import java.awt.*;
import javax.swing.*;

// The number displays in the game
public class NumberDisplay extends JComponent {
	// The dimensions of each individual digit
	public static final int DIGIT_WIDTH = 11;
	public static final int DIGIT_HEIGHT = 21;
	// The dimensions of the big box
	public static final int BACKDROP_WIDTH = 41;
	public static final int BACKDROP_HEIGHT = 25;
	// The index of the minus sign
	public static final int MINUS_INDEX = 10;

	// The x-positions of each digit: units -> tens -> hundreds
	private static final int[] DIGIT_X = {28, 15, 2};
	// The y-position of each digit
	private static final int DIGIT_Y = 2;

	public Image backdrop;
	public Image[] digits;

	private int num;
	private boolean negative;

	public NumberDisplay() {
		setPreferredSize(new Dimension(BACKDROP_WIDTH, BACKDROP_HEIGHT));
	}

	public void setImages(Image[] digits, Image backdrop) {
		this.digits = digits;
		this.backdrop = backdrop;
	}

	public void setNum(int num) {
		setClamped(num);
		repaint();
	}

	private void setClamped(int num) {
		// Clamp all number assignments between -99 and 999, inclusive
		if (num < 0) {
			this.num = Math.min(-num, 99);
			negative = true;
		} else {
			this.num = Math.min(num, 999);
			negative = false;
		}
	}

	@Override
	public void paintComponent(Graphics gr) {
		super.paintComponent(gr);
		Graphics2D g = (Graphics2D) gr;

		g.drawImage(backdrop, 0, 0, this);
		// Preserve the original num for in-place divison, because we don't want
		// non-graphical side effects in paintComponent
		int num = this.num;
		for (int i = 0; i < 3; i++) {
			int digitsIndex;
			// Get the index of the proper digit for this position, drawing the
			// minus sign in the hundreds digit if necessary
			if (negative && i == 2)
				digitsIndex = MINUS_INDEX;
			else
				digitsIndex = num % 10;
			g.drawImage(digits[digitsIndex], DIGIT_X[i], DIGIT_Y, this);
			// Next digit
			num /= 10;
		}
	}
}