#include <Arduino.h>
#include <TM1637Display.h>
#include "PinChangeInterrupt.h"

volatile int16_t counter = 0;
volatile bool Update = false;
volatile int currentStatePhase_B;
volatile int lastStatePhase_B;
volatile int pulses = 0;

// Shutdown Output
#define SW 11

// Rotary Encoder Inputs
#define Phase_A 13
#define Phase_B 12
#define DIO 3
#define CLK 4

TM1637Display display(CLK, DIO);

void setup() {

  // Set encoder pins as inputs
  pinMode(Phase_A,INPUT);
  pinMode(Phase_B,INPUT);
  pinMode(SW, OUTPUT);

	// Read the initial state of Phase_B
	lastStatePhase_B = digitalRead(Phase_B);
	
	// Call updateEncoder() when any high/low changed seen
	// on interrupt 0 (pin 2), or interrupt 1 (pin 3)
	attachPCINT(digitalPinToPCINT(Phase_A), updateEncoder, CHANGE);
	attachPCINT(digitalPinToPCINT(Phase_B), updateEncoder, CHANGE);

  display.setBrightness(0x0f);
  display.clear();
  display.showNumberDec(0, false);
}

void loop() {
	if (Update){
		// Show decimal numbers with/without leading zeros
    // display.showNumberDec(pulses, false);
    // delay(1000);
    display.showNumberDec(counter, false);
		Update = false;
	}
}

void updateEncoder(){
	// Read the current state of Phase_B
	currentStatePhase_B = digitalRead(Phase_B);

	// If last and current state of Phase_B are different, then pulse occurred
	// React to only 1 state change to avoid double count
	if (currentStatePhase_B != lastStatePhase_B  && currentStatePhase_B == 1){
  		// If the Phase_A state is different than the Phase_B state then
		// the encoder is rotating CCW so decrement
		if (digitalRead(Phase_A) != currentStatePhase_B) {
			counter --;
		} else {
			// Encoder is rotating CW so increment
			counter ++;
		}
    if (counter > 1023){
      counter = 1023;
    }
    if (counter < 0){
      counter = 0;
    }
	}
  pulses ++;
	// Remember last Phase_B state
	lastStatePhase_B = currentStatePhase_B;
	Update = true;
}