const byte hexadecimalNumbers[16][7] = { { 0,0,0,0,0,0,1},  // = 0
                                  { 1,0,0,1,1,1,1 },  // = 1
                                  { 0,0,1,0,0,1,0 },  // = 2
                                  { 0,0,0,0,1,1,0 },  // = 3
                                  { 1,0,0,1,1,0,0 },  // = 4
                                  { 0,1,0,0,1,0,0 },  // = 5
                                  { 0,1,0,0,0,0,0 },  // = 6
                                  { 0,0,0,1,1,1,1 },  // = 7
                                  { 0,0,0,0,0,0,0 },  // = 8
                                  { 0,0,0,1,1,0,0 },  // = 9
                                  { 0,0,0,1,0,0,0 },  // = A
                                  { 0,0,0,0,0,0,0 },  // = B
                                  { 0,1,1,0,0,0,1 },  // = C
                                  { 0,0,0,0,0,0,1 },  // = D
                                  { 0,1,1,0,0,0,0 },  // = E
                                  { 0,1,1,1,0,0,0 }   // = F
};

byte currentNumbersToDisplay[6][7];
byte toDisplay[4][7] = {{ 1,1,1,1,1,1,1}, { 1,1,1,1,1,1,1}, { 1,1,1,1,1,1,1}, { 1,1,1,1,1,1,1}};
byte brightness[4] = {LOW, LOW, LOW, LOW};
unsigned long timeDelay = 0;
int currentWorkingIndex = 0;
boolean notRead = true;

void setup() {
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);

  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);

  Serial.begin(9600);
}

void checkIfCorrectCommand(char firstCharacter){
  if(firstCharacter == 'T'){
    numbersToDisplay();
  }
  else if(firstCharacter == 'D'){
    timeOfDisplaying();
  }
  else if(firstCharacter == 'B'){
    brightnessOfSegments();
  }
  else{
    Serial.println("Unknown command");
  }
  notRead = true;
}

void numbersToDisplay(){
  String numbersSequence = Serial.readString();
  if(checkNumbersToDisplay(numbersSequence)){
    setNumbersToDisplay(numbersSequence);
  }
}

boolean checkNumbersToDisplay(String numbersSequence){
  if(numbersSequence.length() == 6){
    char characterToTest;
    for(int i = 0; i<5; i++){
      characterToTest = numbersSequence.charAt(i);
      if((characterToTest>='a' && characterToTest<='f') ||
        (characterToTest>='A' && characterToTest<='F') ||
        (characterToTest>='0' && characterToTest<='9')){
        }
      else{
        Serial.println("Wrong sequence of characters");
        return false;
      }
    }
  }
  else{
    Serial.println("Too few characters");
    return false;
  }
  return true;
}

void setNumbersToDisplay(String numbersSequence){
  char characterToDisplay;
  for(int i=0; i<5; i++){
    characterToDisplay = numbersSequence.charAt(i);
    copyRowOfMatrix(i, parseCharToInt(characterToDisplay), currentNumbersToDisplay, hexadecimalNumbers);
  }
}

void copyRowOfMatrix(int dest, int from, byte (*firstArray)[7],  byte (*secondArray)[7]){
  for(int i = 0; i<6; i++){
    (*firstArray)[dest] = (*secondArray)[from];
    firstArray++;
    secondArray++;
  }
}

int parseCharToInt(char hexadecimalCharacter){
  currentWorkingIndex = 0;
  if(hexadecimalCharacter>='0' && hexadecimalCharacter<='9'){
    return hexadecimalCharacter - '0';
  }
  else if(hexadecimalCharacter>='a' && hexadecimalCharacter<='f'){
    return hexadecimalCharacter - 'a';
  }
  else{
    return hexadecimalCharacter - 'A';
  }
}

void timeOfDisplaying(){
  String time = Serial.readString();
  if(checkTimeOfDisplaying(time)){
    timeDelay = time.toInt();
  }
}

boolean checkTimeOfDisplaying(String time){
  if(time.length() == 4){
    char characterToTest;
    for(int i = 0; i<3; i++){
      characterToTest = time.charAt(i);
      if((characterToTest>='0' && characterToTest<='9' && i!=0)
      || (characterToTest>='1' && characterToTest<='9' && i==0)){
      }
      else{
        Serial.println("Wrong sequence of characters");
        return false;
      }
    }
  }
  else{
    Serial.println("Too few characters");
    return false;
  }
  return true;
}

void brightnessOfSegments(){
  String brightness = Serial.readString();
  if(checkBrightnessOfSegments(brightness)){
    setBrightness(brightness);
  }
}

boolean checkBrightnessOfSegments(String brightness){
  if(brightness.length() == 4){
    char characterToTest;
    for(int i = 0; i<3; i++){
      characterToTest = brightness.charAt(i);
      if(characterToTest>='0' && characterToTest<='2'){
      }
      else{
        Serial.println("Wrong sequence of characters");
        return false;
      }
    }
  }
  else{
    Serial.println("Too few characters");
    return false;
  }
  return true;
}

void setBrightness(String brightnessString){
  char brightnessLevel;
  for(int i=0; i<3; i++){
    brightnessLevel = brightnessString.charAt(i);
    if(brightnessLevel == '0'){
      brightness[i] = HIGH;
    }
    else if(brightnessLevel == '1'){
      brightness[i] = LOW;
    }
    else{
      brightness[i] = LOW;
    }
  }
}

void moveNumbers(){
  if((Serial.available() > 0) && (notRead)){
    checkIfCorrectCommand(Serial.read());
    notRead = false;
  }
  for(int i=0; i<2; i++){
    copyRowOfMatrix(i, i+1, toDisplay, toDisplay);
  }
  copyRowOfMatrix(3, currentWorkingIndex++, toDisplay, currentNumbersToDisplay);
  if(currentWorkingIndex == 6){
    currentWorkingIndex = 0;
  }
  display();
  delay(timeDelay);
}

void display(){
  for(int i = 0; i < 3; i++){
      prepareOneSegment(i);
      displayOneSegment(i);
      setAppropriateBrightness();
  }
}

void prepareOneSegment(int whichOne){
  for(int i = 0; i < 3; i++){
    if(i == whichOne){
      digitalWrite(i+9, LOW);
    }
    else{
      digitalWrite(i+9, HIGH);
    }
  }
}

void displayOneSegment(int whichOne){
  byte pin = 2;
  for (byte segCount = 0; segCount < 7; ++segCount) {
    digitalWrite(pin, toDisplay[whichOne][segCount]);
    ++pin;
  }
}

void setAppropriateBrightness(){
  for(int i = 0; i < 3; i++){
    digitalWrite(i+9, brightness[i]);
  }
}

void loop() {
  moveNumbers();
}