#include <sha256.h>
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <Time.h>

String message = "Close";
String timestamp = "1413175970";
String secret = "j344rfdas";
String device_ID = "a421";
String temp;
String pakett;
String payload;

String rand_valgus;
String rand_temp;

unsigned int localPort = 888; 
IPAddress timeServer(192, 98, 49, 11); // ntp.elion.ee
const int NTP_PACKET_SIZE= 48; // NTP time stamp is in the first 48 bytes of the message
byte packetBuffer[ NTP_PACKET_SIZE];

EthernetUDP Udp;
const  int timeZoneOffset = +2; // GMT zone;

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress server(192,168,2,100);  
IPAddress ip(192,168,2,110);


int client_id = 34;
uint8_t *hash;

void setup() {
  uint8_t* hash;
  uint32_t a;

  Serial.begin(9600);
  while (!Serial) {}
  
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    Ethernet.begin(mac, ip);
  }  
   Udp.begin(localPort);
   setSyncProvider(getNtpTime);
   while(timeStatus()== timeNotSet); 
   randomSeed(now());
   
}
  void loop() {
  Serial.println(now());
  loe_valgus();
  loe_temp();


  delay(2000);
  create_packet("Temperature", rand_temp);
  create_hmac(pakett);
  compile_packet(pakett, temp);
  Serial.println(payload);
  eth_connect(payload);
  temp ="";
  pakett="";

  delay(10000);

  create_packet( "Valgus",rand_valgus);
  create_hmac(pakett);
  compile_packet(pakett,temp);
  Serial.println(payload);
  eth_connect(payload);
  temp="";
  pakett="";
  delay (2000);
  }
 
 void create_packet(String event, String request)
 {
       Serial.println(device_ID);
       Serial.println(event);
       Serial.println(request);     
       pakett = device_ID + "." + event + "." + now() + "." + request;
 }
 
void create_hmac (String hmac_data)
{
  Sha256.initHmac((uint8_t*)"j344rfdas",9);
  Sha256.print(hmac_data);
  printHash(Sha256.resultHmac());
}

void printHash(uint8_t* hash) {
  int i;
  for (i=0; i<32; i++) {  
    temp = temp + ("0123456789abcdef"[hash[i]>>4]);
    temp = temp + ("0123456789abcdef"[hash[i]&0xf]);  
  }
}

void compile_packet(String data_in, String hmac_in)
{
       payload = data_in + "." + hmac_in;
}

void eth_connect(String kirjutada)
{
    EthernetClient client;    
    if (client.connect(server, 8888)) {
    Serial.println("Sent");
 
    
    int str_leng = kirjutada.length()+1;
    char ch_ary[str_leng];
    kirjutada.toCharArray(ch_ary, str_leng);
    client.write(ch_ary);
  } 
  else {
    Serial.println("connection failed");
  }
}

void loe_valgus()
{
  int a = random(3,15);
  rand_valgus = String(a * 100);
  Serial.println(rand_valgus);
}
void loe_temp()
{
  int b = random(10,25);
  rand_temp = String(b);
  Serial.println(rand_temp);
}


/*-------- NTP code ----------*/
/* CC arduino.cc https://www.arduino.cc/en/Tutorial/UdpNtpClient */

unsigned long getNtpTime()
{
 sendNTPpacket(timeServer); // send an NTP packet to a time server
 delay(1000);
 if ( Udp.parsePacket() ) {  
   // We've received a packet, read the data from it
   Udp.read(packetBuffer,NTP_PACKET_SIZE);  // read the packet into the buffer

   //the timestamp starts at byte 40 of the received packet and is four bytes,
   // or two words, long. First, esxtract the two words:

   unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
   unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);  
   // combine the four bytes (two words) into a long integer
   // this is NTP time (seconds since Jan 1 1900):
   unsigned long secsSince1900 = highWord << 16 | lowWord; 
   Serial.print(secsSince1900);
   const unsigned long seventyYears = 2208988800UL;     
   // subtract seventy years and add the time zone:
   unsigned long epoch = secsSince1900 - seventyYears + (timeZoneOffset * 3600L);
   Serial.print(epoch);
   return epoch;
 }
 return 0;
}

// send an NTP request to the time server at the given address 
unsigned long sendNTPpacket(IPAddress& address)
{
 // set all bytes in the buffer to 0
 memset(packetBuffer, 0, NTP_PACKET_SIZE); 
 // Initialize values needed to form NTP request
 // (see URL above for details on the packets)
 packetBuffer[0] = 0b11100011;   // LI, Version, Mode
 packetBuffer[1] = 0;     // Stratum, or type of clock
 packetBuffer[2] = 6;     // Polling Interval
 packetBuffer[3] = 0xEC;  // Peer Clock Precision
 // 8 bytes of zero for Root Delay & Root Dispersion
 packetBuffer[12]  = 49; 
 packetBuffer[13]  = 0x4E;
 packetBuffer[14]  = 49;
 packetBuffer[15]  = 52;

 // all NTP fields have been given values, now
 // you can send a packet requesting a timestamp: 		   
 Udp.beginPacket(address, 123); //NTP requests are to port 123
 Udp.write(packetBuffer,NTP_PACKET_SIZE);
 Udp.endPacket(); 
}