#define BUTTON_PIN 5     // Button connected to GPIO 5
#define RELAY_PIN  18    // Relay IN pin connected to GPIO 18

bool relayState = false;
bool lastButtonState = HIGH;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);  
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, HIGH);     // Start with relay OFF (HIGH = OFF for active LOW relay)
  Serial.begin(115200);
  Serial.println("System started - Relay OFF");
}

void loop() {
  bool buttonState = digitalRead(BUTTON_PIN);
  
  // Toggle relay on button press (button is active LOW)
  if (buttonState == LOW && lastButtonState == HIGH) {
    relayState = !relayState;
    
    // Fixed: Inverted logic for active LOW relay module
    digitalWrite(RELAY_PIN, relayState ? LOW : HIGH);
    
    // Debug output
    Serial.print("Button pressed! Relay is now: ");
    Serial.println(relayState ? "ON" : "OFF");
    Serial.print("Relay pin set to: ");
    Serial.println(relayState ? "LOW" : "HIGH");
    
    delay(200); // debounce delay
  }
  
  lastButtonState = buttonState;
}