#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_MPU6050.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
Adafruit_MPU6050 mpu;

const int potPin = 36;
const int greenLED = 26;
const int redLED = 27;
const int buzzer = 25;
const int buttonPin = 33;

bool alertActive = false;

void setup() {
  Serial.begin(115200);

  pinMode(greenLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 failed");
    for (;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  if (!mpu.begin()) {
    Serial.println("MPU6050 failed");
    for (;;);
  }

  display.println("System Ready");
  display.display();
  delay(1000);
}

void loop() {
  int potValue = analogRead(potPin); // simulating occupancy
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);

  if (digitalRead(buttonPin) == LOW) {
    alertActive = false;
  }

  if (potValue > 2000) {  // Occupied
    digitalWrite(greenLED, HIGH);
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Occupied");
    display.display();
  } else {
    digitalWrite(greenLED, LOW);
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Empty");
    display.display();
  }

  if (abs(a.acceleration.x) > 15 || abs(a.acceleration.y) > 15) {
    alertActive = true;
  }

  if (alertActive) {
    digitalWrite(redLED, HIGH);
    tone(buzzer, 1000);
    display.setCursor(0, 16);
    display.println("ALERT: Movement!");
    display.display();
  } else {
    digitalWrite(redLED, LOW);
    noTone(buzzer);
  }

  delay(500);
}