#include <LiquidCrystal_I2C.h>
#include <HX711.h>
#include <WiFi.h>
#include <PubSubClient.h>

/* -------- PIN DEFINITIONS -------- */
#define LC_DATA_PIN 27
#define LC_SCLK_PIN 26
#define RELAY_PIN   25
#define LED_PIN     18
#define POWER_PIN   32

/* -------- LOAD LIMIT -------- */
#define LOAD_LIMIT 3.6   // kg

/* -------- WIFI CREDENTIALS -------- */
const char* ssid = "Wokwi-GUEST";
const char* password = "";   // ✅ fixed

/* -------- MQTT BROKER -------- */
const char* mqtt_server = "broker.hivemq.com";
WiFiClient espClient;
PubSubClient client(espClient);

/* -------- OBJECTS -------- */
LiquidCrystal_I2C lcd(0x27, 16, 2);
HX711 scale;

float loadValue;
const float analogScale = 3.3/4095;
bool isPowerOn = false;

/* -------- MQTT CONNECT FUNCTION -------- */
void connectMQTT() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");
    if (client.connect("ESP32_Vehicle_Load_01")) {
      Serial.println("Connected to MQTT Cloud");
    } else {
      delay(1000);
    }
  }
}

/* -------- SETUP -------- */
void setup() {
  Serial.begin(9600);

  lcd.init();
  lcd.backlight();

  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(POWER_PIN, INPUT);

  digitalWrite(LED_PIN, LOW);
  digitalWrite(RELAY_PIN, HIGH);

  scale.begin(LC_DATA_PIN, LC_SCLK_PIN);
  scale.set_scale(420.0);
  scale.tare();

  /* -------- WIFI CONNECTION -------- */
  WiFi.begin(ssid, password);
  lcd.setCursor(0,0);
  lcd.print("Connecting WiFi");

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

  lcd.clear();
  lcd.print("WiFi Connected");
  delay(1000);

  /* -------- MQTT SETUP -------- */
  client.setServer(mqtt_server, 1883);
  connectMQTT();
}

/* -------- LOOP -------- */
void loop() {

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

  lcd.clear();

  isPowerOn = (analogRead(POWER_PIN) * analogScale) >= 1;

  loadValue = scale.get_units(5);
  if (loadValue < 0) loadValue = 0;

  lcd.setCursor(0,0);
  lcd.print("Load: ");
  lcd.print(loadValue);
  lcd.print("kg");

  Serial.print("Load: ");
  Serial.println(loadValue);

  // Publish load to cloud
  client.publish("vehicle/load", String(loadValue).c_str());

  if (loadValue > LOAD_LIMIT) {
    lcd.setCursor(0,1);
    lcd.print("OVERLOAD!");
    
    digitalWrite(LED_PIN, HIGH);
    if(!isPowerOn)
    digitalWrite(RELAY_PIN, LOW);

    client.publish("vehicle/status", "OVERLOAD");
  } 
  else {
    lcd.setCursor(0,1);
    lcd.print("Normal Load");

    digitalWrite(LED_PIN, LOW);
    digitalWrite(RELAY_PIN, HIGH);

    client.publish("vehicle/status", "NORMAL");
  }

  delay(1000);
}