/* 
 * udpclient.c - A simple UDP client
 * usage: udpclient <host> <port>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

#define BUFSIZE 1024

struct gretaCntlMsg {
  uint8_t version;     /* protocol version */
  uint8_t flags;       /* for future use, e.g. for debugging */
  uint8_t msg_type;    /* reg_load=1, reg_dump=2, scalar_dump=3 */
  uint8_t device;      /* device id recognized by the electronics board */
  uint16_t numEntries; /* number of address/value pairs */
  uint16_t seqnum;     /* sequence number */
  int64_t timestamp;   /* generated by trigger (10 nS clock) */
  struct {
    uint32_t addr;
    uint32_t val;
  } av_pairs[1];
};

/* 
 * error - wrapper for perror
 */
void error(char *msg) {
    perror(msg);
    exit(0);
}

int main(int argc, char **argv) {
    int sockfd, portno, n;
    int serverlen;
    struct sockaddr_in serveraddr;
    struct hostent *server;
    char *hostname;
    char buf[BUFSIZE];

    unsigned long long addr;
    unsigned long long value;
    unsigned long long reg[3];

    struct gretaCntlMsg msg;

    reg[0] = 0;

    /* check command line arguments */
    if (argc != 5) {
       fprintf(stderr,"usage: %s <hostname> <port> <addr> <value>\n", argv[0]);
       exit(0);
    }
    hostname = argv[1];
    portno = atoi(argv[2]);

    addr = atol(argv[3]);
    value = atol(argv[4]);
    reg[1] = (addr<<32) + value;
    reg[0] = reg[1];
    reg[2] = reg[1];
    //printf("0x%016llX\n", addr);
    //printf("0x%016llX\n", value);
    //printf("0x%016llX\n", addr<<32);
    printf("0x%016llX\n", reg[1]);

    msg.version          = 255;
    msg.flags            = 2;
    msg.msg_type         = 1;
    msg.device           = 254;
    msg.numEntries       = htons(1);
    msg.seqnum           = htons(3);
    msg.timestamp        = 0x123456789abcdef0;
    msg.av_pairs[0].addr = htonl(atol(argv[3]));
    msg.av_pairs[0].val  = htonl(atol(argv[4]));

    /* socket: create the socket */
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");

    /* gethostbyname: get the server's DNS entry */
    server = gethostbyname(hostname);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host as %s\n", hostname);
        exit(0);
    }

    /* build the server's Internet address */
    bzero((char *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
	  (char *)&serveraddr.sin_addr.s_addr, server->h_length);
    serveraddr.sin_port = htons(portno);

    /* get a message from the user */
    //bzero(buf, BUFSIZE);
    //printf("Please enter msg: ");
    //fgets(buf, BUFSIZE, stdin);

    /* send the message to the server */
    serverlen = sizeof(serveraddr);
    //n = sendto(sockfd, buf, strlen(buf), 0, &serveraddr, serverlen);
    //n = sendto(sockfd, &reg, sizeof(reg), 0, &serveraddr, serverlen);
    n = sendto(sockfd, (void*)&msg, sizeof(msg), 0, (const struct sockaddr*)&serveraddr, serverlen);
    if (n < 0) 
      error("ERROR in sendto");
    
    /* print the server's reply */
    //    n = recvfrom(sockfd, buf, strlen(buf), 0, &serveraddr, &serverlen);
    //    if (n < 0) 
    //      error("ERROR in recvfrom");
    //    printf("Echo from server: %s", buf);
    return 0;
}