#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/prctl.h>
#include <assert.h>

#include "utils.h"
#include "log.h"

#define _POSIX_PATH_MAX 256

char *arg0 = NULL;


static void sighandler_child(int signo)
{
    switch (signo) {
        case SIGHUP:
            if (getppid() == 1) {
                N("Master process %d died, exiting", getpgrp());
                exit(EXIT_SUCCESS);
            }
            break;
    }
}

int set_child_sighandler(void)
{
    /* not portable */
    if (prctl(PR_SET_PDEATHSIG, SIGHUP) != 0)
        return 1;
    return signal(SIGHUP, sighandler_child) == SIG_ERR;
}

void set_procname(const char *new_arg0)
{
    assert(arg0);
	memset(arg0, 0, _POSIX_PATH_MAX);
	strncpy(arg0, new_arg0, _POSIX_PATH_MAX);
}

pid_t daemonize(int stay_foreground)
{
    int status = -1;
    pid_t pid;

    /* Fork off the parent process */
    pid = fork();

    /* An error occurred */
    if (pid < 0)
        return pid;

    /* Success: Let the parent terminate */
    if (pid > 0) {
        if (!stay_foreground)
            exit(EXIT_SUCCESS);
        waitpid(-1, &status, 0);
        exit(EXIT_SUCCESS);
    }

    /* On success: The child process becomes session leader */
    if (!stay_foreground && setsid() < 0) {
        E_STRERR("setsid");
        exit(EXIT_FAILURE);
    }

    /* Catch, ignore and handle signals */
    //TODO: Implement a working signal handler */
    //signal(SIGCHLD, SIG_IGN);
    //signal(SIGHUP, SIG_IGN);

    /* Fork off for the second time*/
    if (!stay_foreground) {
        pid = fork();

        /* An error occurred */
        if (pid < 0)
            exit(EXIT_FAILURE);

        /* Success: Let the parent terminate */
        if (pid > 0)
            exit(EXIT_SUCCESS);
    }

    if (!stay_foreground && setpgrp()) {
        E_STRERR("setpgrp");
        exit(EXIT_FAILURE);
    }

    /* Set new file permissions */
    umask(0);

    if (stay_foreground)
        return pid;

    /* Change the working directory to the root directory */
    /* or another appropriated directory */
//    chdir("/");

    /* Close all open file descriptors */
    int x;
    for (x = sysconf(_SC_OPEN_MAX); x>=0; x--) {
//        close (x);
    }

    return pid;
}