void setup(){
 background(175);
 size(600,400);
 rectMode(CORNER);
}

String textBoxInput = "";

boolean textLimit = false;
boolean drawCap = false;
boolean drawRev = false;
boolean drawReverse = false;
boolean drawDelSp = false;
boolean drawMidChar = false;
boolean doOnce = true;
boolean storeRev = false;

void draw(){
  background(175);

  float buttonWidth = width*0.2916;
  float buttonHeight = height*0.08;
  int buttonPosX = (width/14)*9;
  int buttonPosY = height/6;

  int textBoxPosX = width/14;
  int textBoxPosY = height/6;
  float textBoxWidth = width*0.533;

  String clearText = "Clear";
  String capText = "Capitals";
  String revText = "Reverse";
  String delSpText = "Delete Spaces";
  String midCharText = "Middle Character";

  float textMarginX = buttonWidth/20;
  float textMarginY = buttonHeight/4;

  String textCap = textBoxInput.toUpperCase();
  String textRev ="";
  String finalReversed = "";


  //TextBox
  fill(255);
  rect(textBoxPosX,textBoxPosY,textBoxWidth,buttonHeight);
  fill(0);
  textSize(width*0.03);
  text(textBoxInput,textBoxPosX+textMarginX,textBoxPosY+buttonHeight-textMarginY);

  //BUTTONS
    //Clear button
    fill(175);
    rect(buttonPosX,buttonPosY,buttonWidth,buttonHeight);
    fill(0);
    textSize(width*0.03);
    text(clearText,buttonPosX+textMarginX,buttonPosY+buttonHeight-textMarginY);

    //Capital button
    fill(175);
    rect(buttonPosX,buttonPosY*2,buttonWidth,buttonHeight);
    fill(0);
    textSize(width*0.03);
    text(capText,buttonPosX+textMarginX,(buttonPosY*2)+buttonHeight-textMarginY);

    //Reverse button
    fill(175);
    rect(buttonPosX,buttonPosY*3,buttonWidth,buttonHeight);
    fill(0);
    textSize(width*0.03);
    text(revText,buttonPosX+textMarginX,(buttonPosY*3)+buttonHeight-textMarginY);

    //Delete Spaces button
    fill(175);
    rect(buttonPosX,buttonPosY*4,buttonWidth,buttonHeight);
    fill(0);
    textSize(width*0.03);
    text(delSpText,buttonPosX+textMarginX,(buttonPosY*4)+buttonHeight-textMarginY);

    //Middle Character button
    fill(175);
    rect(buttonPosX,buttonPosY*5,buttonWidth,buttonHeight);
    fill(0);
    textSize(width*0.03);
    text(midCharText,buttonPosX+textMarginX,(buttonPosY*5)+buttonHeight-textMarginY);

    if(textLimit){
       fill(255,0,0);
      text("Text limit reached!",textBoxPosX,height/8);
    }

    if(drawRev){
      int i = textBoxInput.length();
      while(i>0){
        textRev += textBoxInput.substring(i-1,i);
        i--;
      }
    }

    println(textRev);

    //BUTTON BOOLEANS
    //CAPITAL
      if(drawCap){
        text(textCap,textBoxPosX,(buttonPosY*2)+buttonHeight-textMarginY);
      }
      if(drawRev){
        text(textRev,textBoxPosX,(buttonPosY*3)+buttonHeight-textMarginY);
      }

    //BUTTON CLICK
    if(mousePressed && doOnce == false){
     //Clear button
     if(mouseX >= buttonPosX && mouseX <= buttonPosX+buttonWidth && mouseY >= buttonPosY && mouseY <= buttonPosY+buttonHeight){
      textBoxInput = "";
     }
     //Capital button
     if(mouseX >= buttonPosX && mouseX <= buttonPosX+buttonWidth && mouseY >= buttonPosY*2 && mouseY <= (buttonPosY*2)+buttonHeight){
       drawCap = true;
     }
     //Reverse button
     if(mouseX >= buttonPosX && mouseX <= buttonPosX+buttonWidth && mouseY >= buttonPosY*3 && mouseY <= (buttonPosY*3)+buttonHeight){
       drawRev = true;
     }
     doOnce = true;
    }

}

void mouseReleased(){
 doOnce = false;
}

void keyTyped(){
  if((key >= 'a' && key <= 'z') || key == ' '){
    if(textBoxInput.length()<=20){
      textBoxInput = textBoxInput + key;
    } else {
      textLimit = true;
    }
  } else if ((key == BACKSPACE) && textBoxInput.length()>0){
    int inputLength = textBoxInput.length();
     textBoxInput = textBoxInput.substring(0,inputLength-1);
   }
}