import objectdraw.*;
import java.awt.*;

// a textual countdown to zero
public class Countdown extends ActiveObject {

    // the delay between countdown stages
    private static final int MILLISECONDS_COUNTDOWN_PAUSE = 100;

    // multiplies stage of countdown to get font size
    private static final int COUNTDOWN_MULTIPLIER = 5;

    // font sizse for final exclamation point
    private static final int EXCLAMATION_POINT_FONT_SIZE = 200;

    // keeps track of the current countdown stage
    private int countdownStage;

    // the countdown text
    private Text countdownText;

    // need to have the center that was sent in to the constructor so we
    // can always make sure the Text object is centered
    private Location textCenter;

    // start the countdown with countdownStart, save the Location the Text
    // should be centered on, and create and center the Text object
    public Countdown(Location inTextCenter, int countdownStart, DrawingCanvas canvas) {

        countdownStage = countdownStart; 
        textCenter = inTextCenter;

        countdownText = new Text(countdownStage, 0, 0, canvas);
        countdownText.moveTo(textCenter.getX() - countdownText.getWidth()/2, 
            textCenter.getY() - countdownText.getHeight()/2);
        start();
    }

    // while the countdown has not reached zero, reset the Text object to the next
    // countdown level, make the font smaller, and recenter
    public void run() {

        while (countdownStage >= 0) {

            countdownText.setText(countdownStage);
            countdownText.setFontSize(countdownStage * COUNTDOWN_MULTIPLIER);
            countdownText.moveTo(textCenter.getX() - countdownText.getWidth()/2, 
                textCenter.getY() - countdownText.getHeight()/2);
            pause(MILLISECONDS_COUNTDOWN_PAUSE);
            countdownStage--;

        }

        countdownText.setText("!");
        countdownText.setFontSize(EXCLAMATION_POINT_FONT_SIZE);
        countdownText.moveTo(textCenter.getX() - countdownText.getWidth()/2, 
            textCenter.getY() - countdownText.getHeight()/2);          
    }

}