const int redLedPin = 13;     // Red LED pin
const int yellowLedPin = 11; // Yellow LED pin
const int greenLedPin = 9;  // Green LED pin
const int ldrPin = A0;       // LDR connected to A0

bool redLedState = false;     // State of red LED
bool yellowLedState = false;  // State of yellow LED
bool greenLedState = false;   // State of green LED

unsigned long previousRedMillis = 0;
unsigned long previousYellowMillis = 0;
unsigned long previousGreenMillis = 0;

const int redOnTime = 200;   // Red LED ON time (ms)
const int redOffTime = 800;  // Red LED OFF time (ms)
unsigned long redInterval = redOnTime; // Initial interval for red LED

int yellowBlinkInterval = 500; // Initial blink speed for yellow LED
bool greenLedActivated = false; // Prevents continuous triggering of green LED

void setup() {
  pinMode(redLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);
  Serial.begin(9600); // Debugging
}

void loop() {
  unsigned long currentMillis = millis();

  // Red LED Blinking (200ms ON, 800ms OFF)
  if (currentMillis - previousRedMillis >= redInterval) {
    previousRedMillis = currentMillis; // Reset timer
    redLedState = !redLedState;        // Toggle LED state
    digitalWrite(redLedPin, redLedState); // Apply state

    // Set next interval (switch between ON and OFF time)
    redInterval = redLedState ? redOnTime : redOffTime;
  }

  // Read LDR value
  int ldrValue = analogRead(ldrPin);  // Read LDR (0-1023)

  // Smoothly adjust yellow LED blink interval using LDR value
  yellowBlinkInterval += (ldrValue - yellowBlinkInterval) * 0.1; // Smooth transition

  // Ensure blinking remains visible (limit range)
  //if (yellowBlinkInterval < 200) yellowBlinkInterval = 200; // Fastest blink
  //if (yellowBlinkInterval > 1000) yellowBlinkInterval = 1000; // Slowest blink

  // Yellow LED Blinking based on LDR value
  if (currentMillis - previousYellowMillis >= yellowBlinkInterval) {
    previousYellowMillis = currentMillis; // Reset timer
    yellowLedState = !yellowLedState; // Toggle LED state
    digitalWrite(yellowLedPin, yellowLedState); // Apply state
  }

  // Check if Red and Yellow LEDs blink exactly at 200ms ON / 800ms OFF
  if (!greenLedActivated && yellowBlinkInterval == (redOnTime + redOffTime)) {
    greenLedState = true;
    greenLedActivated = true; // Prevent retriggering
    previousGreenMillis = currentMillis;
    digitalWrite(greenLedPin, HIGH); // Turn on Green LED for 3 seconds
  }

  // Turn off Green LED after 3 seconds
  if (greenLedState && currentMillis - previousGreenMillis >= 3000) {
    greenLedState = false;
    digitalWrite(greenLedPin, LOW);
  }

  // Reset green LED activation when yellow and red are no longer in sync
  if (yellowBlinkInterval != (redOnTime + redOffTime)) {
    greenLedActivated = false;
  }

  // Debug output
  Serial.print("LDR Value: ");
  Serial.print(ldrValue);
  Serial.print(" - Yellow Blink Interval: ");
  Serial.print(yellowBlinkInterval);
  Serial.print(" - Green LED State: ");
  Serial.println(greenLedState);
}