#include <nRF905.h>
#include <SPI.h>

#define RXADDR {0x58, 0x6F, 0x2E, 0x10} // Address of this device (4 bytes)
#define TXADDR {0xFE, 0x4C, 0xA6, 0xE5} // Address of device to send to (4 bytes)

String ENQ = "0x05";
String ACK = "0x06";
String reply;
String frame;
String okF = "0x120" ;
String SOH = "0x01";
String EOT = "0x04";

void setup() {
  nRF905_init();
  byte addr[] = RXADDR;
  nRF905_setRXAddress(addr);
  byte addr1[] = TXADDR;
  nRF905_setTXAddress(addr1);
  nRF905_receive();
  Serial.begin(38400);
}

void loop() {


  /******************WAIT FOR ENQUIRY (RECEIVE)*******************/
  delay(100);
  reply = "\0";
  Serial.println("WAITING FOR ENQ");
  byte buffer[50] = {0};
  while (!nRF905_getData(buffer, sizeof(buffer)));
  nRF905_setData(buffer, sizeof(buffer));
  while (!nRF905_send());
  nRF905_receive();
  Serial.print(F("Data: "));
  Serial.write(buffer, sizeof(buffer));
  Serial.println();

  for (int i = 0; i < sizeof(buffer); i++) {
    if ((buffer[i] > 0) && (buffer[i] < 127) && (buffer[i] != 32))
      reply = reply + char(buffer[i]);
  }

  Serial.println(reply);
  delay(100);

  if (reply == ENQ) {
ACKLoop:
    /******************SEND ACK (TRANSMIT)*******************/
    delay(100);
    byte replyH[50] = {0};
    ACK.getBytes(replyH, 50);
    nRF905_setData(replyH, sizeof(replyH));
    while (!nRF905_send());
    nRF905_receive();
    Serial.println("ACK SENT");
    Serial.write(replyH, sizeof(replyH));
    Serial.println();

    /*****************RECEIVE FRAME (RECEIVE)******************/
    frame = "\0";
    Serial.println("WAITING FOR FRAME");
    byte buffer[50] = {0};
    while (!nRF905_getData(buffer, sizeof(buffer)));
    nRF905_setData(buffer, sizeof(buffer));
    while (!nRF905_send());
    nRF905_receive();
    Serial.print(F("Data: "));
    Serial.write(buffer, sizeof(buffer));
    Serial.println();

    for (int i = 0; i < sizeof(buffer); i++) {
      if ((buffer[i] > 0) && (buffer[i] < 127) && (buffer[i] != 32))
        frame = frame + char(buffer[i]);
    }

    Serial.println(frame);
    Serial.println(frame.substring(0,4));

    /*****************SEND RECEIVE FRAME **********************/
    delay(100);

    if ((frame.substring(0, 4) == SOH)&&(frame.substring(n-4, n) == EOT)) {
      Serial.println("FRAME RECEIVED");
      delay(100);
      byte replyH[50] = {0};
      okF.getBytes(replyH, 50);
      nRF905_setData(replyH, sizeof(replyH));
      while (!nRF905_send());
      nRF905_receive();
      Serial.println("ACK SENT");
      Serial.write(replyH, sizeof(replyH));
      Serial.println();
    }
    else {

    /*****************NOT RECEIVE FRAME **********************/

      Serial.println("FRAME NOT RECEIVED");
      goto ACKLoop;
    }

  }
  else {
    Serial.println("Not Received");

  }
}