#include <Arduino.h>

// Define the LED pins and serial communication baud rate
const int ledPin1 = 14;
const int ledPin2 = 12;
const long baudRate = 9600;

// The predefined correct answer string
const char* correctAnswer = "password";

// Variables for the blinking logic
bool isBlinking = true;
unsigned long previousMillis = 0;
long currentInterval = 1000; // This will change dynamically

// Variables for the timer logic
const long timerDuration = 10000; // 10 seconds in milliseconds
unsigned long startTimer;
bool timerActive = true;

// A buffer to store incoming serial data
char incomingData[10];

// A custom function to get the blink interval based on remaining time
// This function is specialized for this application and uses the global timerDuration
long getBlinkInterval(long remainingTime) {
  // Input range for remainingTime: 0 to timerDuration
  // Output range for the blink interval: 0ms (fastest) to 1000ms (slow)
  return remainingTime * (1000 - 0) / (timerDuration - 0) + 0;
}

void setup() {
  // Initialize both LED pins as outputs
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  
  // Start serial communication at the specified baud rate
  Serial.begin(baudRate);
  
  // Inform the user about the initial state and how to play
  Serial.println("LED 1 is blinking. What's the secret word? You have 10 seconds!");
  Serial.println("Enter your answer below and press Enter.");
  
  // Start the timer
  startTimer = millis();
}

void loop() {
  // Handle serial input first
  if (Serial.available() > 0) {
    // Read the incoming bytes until a newline character is found
    int bytesRead = Serial.readBytesUntil('\n', incomingData, sizeof(incomingData) - 1);
    
    // Add a null terminator to the string
    incomingData[bytesRead] = '\0';
    
    // Check if the received command matches the correct answer
    if (strcmp(incomingData, correctAnswer) == 0) {
      Serial.println("That's the correct answer! ");
      
      // Stop the blinking and timer, then turn LED 1 and 2 on permanently
      isBlinking = false;
      timerActive = false;
      digitalWrite(ledPin1, HIGH);
      digitalWrite(ledPin2, HIGH);
      
      Serial.println("LED 2 is now also on permanently.");
    } else {
      // The answer was incorrect, reset the timer
      Serial.println("Wrong answer. You have 10 seconds to try again!");
      digitalWrite(ledPin1, LOW); // Turn off the LED to restart the blink cycle
      startTimer = millis(); // Reset the timer
    }
  }
  
  // Check if the timer has expired
  if (timerActive && millis() - startTimer >= timerDuration) {
    Serial.println("Time's up! The LED is off. Try again!");
    digitalWrite(ledPin1, LOW); // Turn off the LED to reset
    startTimer = millis(); // Restart the timer for a new attempt
  }

  // Blinking logic only runs if isBlinking is true
  if (isBlinking) {
    // Calculate the time remaining
    long elapsedTime = millis() - startTimer;
    long remainingTime = timerDuration - elapsedTime;
    
    // Dynamically adjust the blinking speed using the new function
    currentInterval = getBlinkInterval(remainingTime);
    
    // Check if the blinking interval has passed
    if (millis() - previousMillis >= currentInterval) {
      // Save the last time the LED was toggled
      previousMillis = millis();

      // Toggle the state of the first LED
      if (digitalRead(ledPin1) == LOW) {
        digitalWrite(ledPin1, HIGH);
      } else {
        digitalWrite(ledPin1, LOW);
      }
    }
  }
}