const dataArr = Array(40).fill(0, 0, 40)

// 获取当前日期
getCurrentDate() {
  this.selectData = {
    year: new Date().getFullYear(),
    month: new Date().getMonth() + 1,
    day: new Date().getDate(),
  }
}

const { year } = this.selectData
let daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

if ((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0) { // 闰年处理
  daysInMonth[1] = 29
}

const { year, month } = this.selectData
const monthStartWeekDay = new Date(year, month - 1, 1).getDay()

// 切换点选日期
checkoutDate(selectData) {
  if (selectData.type !== 'normal') return // 非有效日期不可点选

  this.selectData.day = selectData.day // 对选中日期赋值

   // 查找当前选中日期的索引
  const oldSelectIndex = this.dataArr.findIndex(item => item.isSelected && item.type === 'normal')
  // 查找新切换日期的索引 (tips: 这里也可以直接把索引值传过来 -> index)
  const newSelectIndex = this.dataArr.findIndex(item => item.day === selectData.day && item.type === 'normal')

  // 更改isSelected值
  if (this.dataArr[oldSelectIndex]) this.$set(this.dataArr[oldSelectIndex], 'isSelected', false)
  if (this.dataArr[newSelectIndex]) this.$set(this.dataArr[newSelectIndex], 'isSelected', true)
}

checkoutPreMonth() {
  let { year, month, day } = this.selectData
  if (month === 1) {
    year -= 1
    month = 12
  } else {
    month -= 1
  }

  this.selectData = { year, month, day: 1 }
  this.dataArr = this.getMonthData(this.selectData)
},

checkoutCurrentDate() {
  this.getCurrentDate()
  this.dataArr = this.getMonthData(this.selectData)
},

allDataArr: [], // 轮播数组
isSelectedCurrentDate: false, // 是否点选的当月日期
translateIndex: 0, // 轮播所在位置
transitionDuration: 0.3, // 动画持续时间
needAnimation: true, // 左右滑动是否需要动画
isTouching: false, // 是否为滑动状态
touchStartPositionX: null, // 初始滑动X的值
touchStartPositionY: null, // 初始滑动Y的值
touch: { // 本次touch事件，横向，纵向滑动的距离的百分比
  x: 0,
  y: 0,
},

isWeekView: false, // 周视图还是月视图
itemHeight: 50, // 日历行高
lineNum: 0, // 当前视图总行数

this.lineNum = Math.ceil(this.dataArr.length / 7)

offsetY: 0, // 周视图 Y轴偏移量

// 处理周视图的数据变化
dealWeekViewData() {
  const selectedIndex = this.dataArr.findIndex(item => item.isSelected)
  const indexOfLine = Math.ceil((selectedIndex + 1) / 7)
  this.offsetY = -((indexOfLine - 1) * this.itemHeight)
},

const nextInfo = this.getNextMonth()

let nextObj = {
  type: 'next',
  day: i + 1,
  month: nextInfo.month,
  year: nextInfo.year,
}

const preInfo = this.getPreMonth(date)

let preObj = {
  type: 'pre',
  day: daysInMonth[preInfo.month - 1] - (monthStartWeekDay - i - 1),
  month: preInfo.month,
  year: preInfo.year,
}

// 获取处理周视图所需的位置信息
getInfoOfWeekView(selectedIndex, length) {
  const indexOfLine = Math.ceil((selectedIndex + 1) / 7) // 当前行数
  const totalLine = Math.ceil(length / 7) // 总行数
  const sliceStart = (indexOfLine - 1) * 7 // 当前行左端索引
  const sliceEnd = sliceStart + 7 // 当前行右端索引

  return { indexOfLine, totalLine, sliceStart, sliceEnd }
},

// 处理lastWeek、nextWeek, 并返回替换行索引
dealWeekViewSliceStart() {
  const selectedIndex = this.dataArr.findIndex(item => item.isSelected)
  const {
    indexOfLine,
    totalLine,
    sliceStart,
    sliceEnd
  } = this.getInfoOfWeekView(selectedIndex, this.dataArr.length)

  this.offsetY = -((indexOfLine - 1) * this.itemHeight)

  // 前一周数据
  if (indexOfLine === 1) {
    const preDataArr = this.getMonthData(this.getPreMonth(), true)
    const preDay = this.dataArr[0].day - 1 || preDataArr[preDataArr.length - 1].day
    const preIndex = preDataArr.findIndex(item => item.day === preDay && item.type === 'normal')
    const { sliceStart: preSliceStart, sliceEnd: preSliceEnd } = this.getInfoOfWeekView(preIndex, preDataArr.length)
    this.lastWeek = preDataArr.slice(preSliceStart, preSliceEnd)
  } else {
    this.lastWeek = this.dataArr.slice(sliceStart - 7, sliceEnd - 7)
  }

  // 后一周数据
  if (indexOfLine >= totalLine) {
    const nextDataArr = this.getMonthData(this.getNextMonth(), true)
    const nextDay = this.dataArr[this.dataArr.length - 1].type === 'normal' ? 1 : this.dataArr[this.dataArr.length - 1].day + 1
    const nextIndex = nextDataArr.findIndex(item => item.day === nextDay)
    const { sliceStart: nextSliceStart, sliceEnd: nextSliceEnd } = this.getInfoOfWeekView(nextIndex, nextDataArr.length)
    this.nextWeek = nextDataArr.slice(nextSliceStart, nextSliceEnd)
  } else {
    this.nextWeek = this.dataArr.slice(sliceStart + 7, sliceEnd + 7)
  }

  return sliceStart
},

dealWeekViewData() {
  const sliceStart = this.dealWeekViewSliceStart()
  this.allDataArr[0].splice(sliceStart, 7, ...this.lastWeek)
  this.allDataArr[2].splice(sliceStart, 7, ...this.nextWeek)
},