// Christian Angelus 24/09/2026
// gpio command tool
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

//prototype functions
int gpio_export(const char *gpio);
int gpio_direction(int gpio, const char *direction);
int gpio_write(int gpio, int value);

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

	int fd;
	char pin[] = "17";
	gpio_export(pin);

	//pin direction
	fd = open("/sys/class/gpio/chip0/gpio17/direction", O_WRONLY);
	if(fd<0)
	{
		perror("Error openng the GPIO export path");
		return -1;
	}
	write(fd, "out",3);
	close(fd);
	//pin value
	fd = open("/sys/class/gpio/chip0/gpio17/value", O_WRONLY);
	if(fd<0)
	{
		perror("Error openng the GPIO export path");
		return -1;
	}
	write(fd, "1",1);
	close(fd);
	//pin apagao
	
	//unexport
	
	fd = open("/sys/class/gpio/chip0/unexport", O_WRONLY);
	if(fd<0)
	{
		perror("Error openng the GPIO export path");
		return -1;
	}
	write(fd, "17",2);
	close(fd);


	printf("Hello from Rasperry Pi!\n");
	printf("Number of arguments: %d\n", argc);
	printf("Program is reciving: %s\n", argv[0]);

	if(argc > 1)
		printf("Argument: %s\n", argv[1]);
	return 0;
}

//Complete functions
//
//gpio export
int gpio_export(const char *gpio){
	int fd;
	//export
	fd = open("/sys/class/gpio/chip0/export", O_WRONLY);
	if(fd<0){
		perror("Error openng the GPIO path");
		return -1;
	}
	write(fd,gpio, strlen(gpio));
	close(fd);
	return 0;
}

//Gpio direction
int gpio_direction(int gpio, const char *direction){
	int fd;
	//export
	fd = open("/sys/class/gpio/chip0/export", O_WRONLY);
	if(fd<0){
		perror("Error openng the GPIO path");
		return -1;
	}
	write(fd,gpio, strlen(gpio));
	close(fd);
	return 0;
	}