#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <HX711.h>

// OLED display width and height, in pixels
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET -1 // Reset pin not used
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// HX711 Load Cell setup
HX711 scale;
const int loadCellDoutPin = 16;  // Connect to HX711 DT
const int loadCellSckPin = 17;   // Connect to HX711 SCK

// LED and Buzzer Pins
const int greenLedPin = 23;
const int redLedPin = 19;
const int buzzerPin = 18;

// Threshold weight (you can adjust this)
float weightThreshold = 10.0;  // Example threshold for full bin

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // Initialize the OLED display with I2C address 0x3C
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }

  // Initialize the HX711
  scale.begin(loadCellDoutPin, loadCellSckPin);

  // Initialize the LEDs and buzzer as outputs
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);

  // Clear the display buffer
  display.clearDisplay();
  display.setTextSize(1);      // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_WHITE); // Draw white text
  display.setCursor(0,0);      // Start at top-left corner
  display.println("Weight Sensing Bin");
  display.display();           // Display initial text
  delay(2000);                 // Pause for 2 seconds
}

void loop() {
  // Check if the scale is ready to provide readings
  if (scale.is_ready()) {
    float weight = scale.get_units(10);  // Take an average of 10 readings
    Serial.print("Weight: ");
    Serial.println(weight);

    // Display weight on the OLED screen
    display.clearDisplay();
    display.setCursor(0, 0);   // Set cursor at top-left corner
    display.println("Current Weight:");
    display.setTextSize(2);    // Make the text larger
    display.setCursor(0, 16);
    display.print(weight, 2);  // Print the weight with two decimal points
    display.print(" kg");
    display.display();         // Update the display

    // Handle LED and buzzer alerts
    if (weight >= weightThreshold) {
      digitalWrite(redLedPin, HIGH);     // Turn on red LED
      digitalWrite(greenLedPin, LOW);    // Turn off green LED
      tone(buzzerPin, 1000);             // Buzzer ON
    } else {
      digitalWrite(greenLedPin, HIGH);   // Turn on green LED
      digitalWrite(redLedPin, LOW);      // Turn off red LED
      noTone(buzzerPin);                 // Buzzer OFF
    }

    delay(1000);  // Wait for 1 second before the next reading
  } else {
    Serial.println("HX711 not found.");
  }
}