/*
 * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
 * Date: 2022-04-14
 * Description: Circle class inherit from Shape class
 */

public class Circle extends Shape {
	private double radius;

	/**
	 * Constructor.
	 *
	 * @param x      the x coordinate of the center of the circle
	 * @param y      the y coordinate of the center of the circle
	 * @param radius the radius of the circle
	 */
	public Circle(double x, double y, double radius) {
		super(x, y);
		this.radius = radius;
	}

	/**
	 * Calculates the area of the circle.
	 *
	 * @return the area of the circle
	 */
	@Override
	public double area() {
		return Math.PI * radius * radius;
	}

	/**
	 * Resizing a circle cahnges its radius to be newRadius.
	 *
	 * @param newRadius
	 */
	@Override
	public void resize(double newRadius) {
		radius = newRadius;
	}

	/**
	 * Test.
	 */
	public static void testCircle() {
		Circle c = new Circle(1.2, 3.4, 4.0);
		// getX, getY, and move are inherited from Shape.
		// area and resize come from Circle itself.
		System.out.println(c.getX() == 1.2);
		System.out.println(c.getY() == 3.4);
		System.out.println(c.area() == Math.PI * 16.0);
		// Move the circle. The area does not change.
		c.move(7.8, 9.0);
		System.out.println(c.getX() == 9.0);
		System.out.println(c.getY() == 12.4);
		System.out.println(c.area() == Math.PI * 16.0);
		// Resize the circle. The area changes but not the position.
		c.resize(8.0);
		System.out.println(c.getX() == 9.0);
		System.out.println(c.getY() == 12.4);
		System.out.println(c.area() == Math.PI * 64.0);
	}
}