//Include Libraries
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

//create an RF24 object
RF24 radio(D6, D7);  // CE, CSN

#define buttonPin D0
#define ledPin D1

//address through which two modules communicate.
const byte address[6] = "00001";
int button_index;



// ---
// H-bridge motor control, using the TB67H451FNG, should run with input 2-5V
// I'm using some geared "micro-motors", supposed to run at 3-7V (~30rpm).
#define FORWARD_PIN D4
#define BACKWARD_PIN D5

uint8_t dirn = 1; // direction, 1 or 0.
uint8_t state = 0; // state variable, so we can change direction when there is a new state.
// ---



void setup() {
  Serial.begin(9600);                       // initialize serial communication
  // Serial.setTimeout(10);                    // set the timeout for parseInt
  pinMode(ledPin, OUTPUT);                  // initialize the LED pin as an output
  pinMode(buttonPin, INPUT_PULLUP);
  radio.begin();


  //set the address
  radio.openWritingPipe(address);

  // Set module as transmitter
  radio.stopListening();


  // ---
  pinMode(FORWARD_PIN, OUTPUT);
  pinMode(BACKWARD_PIN, OUTPUT);
  // ---

}

void loop() {

  int button_state = digitalRead(buttonPin);
  if (button_state == LOW) {
    dirn = !dirn; // change_direction
  }
  
  if (Serial.available() > 0 || button_state == LOW) {             // see if there's incoming serial data

    int inByte = Serial.read();
    //    int inByte = Serial.parseInt();
    int integer_val = inByte - '0';         // ASCII to integer conversion ... numbers 0 - 9, are 48-57. Saying "-'0'", is basically subtracting 48.

    if (integer_val >= 0) {
      for (int i = 0; i < integer_val; i++) {
        digitalWrite(ledPin, HIGH);
        delay(100);
        digitalWrite(ledPin, LOW);
        delay(100);
      }
    }


    // simple test mode (e.g. with serial monitor)
    if (inByte == 'q' || inByte == '1' || inByte == '3' || button_state == LOW) {
      digitalWrite(ledPin, HIGH);
      delay(100);
      digitalWrite(ledPin, LOW);
      delay(100);

      // turn the motor of the transmitter module
      // ---
      // spin motor forward
      digitalWrite(FORWARD_PIN, dirn);
      digitalWrite(BACKWARD_PIN, !dirn);
      delay(500);
      // stop motor
      digitalWrite(FORWARD_PIN, LOW);
      digitalWrite(BACKWARD_PIN, LOW);
      // ---

    }
    else if (inByte == 'w' || inByte == '2') {
      digitalWrite(ledPin, HIGH);
      delay(100);
      digitalWrite(ledPin, LOW);
      delay(100);
      digitalWrite(ledPin, HIGH);
      delay(100);
      digitalWrite(ledPin, LOW);
      delay(100);
    }
    else {
      digitalWrite(ledPin, LOW);
    }

    // -------------------------------
    //Send message to peripheral module (Q: how to do this for multipel modules, e.g. with different addresses?)
    if (integer_val == 2 || integer_val == 3) { // i.e. if we've selected the second module
      const char text[] = "Hello World";
      radio.write(&text, sizeof(text));
      delay(1000); // why this delay
    }
    // -------------------------------

    // Serial.write("ok!");
    Serial.write(inByte);
  }
}