/* 基础小工具，可通用于服务端和用户端
 */

module.exports = {
  sleep: (ms) => new Promise((resolve, reject) => setTimeout(resolve, ms)),

  parseJsonPossible(value) {
    try {
      return JSON.parse(value)
    } catch (e) {
      return value
    }
  },

  // 按顺序展开，哪怕嵌套。
  stringifyOrdered (obj, {cmp, cycles = false, space = '', replacer, schemaColumns, excludeKeys = []} = {}) {

    /* 这个解决方法不考虑缺省值，不能把嵌套对象也按顺序展开。*/
//    return JSON.stringify(obj, Object.keys(schemaColumns || entity).sort().filter(key => ! excludeKeys.includes(key))) // JSON.stringify 可根据第二个数组参数的顺序排序，但这导致了嵌套对象不能按顺序展开。

    let newObj = {}
    if (schemaColumns) {
      for (let key in schemaColumns){
        if (schemaColumns.hasOwnProperty(key) && ! schemaColumns[key].hashExclusive && ! excludeKeys.includes(key)) {
          // JSON.stringify (包括本函数）会把 NaN 或 Infinity 输出为 null，会把 undefined 忽略掉。
          // 而在 typeorm sqlite 数据库中，undefined 会自动存为 schemaColumns[key].default 或 null。从数据库读出时，就会和事先JSON.stringify的结果不一致。
          // 为了和 torm 数据库保持一致习惯，对schemaColumns里的键值应当把 undefined 也设为 default 或 null。
          if (obj[key] === undefined || Number.isNaN(obj[key]) || obj[key] === Infinity) {
            newObj[key] = typeof schemaColumns[key].default === 'undefined' ? null : schemaColumns[key].default
            obj[key] = newObj[key] // 确保内存中的数据和数据库保持一致
          }else {
            newObj[key] = obj[key]
          }
        }
      }
    }else{
      newObj = obj
    }

    /* 以下代码来自 https://github.com/substack/json-stable-stringify 可把嵌套的复杂值也按顺序输出，例如 { c: 8, b: [{z:6,y:5,x:4},7], a: 3 } */
    if (typeof space === 'number') space = Array(space+1).join(' ')
    var cycles = (typeof cycles === 'boolean') ? cycles : false
    var replacer = replacer || function(key, value) { return value }

    var cmp = cmp && (function (f) {
        return function (node) {
            return function (a, b) {
                var aobj = { key: a, value: node[a] }
                var bobj = { key: b, value: node[b] }
                return f(aobj, bobj)
            }
        }
    })(cmp)

    var seen = []
    return (function stringify (parent, key, node, level) {
        var indent = space ? ('\n' + new Array(level + 1).join(space)) : ''
        var colonSeparator = space ? ': ' : ':'

        if (node && node.toJSON && typeof node.toJSON === 'function') {
            node = node.toJSON()
        }

        node = replacer.call(parent, key, node)

        if (node === undefined) {
            return
        }
        if (typeof node !== 'object' || node === null) {
            return JSON.stringify(node)
        }
        if (Array.isArray(node)) {
            var out = []
            for (var i = 0; i < node.length; i++) {
                var item = stringify(node, i, node[i], level+1) || JSON.stringify(null)
                out.push(indent + space + item)
            }
            return '[' + out.join(',') + indent + ']'
        }
        else {
            if (seen.indexOf(node) !== -1) {
                if (cycles) return JSON.stringify('__cycle__')
                throw new TypeError('Converting circular structure to JSON')
            }
            else seen.push(node)

            var keys = Object.keys(node).sort(cmp && cmp(node))
            var out = []
            for (var i = 0; i < keys.length; i++) {
                var key = keys[i]
                var value = stringify(node, key, node[key], level+1)

                if(!value) continue

                var keyValue = JSON.stringify(key)
                    + colonSeparator
                    + value
                
                out.push(indent + space + keyValue)
            }
            seen.splice(seen.indexOf(node), 1)
            return '{' + out.join(',') + indent + '}'
        }
    })({ '': newObj }, '', newObj, 0)
  },

  name2port(name='') {
    let port = name.toLowerCase()
      .replace(/[abc]/g, 2)
      .replace(/[def]/g, 3)
      .replace(/[ghi]/g, 4)
      .replace(/[jkl]/g, 5)
      .replace(/[mno]/g, 6)
      .replace(/[pqrs]/g, 7)
      .replace(/[tuv]/g, 8)
      .replace(/[wxyz]/g, 9)
    return parseInt(port)
  },

  randomNumber ({ length, min, max } = {}) {
    // 长度为 length 的随机数字，或者 (min||0) <= num < max
    var num = 0
    if (typeof length === 'number' && length > 0) {
      num = parseInt(Math.random() * Math.pow(10, length))
      num = num.toString().padStart(length, '0')
    } else if (typeof max === 'number' && max > 0) {
      min = typeof min === 'number' && min >= 0 ? min : 0
      num = parseInt(Math.random() * (max - min)) + min
    } else {
      // 如果 option 为空
      num = Math.random()
    }
    return num
  },

  hash (data, { hasher = 'sha256', salt, input = 'utf8', output = 'hex' } = {}) {
    if (typeof data !== 'string' && !(data instanceof Buffer) && !(data instanceof DataView)) data = JSON.stringify(data)
    if (salt && typeof salt === 'string') data = data + salt
    const inputEncoding = input // my.INPUT_LIST.indexOf(option.input)>=0?option.input:my.INPUT // 'utf8', 'ascii' or 'latin1' for string data, default to utf8 if not specified; ignored for Buffer, TypedArray, or DataView.
    const outputEncoding = output === 'buf' ? undefined : output // (my.OUTPUT_LIST.indexOf(output)>=0?output:my.OUTPUT)  // option.output: 留空=》默认输出hex格式；或者手动指定 'buf', hex', 'latin1' or 'base64'
    return require('crypto').createHash(hasher).update(data, inputEncoding).digest(outputEncoding)
  },

  /**
   * 用户编号转邀请码
   *
   * @static
   * @param {*} aiid
   * @return {*}
   * @memberof TICrypto
   */
  aiid2regcode (aiid) {
    const alphabet = 'e5fcdg3hqa4b1n0pij2rstuv67mwx89klyz'
    const base = 16367
    let num = (aiid + base) * (base - alphabet.length)
    let code = ''
    let mod
    while (num > 0) {
      mod = num % alphabet.length
      num = (num - mod) / alphabet.length
      code = code + alphabet[mod] // 倒序存放
    }
    return code
  },

  /**
   * 邀请码转用户编号
   *
   * @static
   * @param {*} code
   * @return {*}
   * @memberof TICrypto
   */
  regcode2aiid (code) {
    if (typeof code === 'string' && /^[a-zA-Z0-9]+$/.test(code)) {
      const alphabet = 'e5fcdg3hqa4b1n0pij2rstuv67mwx89klyz'
      const base = 16367
      code = code.toLowerCase()
      let len = code.length
      let num = 0
      for (let i = 0; i < len; i++) {
        num += alphabet.indexOf(code[i]) * Math.pow(alphabet.length, i)
      }
      let aiid = num / (base - alphabet.length) - base
      if (aiid >= 0 && Number.isInteger(aiid)) {
        // 允许 aiid===0：当第一个用户（aiid==1）登录时，需要一个系统默认的邀请码。
        return aiid
      }
    }
    return null // null 代表一切非法的regcode
  },

}