/* sender for internet datagram demo */
/* modification 9/20/93 with Louis Sanchez's bug fix */

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

#define ENDPACKET "end"

struct Message_header {
	char sender[10]; /* sender login */
	int sessionID; /* starting from 1 */
};
struct Pen_Message {
	struct Message_header header;
	unsigned char msg_type;
	unsigned char size;
	short x;
	short y;
} pen;

help_msg()
{
	printf("format: pens -[ds:i:t:z:x:y:] hostname portno\n");
	printf("          option: s set the sender's name\n");
	printf("                  d set debug mode\n");
	printf("                  i set sessionID\n");
	printf("                  t set msg_type\n");
	printf("                  z set size of pen point\n");
	printf("                  x set pen x location\n");
	printf("                  y set pen y location\n");
}

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

	int n;
	char toBuf[1024];
	char fromBuf[1024];
	char hostname[64];
	extern char *optarg;
	extern int   optind;
	extern char *getlogin();
	int option_exist = 0;
	int c;
	int debug = 0;
	char *rcv_name;  /* receiver's socket name */
	int toPort_no;
	int length;
	int flag;
        char sender[10] = "cs522";
        int sessionID = 1;
        unsigned char msg_type=3;
        unsigned char size=8;
        short x = 2;
        short y = 32;
        

	/* process command line args */
	while ((c=getopt(argc,argv,"ds:i:t:z:x:y:")) != EOF)
	{
		option_exist = 1;
		switch(c)
		{
		case 'd':
			debug = 1;
			if (debug)
				printf("turn on debug mode.\n");
			break;

                case 's':
                        strcpy(sender, optarg);
                        printf("sender set to %s\n ", sender); 
                        break;
		case 'i':
			if ((sessionID = atoi(optarg)) < 1) sessionID = 1;
			printf("The sessionID is set to  %d\n", sessionID);
			break;
		case 't':
			msg_type = atoi(optarg);
			printf("The msg_type is set to  %d\n", msg_type);
			break;
		case 'z':
			size = atoi(optarg);
			printf("The size is set to  %d\n", size);
			break;
		case 'x':
			x = atoi(optarg);
			printf("The x is set to  %d\n", x);
			break;
		case 'y':
			y = atoi(optarg);
			printf("The y is set to  %d\n", y);
			break;
		case '?':
			help_msg();
			exit (1);
		default:
			fprintf (stderr, "unrecognized arg >%s<\n", optarg);
			help_msg();
			exit (1);
		}
	}

	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 */
	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock < 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(sock, &from, sizeof(struct sockaddr_in))) {
		perror("binding name to datagram socket");
		exit(1);
	}
	length = sizeof(from);
	if (getsockname(sock, &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));

	/* 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); */
	memcpy(&to.sin_addr, hp->h_addr, hp->h_length);
	to.sin_family = AF_INET;
	to.sin_port = htons(toPort_no);

	/* set pen message field */
	strcpy(pen.header.sender, sender);
	pen.header.sessionID = sessionID;
	pen.msg_type = msg_type;
	pen.size = size;
	pen.x = x; /* modify pen.x so that it contains the last digit of your SS# */
	pen.y = y;
	/*send pen message */
	printf("sizeof(pen)=%d\n", sizeof(pen));
	printf("send pen message:\n\t pen.header.sender = %s\n", pen.header.sender);
	printf("\t pen.header.sessionID = %d\n", pen.header.sessionID);
	printf("\t pen.msg_type = %d\n", pen.msg_type);
	printf("\t pen.size = %d\n", pen.size);
	printf("\t pen.x = %d\n", pen.x);
	printf("\t pen.y = %d\n", pen.y);
	if (sendto(sock, &pen, sizeof(pen), 0, &to, sizeof(to)) < 0) 
		perror("sending datagram message");
	close(sock);
}