package challenge;

import basic.Shape;

/**
 * 圆形到椭圆形的转换器，实现ShapeConverter接口
 */
public class CircleToEllipseConverter implements ShapeConverter {
    private double stretchFactor; // 拉伸因子，用于确定椭圆的长半轴
    
    /**
     * 构造方法
     * @param stretchFactor 拉伸因子，大于1时会将圆形拉伸成椭圆形
     */
    public CircleToEllipseConverter(double stretchFactor) {
        this.stretchFactor = Math.max(stretchFactor, 1.0); // 确保拉伸因子至少为1
    }
    
    @Override
    public Shape convert(Shape sourceShape) {
        if (!canConvert(sourceShape)) {
            return null;
        }
        
        Circle circle = (Circle) sourceShape;
        double radius = circle.getRadius();
        
        // 将圆形转换为椭圆形：保持颜色不变，半径作为短半轴，拉伸后的半径作为长半轴
        double semiMinorAxis = radius;
        double semiMajorAxis = radius * stretchFactor;
        
        return new Ellipse(circle.getColor(), semiMajorAxis, semiMinorAxis);
    }
    
    @Override
    public boolean canConvert(Shape sourceShape) {
        return sourceShape instanceof Circle;
    }
    
    @Override
    public String getConversionDescription() {
        return "将圆形转换为椭圆形，拉伸因子为：" + stretchFactor;
    }
    
    /**
     * 获取拉伸因子
     * @return 拉伸因子
     */
    public double getStretchFactor() {
        return stretchFactor;
    }
    
    /**
     * 设置拉伸因子
     * @param stretchFactor 新的拉伸因子
     */
    public void setStretchFactor(double stretchFactor) {
        this.stretchFactor = Math.max(stretchFactor, 1.0);
    }
}