function formatTime(date) {
  var year = date.getFullYear()
  var month = date.getMonth() + 1
  var day = date.getDate()

  var hour = date.getHours()
  var minute = date.getMinutes()
  var second = date.getSeconds()

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

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

function formatDateString(dateStr) {
  var date = new Date()
  date.setTime(dateStr * 1000)
  var newDate = this.formatTime(date)
  return newDate
}
function yearFormString(dateStr) {
  var date = new Date()
  date.setTime(dateStr * 1000)
  var year = date.getFullYear()
  return year
}
function monthFormString(dateStr) {
  var date = new Date()
  date.setTime(dateStr * 1000)
  var month = date.getMonth() + 1
  return month
}
function dayFormString(dateStr) {
  var date = new Date()
  date.setTime(dateStr * 1000)
  var day = date.getDate()
  return day
}

/** 
  * 检验18位身份证号码（15位号码可以只检测生日是否正确即可） 
  * @author wolfchen 
  * @param idCardNo 18为的身份证号码
  * @return Boolean 是否合法 
  **/
function isIDCardNum(idCardNo) {
  var regID_18 = /^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$/;
  var regID_15 = /^[1-9]\d{5}\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{2}$/;
  var arrExp = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];//加权因子  
  var arrValid = [1, 0, "X", 9, 8, 7, 6, 5, 4, 3, 2];//校验码  
  if (regID_15.test(idCardNo)) {
    return true;
  } else if (regID_18.test(idCardNo)) {
    var sum = 0, idx;
    for (var i = 0; i < idCardNo.length - 1; i++) {
      // 对前17位数字与权值乘积求和  
      sum += parseInt(idCardNo.substr(i, 1), 10) * arrExp[i];
    }
    // 计算模（固定算法）  
    idx = sum % 11;
    // 检验第18为是否与校验码相等  
    return arrValid[idx] == idCardNo.substr(17, 1).toUpperCase();
  } else {
    return false;
  }
}

module.exports = {
  formatTime: formatTime,
  formatDateString: formatDateString,
  yearFormString: yearFormString,
  monthFormString: monthFormString,
  dayFormString: dayFormString,
  isIDCardNum: isIDCardNum
}