#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include "md5.h"

int main(int argc, char **argv) {
  if (argc != 5) {
    printf("wrong number of arguments, requires dynid, shared secret, server ip, server port\n");
    return 1;
  }

  const char *dynid = argv[1];
  const char *sharedSecret = argv[2];
  const char *serverIp = argv[3];
  int serverPort = atoi(argv[4]);

  if (strlen(dynid) > 64 || strlen(sharedSecret) > 64) {
    printf("dynid or shared secret too long, max 64 chars each\n");
    return 2;
  }
  if (strlen(serverIp) < 7 || strlen(serverIp) > 15) {
    printf("server ip too short or too long\n");
    return 3;
  }


  int t = (int) time(NULL);

  char buf[256];
  sprintf(buf, "%s %s %d", dynid, sharedSecret, t);

  md5_state_t state;

  md5_init(&state);
  md5_append(&state, buf, strlen(buf));

  char c[16];
  md5_finish(&state, c);

  sprintf(buf, "%s %d %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
	  dynid, t, 
	  (c[0] & 0xff), (c[1] & 0xff), (c[2] & 0xff), (c[3] & 0xff), 
	  (c[4] & 0xff), (c[5] & 0xff), (c[6] & 0xff), (c[7] & 0xff),
	  (c[8] & 0xff), (c[9] & 0xff), (c[10] & 0xff), (c[11] & 0xff), 
	  (c[12] & 0xff), (c[13] & 0xff), (c[14] & 0xff), (c[15] & 0xff));

  struct sockaddr_in servaddr;
  memset(&servaddr, 0, sizeof(servaddr));
  servaddr.sin_family = AF_INET;
  servaddr.sin_port = htons(serverPort);
  inet_pton(AF_INET, serverIp, &servaddr.sin_addr);
  
  int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
  sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr*) &servaddr, sizeof(servaddr));
  close(sockfd);

  return 0;
}