#include <WiFi.h>
#include <HTTPClient.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <DHT.h>
#include <math.h>

// Wi-Fi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// MQTT settings
const char* mqtt_server = "mqtt.eclipseprojects.io";
const int mqtt_port = 1883;
const char* mqtt_weather_topic = "weather/data";
const char* mqtt_sensor_topic = "sensors/esp32";

// OpenWeatherMap
const char* apiKey = "0897ec6053fd70b586341d0cc5e0d88a";
const char* city = "Cape Town";
const char* countryCode = "ZA";

// DHT and thermistor setup
#define DHTPIN 26
#define DHTTYPE DHT22
#define THERMISTOR_PIN 34
DHT dht(DHTPIN, DHTTYPE);

// Clients
WiFiClient wifiClient;
PubSubClient mqttClient(wifiClient);

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

// MQTT reconnect
void reconnectMQTT() {
  while (!mqttClient.connected()) {
    Serial.print("Connecting to MQTT...");
    if (mqttClient.connect("ESP32_Combined_Client")) {
      Serial.println(" connected.");
    } else {
      Serial.print(" failed, rc=");
      Serial.println(mqttClient.state());
      delay(2000);
    }
  }
}

// Thermistor temperature reading
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;
  steinhart = log(steinhart);
  steinhart /= 3950.0;
  steinhart += 1.0 / (25.0 + 273.15);
  steinhart = 1.0 / steinhart;
  steinhart -= 273.15;
  return steinhart;
}

// Fetch and publish weather data
void fetchWeather() {
  String cityEncoded = "Cape%20Town";
  String apiUrl = "http://api.openweathermap.org/data/2.5/weather?q=" + cityEncoded + "," + countryCode + "&appid=" + apiKey + "&units=metric";

  HTTPClient http;
  http.begin(apiUrl);
  int httpCode = http.GET();

  if (httpCode > 0) {
    String payload = http.getString();
    StaticJsonDocument<1024> doc;
    DeserializationError error = deserializeJson(doc, payload);

    if (!error) {
      StaticJsonDocument<512> outDoc;
      outDoc["city"] = city;
      outDoc["country"] = countryCode;
      outDoc["temp"] = doc["main"]["temp"];
      outDoc["humidity"] = doc["main"]["humidity"];
      outDoc["description"] = doc["weather"][0]["description"];
      outDoc["wind"] = doc["wind"]["speed"];

      char buffer[512];
      serializeJson(outDoc, buffer);
      mqttClient.publish(mqtt_weather_topic, buffer);
      Serial.println("Published weather:");
      Serial.println(buffer);
    } else {
      Serial.print("JSON error: ");
      Serial.println(error.c_str());
    }
  } else {
    Serial.print("HTTP error: ");
    Serial.println(httpCode);
  }

  http.end();
}

// Read and publish local sensor data
void publishSensorData() {
  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;
  }

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

  mqttClient.publish(mqtt_sensor_topic, payload.c_str());
  Serial.println("Published sensor data:");
  Serial.println(payload);
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  setupWiFi();
  mqttClient.setServer(mqtt_server, mqtt_port);
}

void loop() {
  if (!mqttClient.connected()) {
    reconnectMQTT();
  }

  mqttClient.loop();

  // Get and send data
  fetchWeather();
  publishSensorData();

  // Wait before next cycle
  delay(60000);  // Every 60 seconds
}