/* client4.c client skeleton for ex4 16 */
/* gcc -o client4 client4.c -lnsl -lsocket -lresolv */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

/* official network end-of-line is CR LF */
#define EOL "\r\n"

/* size of the send/receive buffer */
#define MAXMSG 1000

/* this macro can be used to check errors, see server.c for examples */
#define ERRORCHECK(var, value, command)	if (var == value) {		\
											perror(command);	\
											exit(1); 			\
										}
int main(int argc, char *argv[])
{
    int ssock; /* socket to server */
	int numbytes, status;  
    char rbuf[MAXMSG]; /* receive buffer */
    char sbuf[MAXMSG*2]; /* send buffer */
    struct hostent *he;
    struct sockaddr_in se_addr; /* server address */
	int sin_size = sizeof(struct sockaddr_in); /* convenience constant */
	int port = 9876;      /* default port */

    if (argc < 2) {
        fprintf(stderr,"usage: %s hostname [message] [port]\n", argv[0]);
        exit(1);
    }

	/* get server address */
    he=gethostbyname(argv[1]);
	ERRORCHECK(he, NULL, "gethostbyname");

	/* port as optional third parameter */
	if (argc > 3)
		port = atoi(argv[3]);

	/* get socket */
    ssock = socket(AF_INET, SOCK_STREAM, 0);
	ERRORCHECK(ssock, -1, "socket");

	/* contruct address struct */
    se_addr.sin_family = AF_INET;    
    se_addr.sin_port = htons(port);  /* NBO */
    se_addr.sin_addr = *((struct in_addr *)he->h_addr);
    memset(&(se_addr.sin_zero), '\0', 8); 

	/* connect to the server */
    status = connect(ssock, (struct sockaddr *)&se_addr, sin_size);
	ERRORCHECK(status, -1, "connect");

	/* send something to server */
	sprintf(sbuf, "%s%s", ((argc > 2) ? argv[2] : "Hello"), EOL);

	/* single send for short messages is ok */
	numbytes = send(ssock, sbuf, strlen(sbuf), 0);
	if (numbytes == -1) {
		perror("send");
		exit(1);
	} else if (numbytes != strlen(sbuf))
		printf("Only %d bytes sent! Should have used repeated send...\n", numbytes);


	/* receive */
	/* receive several times here !!! */
    numbytes=recv(ssock, rbuf, MAXMSG-1, 0);
	ERRORCHECK(numbytes, -1, "recv");
    
	/* terminate message to make a string */
    rbuf[numbytes] = '\0';

    printf("Received: %s",rbuf);

    close(ssock);

    return 0;
}