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

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int greenLEDPin = 8;
const int redLEDPin = 9;
const int buttonPin = 2;
const int speakerPin = 10;

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

unsigned long bestTime = 9999;
unsigned long worstTime = 0;

void playHappyTune() {
  tone(speakerPin, 523, 200); delay(200);
  tone(speakerPin, 659, 200); delay(200);
  tone(speakerPin, 784, 300); delay(300);
  noTone(speakerPin);
}

void playNewBestTune() {
  tone(speakerPin, 784, 200); delay(200);
  tone(speakerPin, 880, 200); delay(200);
  tone(speakerPin, 988, 300); delay(300);
  tone(speakerPin, 1047, 400); delay(400);
  noTone(speakerPin);
}

void playSadTune() {
  tone(speakerPin, 220, 300); delay(300);
  tone(speakerPin, 196, 300); delay(300);
  tone(speakerPin, 174, 400); delay(400);
  noTone(speakerPin);
}

void setup() {
  pinMode(greenLEDPin, OUTPUT);
  pinMode(redLEDPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(speakerPin, OUTPUT);

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

  randomSeed(analogRead(A0)); // Improve randomness
}

void loop() {
  digitalWrite(greenLEDPin, LOW);
  digitalWrite(redLEDPin, LOW);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Get ready...");
  delay(1000);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Wait for signal");

  // Wait randomly, and watch for early button press
  int waitTime = random(2000, 5000);
  unsigned long waitStart = millis();
  while (millis() - waitStart < waitTime) {
    if (digitalRead(buttonPin) == LOW) {
      // Too early!
      digitalWrite(redLEDPin, HIGH);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Too fast!");
      playSadTune();
      delay(2000);
      digitalWrite(redLEDPin, LOW);
      lcd.clear();
      return; // Restart loop
    }
  }

  // Start actual round
  isGreen = random(0, 2) == 1;

  if (isGreen) {
    digitalWrite(greenLEDPin, HIGH);
  } else {
    digitalWrite(redLEDPin, HIGH);
  }

  ledOnTime = millis();
  waitingForReaction = true;

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("GO!");

  bool redLEDTimeoutHandled = false;

  while (waitingForReaction) {
    unsigned long currentTime = millis();

    if (digitalRead(buttonPin) == LOW) {
      waitingForReaction = false;
      digitalWrite(greenLEDPin, LOW);
      digitalWrite(redLEDPin, LOW);

      lcd.clear();
      if (isGreen) {
        unsigned long reactionTime = currentTime - ledOnTime;

        bool isNewBest = reactionTime < bestTime;
        if (isNewBest) bestTime = reactionTime;
        if (reactionTime > worstTime) worstTime = reactionTime;

        lcd.setCursor(0, 0);
        lcd.print("You: ");
        lcd.print(reactionTime);
        lcd.print("ms");

        lcd.setCursor(0, 1);
        lcd.print("B:");
        lcd.print(bestTime);
        lcd.print(" W:");
        lcd.print(worstTime);

        isNewBest ? playNewBestTune() : playHappyTune();
      } else {
        lcd.setCursor(0, 0);
        lcd.print("Wrong LED!");
        playSadTune();
      }

      delay(3000);
      lcd.clear();
    }

    if (!isGreen && !redLEDTimeoutHandled && (currentTime - ledOnTime >= 3000)) {
      waitingForReaction = false;
      redLEDTimeoutHandled = true;

      digitalWrite(redLEDPin, LOW);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Good job!");
      delay(3000);
      lcd.clear();
    }
  }
}