/*
 *  Simple real-time data plotter for byte-oriented RS232 data sources
 *
 *  Copyright (C) 2012  Claire Xenia Wolf <claire@clairexen.net>
 *
 *  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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <SDL/SDL.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>

struct {
	char *name;
	int flag;
} speeds[] = {
	{"50", B50},
	{"75", B75},
	{"110", B110},
	{"134", B134},
	{"150", B150},
	{"200", B200},
	{"300", B300},
	{"600", B600},
	{"1200", B1200},
	{"2400", B2400},
	{"4800", B4800},
	{"9600", B9600},
	{"19200", B19200},
	{"38400", B38400},
	{"57600", B57600},
	{"115200", B115200},
	{"230400", B230400},
	{"460800", B460800},
	{"500000", B500000},
	{"576000", B576000},
	{"921600", B921600},
	{"1000000", B1000000},
	{"1152000", B1152000},
	{"1500000", B1500000},
	{"2000000", B2000000},
	{"2500000", B2500000},
	{"3000000", B3000000},
	{"3500000", B3500000},
	{"4000000", B4000000},
	{NULL, 0}
};

SDL_Surface *screen;

#define MAX_NUM_SAMPLES 1024
uint8_t buffer[MAX_NUM_SAMPLES];
int num_samples = MAX_NUM_SAMPLES;
int idx = 0;

void update_sdl()
{
	struct SDL_Rect rect = { 0, 0, num_samples, 256 };
	SDL_FillRect(screen, &rect, 0x00000000);

	rect.x = idx, rect.y = 0, rect.w = 1, rect.h = 256;
	SDL_FillRect(screen, &rect, 0x00888888);

	for (int i  = 0; i < num_samples; i++)
	{
		rect.x = i, rect.y = 255-buffer[i], rect.w = 1, rect.h = buffer[i]+1;
		SDL_FillRect(screen, &rect, i == idx ? 0x00ff8888 : 0x00ff0088);
	}

	SDL_UpdateRect(screen, 0, 0, num_samples, 256);
}

int main(int argc, char **argv)
{
	int opt;
	int zero_reset = 0;

	while ((opt = getopt(argc, argv, "n:z")) != -1) {
		switch (opt) {
		case 'n':
			num_samples = atoi(optarg);
			if (num_samples < 1)
				goto usage;
			if (num_samples > MAX_NUM_SAMPLES)
				num_samples = MAX_NUM_SAMPLES;
			break;
		case 'z':
			zero_reset = 1;
			break;
		default:
			goto usage;
		}
	}
	if (optind + 2 != argc) {
usage:
		fprintf(stderr, "Usage: %s [-n N] [-z] tty-dev baud-rate\n", argv[0]);
		return 1;
	}

	SDL_Init(SDL_INIT_VIDEO);
	SDL_WM_SetCaption("RS232 Plot", "RS232 Plot");
	screen = SDL_SetVideoMode(num_samples, 256, 32, SDL_SWSURFACE);

	if (screen == NULL) {
		fprintf(stderr, "Failed to init SDL!\n");
		return 1;
	}

	int fd = open(argv[optind], O_RDONLY);
	if (fd < 0) {
		fprintf(stderr, "Failed to open device `%s'!\n", argv[1]);
		return 1;
	}

	struct termios oldtio;
	tcgetattr(fd, &oldtio);
	
	struct termios newtio = oldtio;
	newtio.c_cflag = CS8 | CREAD;
	newtio.c_iflag = IGNPAR;
	newtio.c_oflag = 0;
	newtio.c_lflag = 0;
	newtio.c_cc[VMIN] = 1;
	newtio.c_cc[VTIME] = 0;

	for (int i = 0; 1; i++) {
		if (speeds[i].name == NULL) {
			fprintf(stderr, "Unknown baud rate `%s'!\n", argv[optind+1]);
			return 1;
		}
		if (strcmp(argv[optind+1], speeds[i].name) == 0) {
			newtio.c_cflag |= speeds[i].flag;
			break;
		}
	}

	tcflush(fd, TCIFLUSH);
	tcsetattr(fd, TCSANOW, &newtio);

	uint8_t sample = 0;
	while (read(fd, &sample, 1) == 1)
	{
		SDL_Event event;
		while (SDL_PollEvent(&event)) {
			if (event.type == SDL_QUIT)
				goto finish;
			if (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_q)
				goto finish;
		}

		if (sample == 0 && zero_reset) {
			while (idx > 0) {
				buffer[idx] = 0;
				idx = (idx + 1) % num_samples;
			}
		} else {
			buffer[idx] = sample;
			idx = (idx + 1) % num_samples;
		}

		update_sdl();
	}

finish:
	tcsetattr(fd, TCSANOW, &oldtio);
	close(fd);

	return 0;
}