/*
 *  File description
 *
 */
#include <stdio.h>
#include <sys/types.h> 
#include <sys/socket.h>  /* Contains socket, accept, listen, etc. */
#include <netinet/in.h>
#include <unistd.h>        

void error(char *msg)
{
  perror(msg);
  exit(1);
}

int main(int argc, char *argv[])
{
  int sockfd, newsockfd, portno, clilen;
  char buffer[256];
  struct sockaddr_in serv_addr, cli_addr;
  int n;

  if (argc < 2) {
    fprintf(stderr,"ERROR, no port provided\n");
    exit(1);
  }
  
  /* Use the following command
     
     man -s 3head socket
     
     to take a look at what socket is. */
  sockfd = socket(AF_INET, SOCK_STREAM, 0);
     
  if (sockfd < 0) 
    error("ERROR opening socket");
  
  /* Use the following command
     
     man bzero
     
     to take a look at what bzero is. */
  bzero((char *) &serv_addr, sizeof(serv_addr));
  
  portno = atoi(argv[1]);
  
  serv_addr.sin_family = AF_INET;
  serv_addr.sin_addr.s_addr = INADDR_ANY;
  serv_addr.sin_port = htons(portno);

  /* Use the following command
     
     man -s 3socket bind
     
     to take a look at what bind is. */
  if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) 
    error("ERROR on binding");

  /* Use the following command
     
     man -s 3socket listen
     
     to take a look at what bind is. */
  listen(sockfd, 5);
  clilen = sizeof(cli_addr);
  
  /* Keep listening to the port. */
  for(;;) {
     /* Use the following command
     
	man -s 3socket accept
     
	to take a look at what bind is. */
    newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);

    if (newsockfd < 0) 
	 error("ERROR on accept");

    bzero(buffer,256);
    n = read(newsockfd,buffer,255);

    if (n < 0) 
      error("ERROR reading from socket");

    printf("[Server]Here is the message: %s\n",buffer);

    n = write(newsockfd,buffer,256);
    if (n < 0) 
      error("ERROR writing to socket");

    /* What does this mean? */
    close(newsockfd);
  }
}