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

#define DHTPIN 26
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

#define THERMISTOR_PIN 34  // Analog pin for thermistor

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqttServer = "mqtt.eclipseprojects.io";
const int mqttPort = 1883;
const char* mqttTopic = "sensors/esp32";

WiFiClient espClient;
PubSubClient client(espClient);

void setupWiFi() {
  Serial.print("Connecting to WiFi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" connected.");
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");
    if (client.connect("ESP32Client")) {
      Serial.println(" connected.");
    } else {
      Serial.print(" failed, rc=");
      Serial.println(client.state());
      delay(1000);
    }
  }
}

float readThermistorC() {
  int analogValue = analogRead(THERMISTOR_PIN);
  float voltage = analogValue * (3.3 / 4095.0);
  float resistance = (3.3 * 10000.0 / voltage) - 10000.0;

  float steinhart;
  steinhart = resistance / 10000.0;          // R/Ro
  steinhart = log(steinhart);                // ln(R/Ro)
  steinhart /= 3950.0;                       // 1/B * ln(R/Ro)
  steinhart += 1.0 / (25.0 + 273.15);        // + (1/To)
  steinhart = 1.0 / steinhart;               // Invert
  steinhart -= 273.15;                       // Convert to °C

  return steinhart;
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  setupWiFi();
  client.setServer(mqttServer, mqttPort);
}

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

  float dhtTemp = dht.readTemperature();
  float dhtHum = dht.readHumidity();
  float thermistorTemp = readThermistorC();

  if (isnan(dhtTemp) || isnan(dhtHum)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  // Create JSON payload
  String payload = "{";
  payload += "\"dht22_temp\":" + String(dhtTemp, 1) + ",";
  payload += "\"dht22_humidity\":" + String(dhtHum, 1) + ",";
  payload += "\"thermistor_temp\":" + String(thermistorTemp, 1);
  payload += "}";

  client.publish(mqttTopic, payload.c_str());
  Serial.println("Published: " + payload);

  delay(5000); // Delay between publishes
}