#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <MQUnifiedsensor.h>
#include <WiFi.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
/************************Hardware Related Macros************************************/
#define         Board                   ("ESP-32")
#define         Pin                     (32)  //Analog input 3 of your arduino
/***********************Software Related Macros************************************/
#define         Type                    ("MQ-2") //MQ2
#define         Voltage_Resolution      (3.3)
#define         ADC_Bit_Resolution      (12) // For arduino UNO/MEGA/NANO
#define         RatioMQ2CleanAir        (9.83) //RS / R0 = 9.83 ppm 
#define         DHTPIN                  26
#define         DHTTYPE                 DHT22
#define         LDR_PIN                 35
#define         STATUS_LED              2    // Built-in LED on most ESP32 boards

/*****************************Globals***********************************************/
MQUnifiedsensor MQ2(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHTPIN, DHTTYPE);

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

// MQTT Broker settings
const char* mqtt_server = "broker.hivemq.com"; // Public MQTT broker
const int mqtt_port = 1883;
const char* mqtt_topic = "esp32/data";
const char* mqtt_client_id = "ESP32Client";

// Set up WiFi and MQTT clients
WiFiClient espClient;
PubSubClient client(espClient);

// Sensor values
int valor_gas = 0; 
float temperature = 0;
float humidity = 0;
float lux = 0;
float Ph =0;
float soil_hum =0;
int gas_level = 0;  // Added for compatibility with your publish function
const float TEMP_THRESHOLD_HIGH = 30.0;
const float GAMMA = 0.7;
const float RL10 = 33;

// Timer for sending data
unsigned long previousMillis = 0;
const long interval = 10000; // Send data every 10 seconds

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  
  // Initialize status LED
  pinMode(STATUS_LED, OUTPUT);
  digitalWrite(STATUS_LED, LOW);
  
  // Initialize DHT sensor
  dht.begin();
  
  // Initialize LCD
  lcd.init();
  lcd.begin(16, 2);
  lcd.clear();
  lcd.backlight();
  lcd.print("PRACTICA");
  delay(1000);
   
  lcd.clear();
  lcd.print("SENSADO LM35");
  lcd.setCursor(0,1);
  lcd.print("CURSO 1 ");
  delay(1000);
  lcd.clear();
  
  // Initialize MQ2 sensor
  MQ2.setRegressionMethod(1); //_PPM =  a*ratio^b
  MQ2.setA(574.25); MQ2.setB(-2.222); // Configure the equation to calculate LPG concentration

  Serial.print("Calibrating please wait.");
  float calcR0 = 0;
  for(int i = 1; i<=10; i ++)
  {
    MQ2.update(); // Update data, the arduino will read the voltage from the analog pin
    calcR0 += MQ2.calibrate(RatioMQ2CleanAir);
    Serial.print(".");
  }
  MQ2.setR0(calcR0/10);
  Serial.println("R0 = " + String(calcR0/10));
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("MQ2 = ");
  lcd.print(calcR0/10);
  delay(500);
  
  if(isinf(calcR0)) {
    Serial.println("Warning: Connection issue, R0 is infinite (Open circuit detected) please check your wiring and supply"); 
    while(1);
  }
  if(calcR0 == 0) {
    Serial.println("Warning: Connection issue found, R0 is zero (Analog pin shorts to ground) please check your wiring and supply"); 
    while(1);
  }
  
  // Setup WiFi
  setup_wifi();
  
  // Setup MQTT
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
  
  MQ2.serialDebug(true);
}

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to WiFi: ");
  Serial.println(ssid);
  displayMessage("Connecting WiFi...");

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  
  displayMessage("WiFi connected!");
  delay(1000);
}

void reconnect() {
  // Loop until we're reconnected to the MQTT broker
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    displayMessage("Connecting MQTT...");
    
    // Attempt to connect
    if (client.connect(mqtt_client_id)) {
      Serial.println("connected");
      displayMessage("MQTT connected!");
      delay(1000);
      
      // Subscribe to topics if needed
      // client.subscribe("sensor/commands");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      displayMessage("MQTT failed!");
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  // Handle incoming messages here
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  
  String message = "";
  for (int i = 0; i < length; i++) {
    message += (char)payload[i];
  }
  Serial.println(message);
  
  // You can add commands handling here
  // if (String(topic) == "sensor/commands") {
  //   // Process commands
  // }
}

void displayMessage(const char* message) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(message);
}

// Using your custom MQTT publish function
void publish_mqtt_data() {
  StaticJsonDocument<256> doc;

  doc["nhiet_do"] = temperature;
  doc["do_am"] = humidity;
  doc["nong_do_khoi"] = gas_level;
  doc["cuong_do_sang"] = lux;
  doc["do_PH"] = Ph;
  doc["do_am_dat"] = soil_hum;

  char buffer[256];
  serializeJson(doc, buffer);

  if (client.publish(mqtt_topic, buffer)) {
    Serial.println("MQTT published");
    delay(100);
  } else {
    Serial.println("MQTT publish failed");
  }
}

void readSensors() {
  // Read MQ2 sensor
  MQ2.update();
  MQ2.readSensor();
  
  // Read gas value
  valor_gas = analogRead(Pin);
  valor_gas = map(valor_gas, 0, 4095, 0, 100);
  gas_level = valor_gas;  // Set gas_level for MQTT publishing
  
  // Read temperature and humidity
  temperature = dht.readTemperature();
  humidity = dht.readHumidity();
  
  // Read light sensor
  int analogValue = analogRead(LDR_PIN);
  float voltage = analogValue / 4096.0 * 3.3;
  float resistance = 2000 * voltage / (1 - voltage / 3.3);
  lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  Ph = random(5.5,7.7);
  soil_hum = random(40,100);
   // Print to serial
  Serial.println("-------- Sensor Readings --------");
  Serial.println("Gas: " + String(gas_level) + "%");
  Serial.println("Temperature: " + String(temperature) + "°C");
  Serial.println("Humidity: " + String(humidity) + "%");
  Serial.println("Light: " + String(lux) + " lux");
  Serial.println("PH: " + String(Ph) + " Ph");
  Serial.println("Soil humidity: " + String(soil_hum) + " %");
  Serial.println("---------------------------------");
}

void updateLCD() {
  // Clear the LCD and update with new values
  lcd.clear();
  
  // First row - Gas sensor value and light
  lcd.setCursor(0, 0);
  lcd.print("G:");
  lcd.print(gas_level);
  lcd.print("% L:");
  lcd.print((int)lux);
  lcd.print("lx");
  // lcd.print("% SH:");
  // lcd.print((int)soil_hum);
  // lcd.print("%");
  // Second row - Temperature and humidity
  lcd.setCursor(0, 1);
  lcd.print("T:");
  lcd.print(temperature, 1);
  lcd.print("C H:");
  lcd.print(humidity, 0);
  lcd.print("%");
  lcd.print("PH:");
  lcd.print(Ph);
  lcd.print("lx");
}

void loop() {
  // Ensure MQTT connection
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
  
  // Read all sensors
  readSensors();
  
  // Update the LCD with current readings
  updateLCD();
  
  // Check if it's time to send data to MQTT broker
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    publish_mqtt_data();  // Use your custom publish function
  }
  
  delay(500); // Update LCD every 500ms
}