class Timer {
public:
  void start() { timeStamp = millis(); }
  bool operator()(const unsigned long duration) const { return (millis() - timeStamp >= duration) ? true : false; }

private:
  unsigned long timeStamp{0};
};

struct Symbols {
  const char* letters[26] {
  ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", 
  ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.",  
  "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.." 
  };

  const char* numbers[10] {
    "-----", ".----", "..---", "...--", "....-", ".....",
  "-....", "--...", "---..", "----."
  };

  const char* whitespace[1] {" "};

  const char* getCode(char character) const {
    switch(character) {
      case 'A'...'Z': return letters[character-'A'];
      case 'a'...'z': return letters[character-'a'];
      case '0'...'9': return numbers[character-'0'];
    }     
    // Any character for which no encoding was stored
    // it is treated like a space character (yet)
    return  whitespace[0];
  }
};

enum class Fstm : byte {next, startword, wait, lightup, lightoff, spacing, stop};

constexpr unsigned int DIT {200};
constexpr unsigned int DAH {3 * DIT};
constexpr unsigned int SYMBOL_SPACING {1 * DIT};
constexpr unsigned int LETTER_SPACING {3 * SYMBOL_SPACING};
constexpr unsigned int WORD_SPACING {7 * SYMBOL_SPACING};
// constexpr byte LED_PIN {LED_BUILTIN};
constexpr byte LED_PIN {3};

constexpr Symbols morse;

// This text is translated into Morse code
constexpr char text[] {"Hello can someone please help"};

Timer timer;

void fstm() {
  static Fstm state {Fstm::next};
  static unsigned long timerValue;
  static byte characterIdx {0};

  switch(state) {
    case Fstm::next:
      static byte codeIdx {0};
      const char* code;
      if (!codeIdx) {Serial.print(text[characterIdx]);}
      if (text[characterIdx]) { 
        code = morse.getCode(text[characterIdx]);
        if (*code == 32) {  // It's a "non morsable character". Treat it as a word space.
          ++characterIdx;
          state = Fstm::startword; 
          break;
        }
      } else { 
        // If the text has been morst, start from the beginning
        // If this should not happen, then set the status Fstm::stop.
        characterIdx= 0;
        state = Fstm::startword;
        Serial.println();
        //state = Fstm::stop;
        break;
      }
      timerValue = (code[codeIdx] == '.') ? DIT : DAH;
      if(!code[codeIdx++]) { 
        codeIdx = 0; 
        ++characterIdx; 
        timerValue = LETTER_SPACING;
        state = Fstm::spacing;
        timer.start();
      } else { state = Fstm::lightup; }
      break;
    case Fstm::startword:
        timerValue = WORD_SPACING;
        state = Fstm::spacing; 
        timer.start();
        break;
    case Fstm::lightup:
      digitalWrite(LED_PIN,HIGH);
      state = Fstm::wait;
      timer.start();
      break;
    case Fstm::wait:
      if(timer(timerValue)) { state = Fstm::lightoff; }
      break;
    case Fstm::lightoff:
      digitalWrite(LED_PIN,LOW);
      timerValue = SYMBOL_SPACING;
      state = Fstm::spacing;
      timer.start();
      break;
    case Fstm::spacing:
      if(timer(timerValue)) { state = Fstm::next; }
      break;
    default:
      break;
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  Serial.print("Morsetext: "); Serial.println(text);
}

void loop() {  
  fstm();
}