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

// LCD Setup
LiquidCrystal_I2C lcd(0x27, 16, 2); // Update with your I2C address

// Keypad Setup
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {25, 26, 27, 32}; // Row pins
byte colPins[COLS] = {12, 14, 33, 15}; // Column pins
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Potentiometer Setup
const int potPin = 34; // Analog input pin for potentiometer (ADC pin)

// LED Setup
const int ledPin = 23; // GPIO pin for LED

// Variables
int brightness = 0;           // LED brightness (1-100%)
int lastBrightness = 0;       // To detect brightness changes
bool isKeypadControl = false; // Toggle between keypad and potentiometer control
String keypadInput = "";      // Store multi-digit input from the keypad

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

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Initializing...");

  // Initialize LED
  pinMode(ledPin, OUTPUT);

  // Confirmation
  lcd.setCursor(0, 1);
  lcd.print("System Ready!");
  delay(2000);
  lcd.clear();
}

void loop() {
  // 1. Read Keypad Input
  char key = keypad.getKey();
  if (key) {
    handleKeypadInput(key); // Process keypad input
  }

  // 2. Adjust Brightness
  if (!isKeypadControl) {
    // Potentiometer control (only if not using keypad)
    int potValue = analogRead(potPin); // Read potentiometer value
    brightness = map(potValue, 0, 4095, 1, 100); // Map to 1-100%
    int pwmValue = map(brightness, 1, 100, 0, 255); // Map to PWM (0-255)
    analogWrite(ledPin, pwmValue); // Update LED brightness

    // Update LCD only if brightness changes
    if (brightness != lastBrightness) {
      lastBrightness = brightness;
      updateLCD();
    }
  }
}

void handleKeypadInput(char key) {
  lcd.setCursor(0, 1); // Move to the second row
  lcd.print("Key: ");
  lcd.print(key);
  lcd.print("     "); // Clear extra characters

  // Handle special keys
  if (key == '#') {
    // Finalize keypad input
    if (keypadInput.length() > 0) {
      int value = keypadInput.toInt(); // Convert input to integer
      if (value >= 1 && value <= 100) {
        brightness = value; // Set brightness
        int pwmValue = map(brightness, 1, 100, 0, 255); // Map to PWM (0-255)
        analogWrite(ledPin, pwmValue); // Update LED brightness
        isKeypadControl = true; // Switch to keypad control

        lcd.setCursor(0, 1);
        lcd.print("Set Bright: ");
        lcd.print(brightness);
        lcd.print("%   ");
      } else {
        lcd.setCursor(0, 1);
        lcd.print("Invalid Input    ");
      }
    } else {
      lcd.setCursor(0, 1);
      lcd.print("No Input         ");
    }
    keypadInput = ""; // Clear input buffer
  } else if (key == '*') {
    // Clear input
    keypadInput = "";
    lcd.setCursor(0, 1);
    lcd.print("Input Cleared    ");
  } else if (key >= '0' && key <= '9') {
    // Build multi-digit input
    if (keypadInput.length() < 3) { // Limit input to 3 digits
      keypadInput += key;
      lcd.setCursor(0, 1);
      lcd.print("Input: ");
      lcd.print(keypadInput);
      lcd.print("       ");
    } else {
      lcd.setCursor(0, 1);
      lcd.print("Max 3 digits!    ");
    }
  }
}

void updateLCD() {
  // Display the current brightness on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Brightness: ");
  lcd.print(brightness);
  lcd.print("%   ");
}