#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int redPin = 9;
const int greenPin = 10;
const int bluePin = 11;
const int buttonPin = 2;

unsigned long ledOnTime;
bool waitingForReaction = false;
bool isGreen = false;

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);

  lcd.begin(16, 2);
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Reaction Timer");
  delay(2000);
  lcd.clear();
}

void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Wait for color...");
  delay(random(2000, 5000));

  // Randomly choose green or a "wrong" color
  int color = random(0, 4); // 0 = green, others = wrong
  setColorByCode(color);
  isGreen = (color == 0);

  ledOnTime = millis();
  waitingForReaction = true;

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(isGreen ? "GO!" : "Don't Press!");

  while (waitingForReaction) {
    if (digitalRead(buttonPin) == LOW) {
      setColor(0, 0, 0); // Turn off LED

      lcd.clear();
      if (isGreen) {
        unsigned long reactionTime = millis() - ledOnTime;
        lcd.print("Reaction Time:");
        lcd.setCursor(0, 1);
        lcd.print(reactionTime);
        lcd.print(" ms");
      } else {
        lcd.print("Too Soon!");
      }

      waitingForReaction = false;
      delay(3000);
      lcd.clear();
    }
  }
}

// Set RGB color using inverted analogWrite for common cathode
void setColor(int r, int g, int b) {
  analogWrite(redPin, 255 - r);
  analogWrite(greenPin, 255 - g);
  analogWrite(bluePin, 255 - b);
}

// Color code selector
void setColorByCode(int code) {
  switch (code) {
    case 0: setColor(0, 255, 0); break;   // Green = correct
    case 1: setColor(255, 0, 0); break;   // Red
    case 2: setColor(0, 0, 255); break;   // Blue
    case 3: setColor(255, 0, 255); break; // Purple
  }
}