#include <Servo.h>

Servo myFan;
const int andGatePin = 2; 

// LED Pins
const int redLed = 13;   // Warning (Fan Moving)
const int greenLed = 12; // Safe (Fan Stopped)

// Variables for the Fan
int angle = 0;
int step = 2; // Speed of fan
unsigned long lastServoTime = 0;

// Variables for Blinking
int ledState = LOW;
unsigned long lastBlinkTime = 0;
const long blinkSpeed = 300; // How fast the LEDs blink (milliseconds)

void setup() {
  myFan.attach(9);
  pinMode(andGatePin, INPUT);
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  
  myFan.write(0); // Start at 0
}

void loop() {
  unsigned long currentMillis = millis();
  int isSystemOn = digitalRead(andGatePin);

  // --- BLINK LOGIC TIMER ---
  // Every 300ms, flip the "ledState" from LOW to HIGH or vice versa
  if (currentMillis - lastBlinkTime >= blinkSpeed) {
    lastBlinkTime = currentMillis;
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }
  }

  // --- MAIN DECISION ---
  if (isSystemOn == HIGH) {
    // === DANGER ZONE (Fan Moving) ===
    
    // 1. Blink Red LED
    digitalWrite(redLed, ledState);
    digitalWrite(greenLed, LOW); // Green must be OFF

    // 2. Move Fan Smoothly (without stopping the code)
    if (currentMillis - lastServoTime >= 15) {
      lastServoTime = currentMillis;
      angle = angle + step;
      if (angle >= 180 || angle <= 0) {
        step = -step; // Reverse direction
      }
      myFan.write(angle);
    }
  } 
  else {
    // === SAFE ZONE (Fan Stopped) ===
    
    // 1. Blink Green LED
    digitalWrite(greenLed, ledState);
    digitalWrite(redLed, LOW); // Red must be OFF

    // 2. Stop Fan
    myFan.write(0);
    angle = 0; 
  }
}