/*
External Interrupt:
These interrupt are interpreted by hardware and are very fast. 
which have the ability to detect RISING and FALLING pin change interrupts.

UNO , NANO has only 2 External Interrupt pins: 2,3
Mega has 	
2,3,18,19,20,21

Here need 3 interrupts so we need Mega
*/


// Define pins for rotary encoder
const int encoderPinA = 19; // CLK
const int encoderPinB = 20; // DT
const int buttonPin = 21;   // Pin for push button (change as needed)

int counter = 0;
int currentStateCLK;
int lastStateCLK;
String currentDir ="";
volatile bool buttonPressed = false;

void setup() {
  pinMode(encoderPinA, INPUT_PULLUP);
  pinMode(encoderPinB, INPUT_PULLUP);
  pinMode(buttonPin, INPUT_PULLUP);

	// Read the initial state of CLK
	lastStateCLK = digitalRead(encoderPinA);

  // Attach interrupts
  attachInterrupt(digitalPinToInterrupt(encoderPinA), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(encoderPinB), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(buttonPin), handleButtonPress, FALLING);

  Serial.begin(9600);
}

void loop() {
  if (buttonPressed) {
    Serial.println("Button Pressed! Reset Counter");
    buttonPressed = false; // Reset button state
    counter =0;
  }
  delay(100); // Adjust as needed
}

void updateEncoder(){
	// Read the current state of CLK
	currentStateCLK = digitalRead(encoderPinA);

	// If last and current state of CLK are different, then pulse occurred
	// React to only 1 state change to avoid double count
	if (currentStateCLK != lastStateCLK  && currentStateCLK == 1){

		// If the DT state is different than the CLK state then
		// the encoder is rotating CW so decrement
		if (digitalRead(encoderPinB) != currentStateCLK) {
			counter ++;
			currentDir ="CW";
		} else {
			// Encoder is rotating CCW so increment
			counter --;
			currentDir ="CCW";
		}

		Serial.print("Direction: ");
		Serial.print(currentDir);
		Serial.print(" | Counter: ");
		Serial.println(counter);
	}

	// Remember last CLK state
	lastStateCLK = currentStateCLK;
}

void handleButtonPress() {
  // Handle button press
  buttonPressed = true;

}