#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

const int buttonPin = 7;
const int ledPin = 8;
const int buzzerPin = 9;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  
  lcd.begin(16, 2);
  
  lcd.setCursor(0, 0);
  lcd.print("Test Reaksi");
  lcd.setCursor(0, 1);
  lcd.print("Pencet utk mulai");
  
  digitalWrite(ledPin, LOW);
  digitalWrite(buzzerPin, LOW);
}

void loop() {
  if (digitalRead(buttonPin) == HIGH) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Bersiaplah...");
    
    // Wait for the button to be released to prevent immediate reaction
    while(digitalRead(buttonPin) == HIGH) {}
    
    // Random delay between 1 to 5 seconds
    long randDelay = random(1000, 5000);
    delay(randDelay);
    
    // Signal start
    digitalWrite(ledPin, HIGH);
    digitalWrite(buzzerPin, HIGH);
    
    unsigned long startTime = millis();
    
    // Wait for the user to press the button
    while (digitalRead(buttonPin) == LOW) {}
    
    unsigned long endTime = millis();
    
    digitalWrite(ledPin, LOW);
    digitalWrite(buzzerPin, LOW);
    
    unsigned long reactionTime = endTime - startTime;
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Delay: ");
    lcd.setCursor(0, 1);
    lcd.print(reactionTime);
    lcd.print(" ms");
    
    delay(3000); // Display result for 3 seconds
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Pencet utk mulai");
    lcd.setCursor(0, 1);
    lcd.print("lagi");
  }
}