#include <sys/socket.h>/* socket, connect, bind, listen, AF_INET, SOCK_STREAM */
#include <stdio.h>     /* printf, perror                                      */
#include <unistd.h>    /* read, write, close, STDIN_FILENO                    */
#include <arpa/inet.h> /* htons, sockaddr_in, INADDR_ANY                      */
#include "socktest2.h" /* shared defines                                      */

/* How many pending connections we'll allow */
#define BACKLOG 5

int main(void)
{
  int sfd;                       /* server file descriptor          */
  int cfd;                       /* client file descriptor          */
  ssize_t bytes_read;            /* count of bytes read from socket */
  char buffer[BUF_SIZE];         /* to transfer data in the socket  */
  struct sockaddr_in addr = {0}; /* address for connecting          */

    /* Create the server socket */
  sfd = socket(AF_INET, SOCK_STREAM, 0);
  if (sfd == -1)
  {
    perror("socket");
    return 1;    
  }

    /* Set the domain type (Internet) */
  addr.sin_family = AF_INET;          /* Internet Protocol v4         */
  addr.sin_addr.s_addr = INADDR_ANY;  /* Any address on this computer */
  addr.sin_port = htons(PORT_NUMBER); /* Port (arbitrary 12345)       */

    /* Bind the socket to the IP address */
  if (bind(sfd, (struct sockaddr *) &addr, sizeof(struct sockaddr_in)) == -1)
  {
    perror("bind");
    return 2;
  }  

    /* Indicate that the socket is ready (listening) for a connection */
  if (listen(sfd, BACKLOG) == -1)
  {
    perror("listen");
    return 3;
  }

    /* Process incoming connections forever */
  for (;;)
  {
      /* sleep(5); */ /* Test BACKLOG values */

      /* 
       * Accept the next incoming connection. It returns the socket 
       * descriptor from the client that is connecting in case we want
       * to send data back.            
       */
    cfd = accept(sfd, NULL, NULL);
    if (cfd == -1)
    {
      perror("accept");
      return 4;
    }
    
      /* Read from client socket until EOF (in BUF_SIZE chunks) */
    while ((bytes_read = read(cfd, buffer, BUF_SIZE)) > 0)
    {
        /* Write bytes to stdout */
      if (write(STDOUT_FILENO, buffer, bytes_read) != bytes_read)
      {
        printf("write failed\n");
        return 5;
      }
    }
    
      /* Check if the read had an error */
    if (bytes_read == -1)
    {
      perror("read");
      return 6;
    }
    
      /* Close client file descriptor */
    if (close(cfd) == -1)
    {
      perror("close");
      return 7;
    }
  }

    /* Close server file descriptor */
  if (close(sfd) == -1)
  {
    perror("close");
    return 8;
  }

  return 0;
}