#include <netinet/in.h>
#include <poll.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

struct client {
  char nickname[32];
  int has_nickname;
};
int prompt_nickname(int fd) {
  char *message = "Enter your nickname:\n";
  write(fd, message, strlen(message));
  return 0;
}
int set_nickname(struct client *c, const char *input, ssize_t n);

// returns a socket file descriptor.
// if connection could not be established, -1 gets returned
int establish_connection(struct sockaddr_in addr) {
  int sfd = socket(AF_INET, SOCK_STREAM, 0);
  if (sfd == -1) {
    return -1;
  }
  int opt = -1;
  setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
  int bind_addr = bind(sfd, (struct sockaddr *)&addr, sizeof(addr));
  if (bind_addr == -1) {
    close(sfd);
    return -1;
  }
  int listen_addr = listen(sfd, 100);
  if (listen_addr == -1) {
    close(sfd);
    return -1;
  }
  return sfd;
}

// handles new telnet connections.
// returns 0 on success and -1 on failure.
int handle_new_connection(int sfd, struct pollfd *fds, nfds_t *nfds,
                          struct client *clients) {
  int conn = accept(sfd, NULL, NULL);
  if (conn == -1)
    return -1;
  fds[*nfds].fd = conn;
  fds[*nfds].events = POLLIN;
  clients[*nfds].has_nickname = 0;
  prompt_nickname(fds[*nfds].fd);
  (*nfds)++;
  return 0;
}

// process message to all the connected clients.
// returns 0 on success and -1 on failure.
// TODO: add struct client *clients
int process_message(struct pollfd *fds, nfds_t *nfds, struct client *clients) {
  for (nfds_t i = 1; i < *nfds; i++) {
    /* if client has something to say */
    if (fds[i].revents & POLLIN) {
      char buffer[1024]; /* create a new empty buffer */
      ssize_t message =
          read(fds[i].fd, buffer,
               sizeof(buffer)); /* read the message which the client sent */
      if (message == 0) {
        /* close the connection if client disappeared or disconnected */
        close(fds[i].fd);
        fds[i] = fds[*nfds - 1]; /* move back last slot */
        (*nfds)--;               /* size down the current array */
        i--;
      } else if (message == -1) {
        /* if message of the client returns an error */
        close(fds[i].fd);
        fds[i] = fds[*nfds - 1]; /* move back last slot */
        (*nfds)--;               /* size down the current array */
        i--;
        return -1;
      } else {
        /* send every message bytes to the other clients */
        for (nfds_t j = 1; j < *nfds; j++) {
          if (j != i) {
            write(fds[j].fd, buffer, message);
          }
        }
      }
    }
  }
  return 0;
}