#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>

#include <errno.h>
#include <signal.h>
#include <sys/epoll.h>
#include <sys/signalfd.h>

#include "event_loop.h"

/*
 * Data
 */
static bool _to_work = true;
static int _sig_fd = -1;

/*
 * Private API
 */
// Initialize signals.
// Returns:
//  - true on success
// Remarks:
//  - loop_init() must be called before this one
static bool signals_init() {
    sigset_t mask;
    sigemptyset(&mask);
    sigaddset(&mask, SIGTERM);
    sigaddset(&mask, SIGINT);
    sigaddset(&mask, SIGQUIT);
    if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) {
        printf("[!] sigprocmask failed: %d\n", errno);
        return false;
    }
    _sig_fd = signalfd(
        -1,
        &mask,
        SFD_NONBLOCK
    );
    if (_sig_fd == -1) {
        printf("[!] signalfd failed: %d\n", errno);
        return false;
    }
    struct epoll_event ev;
    ev.data.fd = _sig_fd;
    ev.events = EPOLLIN;
    bool loop_res = loop_ctl(
        EPOLL_CTL_ADD,
        _sig_fd,
        &ev
    );
    if (!loop_res) {
        close(_sig_fd);
        printf("[!] loop_ctl failed\n");
        return false;
    }
    return true;
}

static void signals_deinit() {
    close(_sig_fd);
}

/*
 * Callbacks and main
 */
// This callback is called by loop_wait when event happens.
static void on_fd_event(int fd, uint32_t events) {
    // Termination
    if (fd == _sig_fd) {
        _to_work = false;
    }
    else {
        printf("[!] Event has happened on an unknown file descriptor\n");
    }
}

int main(int argc, char **argv) {
    if (!loop_init(on_fd_event)) {
        return 1;
    }
    if (!signals_init()) {
        loop_deinit();
        return 1;
    }

    while (_to_work) {
        if (!loop_wait()) {
            printf("[!] loop_wait returns false, stopping...\n");
            break;
        }
        printf("--- loop ---\n");
    }
    
    signals_deinit();
    loop_deinit();
    return 0;
}