int maxmatches=21, index, indexPc, counter;
String str= "Push 1, 2 or 3 to take matches from the pile";
boolean pc;

void setup() {
  size(400, 200);
}

void draw() {
  background(255);

  drawMatches(25, 15, 40, 10, 15, 50);

  textSize(15);
  fill(0);
  text(str, 25, 20);
  if (pc==false) {
    myTurn();
  } else {
    PcTurn();
  }
}

//draw all remaining matches
void drawMatches(int xPos, int space, int yPos, int w, int h, int hRect) {
  for (int i=0; i<maxmatches; i++) {
    fill(255, 0, 0);
    ellipseMode(CENTER);
    ellipse(xPos+i*space, yPos, w, h);

    fill(#C9C314);
    rect(xPos-w/2+i*space, yPos+h/4, w, hRect);
  }
}

void myTurn() {

  text("You turn:", 25, 120);
  if (key>='0'&& key<='9') {
    if (key<='3') {
      index = key-48;
      text(index + "(press enter to continue)", 100, 120);
    } else {
      text ("Only 1,2 or 3 allowed! Try again!", 100, 120);
    }
  }

  if (keyPressed) {
    if (key==ENTER && index>=0 && index<=3) {
      maxmatches-=index;
      index=5;
      pc=true;
    }
  }
}

void PcTurn() {
  counter++;
  text("PC turn:", 25, 120);
  if (counter==0) {
    indexPc=(int)random(1, 4);
  }
  if (counter>=120) {
    text(indexPc + "(press enter to continue)", 100, 120);
    if (keyPressed) {
      if (key==ENTER) {
        counter=0;
        maxmatches-=indexPc;
        pc=false;
      }
    }
  }
}