import type { VNodeTypes } from 'vue'

export type valueType = number | string
export type countdownValueType = number | string

export type Formatter =
  | false
  | 'number'
  | 'countdown'
  | (({ value, config }: { value: valueType; config?: FormatConfig }) => VNodeTypes)

export interface FormatConfig {
  formatter?: Formatter
  decimalSeparator?: string
  groupSeparator?: string
  precision?: number
  prefixCls?: string
}

export interface CountdownFormatConfig extends FormatConfig {
  format?: string
}

// Countdown
const timeUnits: [string, number][] = [
  ['Y', 1000 * 60 * 60 * 24 * 365], // years
  ['M', 1000 * 60 * 60 * 24 * 30], // months
  ['D', 1000 * 60 * 60 * 24], // days
  ['H', 1000 * 60 * 60], // hours
  ['m', 1000 * 60], // minutes
  ['s', 1000], // seconds
  ['S', 1], // million seconds
]

export function formatTimeStr(duration: number, format: string) {
  let leftDuration: number = duration

  const escapeRegex = /\[[^\]]*\]/g
  const keepList: string[] = (format.match(escapeRegex) || []).map((str) => str.slice(1, -1))
  const templateText = format.replace(escapeRegex, '[]')

  const replacedText = timeUnits.reduce((current, [name, unit]) => {
    if (current.includes(name)) {
      const value = Math.floor(leftDuration / unit)
      leftDuration -= value * unit
      return current.replace(new RegExp(`${name}+`, 'g'), (match: string) => {
        const len = match.length
        return value.toString().padStart(len, '0')
      })
    }
    return current
  }, templateText)

  let index = 0
  return replacedText.replace(escapeRegex, () => {
    const match = keepList[index]
    index += 1
    return match
  })
}

export function formatCountdown(value: valueType, config: CountdownFormatConfig) {
  const { format = '' } = config
  const target = new Date(value).getTime()
  const current = Date.now()
  const diff = Math.max(target - current, 0)

  return formatTimeStr(diff, format)
}
