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

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

const int temp = 2; // temperature indication
const int occupancy = 4; // occupancy indication
const int systemstatus = 5; // system status
const int pot = 34; // potentiometer pin 
const int pirPin = 15; // pir sensor
const int irPin = 16; // ir sensor
const int trigPin = 17; // trigger pin
const int echoPin = 18; // echo pin

void setup() {
  // put your setup code here, to run once:
  pinMode(temp, OUTPUT);
  pinMode(occupancy, OUTPUT);
  pinMode(systemstatus, OUTPUT);
  pinMode(pot, INPUT);
  pinMode(pirPin, INPUT);
  pinMode(irPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  digitalWrite(temp, LOW);
  digitalWrite(occupancy, LOW);
  digitalWrite(systemstatus, HIGH); // system is on or off
  Serial.begin(115200);
  Serial.println("Hello");
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.display();
}


void loop() {
  int tempValue = analogRead(pot); 
  if (tempValue > 2048) { 
    digitalWrite(temp, HIGH);
  } else {
    digitalWrite(temp, LOW);
  }

  int occupancyStatus = (digitalRead(pirPin) == HIGH || digitalRead(irPin) == HIGH || isThereMotion()) ? 1 : 0;
  if (occupancyStatus) {
    digitalWrite(occupancy, HIGH); 
  } else {
    digitalWrite(occupancy, LOW);
  }

  display.clearDisplay();
  display.setCursor(0,0);
  display.print("Temp Value: ");
  display.println(tempValue);
  display.print("Occupancy: ");
  display.println(occupancy ? "Yes" : "No");
  display.print("Distance: ");
  long distance = measureDistance();
  display.print(distance);
  display.println(" cm");
  display.display();

  delay(1000);
}

long measureDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  long duration = pulseIn(echoPin, HIGH);
  return duration * 0.034 / 2; 
}

int isThereMotion() {
  long distance = measureDistance();
  return distance < 100 ? 1 : 0; 
}