import moment, { Moment } from 'moment'
import type { GenerateConfig } from 'rc-picker/lib/generate'

export function getGenerateConfigWithUtcOffset(
  utcOffset: number
): GenerateConfig<Moment> {
  if (utcOffset >= 16 || utcOffset <= -16) {
    throw Error('utcOffset is invalid.')
  }

  return {
    // get
    getNow: () => moment().utcOffset(utcOffset),
    getFixedDate: string => moment(string, 'YYYY-MM-DD').utcOffset(utcOffset, true),
    getEndDate: date => date.clone().utcOffset(utcOffset).endOf('month'),
    getWeekDay: date => {
      // weekday() + firstDayOfWeek() 结果跟语言无关，所以指定了一个确定存在的 locale
      const clone = date.clone().locale('en_US').utcOffset(utcOffset)
      return clone.weekday() + clone.localeData().firstDayOfWeek()
    },
    getYear: date => date.clone().utcOffset(utcOffset).year(),
    getMonth: date => date.clone().utcOffset(utcOffset).month(),
    getDate: date => date.clone().utcOffset(utcOffset).date(),
    getHour: date => date.clone().utcOffset(utcOffset).hour(),
    getMinute: date => date.clone().utcOffset(utcOffset).minute(),
    getSecond: date => date.clone().utcOffset(utcOffset).second(),

    // set
    addYear: (date, diff) => date.clone().utcOffset(utcOffset).add(diff, 'year'),
    addMonth: (date, diff) => date.clone().utcOffset(utcOffset).add(diff, 'month'),
    addDate: (date, diff) => date.clone().utcOffset(utcOffset).add(diff, 'day'),
    setYear: (date, year) => date.clone().utcOffset(utcOffset).year(year),
    setMonth: (date, month) => date.clone().utcOffset(utcOffset).month(month),
    setDate: (date, num) => date.clone().utcOffset(utcOffset).date(num),
    setHour: (date, hour) => date.clone().utcOffset(utcOffset).hour(hour),
    setMinute: (date, minute) => date.clone().utcOffset(utcOffset).minute(minute),
    setSecond: (date, second) => date.clone().utcOffset(utcOffset).second(second),

    // compare
    isAfter: (date1, date2) => date1.isAfter(date2),
    isValidate: date => date.isValid(),

    locale: {
      getWeekFirstDay: locale => moment().locale(locale).localeData().firstDayOfWeek(),
      getWeekFirstDate: (locale, date) => date.clone().utcOffset(utcOffset).locale(locale).weekday(0),
      getWeek: (locale, date) => date.clone().utcOffset(utcOffset).locale(locale).week(),
      getShortWeekDays: locale => moment().locale(locale).localeData().weekdaysMin(),
      getShortMonths: locale => moment().locale(locale).localeData().monthsShort(),
      format: (locale, date, format) => date.clone().utcOffset(utcOffset).locale(locale).format(format),
      // copy from https://github.com/react-component/picker/blob/master/src/generate/moment.ts
      parse: (locale, text, formats) => {
        const fallbackFormatList: string[] = []

        for (let i = 0; i < formats.length; i += 1) {
          let format = formats[i]
          let formatText = text

          if (format.includes('wo') || format.includes('Wo')) {
            format = format.replace(/wo/g, 'w').replace(/Wo/g, 'W')
            const matchFormat = format.match(/[-YyMmDdHhSsWwGg]+/g)
            const matchText = formatText.match(/[-\d]+/g)

            if (matchFormat && matchText) {
              format = matchFormat.join('')
              formatText = matchText.join('')
            } else {
              fallbackFormatList.push(format.replace(/o/g, ''))
            }
          }

          const date = moment(formatText, format, locale, true).utcOffset(utcOffset, true)
          if (date.isValid()) {
            return date
          }
        }

        // Fallback to fuzzy matching, this should always not reach match or need fire a issue
        for (let i = 0; i < fallbackFormatList.length; i += 1) {
          const date = moment(text, fallbackFormatList[i], locale, false).utcOffset(utcOffset, true)
          if (date.isValid()) {
            return date
          }
        }

        return null
      }
    }
  }
}