#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdbool.h>
#include <poll.h>
#include <unistd.h>

#define ARRAY_LEN(x) (sizeof(x)/sizeof(x[0]))

int main() {
  int port = 12345;
  int stdin_fd = 0;

  int server_fd = socket(AF_INET, SOCK_STREAM, 0);
  if (server_fd == -1) {
    fprintf(stderr, "Failed to open socket\n");
    return -1;
  }

  int on = 1;
  setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

  struct sockaddr_in addr = { AF_INET, htons(port), 0 };
  if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
    fprintf(stderr, "Failed to bind\n");
    return -1;
  }

  listen(server_fd, 10);

  int client_fd = accept(server_fd, NULL, NULL);

  while (true) {
    struct pollfd fds[] = {
      { .fd = stdin_fd , POLLIN, 0 },
      { .fd = client_fd, POLLIN, 0 }
    };

    poll(fds, ARRAY_LEN(fds), -1);

    char buffer[256] = { 0 };
    if (fds[0].revents & POLLIN) {
      int read_bytes = read(stdin_fd, buffer, sizeof(buffer) - 1);
      send(client_fd, buffer, read_bytes, 0);
    } else if (fds[1].revents & POLLIN) {
      if (recv(client_fd, buffer, sizeof(buffer) - 1, 0) == 0) {
        return 0;
      }

      printf("%s\n", buffer);
    }
  }

  return 0;
}