/* Loesung von Jan Siersch */

#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "morse.h"

#define DIT '.'
#define DAH '-'

char* self;
volatile int sig = 0;
volatile pid_t pid = 0;

long xatol(const char *nptr) {
	char *endPtr;
	long value = strtol(nptr, &endPtr, 10);
	
	if (*endPtr != '\0') {
		perror("xatol failed");
		exit(EXIT_FAILURE);
	}
	return value;
}

void xtransmit(pid_t target, char encoded) {
	int signal;
	switch(encoded) {
		case DIT:
			signal = SIGUSR1;
			break;
		case DAH:
			signal = SIGUSR2;
			break;
		case '\0':
			signal = SIGTERM;
			break;
		default:
			perror("invalid encoded char");
			exit(EXIT_FAILURE);
			break;
	}
	
	if (kill(target, signal)) {
		perror("kill failed");
		exit(EXIT_FAILURE);
	}
}

void helpQuit() {
	printf("usage: %s TARGET_PID\n", self);
	exit(EXIT_FAILURE);
}

void sigAction(int _sig, siginfo_t *info, void *context) {
	sig = _sig;
	pid = info->si_pid;
}

int main(int argc, char *argv[]) {
	// parse arguments
	self = *argv++;
	argc--;
	
	if (argc != 1) {
		helpQuit();
	}
	
	pid_t target = xatol(*argv);
	
	// register action for the necessary signals
	int signals[] = {SIGINT};
	struct sigaction sigAct = {{0}};
	sigAct.sa_sigaction = sigAction;
	sigAct.sa_flags = SA_SIGINFO;
	for (int i = 0; i < (sizeof(signals) / sizeof(int)); ++i) {
		sigaction(signals[i], &sigAct, 0);
	}
	
	int letter;
	while((letter = getchar()) != EOF) {
		char* encoded = encode((unsigned char) letter);
		
		// interpret other characters (newlines etc.) as FULL STOPS
		if (!encoded)
			encoded = encode((unsigned char) '.');
		
		for(int i = 0; i < strlen(encoded) + 1; ++i) {
			// send part of the letter (including the '\0')
			xtransmit(target, encoded[i]);
			
			// wait for confirmation
			pause();
			
			// sanity check
			if (pid != target || sig != SIGINT) {
				perror("who did that?");
				exit(EXIT_FAILURE);
			}
		}
		
		
	}
	
	return EXIT_SUCCESS;
}