/*Author: Sebastian Vendt, version 1.0 (2019)
* compile with gcc -Wall -o bpi -lwirinigPi bpi.c
* Usage: call ./bpi -p 10 in your bash script to wait for the event on pin 10
* the command will terminate once the event occured
*/

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <wiringPi.h>



extern int optopt;
void printUsage(char* command);
void isr();
int verbose = FALSE;

int main(int argc, char* argv[]){
	if(argc < 2){
		fprintf(stderr, "%s requires at least option -p\n", argv[0]);
		printUsage(argv[0]);
		exit(EXIT_FAILURE);
	}
	int pin = -1;
	int opt;
	int edge = 1;

	wiringPiSetup();

	while((opt = getopt(argc, argv, ":p:ve:")) != -1){
		switch(opt){
		case 'p':
			pin = atoi(optarg);
			break;
		case 'v':
			verbose = TRUE;
			break;
		case 'e':
			edge = atoi(optarg);
			break;
		case '?':
			fprintf(stderr, "unknown option\n");
			printUsage(argv[0]);
			exit(EXIT_FAILURE);
			break;
		case ':':
			fprintf(stderr, "option %c needs a value\n", optopt);
			printUsage(argv[0]);
			exit(EXIT_FAILURE);
			break;
		}
	}
	if(pin == -1) {
		fprintf(stderr, "option -p requried\n");
		printUsage(argv[0]);
		exit(EXIT_FAILURE);
	}
	if(!(edge == 1 || edge == 2 || edge == 3)) {
		fprintf(stderr, "option -e only takes values 1, 2 or 3\n");
		printUsage(argv[0]);
		exit(EXIT_FAILURE);
	}
	if(verbose) printf("Registering interrupt for pin %d with edge %d\n", pin, edge);
	pinMode(pin, INPUT);
	if(wiringPiISR(pin, edge, &isr) < 0) {
		fprintf(stderr, "Failed registering interrupt for pin %d with edge %d\n", pin, edge);
		exit(EXIT_FAILURE);
	}
	pause();
	fprintf(stderr, "could not suspend execution\n");
	exit(EXIT_FAILURE);
}


void printUsage(char* command){
	fprintf(stderr, "Usage: %s -p [-v] [-e]\n", command);
	fprintf(stderr, "-p	BCM pin number (required)\n");
	fprintf(stderr, "-v	be verbose\n");
	fprintf(stderr, "-e	interrupt mode 1:INT_EDGE_FALLING (default), 2:INT_EDGE_RISING, 3:INT_EDGE_BOTH\n");
}

void isr(){
	if(verbose) printf("Triggered!\n");
	exit(EXIT_SUCCESS);
}