/*
 * Example of client using TCP protocol.
 */

#include <stdio.h>
#include <sys/types.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
/* Need fcntl.h to use fcntl() to make recvfrom non-blocking */
#include <fcntl.h>

#include "message.h"

#define MaxTries 25	/* Maximum Tries to Receive from Server */
#define SERV_HOST_ADDR "130.108.2.22"
/*   gamma's Internet address, defined in /etc/hosts */

// #define SERV_HOST_ADDR "156.12.23.5"
// #define SERV_HOST_ADDR "156.12.1.120"
/* pooh's Internet address, defined in /etc/hosts */


main(argc, argv)
int argc;
char *argv[];
{
    int sockfd, i, serlen,Count,err;
    struct sockaddr_in serv_addr,cli_addr;
    int SERV_TCP_PORT;
    char *pname;
    MES mes_out, mes_in, tmp;

    printf("Please input the same integer input to the ser program\n");
    printf("  (which is larger than 1023)\n");
    scanf("%d", &SERV_TCP_PORT);

    pname = argv[0];

    /* create a socket which is one end of a communication channel */
    if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    { perror("client: cannot open datagram socket"); exit(1);  }

    /* specify server address */
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;  /* address family: Internet */
    serv_addr.sin_addr.s_addr = inet_addr(SERV_HOST_ADDR);
    serv_addr.sin_port = htons(SERV_TCP_PORT);

    mes_out.mtype = htonl(getpid());

    /* Make recvfrom() non-blocking */
    // fcntl(sockfd,F_SETFL,FNDELAY); Old way
    fcntl(sockfd,F_SETFL,O_NONBLOCK);

    for(i=0; i<10; i++) 
      {
	mes_out.number = htonl(i);

	if(sendto(sockfd, &mes_out, sizeof(MES),0,
	      	   (struct sockaddr *) &serv_addr, sizeof(serv_addr)) == -1)
	  { perror("client: write"); exit(3); }

	sleep(1);
	Count=0;
	do {
	 if ((err=recv(sockfd,&mes_in,sizeof(MES),0))<0) 
	  if (++Count < MaxTries) {
	   sleep(1);
	   if (!(Count % 5)) fprintf(stderr,"%dth Attempt to receive\n",Count);
	  }
	  else { 
	   perror("client: recv() failed after repeated attempts...Error is "); 
	   exit(4); 
	  }
	} while (err < 0 && Count < MaxTries);
	fprintf(stderr,"Received %d from server\n",ntohl(mes_in.number));

	  
      }
    
    close(sockfd);
    exit(0);
}