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, collapse } = options

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


    // 折叠成显示一周
    if (collapse) {
      const firstDateDay = date.day();
      // 获取当前周的前几天
      for (let i = 1; i <= firstDateDay; i++) {
        const thisDate = date.subtract(i, 'day').startOf('day');
        let item = {
          marks: [],
          _value: thisDate,
          text: thisDate.date(),
          type: getTypeOfMonth(thisDate, date),
          value: thisDate.format(format)
        }
        item = getFullItem(item, options, selectedDate, isShowStatus)
        list.push(item)
      }
      list.reverse();

      let item = {
        marks: [],
        _value: date,
        text: date.date(),
        type: constant.TYPE_NOW_MONTH,
        value: date.format(format)
      }
      item = getFullItem(item, options, selectedDate, isShowStatus)
      list.push(item)

      // 获取当前周的后几天
      let i = 1
      while (list.length < 7 ) {
        const thisDate = date.add(i++, 'day').startOf('day')
        let item = {
          marks: [],
          _value: thisDate,
          text: thisDate.date(),
          type: getTypeOfMonth(thisDate, date),
          value: thisDate.format(format)
        }

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

        list.push(item)
      }
    }

    // 展开成显示一
    else {


      // 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 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')
}


export function getTypeOfMonth(date: dayjs.Dayjs, contrastMonthDate: dayjs.Dayjs): number {
  const month = date.month();
  const contrastMonth = contrastMonthDate.month();
  if(month < contrastMonth) {
    return constant.TYPE_PRE_MONTH;
  }
  else if (month > contrastMonth) {
    return constant.TYPE_NEXT_MONTH;
  }
  else {
    return constant.TYPE_NOW_MONTH;
  }
}