///<reference path="./Polygon.ts" />
/**
 * 多边形的特殊情况。在进行SAT碰撞检查时，我们只需要检查2个轴而不是8个轴
 */
class Box extends Polygon {
    constructor(width: number, height: number){
        super(Box.buildBox(width, height), true);
        this.width = width;
        this.height = height;
    }

    /**
     * 在一个盒子的形状中建立多边形需要的点的帮助方法
     * @param width 
     * @param height 
     */
    private static buildBox(width: number, height: number): Vector2[]{
        // 我们在(0,0)的中心周围创建点
        let halfWidth = width / 2;
        let halfHeight = height / 2;
        let verts = new Array(4);
        verts[0] = new Vector2(-halfWidth, -halfHeight);
        verts[1] = new Vector2(halfWidth, -halfHeight);
        verts[2] = new Vector2(halfWidth, halfHeight);
        verts[3] = new Vector2(-halfWidth, halfHeight);

        return verts;
    }

    public overlaps(other: Shape){
        // 特殊情况，这一个高性能方式实现，其他情况则使用polygon方法检测
        if (other instanceof Box)
            return this.bounds.intersects(other.bounds);

        if (other instanceof Circle)
            return Collisions.isRectToCircle(this.bounds, other.position, other.radius);

        return super.overlaps(other);
    }

    public collidesWithShape(other: Shape){
        // 特殊情况，这一个高性能方式实现，其他情况则使用polygon方法检测
        if (other instanceof Box){
            return ShapeCollisions.boxToBox(this, other);
        }

        // TODO: 让 minkowski 运行于 cricleToBox

        return super.collidesWithShape(other);
    }

    /**
     * 更新框点，重新计算中心，设置宽度/高度
     * @param width 
     * @param height 
     */
    public updateBox(width: number, height: number){
        this.width = width;
        this.height = height;

        // 我们在(0,0)的中心周围创建点
        let halfWidth = width / 2;
        let halfHeight = height / 2;

        this.points[0] = new Vector2(-halfWidth, -halfHeight);
        this.points[1] = new Vector2(halfWidth, -halfHeight);
        this.points[2] = new Vector2(halfWidth, halfHeight);
        this.points[3] = new Vector2(-halfWidth, halfHeight);

        for (let i = 0; i < this.points.length; i ++)
            this._originalPoints[i] = this.points[i];
    }

    /**
     * 
     * @param point 
     */
    public containsPoint(point: Vector2){
        return this.bounds.contains(point.x, point.y);
    }
}