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


#define ELO_EVENT_PATH "/dev/input/event3"
#define BYTES_PER_LINE 10
#define MAX_READ_ERRORS 10


//#ifdef NDEBUG
//#define assert(c,s)
//#else
//#define assert(c,s) { if (!c) { fprintf(stderr,"ASSERTION FAILED '%.32s': %.1024s\n",##c,s); exit(-1); }
//#endif


volatile int _userAbort;


void PrintByte(char byte)
{
	static int xPos = 0;

	++xPos;

	char trailingChar;
	if (xPos == BYTES_PER_LINE)
	{
		xPos = 0;
		trailingChar = '\n';
	}
	else
	{
		trailingChar = ' ';
	}
	
	char printChar = (isprint(byte) ? byte : ' ');
	
	printf ("0x%02hhX %c   %c", byte, printChar, trailingChar);
}

void SignalHandler(int signal)
{
	_userAbort = 1;
}

int main()
{
//	FILE * fpElo = fopen(ELO_EVENT_PATH, "rb");
//	if (fpElo == NULL)
	int fdElo = open(ELO_EVENT_PATH, O_RDONLY | O_SYNC | O_NOCTTY);
	if (fdElo == -1)
	{
		perror ("Open ELO event node failed");
		return (-1);
	}

	int errorCount = 0;
	putchar ('\n');

	_userAbort = 0;
	signal (SIGTERM, SignalHandler);
	signal (SIGINT, SignalHandler);
	signal (SIGQUIT, SignalHandler);

	while (_userAbort == 0)
	{
		char bytes[8];
		//int bytesRead = fread(&byte, 1, 1, fpElo);
		int bytesRead = read(fdElo, bytes, 8);

		if (bytesRead > 0)
		{
			PrintByte (bytes[0]);
		}
		else if (bytesRead == -1)
		{
//			fprintf (stderr, "fread error %i\n", error);
			perror ("Read ELO event node failed");

			++errorCount;
			if (errorCount == MAX_READ_ERRORS)
			{
				break;
			}
		}
		else
		{
			fprintf(stderr,"read() returned 0");
		}
	}

	signal (SIGTERM, SIG_DFL);
	signal (SIGINT, SIG_DFL);
	signal (SIGQUIT, SIG_DFL);

	putchar ('\n');
	//fclose (fpElo);
	close (fdElo);

	return (0);
}