void setup() {
  Serial.begin(115200);
  Serial.println("Start Firmware...");

  pinMode(17, OUTPUT); // A
  pinMode(5, OUTPUT); // B
  pinMode(18, OUTPUT); // C
  pinMode(19, OUTPUT); // D
  pinMode(21, OUTPUT); // E
  pinMode(22, OUTPUT); // G
  pinMode(23, OUTPUT); // F

  pinMode(16, INPUT_PULLUP); // Switch
}

long currentTime = 0;
long LastSaveTime = 0;
bool toggle7segment = true;
int hexIndex = 0;
char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

void loop() {
  currentTime = millis();

  // 500ms loop
  if (currentTime - LastSaveTime >= 500) {
    LastSaveTime = currentTime;
    if (digitalRead(16) == HIGH) {
      // แสดงเลข 0 กระพริบ
      showSevenSegment('0', toggle7segment);
    } else {
      // แสดงเลข 1-9 และ A-F กระพริบ
      showSevenSegment(hexDigits[hexIndex], toggle7segment);
      if (!toggle7segment) {
        hexIndex = (hexIndex + 1) % 16; // เปลี่ยนเป็นตัวถัดไปในอาเรย์เมื่อดับ
      }
    }
    toggle7segment = !toggle7segment;
  }
}

void showSevenSegment(char digit, bool status) {
  if (!status) {
    // ดับ 7-segment
    digitalWrite(17, LOW);
    digitalWrite(5, LOW);
    digitalWrite(18, LOW);
    digitalWrite(19, LOW);
    digitalWrite(21, LOW);
    digitalWrite(22, LOW);
    digitalWrite(23, LOW);
    return;
  }

  if (digit == '0') {
    digitalWrite(17, HIGH); // A
    digitalWrite(5, HIGH); // B
    digitalWrite(18, HIGH); // C
    digitalWrite(19, HIGH); // D
    digitalWrite(21, HIGH); // E
    digitalWrite(22, LOW); // G
    digitalWrite(23, HIGH); // F
  } else if (digit == '1') {
    digitalWrite(17, LOW);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, LOW);
    digitalWrite(21, LOW);
    digitalWrite(22, LOW);
    digitalWrite(23, LOW);
  } else if (digit == '2') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, LOW);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, LOW);
  } else if (digit == '3') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, LOW);
    digitalWrite(22, HIGH);
    digitalWrite(23, LOW);
  } else if (digit == '4') {
    digitalWrite(17, LOW);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, LOW);
    digitalWrite(21, LOW);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == '5') {
    digitalWrite(17, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, LOW);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == '6') {
    digitalWrite(17, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == '7') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, LOW);
    digitalWrite(21, LOW);
    digitalWrite(22, LOW);
    digitalWrite(23, LOW);
  } else if (digit == '8') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == '9') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, LOW);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == 'A') {
    digitalWrite(17, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, LOW);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == 'B') {
    digitalWrite(17, LOW);
    digitalWrite(5, LOW);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == 'C') {
    digitalWrite(17, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(18, LOW);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, LOW);
    digitalWrite(23, HIGH);
  } else if (digit == 'D') {
    digitalWrite(17, LOW);
    digitalWrite(5, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, LOW);
  } else if (digit == 'E') {
    digitalWrite(17, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(18, LOW);
    digitalWrite(19, HIGH);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  } else if (digit == 'F') {
    digitalWrite(17, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(18, LOW);
    digitalWrite(19, LOW);
    digitalWrite(21, HIGH);
    digitalWrite(22, HIGH);
    digitalWrite(23, HIGH);
  }
}