/*
 * switch.c
 * How to register an button and count this
 * author: Simon Wörner, Manuel Vögele,
 * 	   Siegfried Kienzle
 * 24-March-2017
 *  
 *  */

#define BUTTON "17"
#define IN "in\n"
#define OUT "out\n"
#define HIGH "1\n"
#define LOW "0\n"
#define MAXBYTES 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

int writeIntoFile(char* value, char* path)
{
	int fd;
	char buffer[3];
	strcpy(buffer, value);
	if((fd=open(path, O_RDWR | O_CREAT | O_TRUNC)) == -1) {
		perror(NULL);
		return EXIT_FAILURE;
	}

	if((write(fd, &buffer, sizeof(buffer))) == -1) {
		perror("Cannot write into file");
		return EXIT_FAILURE;			
	} 	
	printf("Success");
	close(fd);
	return EXIT_SUCCESS;	
}

int reserve(char* gpioPort)
{
	char str[3];
	strcpy(str, gpioPort);
	strcat(str, "\n");
	return writeIntoFile(str,"/sys/class/gpio/export");
}

int setDirection(char* gpioPort, char* inOut)
{
	char *direc = "/direction";
	char *gpioPath = "/sys/class/gpio/gpio";	
	char path[32];
	strcpy(path, gpioPath);
    strcat(path, gpioPort);
	strcat(path, direc);
	return writeIntoFile(inOut, path);
}

int setOutput(char* gpioPort, char* volt)
{
	char *val = "/value";
	char *gpioPath = "/sys/class/gpio/gpio";
	char path[28];
	strcpy(path, gpioPath);
	strcat(path, gpioPort);
	strcat(path, val);
	return writeIntoFile(volt, path);
}

int mainLoop(char* gpioPort)
{
	int fid, portValue, count, countButton;
	char *val = "/value";
	char *gpioPath = "/sys/class/gpio/gpio";
	char path[28];
	strcpy(path, gpioPath);
	strcat(path, gpioPort);
	strcat(path, val);
	
	while(true)
	{
		if( (fid=open(path, O_RDONLY)) == -1)
			perror("Fehler ");
		if(readInput(fid) == 1)
		{
			countButton++;
			printf("%d", countButton);
		}
		
	
		close(fid);
	}
}

char[] readInput(int fid)
{
	char buffer[MAXBYTES];
	read(fid, &buffer, MAXBYTES);
	return buffer;
}

int unexport(char* gpioport)
{
	char str[3];
	strcpy(str, gpioPort);
	strcat(str, "\n");
	return writeIntoFile(str,"/sys/class/gpio/unexport");
}


int main()
{  
	reserve(BUTTON);
	setDirection(BUTTON, IN);
	mainLoop(BUTTON);
	unexport(BUTTON);
	return 0;
}