#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sysLib.h>

/******************************************************************************/
#define MAX_BUF 1600

#define PORT 6987
#define SERVER_ADDR "192.168.202.51"

/******************************************************************************/
/**
 * MAIN - Client - measure latency
 */ 
int main(int argc, char* argv[])
{                            
    int serverAddrLen;  
    int bindStatus, sendStatus;    
    int clientSocketFD;  
    int recieved;
    char buffer[MAX_BUF];
    char sendBuffer[MAX_BUF];  
    struct sockaddr_in serverAddr;
    struct sockaddr_in clientAddr;
    struct timespec measured, result, systemTime;
    long timeDiff, sysTime;
      
    //set clock
    sysClkRateSet(5000);
        
    //create message
    strcpy(sendBuffer, "1234\n"); //4bytes  
    /*
    memset (sendBuffer,'-',1400);
    sendBuffer[1400]='\n';              
    /**/
          
    //create socket
    socketFD = socket(AF_INET, SOCK_DGRAM, 0); //, , ??  IPPROTO_UDP  ??
    if (socketFD == -1)
    {
        perror("Socket creation error");
        exit(1);
    }
    printf("Socket created\n");  
    
    //client address - set structs
    clientAddr.sin_family = AF_INET;
    clientAddr.sin_addr.s_addr = INADDR_ANY;
    clientAddr.sin_port = 0;
    
    //bind client 
    bindStatus = bind(clientSocketFD, (struct sockaddr*)&clientAddr, sizeof(clientAddr));
    printf("Bind: %d\n",bindStatus);
    printf("Client binded:\n");
    printf("Sending and recieving on port: %d\n", PORT);

    //server address - set strucs 
    serverAddr.sin_family = AF_INET;
    inet_aton(SERVER_ADDR, &srv_addr.sin_addr);
    serverAddr.sin_port = htons(PORT);
    
    //set server addr length
    serverAddrLen = sizeof(serverAddr);
    
    //send + recieve + measure time
    while(1)
    {
        //get system time - start measuring
        clock_gettime(CLOCK_MONOTONIC, &systemTime);	  
    
        //send data
        sendStatus = sendto(   clientSocketFD, sendBuffer, strlen(sendBuffer)+1, 0, (struct sockaddr*)&serverAddr, sizeof(serverAddr)   );
        printf("Send: %d\n",sendStatus);
            
        //recieve data
        recieved = recvfrom(   clientSocketFD, buffer, MAX_BUF, 0,(struct sockaddr*)&serverAddr, &serverAddrLen   );        
        printf("Recieved from %s: %s", inet_ntoa(serverAddr.sin_addr), buffer);
        
        //errors
        if( recieved<=0 )
        {
            printf("ERROR");
        }
        
        //measure end
        clock_gettime(CLOCK_MONOTONIC, &measured);	
                      
        //time diff, system time
        timespec_subtract(&result, &measured, &systemTime);
        
        timeDiff = result.tv_nsec/1000000+result.tv_sec*1000;
        sysTime = systemTime.tv_nsec/1000000+systemTime.tv_sec*1000; 
        
        //store data - timeDiff + SysTime
                        
    }
  
    //CLOSE
    close(sockd);
    return 0;
}

/******************************************************************************/
/**
 * Time spec subtract
 */
int timespec_subtract (struct timespec *result, struct timespec *x, struct timespec *y)
{
  /* Perform the carry for the later subtraction by updating Y. */
  if (x->tv_nsec < y->tv_nsec) {
    int num_sec = (y->tv_nsec - x->tv_nsec) / 1000000000 + 1;
    y->tv_nsec -= 1000000000 * num_sec;
    y->tv_sec += num_sec;
  }
  if (x->tv_nsec - y->tv_nsec > 1000000000) {
    int num_sec = (x->tv_nsec - y->tv_nsec) / 1000000000;
    y->tv_nsec += 1000000000 * num_sec;
    y->tv_sec -= num_sec;
  }

  /* Compute the time remaining to wait.
     `tv_nsec' is certainly positive. */
  result->tv_sec = x->tv_sec - y->tv_sec;
  result->tv_nsec = x->tv_nsec - y->tv_nsec;

  /* Return 1 if result is negative. */
  return x->tv_sec < y->tv_sec;
}