//
// Joy2TX, Version 1.0
// --------------------------------------------------
// PC Joystick -> PCBUDDY Interface -> RC-TX Unit
// Sample/Demo Application for  Linux 2.4 Kernels
// --------------------------------------------------
// Copyright (c) 2004 by Antoni Sawicki <as@tenox.tc>
// Licensed under GPL, terms and conditions apply
// PCBUDDY Interface is a product of RC-ELECTRONICS
// The original concept by Ken Hewitt
// --------------------------------------------------
// Compilation (gcc-x86-linux):
//      gcc joy2tx_pcbuddy_linux.c -o joy2tx -lcurses
//

// PCBUDDY operates internally on 22ms frame rate
// this needs to be set little bit higher
#define INTERVAL 30 

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <sched.h>
#include <curses.h>
#include <termios.h>
#include <linux/joystick.h>


#define VER "Joy2TX_PCBUDDY: Version 1.0; Copyright (c) 2004 by Antoni Sawicki <as@tenox.tc>"

int main(int argc, char **argv) {

	// scheduler data
	struct sched_param prio;

	// joystick stuff
	int joy, joy_x=0, joy_y=0;
	char joyname_buff[1024], joyname[50];
	struct js_event jevent;

	// comm & tx stuff
	struct termios cparms;
	int comm, status;
	unsigned char ch[10];


	//
	// app init
	//
	if(argc!=3) {
		fprintf(stderr, "%s\nUsage: %s <joystick_device> <comm_device>\nExample: %s /dev/input/js0 /dev/ttyS0\n",
			VER, argv[0], argv[0]);
		exit(1);
	}

	// set realtime priority
	prio.sched_priority=sched_get_priority_max(SCHED_FIFO);
	sched_setscheduler(0, SCHED_FIFO, &prio);


	//
	// joystick init
	//
	joy = open(argv[1], O_RDONLY | O_NONBLOCK);
	if(joy<1) {
		fprintf(stderr, "Unable to open %s as joystick.\n", argv[1]);
		exit(1);
	}

	if(ioctl(joy, JSIOCGNAME(sizeof(joyname_buff)), joyname_buff) < 0)
		snprintf(joyname, sizeof(joyname), "Unknown");
	else 
		snprintf(joyname, sizeof(joyname), "%s", joyname_buff);


	//
	// comm & pcbuddy init
	//
	comm = open(argv[2], O_RDWR | O_NOCTTY | O_NDELAY);
	if(comm<1) {
		fprintf(stderr, "Unable to open %s as comm port.\n", argv[2]);
		exit(1);
	}

	if(tcgetattr(comm, &cparms) != 0) {
		fprintf(stderr, "Unable to initialize %s\n", argv[2]);
		exit(1);
	}

	cfmakeraw(&cparms);
	cfsetospeed(&cparms, B19200);
	cparms.c_cflag |= CRTSCTS;

	if(tcsetattr(comm, TCSADRAIN, &cparms) != 0) {
		fprintf(stderr, "Unable to initialize %s\n", argv[2]);
		exit(1);
	}

	// reset pcbuddy (interface is powered by RTS signal)
	ioctl(comm, TIOCMGET, &status);
	status &= ~TIOCM_RTS;
	ioctl(comm, TIOCMSET, &status);
	sleep(1);
	status |= TIOCM_RTS;
	ioctl(comm, TIOCMSET, &status);

	// unused; for buffer safety & and ch index starting with 1
	ch[0]=0;
	ch[9]=0;


	//
	// screen init
	//
	initscr();
	erase();
	mvprintw(0,0, "================================================================================");
	mvprintw(1,0, "%s", VER);
	mvprintw(2,0, "[Input: %s (%s)]", argv[1], joyname);
	mvprintw(3,0, "[Output: %s (PCBUDDY) 19200 8N1 RTS+] [Interval: %dms]", argv[2], INTERVAL);
	mvprintw(4,0, "================================================================================");
	mvprintw(6,0, "     \tInput\tOutput");
	mvprintw(7,0, "   -------------------");

	//
	// main loop
	//
	while(1) {
		if(read(joy, &jevent, sizeof(struct js_event)) == sizeof(struct js_event)) {
			//
			// process event queue
			//
			switch (jevent.type) {
				case JS_EVENT_AXIS: // joystick moved
					switch (jevent.number) {
						case 0: joy_x=jevent.value; break;
						case 1: joy_y=jevent.value; break;
					}
					break;
				// add more event types (buttons, pedals, etc.) here
			}
		} else {
			//
			// process and send data
			//

			// convert joystick to tx-unit channel data
			// (pcbuddy range is 0-250, 255 is off)
			ch[1]=(joy_x+32767)/262; 
			ch[2]=(joy_y+32767)/262; 
			ch[3]=255; 
			ch[4]=255; 
			ch[5]=255; 
			ch[6]=255; 
			ch[7]=255; 
			ch[8]=255; 

			// send out to pcbuddy
			tcflush(comm, TCIOFLUSH);
			write(comm, ch+1, 8);


			// print out to screen
			mvprintw(8,0, "                            \r   X:\t%d\t%d", joy_x, ch[1]);
			mvprintw(9,0, "                            \r   Y:\t%d\t%d", joy_y, ch[2]);
			move(0,0);
			refresh();

			// return some cpu time to system
			usleep(INTERVAL * 1000);
		}
	}

	endwin();
	close(comm);
	close(joy);
	return 0;
}