#include <Arduino.h>
#include <WiFi.h>
#include <Arduino_MQTT_Client.h>
#include <ThingsBoard.h>

#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// ---------- WiFi & ThingsBoard Config ----------
#define WIFI_SSID     "Wokwi-GUEST"
#define WIFI_PASSWORD ""

#define TB_SERVER     "thingsboard.cloud"
#define TB_TOKEN      "ajLNz0u8lYbG7l8JUtdi"


// ---------- Ultrasonic Sensor Pins ----------
const int trigPin = 17;
const int echoPin = 16;
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

// ---------- DHT22 Sensor ----------
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// ---------- LCD ----------
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C Address 0x27

// ---------- LED, Buzzer, Push Button ----------
#define LED_PIN 5
#define BUZZER_PIN 18
#define BUTTON_PIN 2
bool alertEnabled = true;

// ---------- Globals ----------
WiFiClient wifiClient;
Arduino_MQTT_Client mqttClient(wifiClient);
ThingsBoard tb(mqttClient);

long duration;
float distanceCm;
float distanceInch;

// ---------- Connect to WiFi ----------
void connectToWiFi() {
  Serial.print("Connecting to WiFi...");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

// ---------- Connect to ThingsBoard ----------
void connectToThingsBoard() {
  while (!tb.connected()) {
    Serial.println("Connecting to ThingsBoard...");
    if (tb.connect(TB_SERVER, TB_TOKEN)) {
      Serial.println("Connected to ThingsBoard!");
    } else {
      Serial.println("Failed to connect. Retrying...");
      delay(1000);
    }
  }
}

void setup() {
  Serial.begin(115200);

  // Sensor Pin Modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  // Init DHT & LCD
  dht.begin();
  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("Smart Monitor");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");
  delay(2000);
  lcd.clear();

  // Connect
  connectToWiFi();
  connectToThingsBoard();
}

void loop() {
  // Maintain Connections
  if (WiFi.status() != WL_CONNECTED) connectToWiFi();
  if (!tb.connected()) connectToThingsBoard();
  tb.loop();

  // Button Toggle
  if (digitalRead(BUTTON_PIN) == LOW) {
    alertEnabled = !alertEnabled;
    delay(500); // debounce
  }

  // Read Distance
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distanceCm = duration * SOUND_SPEED / 2;
  distanceInch = distanceCm * CM_TO_INCH;

  // Read DHT22
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Display on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("D:");
  lcd.print(distanceCm);
  lcd.print("cm T:");
  lcd.print(temperature, 1);

  lcd.setCursor(0, 1);
  lcd.print("H:");
  lcd.print(humidity, 0);
  lcd.print("% ");
  lcd.print(alertEnabled ? "A:ON" : "A:OFF");

  // Alert System
  if (alertEnabled && distanceCm > 0 && distanceCm < 20) {
    digitalWrite(LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }

  // Serial Monitor Output
  Serial.println("-----");
  Serial.print("Distance (cm): "); Serial.println(distanceCm);
  Serial.print("Distance (inch): "); Serial.println(distanceInch);
  Serial.print("Temperature: "); Serial.print(temperature); Serial.println(" C");
  Serial.print("Humidity: "); Serial.print(humidity); Serial.println(" %");
  Serial.print("Alert: "); Serial.println(alertEnabled ? "ON" : "OFF");

  // Send to ThingsBoard
  tb.sendTelemetryData("Distance_cm", distanceCm);
  tb.sendTelemetryData("Distance_inch", distanceInch);
  tb.sendTelemetryData("Temperature", temperature);
  tb.sendTelemetryData("Humidity", humidity);
  tb.sendTelemetryData("Alert_Triggered", (alertEnabled && distanceCm < 20) ? 1 : 0);

  delay(2000);
}