#include <SPI.h>    // connection library to work with a serial peripheral interface
#include <RF24.h>   // connection library to work with a serial peripheral interface
#include <Servo.h>

RF24 radio(7, 8);   // pin assignment of communication with the module
const uint32_t pipe = 123456789; // setting the address of the radio module in the channel
byte data[2];  // array of values received from the radio module

// pins to which the engine driver is connected

#define M1 6
#define M2 9
#define M3 3
#define M4 5

#define speed_border 128 // speed range separation boundary

/*-------------- engine control function ----------------------------------------*/

void Motor(bool directoin_left, byte speed_left, bool direction_right, byte speed_right) {
  //(left direction, left speed, right direction, right speed) 1 is forward, 0 is back
  if (directoin_left == 1) {
    digitalWrite(M2, 0); // set the direction of movement
    analogWrite(M1, speed_left); // set the rotation speed
  }
  if (directoin_left == 0) {
    digitalWrite(M1, 0);// set the direction of movement
    analogWrite(M2, speed_left); // set the rotation speed
  }
  if (direction_right == 1) {
    digitalWrite(M4, 0); // set the direction of movement
    analogWrite(M3, speed_right); // set the rotation speed
  }
  if (direction_right == 0) {
    digitalWrite(M3, 0);// set the direction of movement
    analogWrite(M4, speed_right); // set the rotation speed
  }
}

/*-------------------------- function "decrypt" the accepted values ---------------------------------*/

void drive() {
  if (data[0] <= speed_border) {            
    if (data[1] <= speed_border) Motor(0, data[0], 0, data[1]);
    else if (data[1] > speed_border) Motor(0, data[0], 1, data[1] - speed_border);
  } else if (data[0] > speed_border) {
    if (data[1] <= speed_border) Motor(1, data[0] - speed_border, 0, data[1]);
    else if (data[1] > speed_border) Motor(1, data[0] - speed_border, 1, data[1] - speed_border);
  }
}

/*-------------------------- function "decrypt" the accepted values with multiplication ---------------------*/

void driveHigh() {
  if (data[0] <= speed_border) { 
    if (data[1] <= speed_border) Motor(0, data[0]*2, 0, data[1]*2);
    else if (data[1] > speed_border) Motor(0, data[0]*2, 1, (data[1] - speed_border)*2);
  } else if (data[0] > speed_border) {
    if (data[1] <= speed_border) Motor(1, (data[0] - speed_border)*2, 0, data[1]*2);
    else if (data[1] > speed_border) Motor(1, (data[0] - speed_border)*2, 1, (data[1] - speed_border)*2);
  }
}

/*----- function of receiving data from the radio module ---------*/

void getData() {
  if (radio.available()){  // if new data is available
    radio.read(&data, sizeof(data)); // read them into the data array
  }
}

/*---- output function to terminal ----------*/

void printData() {
  Serial.print(data[0]); 
  Serial.print("  ");
  Serial.print(data[1]);
  Serial.print("  ");
  Serial.println();
}

void setup(){
  Serial.begin(9600);       // launch of the terminal (serial port) with a speed of 9600
  radio.begin();            // launch of the radio module
  radio.setDataRate(RF24_2MBPS); // set the baud rate of RF24_1MBPS or RF24_2MBPS
  radio.setCRCLength(RF24_CRC_8); // setting the length of the checksum 8-bit or 16-bit
  radio.setPALevel(RF24_PA_MAX); // setting the power level of the RF24_PA_MIN amplifier (minimum), RF24_PA_LOW (low), RF24_PA_HIGH (high) and RF24_PA_MAX (maximum)
  // Corresponds to levels:    -18dBm,      -12dBm,      -6dBM,           0dBm
  radio.setChannel(120);         // channel setup
  radio.setAutoAck(false);       // auto answer off
  radio.powerUp();               // enable or reduce powerDown consumption - powerUp
  radio.openReadingPipe(1, pipe); // channel opening on reception
  radio.startListening(); // start receiving data
  // assigning driver pins to the output
  pinMode(M1, OUTPUT); 
  pinMode(M2, OUTPUT);
  pinMode(M3, OUTPUT);
  pinMode(M4, OUTPUT);
}

void loop(){
  getData();    // read values
  drive();      // processing values
  printData();  // output values to the terminal
}