import dayjs, { Dayjs } from 'dayjs'
import _flow from 'lodash/flow'

import Calendar from '../types'
import plugins from './plugins'
import * as constant from './constant'

const TOTAL = 7 * 6

function getFullItem (
  item: Partial<Calendar.Item>,
  options: Calendar.GroupOptions,
  selectedDate: Calendar.SelectedDate,
  isShowStatus?: boolean
) {
  if (!isShowStatus) return item

  const bindedPlugins = plugins.map(fn =>
    fn.bind(null, {
      options,
      selectedDate
    })
  )
  return _flow(bindedPlugins)(item)
}

export default function generateCalendarGroup (
  options: Calendar.GroupOptions
): (
    generateDate: number,
    selectedDate: Calendar.SelectedDate,
    isShowStatus?: boolean
  ) => Calendar.ListInfo<Calendar.Item> {
  return function (
    generateDate: number,
    selectedDate: Calendar.SelectedDate,
    isShowStatus?: boolean
  ): Calendar.ListInfo<Calendar.Item> {
    const date = dayjs(generateDate)

    const { format } = options

    // 获取生成日期的第一天 和 最后一天
    const firstDate = date.startOf('month')
    const lastDate = date.endOf('month')

    const preMonthDate = date.subtract(1, 'month')

    const list: Calendar.List<Calendar.Item> = []

    const nowMonthDays: number = date.daysInMonth() // 获取这个月有多少天
    const preMonthLastDay = preMonthDate.endOf('month').day() // 获取上个月最后一天是周几

    // 生成上个月的日期
    for (let i = 1; i <= preMonthLastDay + 1; i++) {
      const thisDate = firstDate.subtract(i, 'day').startOf('day')

      let item = {
        marks: [],
        _value: thisDate,
        text: thisDate.date(),
        type: constant.TYPE_PRE_MONTH,
        value: thisDate.format(format)
      }

      item = getFullItem(item, options, selectedDate, isShowStatus)

      list.push(item)
    }
    list.reverse()

    // 生成这个月的日期
    for (let i = 0; i < nowMonthDays; i++) {
      const thisDate = firstDate.add(i, 'day').startOf('day')
      let item = {
        marks: [],
        _value: thisDate,
        text: thisDate.date(),
        type: constant.TYPE_NOW_MONTH,
        value: thisDate.format(format)
      }

      item = getFullItem(item, options, selectedDate, isShowStatus)

      list.push(item)
    }

    // 生成下个月的日期
    let i = 1
    while (list.length < TOTAL) {
      const thisDate = lastDate.add(i++, 'day').startOf('day')
      let item = {
        marks: [],
        _value: thisDate,
        text: thisDate.date(),
        type: constant.TYPE_NEXT_MONTH,
        value: thisDate.format(format)
      }

      item = getFullItem(item, options, selectedDate, isShowStatus)

      list.push(item)
    }

    return {
      list,
      value: generateDate
    }
  }
}

export function getGenerateDate (date: Calendar.DateArg | undefined): Dayjs {
  return dayjs(date).startOf('month')
}