/* sender for internet datagram demo */
/* with select and time-out */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h
#include <netdb.h>
#include <stdio.h>

#define ENDPACKET "end"
#define toGuiSocketName "/tmp/cs522_2Gui"
#define fromGuiSocketName "/tmp/cs522_4Gui"

printmsg(msg, cc)
char *msg;
int cc;
{
        int i;

        printf("Got Message:%s\n", msg);
        for (i= 0; i<cc; i++) {
                if ((i % 80) == 79) printf("\n");
                printf("%2x ", msg[i]);

        }
        printf("\n\n");
}

int 
initSockToGui() { 
	int sock;
	struct sockaddr_un name;

	/* create a unix domain socket from which to read */
    sock = socket(AF_UNIX, SOCK_DGRAM, 0);
	if (sock < 0) {
          perror("opening datagram socket");
          exit(1);
    }
        /* create name structure for the UNIX domain socket */
        /* use the name from cmd argument */
        name.sun_family = AF_UNIX;
        strcpy(name.sun_path, toGuiSocketName);
        if (bind(sock, &name, sizeof(struct sockaddr_un))) {
                perror("binding name to datagram socket");
                exit(1);
        }
        printf("socket to gui-->%s\n", toGuiSocketName);
	return sock;
}

int 
initSockFromGui() {
	int sock;
	struct sockaddr_un name;

	/* create a unix domain socket from which to read */
    sock = socket(AF_UNIX, SOCK_DGRAM, 0);
	if (sock < 0) {
          perror("opening datagram socket");
          exit(1);
    }
    /* create name structure for the UNIX domain socket */
    name.sun_family = AF_UNIX;
    strcpy(name.sun_path, fromGuiSocketName);
    printf("socket from gui-->%s\n", fromGuiSocketName);
	return sock;
}

help_msg()
{
	printf("format: ua -[d] <#timeout.sec> <#timeout.usec> hostname portno\n");
	printf("   option: d set debug mode\n");
}

main(argc, argv)
int argc;
char *argv[];
{
	int sockTo; 
	int sockFrom; 
	int sockToGui;
	int sockFromGui;
	struct sockaddr_in to;
	struct sockaddr_in from;
	struct hostent *hp, *gethostbyname();

	int maxfdpl;
	struct timeval timeout;
	fd_set fdvar;
	long atol();

	int n;
	int i;
	int pcount = 0;  /* count of packets sent */
	int quitFlag = 1;
	char toBuf[1024];
	char fromBuf[1024];
	char hostname[64];
	extern char *optarg;
	extern int   optind;
	int option_exist = 0;
	int c;
	int debug = 0;
	char *rcv_name;  /* receiver's socket name */
	int toPort_no;
	int length;
	int flag;

	/* process command line args */
	while ((c=getopt(argc,argv,"d")) != EOF)
	{
		option_exist = 1;
		switch(c)
		{
		case 'd':
			debug = 1;
			if (debug)
				printf("turn on debug mode.\n");
			break;
		case '?':
			help_msg();
			exit (1);
		default:
			fprintf (stderr, "unrecognized arg >%s<\n", optarg);
			help_msg();
			exit (1);
		}
	}

	if (argc < 5) {
			help_msg();
			exit (1);
	}

	sockFromGui = initSockFromGui();
	sockToGui = initSockToGui();
	timeout.tv_sec = atol(argv[optind++]);
	timeout.tv_usec = atol(argv[optind++]);
	printf("timeout is set to %ld sec., %ld microsec.\n", timeout.tv_sec,
		timeout.tv_usec);
	rcv_name = argv[optind++];
	if ((toPort_no = atoi(argv[optind])) < 1025) toPort_no = 1025;

	if (debug) printf("The receiver's host name is %s, port_no=%d\n", rcv_name, toPort_no);


	/* create socket from which to read */
	sockFrom = socket(AF_INET, SOCK_DGRAM, 0);
	if (sockFrom < 0) {
		perror("opening datagram socket");
		exit(1);
	}
	/* create name structure with wildcard using INADDR_ANY */
	from.sin_family = AF_INET;
	from.sin_addr.s_addr = INADDR_ANY;
	from.sin_port = 0;  
	/* port no. < 1024 IPPORT_RESERVED is for privillege process */
	/* here just initialized it, it will be assigned value after call */
	/* getsockname() */
	if (bind(sockFrom, &from, sizeof(struct sockaddr_in))) {
		perror("binding name to datagram socket");
		exit(1);
	}
	length = sizeof(from);
	if (getsockname(sockFrom, &from, &length)) {
		perror("getting socket name");
		exit(1);
	}
	/* Find assigned port value and print out. */
	printf("socket has port #%d\n", ntohs(from.sin_port));

	/* create socket on which to sent */
	sockTo = socket(AF_INET, SOCK_DGRAM, 0);
	if (sockTo < 0) {
		perror("opening datagram socket");
		exit(1);
	}
	to.sin_family = AF_INET;
	to.sin_addr.s_addr = INADDR_ANY;
	to.sin_port = 0;
	if (bind(sockTo, &to, sizeof(to))) {
		perror("binding datagram socket");
		exit(1);
	}
	/* construct name of the socket to send to 
	 * gethostbyname() returns a structure including the network address
	 * of the specified host from /etc/hosts. The port number is taken from
	 * the cmd line
	 * create name structure for the UNIX domain socket 
	 * use the name from cmd argument 
	 */
	hp = gethostbyname(rcv_name);
	if (hp == 0) {
		fprintf(stderr, "%s: unknown host",rcv_name);
		exit(2);
	}
	bcopy(hp->h_addr, &to.sin_addr, hp->h_length);
	to.sin_family = AF_INET;
	to.sin_port = htons(toPort_no);

	/*send message */
	gethostname(hostname, 64);
	printf("hostname=%s\n", hostname);
	printf("sending message: %s %d This is packet %d!\n", hostname, ntohs(from.sin_port), pcount++);
	sprintf(toBuf, "%s %d This is packet %d!\n", hostname, ntohs(from.sin_port), pcount);
	if (sendto(sockTo, toBuf, strlen(toBuf), 0, &to, sizeof(to)) < 0) 
		perror("sending datagram message");

	FD_ZERO(&fdvar);  /* initialize the set -- all bits off */
	FD_SET(sockFrom, &fdvar);  /* turn on bit for fd sockFrom */
	FD_SET(sockFromGui, &fdvar);  /* turn on bit for fd sockFromGui */
	maxfdpl = (sockFrom > sockFromGui) ? sockFrom+1 : sockFromGui+1;
	while (quitFlag) {
		if (debug) printf("The number of file descriptors to be tested is %d\n",
			sockFrom+1);
		if ((i=select(maxfdpl, &fdvar, (fd_set *) 0, (fd_set *) 0, &timeout)) < 0) 
			perror("select error");
		if (i == 0) {
			printf("Time out! The receiver does not respond.\n");
			exit(1);
		}
		if (FD_ISSET(sockFromGui, &fdvar)) {
			n = recv(sockFrom, fromBuf, 1024, flag);
			if (n < 0) perror("receiving datagram message");
			printmsg(fromBuf, n);
			/* relay the gui data messge to the receiver */
			if (sendto(sockTo, fromBuf, n, 0, &to, sizeof(to)) < 0) 
			    perror("sending datagram message");
			if (fromBuf[0] == 1) quitFlag= 0;
		}
		if (FD_ISSET(sockFrom, &fdvar)) {
			n = recv(sockFrom, fromBuf, 1024, flag);
			if (n < 0) perror("receiving datagram message");
			fromBuf[n] = 0; /* null terminate */
/*	
			printf("received ack msg=%s\n", fromBuf);

			sprintf(toBuf, "%s %d This is packet %d!\n", hostname, ntohs(from.sin_port), pcount++);
			if (sendto(sockTo, toBuf, strlen(toBuf), 0, &to, sizeof(to)) < 0) 
		    perror("sending datagram message");
*/
		}
	}
	close(sockToGui);
	unlink(toGuiSocketName);
	close(sockFromGui);
	unlink(fromGuiSocketName);
	close(sockFrom);
	close(sockTo);
}