/**
 * @file proxy utils
 * @author 闻木
 */

/**
 * 对string进行属性拦截的通用方法，返回一个ProxyString
 * 对所有值为undefined的属性读取，会返回一个空的ProxyString
 * 拦截了String下的valueOf和toString方法，使得该ProxyString可以正常转换成原始值
 * @param str
 */
export const getDefaultProxyString = (str = '') => {
  const emptyStr = new Proxy(new String(str), {
    get(target, property) {
      if (typeof property === 'string' && ['valueOf', 'toString'].includes(property)) {
        return () => str;
      }
      if (typeof property === 'string' && target[property] === undefined) {
        return getDefaultProxyString();
      }
      return target[property];
    }
  });
  return emptyStr;
};

/**
 * 对普通对象进行属性拦截，如果属性值为undefined，则会返回一个ProxyString
 * @param obj
 */
export const getProxyObj = (obj: object) => {
  return new Proxy(obj, {
    get(target, property) {
      const val = target[property];
      if (typeof property === 'string' && val === undefined) {
        return getDefaultProxyString();
      }
      if (typeof property === 'string' && typeof val === 'object') {
        return getProxyObj(val);
      }
      return target[property];
    }
  });
};