#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/ip.h>

#define MAX_EVENTS 10

int set_async(int fd)
{
  /* On get les options du fd */
  int flag = fcntl(fd, F_GETFL, 0);
  if(flag < 0){
    return -1;
  } else {
    /* On rajoute l'option asynchrone */
    flag |= O_NONBLOCK;
  }
  /* On met les changements */
  if(fcntl(fd, F_SETFL, flag) < 0)
    return -1;

  return 0;
}

int main(int argc, char **argv)
{
  int sock, clt;
  struct epoll_event ev, events[10];
  int epollfd, tmp;

  /* Création du socket */
  sock = socket(AF_INET, SOCK_STREAM, 0);
  if(sock < 0){
    perror("socket");
    exit(EXIT_FAILURE);
  }

  tmp = 1;
  /* On passe le socket en mode réutilisable avec le booléen tmp */
  if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&tmp, sizeof(tmp)) < 0){
    perror("setsockopt");
    exit(EXIT_FAILURE);
  }

  /* On passe le socket en mode asynchrone */
  if(set_async(sock) < 0){
    perror("get_async");
    exit(EXIT_FAILURE);
  }

  {
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8888);
    addr.sin_addr.s_addr = INADDR_ANY;
    /* Bind ... */
    if(bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0){
      perror("bind");
      exit(EXIT_FAILURE);
    }
  }

  if(listen(sock, 5) < 0){
    perror("listen");
    exit(EXIT_FAILURE);
  }

  /* Création de l'instance epoll */
  epollfd = epoll_create(MAX_EVENTS);
  if(epollfd < 0){
    perror("epoll_create");
    exit(EXIT_FAILURE);
  }

  ev.events = EPOLLIN; /* read mode */
  ev.data.fd = sock;
  /* Ajout du fd du server au epoll */
  if(epoll_ctl(epollfd, EPOLL_CTL_ADD, sock, &ev) < 0){
    perror("epoll_ctl");
    exit(EXIT_FAILURE);
  }

  {
    struct sockaddr addr; /* Pour get les infos du clients */
    socklen_t addrlen;
    int i;
    char buffer[1024];

    while(1){
      /* Attente d'événements sans timeout */
      tmp = epoll_wait(epollfd, events, 1, -1);
      if(tmp < 0){
    perror("epoll_wait");
    exit(EXIT_FAILURE);
      }
      for(i=0; i < tmp; ++i){
    /* Si le fd est celui du socket server => bloquant */
    if(events[i].data.fd == sock){
      /* => nouvelle connection */
      clt = accept(sock, &addr, &addrlen);
      if(clt < 0){
        perror("accept");
        return -1;
      }
      printf("[+] New client connected\n");
      /* mode asynchrone */
      if(set_async(clt) < 0){
        perror("get_async");
        exit(EXIT_FAILURE);
      }
      ev.events = EPOLLIN | EPOLLET;
      ev.data.fd = clt;
      /* Ajout du nouveau fd dans l'epoll */
      if(epoll_ctl(epollfd, EPOLL_CTL_ADD, clt, &ev) < 0){
        perror("epoll_ctl");
        exit(EXIT_FAILURE);
      }
      printf("[+] Client add in epoll event\n");
    } else {
      printf("[+]Incomming ...\n");
      memset(buffer, 0, 1024);
      i = recv(events[i].data.fd, buffer, 1024, 0);
      if(i <= 0){ /* Si connection perdue */
        ev.data.fd = events[i].data.fd;
        /* On enleve le fd du epoll */
        if(epoll_ctl(epollfd, EPOLL_CTL_DEL, events[i].data.fd, &ev) < 0){
          perror("epoll_ctl");
          exit(EXIT_FAILURE);
        }
        /* On close le socket */
        close(events[i].data.fd);
        printf("[+] Connection lost\n");
      } else
        printf("%s\n", buffer);
    }
      }
    }
  }
  close(sock);
  close(epollfd);
  exit(EXIT_SUCCESS);
}