#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <Wire.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);
const uint8_t ROWS = 4;
const uint8_t COLS = 4;

char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 5, 4, 3, 2 }; 
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 };
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

int percentageValue = 0;
int cursorPos = 0;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.print("Enter % value:");
  lcd.setCursor(0, 1);  // Move to the second row for input
}

void loop() {
  char key = keypad.getKey();
  
  if (key != NO_KEY) {
    if (key >= '0' && key <= '9') { // Check if the key is a number
      if (cursorPos < 3) { // Limit input to 3 digits
        lcd.write(key); // Display key on LCD
        percentageValue = percentageValue * 10 + (key - '0'); // Convert char to int and build number
        cursorPos++;
      }
    }
    else if (key == '#') { // '#' is used as 'Enter' to submit the value
      // Constrain to 0-100% range
      percentageValue = constrain(percentageValue, 0, 100);
      
      // Map percentage to analog range 0-255
      int analogValue = map(percentageValue, 0, 100, 0, 255);
      analogWrite(A0, analogValue); // Write analog value to A0

      lcd.clear();
      lcd.print("Percent: ");
      lcd.print(percentageValue);
      lcd.print("%");
      lcd.setCursor(0, 1);
      lcd.print("Analog: ");
      lcd.print(analogValue);
      delay(2000); // Display the result for 2 seconds

      // Reset for next input
      lcd.clear();
      lcd.print("Enter % value:");
      lcd.setCursor(0, 1);
      percentageValue = 0;
      cursorPos = 0;
    }
    else if (key == '*') { // '*' is used as 'Clear' to reset the input
      lcd.clear();
      lcd.print("Enter % value:");
      lcd.setCursor(0, 1);
      percentageValue = 0;
      cursorPos = 0;
    }
  }
}