#include <WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>
#include <DHT_U.h>
#include <Adafruit_Sensor.h>
#include <HX711.h>

#define DHTPIN 32

const int LOADCELL_DOUT_PIN = 34;
const int LOADCELL_SCK_PIN = 27;
const int redLedPin = 23;
const int greenLedPin = 18;
const int yellowLedPin = 19;
const int irSensorPin = 35; // Define IR sensor pin


unsigned long previousMillis = 0;
const long interval = 500; // Read every 500 milliseconds

// DHT parameters
#define DHTTYPE DHT22 // DHT 22
DHT_Unified dht(DHTPIN, DHTTYPE);
uint32_t delayMS;
HX711 scale;

// Parameters for using non-blocking delay
String msgStr = ""; // MQTT message buffer
float temp, hum, weight;
bool objectDetected = false; // To store the IR sensor state


// WIFI
WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "esp32Client_5810957T"; // yourStudentID must be unique
int PORTNUM = 1883;
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* hostname = "broker.hivemq.com";
const char* mqttTopic = "IoT/LT/5810957T";

void setup_wifi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("Given IP by the router to ESP32 is ");
  Serial.println(WiFi.localIP());
}

void connectMQTT() {
  while (!client.connected()) {
    Serial.println("Connecting to MQTT ...");
    if (client.connect(espClientName)) // , mqttUser, mqttPassword) )
    {
      Serial.println("Connected");
      MQTTSubscribe();
    } else {
      Serial.print("Failed with state ");
      Serial.print(client.state());
      delay(2000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  // Add custom logic to react to messages
}

void MQTTSubscribe() {
  client.subscribe("IoT/LT/5810957T");
}

void setup_MQTT() {
  client.setServer(hostname, PORTNUM);
  client.setCallback(callback);
}

void updateLedStates(float weight) {
  Serial.print("Weight (for LED logic): ");
  Serial.println(weight); // Debug statement to trace weight value

  if (weight < 1.0) {
    digitalWrite(redLedPin, HIGH);   // Turn on red LED
    digitalWrite(yellowLedPin, HIGH); // Turn off yellow LED
    digitalWrite(greenLedPin, LOW);  // Turn off green LED
  } else if (weight >= 1.0 && weight <= 5.0) {
    digitalWrite(redLedPin, HIGH);    // Turn off red LED
    digitalWrite(yellowLedPin, LOW);// Turn on yellow LED
    digitalWrite(greenLedPin, HIGH);  // Turn off green LED
  } else if (weight > 5.0) {
    digitalWrite(redLedPin, LOW);    // Turn off red LED
    digitalWrite(yellowLedPin, HIGH); // Turn off yellow LED
    digitalWrite(greenLedPin, HIGH); // Turn on green LED
  }
}

void setup() {
  Serial.begin(9600);
  delay(5000);

  // Initialize device.
  dht.begin();

  // Get temperature sensor details.
  sensor_t sensor;
  dht.temperature().getSensor(&sensor);
  dht.humidity().getSensor(&sensor);

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(); // Calibrate your scale
  scale.tare(); // Reset the scale to 0

  setup_wifi();
  setup_MQTT();

  // Initialize LED pins as outputs
  pinMode(redLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);

   // Initialize IR sensor pin as input
  pinMode(irSensorPin, INPUT);
}

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

  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    // Read temperature and humidity
    sensors_event_t event;
    dht.temperature().getEvent(&event);
    if (isnan(event.temperature)) {
      Serial.println(F("Error reading temperature!"));
    } else {
      Serial.print(F("Temperature: "));
      temp = event.temperature;
      Serial.print(temp);
      Serial.println(F("°C"));
    }

    // Get humidity event and print its value
    dht.humidity().getEvent(&event);
    if (isnan(event.relative_humidity)) {
      Serial.println(F("Error reading humidity!"));
    } else {
      hum = event.relative_humidity; // Use actual sensor reading
      Serial.print(F("Humidity: "));
      Serial.print(hum);
      Serial.println(F("%"));
    }

  // Read IR sensor state
    objectDetected = digitalRead(irSensorPin);
    if (objectDetected) {
      Serial.println("Object detected!");
    } else {
      Serial.println("No object detected.");
    }

    if (scale.is_ready()) {
      weight = scale.get_units(10); // Average 10 readings for stability
      Serial.print("Weight: ");
      Serial.print(weight);
      Serial.println(" kg");

      updateLedStates(weight);

      // Publish weight to MQTT
      msgStr = String(weight) + " kg";
      client.publish(mqttTopic, msgStr.c_str());
      msgStr = "";
    } else {
      Serial.println("HX711 not found.");
    }

    // Publish temperature and humidity to MQTT
    msgStr = String(temp) + "," + String(hum) + "," + String(weight) + "," + String(objectDetected);;
    byte arrSize = msgStr.length() + 1;
    char msg[arrSize];
    msgStr.toCharArray(msg, arrSize);
    client.publish(mqttTopic, msg);
    msgStr = "";

    delay(1500);
  }
}