const formatTime = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()
  const hour = date.getHours()
  const minute = date.getMinutes()
  const second = date.getSeconds()

  return [year, month, day].map(formatNumber).join('/') + ' ' + [hour, minute, second].map(formatNumber).join(':')
}

const formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}

/**
 * 随机生成指定长度的字符串
 * @param length
 * @returns {string}
 */
function randomString(length = 32) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
  const maxPos = chars.length
  let _string = ''
  for (let i = 0; i < length; i++) {
    _string += chars.charAt(Math.floor(Math.random() * maxPos))
  }
  return _string
}

function guid() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random() * 16 | 0,
      v = c == 'x' ? r : (r & 0x3 | 0x8);
    return v.toString(16);
  });
}

function findChildren(array, path) {

  var paths = path.replace(/^(\s|,)+|(\s|,)+$/g, '').split(',')
  if (paths.length === 0) return
  if (paths.length === 1) return array.filter(n => n.id === parseInt(paths[0]))[0]
  else {
    var child = array.filter(n => n.id === parseInt(paths[0]))[0].children
    var subpaths = paths
    subpaths.shift()
    return findChildren(child, subpaths.join(','))
  }
}

/*用正则表达式实现html转码*/
function htmlEncodeByRegExp(str) {
  var s = "";
  if (str.length == 0) return "";
  s = str.replace(/&/g, "&amp;");
  s = s.replace(/</g, "&lt;");
  s = s.replace(/>/g, "&gt;");
  s = s.replace(/ /g, "&nbsp;");
  s = s.replace(/\'/g, "&#39;");
  s = s.replace(/\"/g, "&quot;");
  return s;

}
/*用正则表达式实现html解码*/
function htmlDecodeByRegExp(str) {
  var s = "";
  if (str.length == 0) return "";
  s = str.replace(/&amp;/g, "&");
  s = s.replace(/&lt;/g, "<");
  s = s.replace(/&gt;/g, ">");
  s = s.replace(/&nbsp;/g, " ");
  s = s.replace(/&#39;/g, "\'");
  s = s.replace(/&quot;/g, "\"");
  return s;

}

module.exports = {
  formatTime: formatTime,
  randomString: randomString,
  guid: guid,
  findChildren: findChildren,
  htmlEncodeByRegExp: htmlEncodeByRegExp,
  htmlDecodeByRegExp: htmlDecodeByRegExp
}