#define _POSIX_C_SOURCE 190607L

#include <fenv.h>
#include <limits.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/wait.h>
#include <string.h>
#include <stdbool.h>

void sigusr1_signal(int signum, siginfo_t *info, void *context) {
    printf("1st scenario:\n");
    if (info->si_code == SI_QUEUE) {
        printf("Signal was sent using sigqueue");
    }
    printf("Attached value: %d\n\n", info->si_value.sival_int);
}

void sigchld_signal(int signum, siginfo_t *info, void *context) {
    printf("2nd scenario:\n");
    printf("Child process %d exited with return code %d\n\n", info->si_pid, info->si_status);
}

void sigalrm_signal(){
  printf("3rd scenarion:\n");
    if (info->si_code == SI_TIMER) {
        printf("Signal was sent by timer with id of %d\n\n", info->si_value.sival_int);
    } else if (info->si_code == SI_USER) {
        printf("SIGALRM was triggered by user\n");
    }
}

int main() {
    //1st
    struct sigaction sigusr1;
    sigusr1.sa_sigaction = sigusr1_signal;
    sigusr1.sa_flags = SA_SIGINFO;
    sigemptyset(&sigusr1.sa_mask);
    sigaction(SIGUSR1, &sigusr1, NULL);
    sigqueue(getpid(), SIGUSR1, (union sigval){.sival_int = 1998});

    //2nd
    struct sigaction sigchld;
    sigchld.sa_sigaction = sigchld_signal;
    sigchld.sa_flags = SA_SIGINFO;
    sigemptyset(&sigchld.sa_mask);
    sigaction(SIGCHLD, &sigchld, NULL);

    //3rd
    struct sigaction sigalrm;
    sigalrm.sa_sigaction = sigalrm_signal;
    sigalrm.sa_flags = SA_SIGINFO;
    sigemptyset(&sigalrm.sa_mask);
    sigaction(SIGALRM, &sigalrm, NULL);

    struct timespec second = {1, 0};
    struct timespec zero = {0, 0};
    const struct itimerspec timer_value = {zero, second};

    timer_t timer;
    timer_create(CLOCK_REALTIME, NULL, &timer);
    timer_settime(timer, 0, &timer_value, NULL);

    kill(getpid(), SIGALRM);

    while(true){}
}