#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

#define outputA 6
#define outputB 5

LiquidCrystal_I2C lcd(0x27, 20, 4);

int aState;
int aLastState;
// -----------------------------------------------------------------------------
// constants
long pwm = 11;
const int                                 PinCLK   = 2 ;     // Used for generating interrupts using CLK signal
const int                                 PinDT    = 35;     // Used for reading DT signal
const int                                 PinSW    = 33;     // Used for the push button switch

//MULTIPLEXER
int s0 = 7;
int s1 = 8;
int s2 = 9;
int s3 = 10;
int muxCh = 0;

// -----------------------------------------------------------------------------
// global vars

volatile int                             virtualPosition    = 0;

// -----------------------------------------------------------------------------
// forward decls


// -----------------------------------------------------------------------------
// Interrupt service routine is executed when a HIGH to LOW transition is detected on CLK

void isr () {

    static unsigned long                lastInterruptTime = 0;

    unsigned long                       interruptTime = millis();

    // If interrupts come faster than 5ms, assume it's a bounce and ignore
    if (interruptTime - lastInterruptTime > 5) {
        if (!digitalRead(PinDT))
            virtualPosition = (virtualPosition + 1);
        else
            virtualPosition = virtualPosition - 1;
        }
    lastInterruptTime = interruptTime;
    } // ISR
// -----------------------------------------------------------------------------

void setup() {
    Serial.begin(9600);
    
    lcd.init();
    lcd.backlight();
    aLastState = digitalRead(outputA);
    attachInterrupt(0, isr, FALLING);   // interrupt 0 is always connected to pin 2 on Arduino UNO

    Serial.println("Start");
    pinMode(pwm, OUTPUT);
    pinMode(PinCLK,INPUT);
    pinMode(PinDT, INPUT);
    pinMode(PinSW, INPUT);
    pinMode(outputA, INPUT);
    pinMode(outputB, INPUT);
    pinMode(s0, OUTPUT);
    pinMode(s1, OUTPUT);
    pinMode(s2, OUTPUT);
    pinMode(s3, OUTPUT);

    digitalWrite(s0, HIGH);
    digitalWrite(s1, HIGH);
    digitalWrite(s2, LOW);
    digitalWrite(s3, HIGH);

    } // setup

// -----------------------------------------------------------------------------

void loop() {

    int                                    lastCount = 0;
    aState = digitalRead(outputA); 
    if (aState != aLastState){     
    if (digitalRead(outputB) != aState) { 
      virtualPosition ++;
    } else {
      virtualPosition --;
    }
    while (true) {

    if(virtualPosition < 0) {virtualPosition = 0;}
    if(virtualPosition > 100) {virtualPosition = 100;}
        if (!(digitalRead(PinSW))) {        // check if pushbutton is pressed
            virtualPosition = 0;            // if YES, then reset counter to ZERO
            while (!digitalRead(PinSW)) {}  // wait til switch is released
            delay(10);                      // debounce
            Serial.println("Reset");        // Using the word RESET instead of COUNT here to find out a buggy encoder
            }
        if (virtualPosition != lastCount) {
            lastCount = virtualPosition;
            Serial.print("Count = ");
            Serial.println(virtualPosition);
            lcd.setCursor(0, 0);
            lcd.print("DutyCycle = ");
            lcd.print(virtualPosition); 
            lcd.print("%  (");
            }
        } // while
    } //loop
}