#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <ESP32Servo.h>

// --------- DHT22 ----------
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// --------- SERVO ----------
Servo tempServo;

// --------- Ultrasonic ----------
#define TRIG 18
#define ECHO 19
#define ULTRASONIC_LED 23

// --------- LDR ----------
#define LDRPIN 34
#define LDR_LED 22

// --------- Gas Sensor ----------
#define GASPIN 35
#define GAS_BUZZER 21
#define GAS_THRESHOLD 400

// --------- PIR ----------
#define PIRPIN 32
#define PIR_RELAY 33

// --------- LCD I2C ----------
#define SDA_PIN 25
#define SCL_PIN 26
LiquidCrystal_I2C lcd(0x27, 16, 2);

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

  // ---------------- SERVO SETUP ----------------
  ESP32PWM::allocateTimer(0);
  ESP32PWM::allocateTimer(1);
  ESP32PWM::allocateTimer(2);
  ESP32PWM::allocateTimer(3);

  tempServo.setPeriodHertz(50);      
  tempServo.attach(5, 500, 2400);    
  
  // ---------------- DHT ----------------
  dht.begin();

  // ---------------- Ultrasonic ----------------
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(ULTRASONIC_LED, OUTPUT);

  // ---------------- LDR ----------------
  pinMode(LDR_LED, OUTPUT);

  // ---------------- Gas ----------------
  pinMode(GAS_BUZZER, OUTPUT);

  // ---------------- PIR ----------------
  pinMode(PIRPIN, INPUT);
  pinMode(PIR_RELAY, OUTPUT);

  // ---------------- LCD ----------------
  Wire.begin(SDA_PIN, SCL_PIN);
  lcd.init();
  lcd.backlight();
}

void loop() {

  // ---------- DHT22 + Servo ----------
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  if (!isnan(temp)) {
    int angle = map(temp, 20, 40, 0, 180);
    angle = constrain(angle, 0, 180);
    tempServo.write(angle);
  }

  // ---------- Ultrasonic ----------
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  long duration = pulseIn(ECHO, HIGH);
  float distance = duration * 0.034 / 2;

  if (distance < 20) digitalWrite(ULTRASONIC_LED, HIGH);
  else digitalWrite(ULTRASONIC_LED, LOW);

  // ---------- LDR ----------
  int light = analogRead(LDRPIN);
  if (light < 2000) digitalWrite(LDR_LED, HIGH);
  else digitalWrite(LDR_LED, LOW);

  // ---------- Gas Sensor ----------
  int gas = analogRead(GASPIN);
  if (gas > GAS_THRESHOLD) digitalWrite(GAS_BUZZER, HIGH);
  else digitalWrite(GAS_BUZZER, LOW);

  // ---------- PIR ----------
  int motion = digitalRead(PIRPIN);
  if (motion == HIGH) digitalWrite(PIR_RELAY, HIGH);
  else digitalWrite(PIR_RELAY, LOW);

  // ---------- LCD DISPLAY ----------
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(temp, 1);
  lcd.print(" H:");
  lcd.print(hum, 0);

  lcd.setCursor(0, 1);
  lcd.print("L:");
  lcd.print(light);
  lcd.print(" D:");
  lcd.print(distance, 0);
  lcd.print("cm");

  // ---------- Serial Monitor ----------
  Serial.print("Temp: "); Serial.print(temp);
  Serial.print("C  Hum: "); Serial.print(hum);
  Serial.print("%  Light: "); Serial.print(light);
  Serial.print("  Dist: "); Serial.print(distance);
  Serial.print(" cm  Gas: "); Serial.print(gas);
  Serial.print("  Motion: "); Serial.println(motion);

  delay(2000);
}