/**
 * @file help.c
 * @author overflowerror
 * @date 2016.11.27
 * @brief code for the help functions
 * 
 * This file contains the code for this lib.
 */

#include "help.h"
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>

/**
 * @see help.h
 */
const char* progname = "";

/**
 * @brief the free function
 * 
 * This function gets executes if bail_out() or usage() are called.
 */
static free_t freeFunction = NULL;

void help_init(free_t function, const char* name) {
    freeFunction = function;
    progname = name;
}

void bail_out(int exitcode, const char* module) {

    if (module != NULL) {
        // output is not split into smaller quantities to 
        // ensure error messages of child and parent 
        // don't get mixed

        if (errno == 0) {
            (void) fprintf(stderr, "%s: %s\n", progname, module);
        } else {
            (void) fprintf(stderr, "%s: %s: %s\n", progname, module, strerror(errno));
        }
    }

    if (freeFunction != NULL)
        (*freeFunction)();
    exit(exitcode);
}

void usage(const char* arguments, const char* description, const char* error, int exitcode) {
    if (error != NULL) {
        (void) fprintf(stderr, "%s\n\n", error);
    }
    (void) fprintf(stderr, "Usage: %s %s\n", progname, arguments);
    if (description != NULL) {
        (void) fprintf(stderr, "\n%s\n", description);
    }

    if (freeFunction != NULL)
        (*freeFunction)();

    exit(exitcode);
}

void setup_signal_handler(const int signal, sighandler_t handler) {
    struct sigaction s;

    s.sa_handler = handler;
    s.sa_flags   = 0;
    if(sigfillset(&s.sa_mask) < 0) {
        bail_out(EXIT_FAILURE, "sigfillset");
    }
    if (sigaction(signal, &s, NULL) < 0) {
        bail_out(EXIT_FAILURE, "sigaction");
    }
}