#include <libudev.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <sys/epoll.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>


#define EPOLL_EVENTS 8

/*Open a connection with the current wayland compositor if it exists
 * A fd is provided which can be polled. When polling the fd returns an error
 * send a signal to any children and terminate.
 */

bool TERMINATE = false;

int fork_and_wait() {
    pid_t pid = fork();
    assert(pid != -1);
    if(pid == 0) {
        /*There's a race condition with adb...*/
        sleep(2);
        return execlp("scrcpy", "scrcpy", (char *) 0);
    }
    int status;
    pid_t _pid;
    do {
        _pid = waitpid(pid, &status, WNOHANG);
    } while (pid != _pid && !TERMINATE);
    int exit_status = WEXITSTATUS(status);
    return exit_status;
}

void handle_hup(int sig) {
    printf("poll-phone: %d\n", sig);
    signal(sig, SIG_IGN);
    kill(0, SIGHUP);
    TERMINATE = true;
}

/*Refactor this so we poll the signal handlers*/

int main(int argc, char **argv) {

    struct epoll_event events[EPOLL_EVENTS];
    int epfd = epoll_create(EPOLL_EVENTS);
    struct udev *_udev = udev_new();
    assert(_udev != NULL);
    struct udev_monitor *_monitor = udev_monitor_new_from_netlink(_udev, "udev");
    assert(_monitor != NULL);
    udev_monitor_enable_receiving(_monitor);
    int fd = udev_monitor_get_fd(_monitor);

    struct epoll_event event;
    event.events = EPOLLIN;
    epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &event);

    signal(SIGTERM, handle_hup);
    signal(SIGINT, handle_hup);

    fork_and_wait();
    while(!TERMINATE) {
        int state = epoll_wait(epfd, &events[0], EPOLL_EVENTS, -1);
        if(state == EINTR) { break; }
        else { exit(-1); }

        struct udev_device *device = udev_monitor_receive_device(_monitor);
        const char *action = udev_device_get_action(device);
        udev_device_unref(device);

        if(!strcmp(action, "bind")) {
            fork_and_wait();
        } 
    }

    udev_monitor_unref(_monitor);
    udev_unref(_udev);
    return 0;
}