const UrlUtils = {
  /**
   * 清理URL（合并多余的?，规范参数分隔符）
   * @param {string} url - 原始URL
   * @returns {string} 清理后的URL
   */
  clean: function(url) {
    let cleanUrl = url.replace(/\?+/g, '?');
    const firstQuestionMarkIndex = cleanUrl.indexOf('?');
    
    if (firstQuestionMarkIndex !== -1) {
      const beforeParams = cleanUrl.substring(0, firstQuestionMarkIndex + 1);
      const afterParams = cleanUrl.substring(firstQuestionMarkIndex + 1).replace(/\?/g, '&');
      cleanUrl = beforeParams + afterParams;
    }
    
    return cleanUrl;
  },

  /**
   * 保留URL中指定的参数（默认只保留merchant_id）
   * @param {string} url - 原始URL
   * @param {string[]} [paramsToKeep=['merchant_id']] - 需要保留的参数名数组
   * @returns {string} 简化后的URL
   */
  keepParams: function(url, paramsToKeep = ['merchant_id']) {
    // 先清理URL
    const cleanedUrl = this.clean(url);
    
    try {
      const urlObj = new URL(cleanedUrl);
      const newSearchParams = new URLSearchParams();
      
      // 遍历原始参数，只保留需要的
      urlObj.searchParams.forEach((value, key) => {
        if (paramsToKeep.includes(key)) {
          newSearchParams.append(key, value);
        }
      });
      
      // 重建URL
      urlObj.search = newSearchParams.toString();
      return urlObj.toString();
    } catch (e) {
      // 如果URL解析失败（如缺少协议），回退到字符串处理
      const [basePart, queryPart] = cleanedUrl.split('?');
      if (!queryPart) return basePart;
      
      const keptParams = queryPart.split('&').filter(param => {
        const [key] = param.split('=');
        return paramsToKeep.includes(key);
      });
      
      return keptParams.length > 0 
        ? `${basePart}?${keptParams.join('&')}`
        : basePart;
    }
  }
};

export default UrlUtils


// // 使用示例
// const dirtyUrl = "http://10.210.254.149:8081/h5_pay/??merchant_id=1&token=xxx&expires_time=123??is_all_api=1";

// // 1. 只清理URL
// console.log(UrlUtils.clean(dirtyUrl)); 
// // 输出: "http://10.210.254.149:8081/h5_pay/?merchant_id=1&token=xxx&expires_time=123&is_all_api=1"

// // 2. 清理并只保留merchant_id
// console.log(UrlUtils.keepParams(dirtyUrl)); 
// // 输出: "http://10.210.254.149:8081/h5_pay/?merchant_id=1"

// // 3. 清理并保留多个参数
// console.log(UrlUtils.keepParams(dirtyUrl, ['merchant_id', 'expires_time']));
// // 输出: "http://10.210.254.149:8081/h5_pay/?merchant_id=1&expires_time=123"