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

// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = ""; // Wokwi doesn't require a password

//  Broker settings
const char* mqtt_server = "broker.hivemq.com";
const int mqtt_port = 1883;

// MQTT Topics
const char* topic_humidity = "greenhouse/humidity";
const char* topic_temperature = "greenhouse/temperature";
const char* topic_soilMoisture = "greenhouse/soilMoisture";
const char* topic_lightIntensity = "greenhouse/lightIntensity"; // light intensity topic
const char* topic_ph = "greenhouse/phLevel"; //  pH topic
const char* topic_control = "greenhouse/control"; //  control topic

// DHT Sensor Configuration
#define DHTPIN 15      // GPIO for DHT22
#define DHTTYPE DHT22  // Define sensor type
DHT dht(DHTPIN, DHTTYPE);

// Sensor Pins
const int soilMoisturePin = A0;
const int photoresistorPin = A4; //  photoresistor pin
const int phSensorPin =A5; // pH sensor pin at A2

// Actuator Pins
const int sprinklerPin = 13;
const int fanPin = 14;
const int heaterPin = 12;
const int lightsPin = 27; //  lights actuator pin

// WiFi and MQTT Client
WiFiClient espClient;
PubSubClient client(espClient);

// Callback function for incoming MQTT messages
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");

  // Convert payload to string
  String message = "";
  for (unsigned int i = 0; i < length; i++) {
    message += (char)payload[i];
  }

  Serial.println(message);

  //  handling control messages
  if (String(topic) == topic_control) {
    if (message == "sprinkler_on") {
      digitalWrite(sprinklerPin, HIGH);
      Serial.println("Sprinkler turned ON");
    }
    else if (message == "sprinkler_off") {
      digitalWrite(sprinklerPin, LOW);
      Serial.println("Sprinkler turned OFF");
    }
    // control logic 
  }
}

// Function to read pH from the sensor
float readPHSensor() {
  int sensorValue = analogRead(phSensorPin);
  
  // Convert analog reading to pH
  // This is a simplified conversion. You might need to calibrate based on your specific sensor
  // Typical pH sensor uses a voltage-based conversion
  float voltage = sensorValue * (5.0 / 1023.0);
  float pH = 7.0 + ((2.5 - voltage) / 0.18);
  
  return pH;
}

void setup() {
  // Initialize Serial communication
  Serial.begin(115200);

  // Initialize DHT sensor
  dht.begin();

  // Setup WiFi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());

  // Configure MQTT client
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback); // Set the message callback function

  // Connect to MQTT Broker
  connectToMQTT();

  // Initialize actuator pins
  pinMode(sprinklerPin, OUTPUT);
  pinMode(fanPin, OUTPUT);
  pinMode(heaterPin, OUTPUT);
  pinMode(lightsPin, OUTPUT); // Initialize lights actuator pin
}

void loop() {
  // Ensure MQTT connection
  if (!client.connected()) {
    connectToMQTT();
  }
  client.loop(); // Handle MQTT communication

  // Read sensors
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();
  int soilMoisture = analogRead(soilMoisturePin);
  int lightIntensity = analogRead(photoresistorPin); // Read photoresistor value
  float phLevel = readPHSensor(); // Read pH level

  // Check if sensor readings are valid
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor!");
    delay(5000);
    return;
  }

  // Publish sensor data to MQTT topics
  client.publish(topic_humidity, String(humidity).c_str());
  client.publish(topic_temperature, String(temperature).c_str());
  client.publish(topic_soilMoisture, String(soilMoisture).c_str());
  client.publish(topic_lightIntensity, String(lightIntensity).c_str()); // Publish light intensity
  client.publish(topic_ph, String(phLevel).c_str()); // Publish pH level

  // Debugging: Print sensor data to Serial Monitor
  Serial.println("Sensor Data Published:");
  Serial.print("Humidity: ");
  Serial.println(humidity);
  Serial.print("Temperature: ");
  Serial.println(temperature);
  Serial.print("Soil Moisture: ");
  Serial.println(soilMoisture);
  Serial.print("Light Intensity: ");
  Serial.println(lightIntensity);
  Serial.print("pH Level: ");
  Serial.println(phLevel);

  // Automatic Actuator Control Logic
  digitalWrite(sprinklerPin, soilMoisture < 500 ? HIGH : LOW);
  digitalWrite(fanPin, temperature > 20 ? HIGH : LOW);
  digitalWrite(heaterPin, temperature > 30 ? HIGH : LOW);
  digitalWrite(lightsPin, lightIntensity < 500 ? HIGH : LOW); // Control lights based on light intensity

  delay(5000); // Wait before next reading
}

// Function to connect to MQTT Broker
void connectToMQTT() {
  while (!client.connected()) {
    Serial.println("Connecting to HiveMQ MQTT...");

    // Generate a unique client ID
    String clientId = "ESP32Client-" + String(random(0xffff), HEX);

    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected to HiveMQ Broker");

      // Subscribe to control topic
      client.subscribe(topic_control);
    }
    else {
      Serial.print("MQTT Connection failed. Error code: ");
      Serial.println(client.state());
      delay(5000); // Retry after delay
    }
  }
}