/**
 * 难度等级类
 * @param {number} level 等级数字代码
 */
function Level(level = config.level || 1) {
  this.lib = library;

  this.level = level;
}

/**
 * 静态方法 封装new init 返回实例
 * @param {number} level 等级数值
 * @returns
 */
Level.of = function (level) {
  const instance = new Level(level);
  instance.init();
  return instance;
};

// 初始化 渲染
// 更新config中的level属性
Level.prototype.init = function () {
  const initX = this.lib.properties.width / 2;
  const initY = 80;
  const target = new this.lib.Level();
  target.x = initX;
  target.y = initY;

  target.gotoAndStop(`level-${this.level}`);
  config.level = this.level;
  stage.addChild(target);
};