const int latchPin = 8;    // ST_CP
const int clockPin = 7;    // SH_CP
const int dataPin = 9;     // D
const int buttonPin = 2; 
const int relayPin = 4;
int buttonState = HIGH;
int lastButtonState = HIGH;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;
bool isLetterH = false;
const byte letterL = ~0b00001110;
const byte letterH = ~0b00110111;
void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);  
  displayPattern(letterL);
}
void displayPattern(byte pattern) {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, LSBFIRST, pattern);  
  digitalWrite(latchPin, HIGH);
}
void loop() {
  int reading = digitalRead(buttonPin);
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      if (buttonState == LOW) {
        isLetterH = !isLetterH;
        displayPattern(isLetterH ? letterH : letterL);
        if (isLetterH) {
          digitalWrite(relayPin, HIGH); 
        } else {
          digitalWrite(relayPin, LOW); 
        }}}}
  lastButtonState = reading;
}


/*const int latchPin = 8;    // ST_CP
const int clockPin = 7;    // SH_CP
const int dataPin = 9;    // D
const int buttonPin = 4;
int buttonState = HIGH;
int lastButtonState = HIGH;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;
bool isLetterH = false;
const byte letterL = ~0b00001110;
const byte letterH = ~0b00110111;
void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  displayPattern(letterL);
}
void displayPattern(byte pattern) {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, LSBFIRST, pattern);  // Use LSBFIRST
  digitalWrite(latchPin, HIGH);
}
void loop() {
  int reading = digitalRead(buttonPin);
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      if (buttonState == LOW) {
        isLetterH = !isLetterH;
        displayPattern(isLetterH ? letterH : letterL);
      }
    }
  }
 lastButtonState = reading;
}*/