import Big from 'big.js'
import dayjs from 'dayjs'
import { MONEY_BIGUNITS, MONEY_DECIMAL_SHOWNAME, MONEY_DIGITS, MONEY_INT_SHOWNAME, MONEY_NUMS, MONEY_POSTFIX } from './consts'
import { isEmpty } from './validate'

/**
 * 从末尾开始插入
 * @param str 需要处理的字符串
 * @param space 间隔
 * @param insertStr 要插入的内容
 * @returns
 */
function reverseInsert (str: string, space: number, insertStr: string) {
  if (space <= 0) return str
  const chars = str.split('')
  const len = chars.length - 1
  return chars
    .reduceRight((collect, int, index) => {
      const resverIndex = len - index
      collect.push(int)
      if (index !== 0 && resverIndex !== 0 && ((resverIndex + 1) % space === 0)) collect.push(insertStr)
      return collect
    }, [] as string[])
    .reverse()
    .join('')
}

/**
 * 格式化金额
 * @param value 数字
 * @param decimalLen 保留小数位数
 * @param splitStr 间隔符
 * @returns
 */
export function formatAmt (value?: string|number, decimalLen = 2, splitStr = ',') {
  if (splitStr === '.') throw new Error('splitStr not allowed to be smae as decimal point')
  if (isEmpty(value)) return ''
  const num = new Big(value).round(decimalLen).toFixed(decimalLen)
  let [integer = '', decimal = ''] = num.split('.')
  if (!isEmpty(splitStr)) {
    integer = reverseInsert(integer, 3, splitStr)
  }

  if (decimalLen === 0) return integer
  decimal = decimal.padEnd(decimalLen, '0')
  return `${integer}.${decimal}`
}

/**
 * 去格式化金额
 * @param val 需要格式化金额的值
 * @param splitStr 去除的分割符
 * @returns 去格式化
 */
export function unFormatAmt (val?: string|number, splitStr = ',') {
  return typeof val === 'number' ? String(val) : isEmpty(val) ? '0' : val.replace(new RegExp(splitStr, 'g'), '')
}

function getIntegerUnits (index: number, reset: number) {
  const units: string[] = []
  const len = MONEY_BIGUNITS.length
  const last = MONEY_BIGUNITS[len - 1]
  while (index >= len) {
    units.push(last)
    index -= len
  }
  units.push(MONEY_BIGUNITS[index])
  units.push(MONEY_DIGITS[reset])
  return units
}

/**
 * 转大写金额
 * @param val 需要转换的值
 * @returns 大写金额
 */
export function formatUpperAmt (val?: number|string) {
  if (isEmpty(val)) return ''
  let [integer, decimal] = unFormatAmt(val).split('.')
  const isAllZero = (str: string) => /^0+$/.test(str)
  const zeroStr = MONEY_NUMS[0]
  if (!isEmpty(integer)) {
    integer = isAllZero(integer)
      ? ''
      : integer
        .split('')
        .reverse()
        .reduce((collect, char, index) => {
          const rest = index % 4
          const cIndex = (index - rest) / 4
          if (rest === 0) collect[cIndex] = []
          if (char === '0') {
            if (collect[cIndex].length > 0 && collect[cIndex][rest - 1] !== '0') {
              collect[cIndex].push(MONEY_NUMS[0])
            }
          } else {
            collect[cIndex].push(...getIntegerUnits(cIndex, rest))
            collect[cIndex].push(MONEY_NUMS[Number(char)])
          }
          return collect
        }, [] as string[][])
        .flat()
        .reverse()
        .join('')
  }
  if (!isEmpty(decimal)) {
    decimal = isAllZero(decimal)
      ? ''
      : decimal
        .padEnd(2, '0')
        .slice(0, 2)
        .split('')
        .map((char, index) => char === '0' ? '' : `${MONEY_NUMS[Number(char)]}${MONEY_DECIMAL_SHOWNAME[index]}`)
        .join('')
  }

  const isIntEmpty = isEmpty(integer)
  const inDecimalEmpty = isEmpty(decimal)

  if (isIntEmpty && inDecimalEmpty) return `${zeroStr}${MONEY_INT_SHOWNAME}${MONEY_POSTFIX}`

  if (!isIntEmpty) {
    integer += MONEY_INT_SHOWNAME
  }
  if (inDecimalEmpty) {
    integer += MONEY_POSTFIX
  }
  return `${integer ?? ''}${decimal ?? ''}`
    .replace(new RegExp(`(${zeroStr})+`, 'g'), zeroStr)
    .replace(new RegExp(`(^${zeroStr}|${zeroStr}$)`, 'g'), '')
}

/**
 * 格式化时间
 * @param date 时间
 * @param pattern 格式化规则 默认 “YYYY-MM-DD”
 */
export function formatDate (date?: dayjs.ConfigType, pattern = 'YYYY-MM-DD') {
  return dayjs(date).format(pattern)
}

/**
 * 将输入串转化为全角字符
 * @param str 需要转换的字符串
 * @returns 转换后的全角字符
 */
export function formatDBC (str: string) {
  return str.split('')
    .reduce((tmp, cur) => {
      const charCode = cur.charCodeAt(0)
      if (charCode === 32) {
        tmp = tmp + String.fromCharCode(12288)
      }
      if (charCode < 127) {
        tmp = tmp + String.fromCharCode(charCode + 65248)
      }
      return tmp
    }, '')
}

/**
 * 格式化账号
 * @param accNo 需要格式化的账号
 * @returns
 */
export function formatAccount (accNo?: number|string) {
  const str = String(accNo ?? '').replace(/^\s|\s$/g, '')
  return reverseInsert(str, 4, ' ')
}