const int buttonPin = 15;  // Button connected to D15
const int relayPin = 4;    // Relay (or LED) connected to D4
boolean state = true;      // Initial state
boolean lastButtonState = HIGH;  // Initial button state
boolean flashing = false;  // Indicates if LED should be flashing

void setup() {
  Serial.begin(115200);
  pinMode(relayPin, OUTPUT);      // Set relayPin as an output
  pinMode(buttonPin, INPUT_PULLUP); // Set buttonPin as an input with pull-up resistor
}

void loop() {
  boolean currentButtonState = digitalRead(buttonPin);

  if (currentButtonState == LOW && lastButtonState == HIGH) {
    flashing = !flashing; // Toggle flashing state
    if (flashing) {
      Serial.println("Button is pressed");
      Serial.println("LED will flash!");
    } else {
      digitalWrite(relayPin, HIGH); // Ensure LED is on when not flashing
      Serial.println("LED is ON!");
    }
    delay(100); // Debounce delay
  }

  if (flashing) {
    static unsigned long lastFlashTime = 0;
    unsigned long currentTime = millis();
    if (currentTime - lastFlashTime >= 125) {
      digitalWrite(relayPin, !digitalRead(relayPin)); // Toggle LED state
      lastFlashTime = currentTime;
    }
  }

  lastButtonState = currentButtonState;
}