/*
Using LCD Screen without library to display a
scrolling list of options. 

For "template" uses the same code as my other project:

LCD Simple Without Libraries (Tutorial)
https://wokwi.com/projects/390024026784443393

&

LCD Scrolling List
https://wokwi.com/projects/390034357673137153


NOTE:
Data will be seen in the serial monitor since the TX and RX pins
are being used to send the bits to the screen
*/

#define RS 13
#define E 12
#define SCROLL_DOWN_PIN 9
#define TOGGLE 10

#define BLUE_PIN A0
#define GREEN_PIN A1
#define RED_PIN A2

const String options[3] = {
  "RED",
  "GREEN",
  "BLUE",
};

const int amountOfOptions = 3;
int index = 0;
int counter = 0;

//Color RED
int R = 1;
int G = 0;
int B = 0;

/*--------------------------------------------------------------------------------------*/

void setup() {
  DDRD = 0XFF;

  pinMode(RS, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(SCROLL_DOWN_PIN, INPUT);
  pinMode(TOGGLE, INPUT);

  screenOnBlink();
  clearDisplay();
  returnHome();
  printString(options[index]);
  
  index = (index + 1 + amountOfOptions) % amountOfOptions;
  cursorToSecondLine();
  printString(options[index]);

  cursorToSecondLine();
  insertArrow();
}

void loop() {

  int scrollDownPinValue = digitalRead(SCROLL_DOWN_PIN);
  int togglePin = digitalRead(TOGGLE);

  /*
  Reversing the mapping because COM is Anode so RGB values
  are "reversed", i.e. for a 255 color RED a 0 is needed on
  the pin
  */

  analogWrite(RED_PIN, map(R, 0, 1, 255, 0));
  analogWrite(GREEN_PIN, map(G, 0, 1, 255, 0));
  analogWrite(BLUE_PIN, map(B, 0, 1, 255, 0));

  if (scrollDownPinValue) {
    clearDisplay();
    scrollDown();
    delay(200);
  }

  if (togglePin) {
    if (options[index] == "RED") {
      R = !R;
    } else if (options[index] == "GREEN") {
      G = !G;
    } else if (options[index] == "BLUE") {
      B = !B;
    }

    updateDisplay();

    delay(200);
  }

}

void updateDisplay() {
  clearDisplay();
  returnHome();
  index = (index - 1 + amountOfOptions) % amountOfOptions;
  printString(options[index]);

  index = (index + 1 + amountOfOptions) % amountOfOptions;
  cursorToSecondLine();
  printString(options[index]);

  cursorToSecondLine();
  insertArrow();
}
void scrollDown() {
  clearDisplay();
  returnHome();
  printString(options[index]);

  index = (index + 1 + amountOfOptions) % amountOfOptions;
  cursorToSecondLine();
  printString(options[index]);

  cursorToSecondLine();
  insertArrow();
}

void readSentData() {
  digitalWrite(E, HIGH);
  digitalWrite(E, LOW);
}

void returnHome() {
  digitalWrite(RS, LOW);
  PORTD = 0X02;
  readSentData();
}

void clearDisplay() {
  digitalWrite(RS, LOW);
  PORTD = 0X01;
  readSentData();
}

void cursorToSecondLine() {
  digitalWrite(RS, LOW);
  PORTD = 0XC0;
  readSentData();
}

void screenOnBlink() {
  digitalWrite(RS, LOW);
  PORTD = 0X0C;
  readSentData();
}

void printCharacter(char character) {

  digitalWrite(RS, HIGH);

  PORTD = (int) character;
  readSentData();

}

void insertArrow(){
  digitalWrite(RS, HIGH);

  PORTD = 0X7E;
  readSentData();
}

void printString(String stringToPrint) {

  String newString = stringToPrint;
  if (stringToPrint == "RED") {
    newString += "   ->";
    newString += (R ? "   [ON]" : "  [OFF]");

  } else if (stringToPrint == "GREEN") {
    newString += " -> ";
    newString += (G ? "  [ON]" : " [OFF]");

  } else if (stringToPrint == "BLUE") {
    newString += "  ->";
    newString += (B ? "   [ON]" : "  [OFF]");

  }
  digitalWrite(RS, HIGH);

  int stringSize = newString.length();
  printCharacter(' ');

  for (int i = 0; i < stringSize; i++) {
    printCharacter(newString[i]);
  }

}