// ავტორი: ზურაბ შერმადინი 4L7ZS
// აკრიბეთ რიცხვი 1 დან 32 მდე და
// დააკლიკეთ * -ს.

// Define the Arduino pins connected to the 74HC595
const int dataPin = 11;   // DS (SER) - Serial Data Input
const int clockPin = 12;  // SHCP (SRCLK) - Shift Register Clock
const int latchPin = 9;   // STCP (RCLK) - Latch Pin

// Keypad pins
const byte ROWS = 4;
const byte COLS = 3;
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};

byte rowPins[ROWS] = {5, 4, 3, 2}; // Connect to row pinouts
byte colPins[COLS] = {8, 7, 6};    // Connect to column pinouts

// We have 4 shift registers = 32 bits
const int numRegisters = 4;
byte registerState[numRegisters]; // Array to hold the state of each register

// Variables for number input
String inputNumber = "";
const int maxDigits = 2; // Maximum 2 digits for numbers 1-32
unsigned long lastKeyPressTime = 0;
const unsigned long debounceTime = 200;

void setup() {
  // Set the pins as outputs
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);

  // Initialize keypad pins
  for (byte r = 0; r < ROWS; r++) {
    pinMode(rowPins[r], INPUT_PULLUP);
  }
  for (byte c = 0; c < COLS; c++) {
    pinMode(colPins[c], OUTPUT);
    digitalWrite(colPins[c], HIGH);
  }

  // Initialize serial for debugging
  Serial.begin(9600);
  
  // Initialize all outputs to 0 (LOW)
  clearRegisters();
  writeRegisters();
  
  Serial.println("Enter a number 1-32 to light up corresponding LED");
  Serial.println("Press '#' to clear input, '*' to confirm");
}

// Sets all register bits to LOW
void clearRegisters() {
  for (int i = 0; i < numRegisters; i++) {
    registerState[i] = 0;
  }
}

// Writes the states from the registerState array to the shift registers
void writeRegisters() {
  // Pull the latch pin LOW to start the update
  digitalWrite(latchPin, LOW);

  // Shift out the data, starting from the LAST register.
  for (int i = numRegisters - 1; i >= 0; i--) {
    shiftOut(dataPin, clockPin, MSBFIRST, registerState[i]);
  }

  // Pull the latch pin HIGH to update the outputs all at once
  digitalWrite(latchPin, HIGH);
}

// Light up a specific LED (1-32)
void lightUpLED(int ledNumber) {
  if (ledNumber < 1 || ledNumber > 32) {
    Serial.println("Invalid LED number! Use 1-32");
    return;
  }
  
  clearRegisters();
  
  // Convert to 0-based index (0-31)
  int index = ledNumber - 1;
  int reg = index / 8;
  int bit = index % 8;
  registerState[reg] = (1 << bit);
  
  writeRegisters();
  
  Serial.print("LED ");
  Serial.println(ledNumber);
}

// Scan keypad for input
char getKey() {
  char key = '\0';
  
  for (byte c = 0; c < COLS; c++) {
    digitalWrite(colPins[c], LOW);
    
    for (byte r = 0; r < ROWS; r++) {
      if (digitalRead(rowPins[r]) == LOW) {
        key = keys[r][c];
      }
    }
    
    digitalWrite(colPins[c], HIGH);
    delay(1);
  }
  
  return key;
}

void processKeypad() {
  char key = getKey();
  
  if (key != '\0' && millis() - lastKeyPressTime > debounceTime) {
    lastKeyPressTime = millis();
    
    if (key >= '0' && key <= '9') {
      // Digit pressed
      if (inputNumber.length() < maxDigits) {
        inputNumber += key;
        Serial.println(inputNumber);
      }
    }
    else if (key == '*') {
      // Confirm/Enter
      if (inputNumber.length() > 0) {
        int number = inputNumber.toInt();
        if (number >= 1 && number <= 32) {
          lightUpLED(number);
        } else {
          Serial.println("Number must be 1-32");
        }
        inputNumber = "";
      }
    }
    else if (key == '#') {
      // Clear
      inputNumber = "";
      clearRegisters();
      writeRegisters();
      Serial.println("Cleared");
    }
  }
}

void loop() {
  // Check for keypad input
  processKeypad();
  
  // Optional: Add a timeout to clear input after inactivity
  if (inputNumber.length() > 0 && millis() - lastKeyPressTime > 5000) {
    inputNumber = "";
    Serial.println("Input timeout - cleared");
  }
}