/* originally from http://www.repairfaq.org/filipg/LINK/F_DTMF.html */
/* changed by Chris Williams */

#include <stdio.h>
#include <ctype.h>

#include "telephone.h"

#define TON  0.100      /* tone duration */
#define TOFF 0.100      /* silence duration */

static const char key[4][4] = {
	{ '1', '2', '3', 'A' },
	{ '4', '5', '6', 'B' },
	{ '7', '8', '9', 'C' },
	{ '*', '0', '#', 'D' },
};

static const struct {
	int row[4];
	int col[4];
} freq = {
	{  697,  770,  852,  941 },	/* rows (lower band) */
	{ 1209, 1336, 1477, 1633 },	/* columns (upper band) */
};

int main(void)
{
	int ch;
	int r, c;
	
	while ((ch = getchar()) != EOF) {
		ch = toupper(ch);
		
		if (ch == ',') /* pause 2 seconds (same as ATD modem command) */
			add_silence(stdout, 2. - TOFF); /* less prev tone off */
		else
			for (r = 0; r < 4; ++r)
			for (c = 0; c < 4; ++c)
				if (ch == key[r][c]) {
					add_dtmf(stdout,
					  freq.row[r], freq.col[c], TON);
					add_silence(stdout, TOFF);
				}
		fflush(stdout);
	}
	
	return 0;
}