/* ======================================================> asynch_server.c 
 *
 * Standard brain-dead server.  Receive and send back junk.
 *
 * =====================================================================
 */

#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h> 
#include <stdio.h>

int main(int argc, char *argv[])
{
   int                sock, clientsock, mlen, addrsize, msgct, chc, chct;
   int                rnd;
   struct sockaddr_in addr;
   char               ch, buf[256];

   if (argc < 2)
   {
      fprintf (stderr, "Syntax: servername port\n");
      exit (0);
   }

   printf ("Server is starting - don't forget to get rid of me when done\n");

   /*
    * Create a socket to use.
    */

   sock = socket(AF_INET, SOCK_STREAM,0);   
   if (sock == -1)
   {   
      perror("opening socket");
      exit(-1);
   }

   /*
    * Bind a name to the socket.  Since the server will bind with
    * any client, the machine address is zero or INADDR_ANY.  The
    * bind call sets up the socket-port pair, where the socket specifies
    * the protocol and the port is used by the operating system to direct
    * messages to this program.
    */

   addr.sin_family = AF_INET;
   addr.sin_port = htons (atoi (argv[1]));
   addr.sin_addr.s_addr = htonl (INADDR_ANY);
   if (bind(sock, &addr, sizeof (struct sockaddr_in)) == -1) 
   {  
      perror ("on bind");
      exit (-1);
   }

   /*
    * Make the socket available.  The listen call causes the operating
    * system to make the socket available for connections.
    */

   if (listen(sock,1) == -1)
   {  
      perror("on listen");
      exit(-1);
   }

   /*
    * Wait for a client to connect.  
    */

   addrsize = sizeof(struct sockaddr_in);
   clientsock = accept(sock, &addr, &addrsize);
   if (clientsock == -1)
   {  
      perror("on accept");
      exit(-1);
   }

/*   printf("connection made with client %s", inet_ntoa (addr . sin_addr)); */

   /*
    * Receive and print a client message where a null character terminates.
    * Note that a single receive may not work in some cases, but is OK for
    * a simple example.
    */

   do
   {
      mlen = recv (clientsock, buf, 256, 0);
/*      printf ("Server has recieved data\n"); */
      if (mlen == 0)
         continue;

      if (strncmp (buf, "quit", 4) == 0)
            break;

/*      printf ("Server sending message\n"); */
      rnd = (int) (1.0 + 3.0 * ((float)random ())/(float)RAND_MAX);
      switch (rnd)
      {
         case 1:
            send (clientsock, "Got your message", 17, 0);
            break;
         case 2:
            send (clientsock, "Whaaazzzzuuuupppp", 18, 0);
            break;
         case 3:
            send (clientsock, "I know what you did last time slice", 36, 0);
            break;
         case 4:
            send (clientsock, "Howdy, pardner", 15, 0);
            break;
      }
   } while (1);
 
   /*  
    * Close the client socket and also the server socket 
    */

   close(clientsock);
   close(sock);
}