#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete
String commandString = "";

void setup() {
  lcd.begin();
  lcd.setBacklight((uint8_t)1);
  Serial.begin(9600);
  initDisplay();
}

void loop() {

  if(stringComplete)
  {
    stringComplete = false;
    getCommand();

    if(commandString.equals("STAR"))
    {
      lcd.clear();
    }
    if(commandString.equals("STOP"))
    {
      lcd.clear();
      lcd.print("Ready to connect");
    }
    else if(commandString.equals("TEXT"))
    {
      String text = getTextToPrint();
      printText(text);
    }

    inputString = "";
  }
}

void initDisplay()
{
  lcd.print("Ready to connect");
}

void getCommand()
{
  if(inputString.length()>0)
  {
     commandString = inputString.substring(1,5);
  }
}

String getTextToPrint()
{
  String value = inputString.substring(5,inputString.length()-2);
  return value;
}

void printText(String text)
{
  lcd.clear();
  lcd.setCursor(0,0);

  int i = 0;
  int dash_pointer = 0;

  for(i=0; i<text.length(); i++){
    if(text[i] == '-' && text[i-1] == ' ' && text[i+1] == ' '){
      dash_pointer = i;
      break;
    }
  }

    if(dash_pointer == 0)
    {
      lcd.print(text);
    }else
    {
      lcd.print(text.substring(0,dash_pointer-1));
      lcd.setCursor(0,1);
      lcd.print(text.substring(dash_pointer+2,dash_pointer+18)); // print 16 letters only (pointer +2 + 16)
    }
}

void serialEvent() {
  while (Serial.available()) {
    // get the new byte:
    char inChar = (char)Serial.read();
    // add it to the inputString:
    inputString += inChar;
    // if the incoming character is a newline, set a flag
    // so the main loop can do something about it:
    if (inChar == '\n') {
      stringComplete = true;
    }
  }
}