}
	if (d->rate_out2 > 0) {
		low_pass_real(d);
		//arbitrary_resample(d->result, d->result, d->result_len, d->result_len * d->rate_out2 / d->rate_out);
	}
}

static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
	int i;
	struct dongle_state *s = static_cast<dongle_state*>(ctx);
	struct demod_state *d = s->demod_target;

	if (exitflag) {
		return;}
	if (!ctx) {
		return;}
	if (s->mute) {
		for (i=0; i<s->mute; i++) {
			buf[i] = 127;}
		s->mute = 0;
	}
	if (!s->offset_tuning) {
		rotate_90(buf, len);}
	for (i=0; i<(int)len; i++) {
		s->buf16[i] = (int16_t)buf[i] - 127;}
	pthread_rwlock_wrlock(&d->rw);
	memcpy(d->lowpassed, s->buf16, 2*len);
	d->lp_len = len;
	pthread_rwlock_unlock(&d->rw);
	safe_cond_signal(&d->ready, &d->ready_m);
}

static void *dongle_thread_fn(void *arg)
{
	struct dongle_state *s = static_cast<dongle_state*>(arg);
	rtlsdr_or_tcp_read_async(s->dev, rtlsdr_callback, s, 0, s->buf_len);
	return 0;
}

static void *demod_thread_fn(void *arg)
{
	struct demod_state *d = static_cast<demod_state*>(arg);
	struct output_state *o = d->output_target;
	while (!exitflag) {
		safe_cond_wait(&d->ready, &d->ready_m);
		pthread_rwlock_wrlock(&d->rw);
		full_demod(d);
		pthread_rwlock_unlock(&d->rw);
		if (d->exit_flag) {
			exitflag = 1;
		}
		if (d->squelch_level && d->squelch_hits > d->conseq_squelch) {
			d->squelch_hits = d->conseq_squelch + 1;  /* hair trigger */
			safe_cond_signal(&controller.hop, &controller.hop_m);
			continue;
		}
		pthread_rwlock_wrlock(&o->rw);
		for (int i = 0; i < d->result_len; i++)
		{
			for (int j=0; j < bandwidth_multiplier; j++){
				o->queue.push(d->result[i]);}
		}
		pthread_rwlock_unlock(&o->rw);
		safe_cond_signal(&o->ready, &o->ready_m);
	}
	return 0;
}

int nearest_gain(rtlsdr_dev_t *dev, int target_gain)
{
	int i, r, err1, err2, count, nearest;
	int* gains;
	r = rtlsdr_or_tcp_set_tuner_gain_mode(dev, 1);
	if (r < 0) {
		fprintf (stderr, "WARNING: Failed to enable manual gain.\n");
		return r;
	}
	count = rtlsdr_or_tcp_get_tuner_gains(dev, NULL);
	if (count <= 0) {
		return 0;
	}
	gains = static_cast<int*>(malloc(sizeof(int) * count));
	count = rtlsdr_or_tcp_get_tuner_gains(dev, gains);
	nearest = gains[0];
	for (i=0; i<count; i++) {
		err1 = abs(target_gain - nearest);
		err2 = abs(target_gain - gains[i]);
		if (err2 < err1) {
			nearest = gains[i];
		}
	}
	free(gains);
	return nearest;
}

int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency)
{
	int r = -1;

  //spam tuning
	for (int i = 0; i < 20; i++)
	{
		r = rtlsdr_or_tcp_set_center_freq(dev, frequency);
		if (r < 0)
			fprintf (stderr, " (RETRY: Failed to set Center Frequency %u). \n", dongle.freq);
		else 
    {
      fprintf (stderr, " (Center Frequency: %u Hz.) \n", frequency);
      break;
    }
	}

	return r;
}

int verbose_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate)
{
	int r;
	r = rtlsdr_or_tcp_set_sample_rate(dev, samp_rate);
	if (r < 0) {
		fprintf (stderr, "WARNING: Failed to set sample rate.\n");
	} else {
		fprintf (stderr, "Sampling at %u S/s.\n", samp_rate);
	}
	return r;
}

int verbose_direct_sampling(rtlsdr_dev_t *dev, int on)
{
	int r;
	r = rtlsdr_or_tcp_set_direct_sampling(dev, on);
	if (r != 0) {
		fprintf (stderr, "WARNING: Failed to set direct sampling mode.\n");
		return r;
	}
	if (on == 0) {
		fprintf (stderr, "Direct sampling mode disabled.\n");}
	if (on == 1) {
		fprintf (stderr, "Enabled direct sampling mode, input 1/I.\n");}
	if (on == 2) {
		fprintf (stderr, "Enabled direct sampling mode, input 2/Q.\n");}
	return r;
}

int verbose_offset_tuning(rtlsdr_dev_t *dev)
{
	int r;
	r = rtlsdr_or_tcp_set_offset_tuning(dev, 1);
	if (r != 0) {
		fprintf (stderr, "WARNING: Failed to set offset tuning.\n");
	} else {
		fprintf (stderr, "Offset tuning mode enabled.\n");
	}
	return r;
}

int verbose_auto_gain(rtlsdr_dev_t *dev)
{
	int r;
	r = rtlsdr_or_tcp_set_tuner_gain_mode(dev, 0);
	if (r != 0) {
		fprintf (stderr, "WARNING: Failed to set tuner gain.\n");
	} else {
		fprintf (stderr, "Tuner gain set to automatic.\n");
	}
	return r;
}

int verbose_gain_set(rtlsdr_dev_t *dev, int gain)
{
	int r;
	r = rtlsdr_or_tcp_set_tuner_gain_mode(dev, 1);
	if (r < 0) {
		fprintf (stderr, "WARNING: Failed to enable manual gain.\n");
		return r;
	}
	r = rtlsdr_or_tcp_set_tuner_gain(dev, gain);
	if (r != 0) {
		fprintf (stderr, "WARNING: Failed to set tuner gain.\n");
	} else {
		fprintf (stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
	}
	return r;
}

int verbose_ppm_set(rtlsdr_dev_t *dev, int ppm_error)
{
	int r;
	// if (ppm_error == 0) {
	// 	return 0;}
	r = rtlsdr_or_tcp_set_freq_correction(dev, ppm_error);
	if (r < 0) {
		fprintf (stderr, "WARNING: Failed to set ppm error.\n");
	} else {
		fprintf (stderr, "Tuner error set to %i ppm.\n", ppm_error);
	}
	return r;
}

int verbose_reset_buffer(rtlsdr_dev_t *dev)
{
	int r;
	r = rtlsdr_or_tcp_reset_buffer(dev);
	if (r < 0) {
		fprintf (stderr, "WARNING: Failed to reset buffers.\n");}
	return r;
}

static void optimal_settings(int freq, int rate)
{
	UNUSED(rate);

	// giant ball of hacks
	// seems unable to do a single pass, 2:1
	int capture_freq, capture_rate;
	struct dongle_state *d = &dongle;
	struct demod_state *dm = &demod;
	struct controller_state *cs = &controller;
	dm->downsample = (1000000 / dm->rate_in) + 1; //dm->rate_in is the rtl_bandwidth value
	if (dm->downsample_passes) {
		dm->downsample_passes = (int)log2(dm->downsample) + 1;
		dm->downsample = 1 << dm->downsample_passes;
	}
	capture_freq = freq;
	capture_rate = dm->downsample * dm->rate_in; //
	if (!d->offset_tuning) {
		capture_freq = freq + capture_rate/4;} //
	capture_freq += cs->edge * dm->rate_in / 2;
	dm->output_scale = (1<<15) / (128 * dm->downsample);
	if (dm->output_scale < 1) {
		dm->output_scale = 1;}
	if (dm->mode_demod == &fm_demod) {
		dm->output_scale = 1;}
	d->freq = (uint32_t)capture_freq;
	d->rate = (uint32_t)capture_rate;
	// fprintf (stderr, "Capture Frequency: %i Rate: %i \n", capture_freq, capture_rate);
}

static void *controller_thread_fn(void *arg)
{
	// thoughts for multiple dongles
	// might be no good using a controller thread if retune/rate blocks
	int i;
	struct controller_state *s = static_cast<controller_state*>(arg);

	if (s->wb_mode) {
		for (i=0; i < s->freq_len; i++) {
			s->freqs[i] += 16000;}
	}

	/* set up primary channel */
	optimal_settings(s->freqs[0], demod.rate_in);
	if (dongle.direct_sampling) {
		verbose_direct_sampling(dongle.dev, 1);}
	if (dongle.offset_tuning) {
		verbose_offset_tuning(dongle.dev);}

	/* Set the frequency */
	verbose_set_frequency(dongle.dev, dongle.freq);
	fprintf (stderr, "Oversampling input by: %ix.\n", demod.downsample);
	fprintf (stderr, "Oversampling output by: %ix.\n", demod.post_downsample);
	fprintf (stderr, "Buffer size: %0.2fms\n",
		1000 * 0.5 * (float)ACTUAL_BUF_LENGTH / (float)dongle.rate);

	/* Set the sample rate */
	verbose_set_sample_rate(dongle.dev, dongle.rate);
	fprintf (stderr, "Output at %u Hz.\n", demod.rate_in/demod.post_downsample);

	while (!exitflag) {
		safe_cond_wait(&s->hop, &s->hop_m);
		if (s->freq_len <= 1) {
			continue;}
		/* hacky hopping */
		s->freq_now = (s->freq_now + 1) % s->freq_len;
		optimal_settings(s->freqs[s->freq_now], demod.rate_in);
		rtlsdr_or_tcp_set_center_freq(dongle.dev, dongle.freq);
		dongle.mute = BUFFER_DUMP;
	}
	return 0;
}

void dongle_init(struct dongle_state *s)
{
	s->rate = rtl_bandwidth;
	s->gain = AUTO_GAIN; // tenths of a dB
	s->mute = 0;
	s->direct_sampling = 0;
	s->offset_tuning = 0; //E4000 tuners only
	s->demod_target = &demod;
}

void demod_init_analog(struct demod_state *s)
{
	s->rate_in = rtl_bandwidth;
	s->rate_out = rtl_bandwidth;
	s->squelch_level = 0;
	s->conseq_squelch = 10;
	s->terminate_on_squelch = 0;
	s->squelch_hits = 11;
	s->downsample_passes = 1; //
	s->comp_fir_size = 0;
	s->prev_index = 0;
	s->post_downsample = 1;  //1 -- once this works, default = 4 -- doesn't work on the official rtl-sdr source code either
	s->custom_atan = 0;
	s->deemph = 1; //
	s->rate_out2 = rtl_bandwidth;  // -1 flag for disabled -- this enables low_pass_real, seems to work okay
	s->mode_demod = &fm_demod;
	s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
	s->prev_lpr_index = 0;
	s->deemph_a = 0; //
	s->now_lpr = 0;
	s->dc_block = 1; //
	s->dc_avg = 0;
	pthread_rwlock_init(&s->rw, NULL);
	pthread_cond_init(&s->ready, NULL);
	pthread_mutex_init(&s->ready_m, NULL);
	s->output_target = &output;
}

void demod_init_ro2(struct demod_state *s)
{
	s->rate_in = rtl_bandwidth;
	s->rate_out = rtl_bandwidth;
	s->squelch_level = 0;
	s->conseq_squelch = 10;
	s->terminate_on_squelch = 0;
	s->squelch_hits = 11;
	s->downsample_passes = 0;
	s->comp_fir_size = 0;
	s->prev_index = 0;
	s->post_downsample = 1;  //1 -- once this works, default = 4 -- doesn't work on the official rtl-sdr source code either
	s->custom_atan = 0;
	s->deemph = 0;
	s->rate_out2 = rtl_bandwidth;  // -1 flag for disabled -- this enables low_pass_real, seems to work okay
	s->mode_demod = &fm_demod;
	s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
	s->prev_lpr_index = 0;
	s->deemph_a = 0;
	s->now_lpr = 0;
	s->dc_block = 1; //enabling by default, but offset tuning is also enabled, so center spike shouldn't be an issue
	s->dc_avg = 0;
	pthread_rwlock_init(&s->rw, NULL);
	pthread_cond_init(&s->ready, NULL);
	pthread_mutex_init(&s->ready_m, NULL);
	s->output_target = &output;
}

void demod_init(struct demod_state *s)
{
	s->rate_in = rtl_bandwidth;
	s->rate_out = rtl_bandwidth;
	s->squelch_level = 0;
	s->conseq_squelch = 10;
	s->terminate_on_squelch = 0;
	s->squelch_hits = 11;
	s->downsample_passes = 0;
	s->comp_fir_size = 0;
	s->prev_index = 0;
	s->post_downsample = 1;  //1 -- once this works, default = 4 -- doesn't work on the official rtl-sdr source code either
	s->custom_atan = 0;
	s->deemph = 0;
	s->rate_out2 = -1;  // -1 flag for disabled -- this enables low_pass_real, seems to work okay
	s->mode_demod = &fm_demod;
	s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
	s->prev_lpr_index = 0;
	s->deemph_a = 0;
	s->now_lpr = 0;
	s->dc_block = 1; //enabling by default, but offset tuning is also enabled, so center spike shouldn't be an issue
	s->dc_avg = 0;
	pthread_rwlock_init(&s->rw, NULL);
	pthread_cond_init(&s->ready, NULL);
	pthread_mutex_init(&s->ready_m, NULL);
	s->output_target = &output;
}

void demod_cleanup(struct demod_state *s)
{
	pthread_rwlock_destroy(&s->rw);
	pthread_cond_destroy(&s->ready);
	pthread_mutex_destroy(&s->ready_m);
}

void output_init(struct output_state *s)
{
	s->rate = rtl_bandwidth;
	pthread_rwlock_init(&s->rw, NULL);
	pthread_cond_init(&s->ready, NULL);
	pthread_mutex_init(&s->ready_m, NULL);
}

void output_cleanup(struct output_state *s)
{
	pthread_rwlock_destroy(&s->rw);
	pthread_cond_destroy(&s->ready);
	pthread_mutex_destroy(&s->ready_m);
}

void controller_init(struct controller_state *s)
{
	s->freqs[0] = 446000000;
	s->freq_len = 0;
	s->edge = 0;
	s->wb_mode = 0;
	pthread_cond_init(&s->hop, NULL);
	pthread_mutex_init(&s->hop_m, NULL);
}

void controller_cleanup(struct controller_state *s)
{
	pthread_cond_destroy(&s->hop);
	pthread_mutex_destroy(&s->hop_m);
}

void sanity_checks(void)
{
	if (controller.freq_len == 0) {
		fprintf (stderr, "Please specify a frequency.\n");
		exit(1);
	}

	if (controller.freq_len >= FREQUENCIES_LIMIT) {
		fprintf (stderr, "Too many channels, maximum %i.\n", FREQUENCIES_LIMIT);
		exit(1);
	}

	if (controller.freq_len > 1 && demod.squelch_level == 0) {
		fprintf (stderr, "Please specify a squelch level.  Required for scanning multiple frequencies.\n");
		exit(1);
	}

}

//UDP remote stuff
static unsigned int chars_to_int(unsigned char* buf) {

	int i;
	unsigned int val = 0;

	for(i=1; i<5; i++) {
		val = val | ((buf[i]) << ((i-1)*8));
	}

	return val;
}

static void *socket_thread_fn(void *arg) {
  UNUSED(arg);

  int n;
  int sockfd;
  unsigned char buffer[5];
  struct sockaddr_in serv_addr;

	sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

  if (sockfd < 0) {
  	perror("ERROR opening socket");
  }

	bzero((char *) &serv_addr, sizeof(serv_addr));

	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = INADDR_ANY;
	serv_addr.sin_port = htons(port);

	if (bind(sockfd, (struct sockaddr *) &serv_addr,  sizeof(serv_addr)) < 0) {
		perror("ERROR on binding");
	}

	bzero(buffer,5);

	fprintf (stderr, "Main socket started! :-) Tuning enabled on UDP/%d \n", port);

	int new_freq;

	while((n = read(sockfd,buffer,5)) != 0) {
		if(buffer[0] == 0) {
			new_freq = chars_to_int(buffer);
			dongle.freq = new_freq;
			optimal_settings(new_freq, demod.rate_in);
			rtlsdr_or_tcp_set_center_freq(dongle.dev, dongle.freq);
			fprintf (stderr, "\nTuning to: %d [Hz] \n", new_freq);
		}


	}

	close(sockfd);
	return 0;
}
//UDP stuff end

void rtlsdr_sighandler()
{
	fprintf (stderr, "Signal caught, exiting!\n");
	rtlsdr_or_tcp_cancel_async(dongle.dev);
}

void open_rtlsdr_stream(dsd_opts *opts)
{
  int r;
	rtl_bandwidth =  opts->rtl_bandwidth * 1000; //reverted back to straight value
	bandwidth_multiplier = (bandwidth_divisor / rtl_bandwidth);
	volume_multiplier = 1; //moved to external handling to be more dynamic

	//this needs to be initted first, then we set the parameters
  dongle_init(&dongle);

	//init with low pass if decoding P25 or EDACS/Provoice
	if (opts->frame_p25p1 == 1 || opts->frame_p25p2 == 1 || opts->frame_provoice == 1)
  	demod_init_ro2(&demod);
	else if (opts->analog_only == 1)
		demod_init_analog(&demod);
	else demod_init(&demod);
  output_init(&output);
  controller_init(&controller);

	if (opts->rtlsdr_center_freq > 0) {
		controller.freqs[controller.freq_len] = opts->rtlsdr_center_freq;
		controller.freq_len++;
	}

	if (opts->rtlsdr_ppm_error != 0) {
		dongle.ppm_error = opts->rtlsdr_ppm_error;
		fprintf (stderr, "Setting RTL PPM Error Set to %d\n", opts->rtlsdr_ppm_error);
	}

	dongle.dev_index = opts->rtl_dev_index;
	// demod.squelch_level = opts->rtl_squelch_level; //no longer used here, used in framesync vc rms value under select conditions
	fprintf (stderr, "Setting RTL Bandwidth to %d Hz\n", rtl_bandwidth);
	// fprintf (stderr, "Setting RTL Sample Multiplier to %d\n", bandwidth_multiplier);
	fprintf (stderr, "Setting RTL RMS Squelch Level to %d\n", opts->rtl_squelch_level);
	if (opts->rtl_udp_port != 0) port = opts->rtl_udp_port; //set this here, only open socket thread if set
	if (opts->rtl_gain_value > 0) {
		dongle.gain = opts->rtl_gain_value * 10; //multiple by ten to make it consitent with the way rtl_fm works
	}

  /* quadruple sample_rate to limit to Δθ to ±π/2 */
	demod.rate_in *= demod.post_downsample;

  if (!output.rate) output.rate = demod.rate_out;

  sanity_checks();

	if (controller.freq_len > 1) demod.terminate_on_squelch = 0;

  ACTUAL_BUF_LENGTH = lcm_post[demod.post_downsample] * DEFAULT_BUF_LENGTH;

  if (opts->rtltcp_enabled == 1)
  {
    if (rtltcp_open(opts->rtltcp_hostname, opts->rtltcp_portno) < 0)
      //rtltcp_open prints its own error messages
      exit(1);
  }
  else
  {
    r = rtlsdr_open(&dongle.dev, (uint32_t)dongle.dev_index);
    if (r < 0)
    {
      fprintf (stderr, "Failed to open rtlsdr device %d.\n", dongle.dev_index);
      exit(1);
    } else {
      fprintf (stderr, "Using RTLSDR Device Index: %d. \n", dongle.dev_index);
    }
  }

  if (demod.deemph) {
		demod.deemph_a = (int)round(1.0/((1.0-exp(-1.0/(demod.rate_out * 75e-6)))));
	}

  /* Set the tuner gain */
	if (dongle.gain == AUTO_GAIN) {
		verbose_auto_gain(dongle.dev);
		fprintf (stderr, "Setting RTL Autogain. \n");
	} else {
		opts->rtl_gain_actual = dongle.gain = nearest_gain(dongle.dev, dongle.gain);
		verbose_gain_set(dongle.dev, dongle.gain);
		// fprintf (stderr, "Setting RTL Nearest Gain to %d. \n", dongle.gain); //seems to be working now
	}

  verbose_ppm_set(dongle.dev, dongle.ppm_error);

  /* Reset endpoint before we start reading from it (mandatory) */
	verbose_reset_buffer(dongle.dev);

  pthread_create(&controller.thread, NULL, controller_thread_fn, (void*)(&controller));
  usleep(100000);
  pthread_create(&demod.thread, NULL, demod_thread_fn, (void*)(&demod));
  pthread_create(&dongle.thread, NULL, dongle_thread_fn, (void*)(&dongle));
	//only create socket thread IF user specified (for legacy uses), else don't use it
	if (port != 0) pthread_create(&socket_freq, NULL, socket_thread_fn, (void *)(&controller));
}

void cleanup_rtlsdr_stream()
{
	fprintf (stderr, "cleaning up...\n");
  rtlsdr_or_tcp_cancel_async(dongle.dev);
  pthread_join(dongle.thread, NULL);
  safe_cond_signal(&demod.ready, &demod.ready_m);
  pthread_join(demod.thread, NULL);
  safe_cond_signal(&output.ready, &output.ready_m);
  safe_cond_signal(&controller.hop, &controller.hop_m);
  pthread_join(controller.thread, NULL);

  //dongle_cleanup(&dongle);
  demod_cleanup(&demod);
  output_cleanup(&output);
  controller_cleanup(&controller);

  rtlsdr_or_tcp_close(dongle.dev);
}

//original for safe keeping
// void get_rtlsdr_sample(int16_t *sample, dsd_opts * opts, dsd_state * state)
// {
// 	if (output.queue.empty())
// 	{
// 		safe_cond_wait(&output.ready, &output.ready_m);
// 	}
// 	pthread_rwlock_wrlock(&output.rw);
// 	*sample = output.queue.front() * volume_multiplier;
// 	output.queue.pop();
// 	pthread_rwlock_unlock(&output.rw);
// }

//find way to modify this function to allow hopping (tuning) while squelched and send 0 sample?
int get_rtlsdr_sample(int16_t *sample, dsd_opts * opts, dsd_state * state)
{
	UNUSED(state);

	//if PPM Error is Manually Changed, Change it here now
	if (opts->rtlsdr_ppm_error != dongle.ppm_error)
	{
		dongle.ppm_error = opts->rtlsdr_ppm_error;

		for (int i = 0; i < 20; i++)
		{
			int r = -1;
			r = verbose_ppm_set(dongle.dev, dongle.ppm_error);
			if (r < 0)
				fprintf (stderr, " Retry Gain.");
			else break;
		}
	}

	//if Gain or AGC Value is Manually Changed, Change it here now
	if (opts->rtl_gain_actual != dongle.gain && opts->rtl_gain_value != 0)
	{
		dongle.gain = (opts->rtl_gain_value * 10);
		opts->rtl_gain_actual = dongle.gain = nearest_gain(dongle.dev, dongle.gain);

		for (int i = 0; i < 20; i++)
		{
			int r = -1;
			r = verbose_gain_set(dongle.dev, dongle.gain);
			if (r < 0)
				fprintf (stderr, " Retry Gain.");
			else break;
		}

		//debug
		// fprintf (stderr, "\n Dongle Gain Set: %d; \n", dongle.gain);
	}

	else if (opts->rtl_gain_value == 0 && dongle.gain != AUTO_GAIN)
	{
		opts->rtl_gain_actual = dongle.gain = AUTO_GAIN;

		for (int i = 0; i < 20; i++)
		{
			int r = 1;
			r = verbose_auto_gain(dongle.dev);
			if (r < 0)
				fprintf (stderr, " Retry Gain.");
			else break;
		}

		//debug
		// fprintf (stderr, "\n AGC Set; \n");
	}

	while (output.queue.empty())
	{
		struct timespec ts;
		clock_gettime(CLOCK_REALTIME, &ts);
		ts.tv_nsec += 10e6;

		pthread_mutex_lock(&output.ready_m);
		pthread_cond_timedwait(&output.ready, &output.ready_m, &ts);
		pthread_mutex_unlock(&output.ready_m);

		if (exitflag)
		{
			return -1;
		}
	}
	pthread_rwlock_wrlock(&output.rw);
	*sample = output.queue.front() * volume_multiplier;
	output.queue.pop();
	pthread_rwlock_unlock(&output.rw);
	return 0;
}

//function may lag since it isn't running as its own thread
void rtl_dev_tune(dsd_opts * opts, long int frequency)
{

	if (opts->payload == 1)
		fprintf (stderr, "\nTuning to %lu Hz.", frequency);
	dongle.freq = opts->rtlsdr_center_freq = frequency;
	optimal_settings(dongle.freq, demod.rate_in); //this too?
	if (opts->payload == 1)
		fprintf (stderr, " (Center Frequency: %u Hz.) \n", dongle.freq);

	//spam tuning
	for (int i = 0; i < 20; i++)
	{
		int r = -1;
		r = rtlsdr_or_tcp_set_center_freq(dongle.dev, dongle.freq);
		if (r < 0)
			fprintf (stderr, " (RETRY: Failed to set Center Frequency %u). \n", dongle.freq);
		else break;
	}

	pthread_rwlock_wrlock(&output.rw); //prevent possible segfault when cleaning the queue
	rtl_clean_queue();
	pthread_rwlock_unlock(&output.rw); //resume

}

static long int prev_rms = 0;

long int rtl_return_rms()
{

	long int sr = rms(demod.lowpassed, 512, 1); //change 512 to 160 if using too much CPU

	// simple 4-block IIR average for stability
	sr = (prev_rms * 3 + sr) / 4;
	prev_rms = sr;

	return sr;
}

//simple function to clear the rtl sample queue when tuning and during other events (ncurses menu open/close)
void rtl_clean_queue()
{
	//insert method to clear the entire queue to prevent sample 'lag'
	std::queue<int16_t> empty; //create an empty queue
	std::swap( output.queue, empty ); //swap in empty queue to effectively zero out current queue
}