#include <WiFi.h>
#include <PubSubClient.h>
#include <DHTesp.h>

// -------------------- SENSOR PINS --------------------
#define DHT_PIN       15
#define TRIG_PIN      5
#define ECHO_PIN      18
#define GAS_PIN       34
#define LDR_PIN       35
#define PIR_PIN       14
#define LED_PIN       23   

DHTesp dht;

// -------------------- WIFI --------------------
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// -------------------- MQTT BROKER --------------------
const char* mqttServer = "broker.emqx.io";
const int   mqttPort   = 1883;
const char* topicData  = "IOT";
const char* topicLed   = "IOT/led";

WiFiClient espClient;
PubSubClient client(espClient);

// -------------------- SETUP --------------------
void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(GAS_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  dht.setup(DHT_PIN, DHTesp::DHT22);

  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(300);
    Serial.print(".");
  }
  Serial.println("\nWiFi Connected");

  client.setServer(mqttServer, mqttPort);
  client.setCallback(mqttCallback);
}

// -------------------- RECONNECT MQTT --------------------
void reconnect() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");
    if (client.connect("esp32ClientWokwi_LED23")) {
      Serial.println("connected");
      // subscribe for LED control
      client.subscribe(topicLed);
      Serial.println(String("Subscribed to: ") + topicLed);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" retrying in 2 sec");
      delay(2000);
    }
  }
}

// -------------------- MQTT CALLBACK --------------------
void mqttCallback(char* topic, byte* message, unsigned int length) {
  String msg = "";
  for (unsigned int i = 0; i < length; i++) {
    msg += (char)message[i];
  }
  Serial.print("MQTT in [");
  Serial.print(topic);
  Serial.print("] ");
  Serial.println(msg);

  // LED control: accept "1"/"0" or "LED_ON"/"LED_OFF"
  if (String(topic) == topicLed) {
    if (msg == "1" || msg.equalsIgnoreCase("LED_ON")) {
      digitalWrite(LED_PIN, HIGH);
      Serial.println("LED -> ON");
    } else if (msg == "0" || msg.equalsIgnoreCase("LED_OFF")) {
      digitalWrite(LED_PIN, LOW);
      Serial.println("LED -> OFF");
    } else {
      Serial.println("Unknown LED command");
    }
  }
}

// -------------------- GET ULTRASONIC DISTANCE --------------------
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); // timeout 30ms
  if (duration == 0) return 0; // no reading
  return (long)(duration * 0.034 / 2);
}

// ===================================================================
//                             MAIN LOOP
// ===================================================================
void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // -------- DHT SENSOR --------
  TempAndHumidity d = dht.getTempAndHumidity();

  float temp = d.temperature;
  float hum  = d.humidity;
  if (isnan(temp)) temp = 0;
  if (isnan(hum)) hum = 0;

  // -------- DISTANCE SENSOR --------
  long distance = getDistance();

  // -------- PIR --------
  int motion = digitalRead(PIR_PIN);

  // -------- GAS SENSOR --------
  int gasValue = analogRead(GAS_PIN); // raw analog 0..4095
  // optionally derive gasDetected boolean threshold:
  int gasDetectedBool = (gasValue > 1800) ? 1 : 0;

  // -------- LDR SENSOR --------
  int ldrValue = analogRead(LDR_PIN); // raw analog 0..4095
  int ldrBool = (ldrValue < 2000) ? 0 : 1;

  // ------------------ CLEAN SERIAL PRINT ------------------
  Serial.println("------ SENSOR STATUS ------");
  Serial.print("Motion : "); Serial.println(motion ? "Detected" : "No Motion");
  Serial.print("Distance : "); Serial.print(distance); Serial.println(" cm");
  Serial.print("Temperature : "); Serial.print(temp); Serial.println(" °C");
  Serial.print("Humidity : "); Serial.print(hum); Serial.println(" %");
  Serial.print("Gas (raw) : "); Serial.print(gasValue); Serial.print("  bool: "); Serial.println(gasDetectedBool);
  Serial.print("LDR (raw) : "); Serial.print(ldrValue); Serial.print("  bool: "); Serial.println(ldrBool);
  Serial.println("---------------------------\n");

  // ------------------ JSON DATA FOR NODE-RED ------------------
  String json = "{";
  json += "\"temp\":" + String(temp, 1) + ",";
  json += "\"hum\":" + String(hum, 1) + ",";
  json += "\"dist\":" + String(distance) + ",";
  json += "\"motion\":" + String(motion) + ",";
  json += "\"gas\":" + String(gasValue) + ",";
  json += "\"ldr\":" + String(ldrValue);
  json += "}";

  client.publish(topicData, json.c_str());
  Serial.print("Published to ");
  Serial.print(topicData);
  Serial.print(": ");
  Serial.println(json);

  delay(2000);
}