// main.ino
#include <LiquidCrystal_I2C.h> // Library for controlling an I2C LCD
#include <HX711.h>            // Library for interfacing with the HX711 load cell amplifier

// HX711 circuit wiring
const int LOADCELL_DOUT_PIN = 2; // Data pin of the HX711
const int LOADCELL_SCK_PIN = 3;  // Clock pin of the HX711
const int RESET_BUTTON_PIN = 5;  // Button pin for user interaction

// Calibration factors
long empty_container = 0;      // Stores the reading of the empty container
long one_liter_weight = 0;     // Stores the reading of the container with 1L water
float calibration_factor = 1.0f; // Derived calibration factor for converting readings to weight

// LCD setup
#define I2C_ADDR    0x27       // I2C address of the LCD
#define LCD_COLUMNS 16         // Number of columns on the LCD
#define LCD_LINES   2          // Number of lines on the LCD

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES); // LCD object
HX711 scale;                                             // HX711 object

void setup() {
    Serial.begin(57600); // Initialize serial communication for debugging
    scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN); // Initialize HX711 with the specified pins
    lcd.init(); // Initialize the LCD
    lcd.backlight(); // Turn on the LCD backlight

    pinMode(RESET_BUTTON_PIN, INPUT); // Set the button pin as input

    // Calibration phase: Measure the weight of the empty container
    lcd.setCursor(0, 0);
    lcd.print("Calibrate:");
    lcd.setCursor(0, 1);
    lcd.print("Place Empty");
    Serial.println("Place empty container and press the button.");

    // Wait for button press to confirm empty container reading
    waitForButtonPress();
    while (!scale.is_ready()); // Wait until the scale is ready
    empty_container = scale.read(); // Store the reading of the empty container
    Serial.println("Empty container weight saved.");
    lcd.clear(); // Clear the screen after empty container calibration

    // Calibration phase: Measure the weight of the container with 1L water
    lcd.print("Add 1L Water"); // Prompt user to place 1L water
    lcd.setCursor(0, 1);
    lcd.print("Press Button");
    Serial.println("Add 1L of water and press the button.");

    // Wait for button press to confirm 1L water reading
    waitForButtonPress();
    while (!scale.is_ready()); // Wait until the scale is ready
    one_liter_weight = scale.read(); // Store the reading with 1L water
    calibration_factor = one_liter_weight - empty_container; // Calculate the calibration factor
    Serial.println("Calibration completed.");
    lcd.clear(); // Clear the screen after 1L water calibration

    lcd.print("Calib. Done!");
    delay(2000);
    lcd.clear(); // Clear the screen after showing calibration completion

    lcd.setCursor(0, 0);
    lcd.print("Ready..."); // Indicate readiness to begin measurement
    delay(2000);
    lcd.clear(); // Clear the screen after readiness message
}

void loop() {
    lcd.setCursor(0, 0); // Set cursor to the top left
    lcd.print("Weight:"); // Display the "Weight" label

    if (scale.is_ready()) { // Check if the HX711 is ready for a reading
        long reading = scale.read(); // Get the raw reading from the HX711
        float weight = (float)(reading - empty_container) / calibration_factor; // Calculate the weight

        // Check for overload condition
        if (weight > 5.0) {
            lcd.clear(); // Clear the screen before displaying overload
            Serial.println("Weight Overload!"); // Debugging log for overload
            lcd.setCursor(0, 1); // Set cursor to the second line
            lcd.print("Overload!"); // Display overload warning
        } 
        // Check for warning condition (near the weight limit)
        else if (weight >= 4.5) {
            lcd.clear(); // Clear the screen before displaying near-limit warning
            Serial.println("Warning: Near limit!"); // Debugging log for near-limit warning

            // Format and display the weight
            char weightStr[16];
            dtostrf(weight, 6, 2, weightStr); // Convert float to string with 2 decimals
            lcd.setCursor(0, 1);
            lcd.print(weightStr);
            lcd.print(" kg");

            // Display the near-limit warning at the top line
            lcd.setCursor(0, 3);
            lcd.print("**Near Limit**");
        } 
        // Normal weight display
        else {
            Serial.print("Weight: ");
            Serial.println(weight, 2); // Debugging log for weight

            // Format and display the weight
            char weightStr[16];
            dtostrf(weight, 6, 2, weightStr); // Convert float to string with 2 decimals
            lcd.setCursor(0, 1);
            lcd.print("                 "); // Clear old value
            lcd.setCursor(0, 1);
            lcd.print(weightStr);
            lcd.print(" kg");
        }
    } else {
        lcd.clear(); // Clear the screen before showing error
        Serial.println("HX711 not ready."); // Debugging log for error
        lcd.setCursor(0, 1);
        lcd.print("Error: No HX711"); // Display error on the LCD
    }

    // Handle reset button press
    if (digitalRead(RESET_BUTTON_PIN) == HIGH) {
        lcd.clear(); // Clear the screen before starting taring process
        lcd.setCursor(0, 1);
        lcd.print("Taring..."); // Indicate taring process
        delay(1000);
        empty_container = scale.read(); // Update the empty container reading for taring
        lcd.clear(); // Clear the screen after taring is done
        lcd.print("Reset Done"); // Indicate that taring is complete
        delay(2000);
        lcd.clear(); // Clear the screen after reset message
    }

    delay(100); // Short delay to prevent rapid updates
}

// Function to wait for the user to press the reset button
void waitForButtonPress() {
    while (digitalRead(RESET_BUTTON_PIN) == LOW) {
        // Wait for the button to be pressed
    }
    delay(500); // Debounce delay
}