#include <DHT.h>

// ---------------- PIN CONFIG ----------------
#define POT_PIN 15

#define TRIG_PIN 4
#define ECHO_PIN 2

#define PIR_PIN 16

#define LED1 17
#define LED2 5
#define LED3 18
#define LED4 19

#define SERVO_PIN 21

#define DHT_PIN 23
#define DHT_TYPE DHT22

DHT dht(DHT_PIN, DHT_TYPE);

// ---------------- VARIABLES ----------------
int servoAngle = 0;
int previousAngle = 0;

bool pirTriggered = false;
bool lastPirState = LOW;

// ---------------- SERVO FUNCTION ----------------
void setServoAngle(int angle) {
  int pulseWidth = map(angle, 0, 180, 500, 2500);

  digitalWrite(SERVO_PIN, HIGH);
  delayMicroseconds(pulseWidth);
  digitalWrite(SERVO_PIN, LOW);

  delay(20);
}

// ---------------- ULTRASONIC ----------------
long getDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH, 30000);
  return duration * 0.034 / 2;
}

// ---------------- SETUP ----------------
void setup() {
  Serial.begin(9600);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);

  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);

  pinMode(SERVO_PIN, OUTPUT);

  dht.begin();

  Serial.println("System Ready (Wait PIR warmup)");
}

// ---------------- LOOP ----------------
void loop() {

  // -------- READ POT (always keep updated) --------
  int potValue = analogRead(POT_PIN);
  int potAngle = map(potValue, 0, 4095, 0, 180);

  // -------- PIR DETECTION --------
  bool pirState = digitalRead(PIR_PIN);

  if (pirState == HIGH && lastPirState == LOW && !pirTriggered) {

    pirTriggered = true;

    previousAngle = potAngle;   // store current position

    Serial.println("PIR DETECTED → Servo to 50°");

    // move to 50°
    for (int i = 0; i < 90; i++) {
      setServoAngle(90);
    }

    delay(3000); // 🔥 3 second hold

    Serial.println("Returning to original position");

    // return to previous angle
    for (int i = 0; i < 50; i++) {
      setServoAngle(previousAngle);
    }

    pirTriggered = false;
  }

  lastPirState = pirState;

  // -------- NORMAL POT CONTROL --------
  if (!pirTriggered) {
    servoAngle = potAngle;
    setServoAngle(servoAngle);
  }

  // -------- ULTRASONIC LEDs (ACTIVE LOW) --------
  long distance = getDistance();

  digitalWrite(LED1, !(distance > 0 && distance < 150));
  digitalWrite(LED2, !(distance > 0 && distance < 100));
  digitalWrite(LED3, !(distance > 0 && distance < 50));

  // -------- DHT --------
  float temp = dht.readTemperature();

  if (!isnan(temp)) {
    digitalWrite(LED4, temp > 30 ? LOW : HIGH);
  }

  // -------- DEBUG --------
  Serial.print("PIR: "); Serial.print(pirState);
  Serial.print(" | Servo: "); Serial.print(servoAngle);
  Serial.print(" | Temp: "); Serial.println(temp);

  delay(500);
}