#include <LiquidCrystal_I2C.h>

#define buttonPin 2
#define ledPin 3
#define buzzerPin 4

LiquidCrystal_I2C lcd(0x27, 16, 2);

unsigned long lightUpLed;
unsigned long pressedAtTime;
bool stav;

#define debounceDelay 50
bool buttonState;
bool lastButtonState = LOW;
unsigned long lastDebounceTime = 0;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);

  lcd.init();
  lcd.backlight();
  zobraz("Cakaj na led");

  lightUpLed = random(5000,7000);
  digitalWrite(ledPin, LOW);

}

void loop() {
  if(lightUpLed == millis()){
    digitalWrite(ledPin, HIGH);
    stav=true;
  }
  if(stav){
    bool reading = digitalRead(buttonPin);

    if(reading){
      stav=false;
      pressedAtTime = millis();
      tone(buzzerPin,262,200);
    }
    if(pressedAtTime > lightUpLed && !stav){
      zobraz(pressedAtTime - lightUpLed);
    }
  }

  if(millis() - pressedAtTime > 1000){
    bool reading = digitalRead(buttonPin);
    if (reading != lastButtonState) {
      lastDebounceTime = millis();
    }
    if ((millis() - lastDebounceTime) > debounceDelay) {
      if (reading != buttonState) {
        buttonState = reading;
        if (buttonState == HIGH) {
          zobraz("Cakaj na led");
          lightUpLed = random(5000,7000) + millis();
          digitalWrite(ledPin, LOW);
        }
      }
    }
    lastButtonState = reading;
  }

}

void zobraz(String text){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print(text);
}

void zobraz(unsigned long number){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Tvoj reakcny cas");
  lcd.setCursor(0,1);
  lcd.print(String(number)+" ms");
}