#include <WiFi.h>
#include <ThingSpeak.h>
#include <HX711.h>
#include <LiquidCrystal_I2C.h>
#include <HTTPClient.h>

#define LED 2
#define LED2 4
#define GREEN_LED_PIN 5  // Green LED for sufficient stock
#define RED_LED_PIN 18   // Red LED for low stock

// Low stock threshold
#define LOW_STOCK_THRESHOLD 1.0  // Weight threshold in kg

// IFTTT Webhooks settings
const char* serverName = "http://maker.ifttt.com/trigger/low_stock/with/key/your_IFTTT_key";  // Replace with your IFTTT key

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int LOADCELL_DOUT_PIN = 15;
const int LOADCELL_SCK_PIN = 2;
const float calibration_factor = 100.0;

HX711 scale; 
long units;
char ssid[] = "Wokwi-GUEST";  // Replace with your Wi-Fi SSID
char pass[] = "";  // Replace with your Wi-Fi password

WiFiClient client;
unsigned long myChannelNumber = 2279390;
const char * myWriteAPIKey = "DMV9RHKW37I550XH";
int statusCode;

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

  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(calibration_factor);
  scale.tare();

  Serial.println("Hello, ESP32!");

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

  pinMode(LED, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);

  // Connect to Wi-Fi
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to Wi-Fi...");
  }
  Serial.println("Connected to Wi-Fi");
}

void loop() {
  // Get the current weight from the load cell
  float weightValue = scale.get_units();
  
  // LED control logic for stock indication
  if (weightValue < LOW_STOCK_THRESHOLD) {
    // Low stock condition
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);

    // Send alert to IFTTT
    sendLowStockAlert();
  } else {
    // Sufficient stock condition
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(RED_LED_PIN, LOW);
  }

  // Print the weight on the LCD and serial monitor
  Serial.print("Weight: ");
  lcd.setCursor(2, 0);
  lcd.print("Weight :");
  lcd.print(weightValue);
  lcd.print(" kg");
  Serial.print(weightValue);
  Serial.println(" kg");

  delay(1000);

  // Update ThingSpeak with the current weight
  ThingSpeak.setField(1, weightValue);
  statusCode = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);

  if (statusCode) { // Successful writing code
    Serial.println("Channel update successful.");
  } else {
    Serial.println("Problem Writing data. HTTP error code: " + String(statusCode));
  }

  delay(10000);  // Check every 10 seconds
}

void sendLowStockAlert() {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    // Send HTTP GET request to IFTTT
    http.begin(serverName);
    int httpResponseCode = http.GET();

    if (httpResponseCode > 0) {
      String response = http.getString();
      Serial.println("IFTTT Response: " + response);
    } else {
      Serial.println("Error in sending request");
    }
    http.end();
  } else {
    Serial.println("Wi-Fi Disconnected");
  }
}