const Base = require('./base.js')
const util = require('util')

/**
 * @implements {Base}
 */
class TypeString extends Base {
  constructor () {
    super()
    this._type = 'string'
    this._max = null
    this._min = null
    this._empty = false
  }

  /**
   * set min length
   * @param {number} num
   */
  min (num) {
    if (!isFinite(num) || num === true || num === false) throw new Error('input wrong')
    if (this._max !== null && this._max <= num) throw new Error(`num >= ${this._max}`)
    this._min = parseFloat(num)
    return this
  }

  /**
   * set max length
   * @param {number} num
   */
  max (num) {
    if (!isFinite(num) || num === true || num === false) throw new Error('input wrong')
    if (this._min !== null && this._min >= num) throw new Error(`num <= ${this._min}`)
    this._max = parseFloat(num)
    return this
  }

  /**
   * set allow empty
   */
  empty () {
    this._empty = true
    return this
  }

  validate (value) {
    if (value === undefined && this._required) return `required`
    if (value === undefined) return null
    /* eslint-disable-next-line */
    if (typeof value !== this._type) return `${util.inspect(value, false, null)} type not ${this._type}`
    if (!this._empty && !value) return `value empty`
    const len = value.length
    if (this._min !== null && len < this._min) return `value length < ${this._min}`
    if (this._max !== null && len > this._max) return `value length > ${this._max}`
    return null
  }
}

module.exports = TypeString