// udp client driver program
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include "common.h"

static const unsigned char payload_request[] = { PAYLOAD_REQUEST, 0xFF};

struct {
    unsigned long long int send_start;
    unsigned long long int received_end;
} timings[MAX_UDP_PACKETS];

static int set_ts(unsigned long long int * const out) {
  struct timeval tv = {};

  if (gettimeofday(&tv, NULL) != 0)
    return 1;

  *out = (tv.tv_sec * 1000 * 1000) + tv.tv_usec;
  return 0;
}

int main() {
  char buffer[BUFSIZ];
  int sockfd;
  struct sockaddr_in servaddr = {};

  servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
  servaddr.sin_port = htons(UDP_PORT);
  servaddr.sin_family = AF_INET;
  sockfd = socket(AF_INET, SOCK_DGRAM, 0);
  if (sockfd < 0) {
    perror("udp socket");
    return 1;
  }

  if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
    perror("udp connect");
    return 1;
  }

  size_t i;
  ssize_t n;
  for (i = 0; i < MAX_UDP_PACKETS; ++i) {
    if (set_ts(&timings[i].send_start) != 0) {
      n = -1;
      break;
    }

    n = sendto(sockfd, payload_request, sizeof(payload_request), 0, NULL, 0);
    if (n < 0) {
      perror("udp sendto");
      break;
    }

    n = recvfrom(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr *)NULL,
                 NULL);
    if (n < 0) {
      perror("udp recvfrom");
      break;
    }

    if (set_ts(&timings[i].received_end) != 0) {
      n = -1;
      break;
    }
  }

  close(sockfd);

  printf("# packet_number rtt\n");
  for (size_t i = 0; i < MAX_UDP_PACKETS; ++i) {
    printf("%zu %lld\n", i, timings[i].received_end - timings[i].send_start);
  }

  return !(i == MAX_UDP_PACKETS);
}