#include "HX711_ADC.h"
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

// HX711 Load Cell
HX711_ADC LoadCell(9, 8);

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

// Keypad setup
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {7, 6, A0, A1};
byte colPins[COLS] = {A2, A3, A4, A5};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Pins
const int buzzer = 11;
const int solenoidPin = 10;

// Variables
String inputWeight = "";
float targetWeight = 0;
bool filling = false;

unsigned long prevTime1 = millis();
unsigned long prevTime2 = millis();
const long Time1 = 3000;  // Alarm interval
const long Time2 = 1000;  // LCD update interval

void setup() {
  pinMode(buzzer, OUTPUT);
  pinMode(solenoidPin, OUTPUT);
  digitalWrite(solenoidPin, LOW); // Valve off

  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(1, 0);
  lcd.print("Weighing Scale");
  lcd.setCursor(3, 1);
  lcd.print("With Alarm");
  delay(2500);
  lcd.clear();

  // Auto tare on startup
  lcd.setCursor(3, 0); lcd.print("Auto Tare...");
  LoadCell.begin();
  LoadCell.start(1000);
  LoadCell.setCalFactor(0.42);
  while (!LoadCell.update());
  float initWeight = LoadCell.getData();
  if (abs(initWeight) > 10.0) {
    LoadCell.tareNoDelay();
    while (!LoadCell.update());
  }
  lcd.clear();
}

void loop() {
  handleKeypad();

  unsigned long currentTime = millis();

  LoadCell.update();
  float weight = LoadCell.getData();

  // Auto tare when scale is near zero and not filling
  if (weight > -1.0 && weight < 1.0 && !filling) {
    LoadCell.tareNoDelay();
    while (!LoadCell.update());
  }

  // Alarm buzzer if weight exceeds target
  if (filling && currentTime - prevTime1 > Time1) {
    if (weight > targetWeight && targetWeight > 0) {
      // Beep pattern
      noTone(buzzer); delay(300);
      tone(buzzer, 250); delay(300); noTone(buzzer); delay(300);
      tone(buzzer, 450); delay(300); noTone(buzzer); delay(300);
    }
    prevTime1 = currentTime;
  }

  // Update display and solenoid control every second
  if (currentTime - prevTime2 > Time2) {
    if (filling) {
      lcd.setCursor(0, 0);
      lcd.print("Filling...       ");
      lcd.setCursor(0, 1);
      lcd.print("Now: ");
      lcd.print(weight, 1);
      lcd.print("g / ");
      lcd.print(targetWeight, 1);
      lcd.print("g");

      if (weight < targetWeight - 1.0) {
        digitalWrite(solenoidPin, HIGH);  // Open valve
      } else {
        digitalWrite(solenoidPin, LOW);   // Close valve
        filling = false;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Target Reached");
        lcd.setCursor(0, 1);
        lcd.print("Final: ");
        lcd.print(weight, 1);
        lcd.print("g");
        tone(buzzer, 1000, 500);
        delay(2000);
        noTone(buzzer);
        lcd.clear();
      }
    } else {
      lcd.setCursor(0, 0);
      lcd.print("Weight:         ");
      lcd.setCursor(0, 1);
      lcd.print(weight, 1);
      lcd.print(" g             ");
    }
    prevTime2 = currentTime;
  }

  // Serial debug
  Serial.print("Target: ");
  Serial.print(targetWeight);
  Serial.print("g | Current: ");
  Serial.print(weight);
  Serial.print("g | Filling: ");
  Serial.println(filling ? "Yes" : "No");
}

// Keypad input handler
void handleKeypad() {
  char key = keypad.getKey();

  if (key != NO_KEY) {
    if (key >= '0' && key <= '9') {
      if (inputWeight.length() < 6) {
        inputWeight += key;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Target (g): ");
        lcd.setCursor(0, 1);
        lcd.print(inputWeight);
      }
    } else if (key == '*') {
      inputWeight = "";
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Input cleared");
      delay(1000);
      lcd.clear();
    } else if (key == '#') {
      if (inputWeight.length() > 0) {
        targetWeight = inputWeight.toFloat();
        filling = true;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Target set: ");
        lcd.print(targetWeight);
        lcd.print("g");
        delay(1500);
        lcd.clear();
        inputWeight = "";
      }
    }
  }
}