#define PIR_PIN 2     // PIR sensor connected to digital pin 2
#define LED_PIN 13    // LED connected to pin 13

unsigned long motionTimestamps[10]; // Store timestamps of recent motions
int motionCount = 0;

bool highAlert = false;
unsigned long lastMotionTime = 0;
unsigned long ledOnTime = 0;

void setup() {
  pinMode(PIR_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  unsigned long currentTime = millis();
  int motionDetected = digitalRead(PIR_PIN);

  // Handle new motion
  if (motionDetected == HIGH && currentTime - lastMotionTime > 1000) {
    lastMotionTime = currentTime;
    Serial.println("Motion detected!");

    // Turn on LED for 5 seconds
    digitalWrite(LED_PIN, HIGH);
    ledOnTime = currentTime;

    // Add to motion history
    motionTimestamps[motionCount % 10] = currentTime;
    motionCount++;

    // Check for high alert condition
    int recentCount = 0;
    for (int i = 0; i < motionCount && i < 10; i++) {
      if (currentTime - motionTimestamps[i] <= 60000) {
        recentCount++;
      }
    }

    if (recentCount > 3) {
      highAlert = true;
      Serial.println("High Alert Mode Activated!");
    }
  }

  // Handle LED timing (keep it ON for 5 seconds unless in high alert)
  if (!highAlert && digitalRead(LED_PIN) == HIGH && currentTime - ledOnTime >= 5000) {
    digitalWrite(LED_PIN, LOW);
  }

  // High alert mode: blink LED continuously
  if (highAlert) {
    if ((currentTime / 500) % 2 == 0) {
      digitalWrite(LED_PIN, HIGH);
    } else {
      digitalWrite(LED_PIN, LOW);
    }
  }
}