<template>
 <van-picker
   :title="title"
   :show-toolbar="showToolbar"
   :columns="columns"
   @confirm="onConfirm"
   @cancel="onCancel"
   @change="onChange"
   :confirm-button-text="confirmButtonText"
   :cancel-button-text="cancelButtonText"
   :loading="loading"
   :readonly="readonly"
   :item-height="itemHeight"
   :visible-item-count="visibleItemCount"
   :swipe-duration="swipeDuration"
 >
  <template slot="default">
   <slot name="default"></slot>
  </template>
  <template slot="title">
   <slot name="title"></slot>
  </template>
  <template slot="confirm">
   <slot name="confirm"></slot>
  </template>
  <template slot="cancel">
   <slot name="cancel"></slot>
  </template>
  <template slot="option">
   <slot name="option"></slot>
  </template>
  <template slot="columns-top">
   <slot name="columns-top"></slot>
  </template>
  <template slot="columns-bottom">
   <slot name="columns-bottom"></slot>
  </template>
 </van-picker>
</template>

<script>
 import Vue from 'vue'
 import { Field, Picker, Popup } from 'vant';
 Vue.use(Field).use(Picker).use(Popup);

 export default {
  name: "VanDatePicker",
  props: {
   value: {
    type: Date,
    default: () => new Date()
   },
   minDate: {
    type: Date,
    default: () => new Date(new Date().getFullYear()-5,0,1)
   },
   maxDate: {
    type: Date,
    default: () => new Date(new Date().getFullYear()+5,0,1)
   },
   showToolbar: {
    type: Boolean,
    default: () => false
   },
   title: {
    type: String,
    default: () => ''
   },
   confirmButtonText: {
    type: String,
    default: () => '确认'
   },
   cancelButtonText: {
    type: String,
    default: () => '取消'
   },
   loading: {
    type: Boolean,
    default: () => false
   },
   readonly: {
    type: Boolean,
    default: () => false
   },
   itemHeight: {
    type: Number||String,
    default: () => 44
   },
   visibleItemCount: {
    type: Number||String,
    default: () => 6
   },
   swipeDuration: {
    type: Number||String,
    default: () => 1000
   },
  },
  data() {
   return {
    monthArr: ['01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12'],
    dayArr: ['01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12','13', '14', '15', '16', '17', '18', '19', '20', '21', '22', '23', '24','25', '26', '27', '28', '29', '30', '31'],
   };
  },
  
  computed: {
   columns: function () {
    let minYear = this.minDate.getFullYear();
    let maxYear = this.maxDate.getFullYear();
    let year = this.value.getFullYear();
    let month = this.value.getMonth();
    let day = this.value.getDate();
    let yearArr = [];
    let i = 0;
    while (i < maxYear - minYear + 1) {
     yearArr.unshift((maxYear - i) + '');
     i ++;
    }
    let columns = [
     {
      values: yearArr,
      defaultIndex: Math.floor(year) - minYear
     },
     {
      values: this.monthArr,
      defaultIndex: Math.floor(month)
     },
     {
      values: this.dayArr,
      defaultIndex: Math.floor(day-1)
     },
     {
      values: ['-']
     },
     {
      values: yearArr,
      defaultIndex: Math.floor(year) - minYear
     },
     {
      values: this.monthArr,
      defaultIndex: Math.floor(month)
     },
     {
      values: this.dayArr,
      defaultIndex: Math.floor(day-1)
     },
    ];
    return columns
   }
  },

  watch: {

  },
  
  methods: {
   onConfirm(value, index) {
    // console.log(`当前值：${value}, 当前索引：${index}`);
    this.$emit('confirm',value,index);
   },
   onChange(picker, value, index) {
    // console.log(`当前值：${value}, 当前索引：${index}`);
    let _this = this;

    let minMonth = this.minDate.getMonth();
    let minDay = this.minDate.getDate();
    let maxMonth = this.maxDate.getMonth();
    let maxDay = this.maxDate.getDate();
    let d = new Date(value[0],value[1],0);

    setDate(0);
    setDate(4);
    function setDate(i) {
     //最小年份
     if (value[i]-0===_this.minDate.getFullYear()) {
      picker.setColumnValues(i+1,_this.monthArr.slice(minMonth));
      let strMinM = '';
      if (minMonth<9) {
       strMinM = '0'+(minMonth+1)
      } else {
       strMinM = strMinM + 1 + ''
      }
      picker.setColumnValue(i+1,value[i+1]-1<minMonth"")>finallyVal.slice(len+1).join("")){
     picker.setValues([...finallyVal.slice(0,len),"-",...finallyVal.slice(0,len)]);
     if (new Date(finallyVal.slice(0,len).join("-")+' 00:00:00').getTime()===this.maxDate.getTime()) {
      console.log(111);
      picker.setColumnValues(5,_this.monthArr.slice(0,maxMonth+1));
      picker.setColumnValues(6,_this.dayArr.slice(0,maxDay));
     }
    }

    this.$emit('change',picker,finallyVal,index);
   },
   onCancel() {
    // console.log('取消');
    this.$emit('cancel');
   },
  },
 }
</script>

<style scoped>

</style>

<template>
 <div>
  <van-field
    readonly
    clickable
    label="时间段"
    :value="value"
    placeholder="选择时间段"
    @click="showPicker = true"
  />
  <van-popup v-model="showPicker" round position="bottom">
   <van-date-picker
     show-toolbar
     v-model="currentDate"
  title="选择时间段"
     :min-date="minDate"
     :max-date="maxDate"
     @cancel="showPicker = false"
     @confirm="onConfirm"
     @change="onChange"
   >
   </van-date-picker>
  </van-popup>
 </div>
</template>

<script>
 import VanDatePicker from '@/components/VanDatePicker';

 export default {
  name: "Test",
  components: {VanDatePicker},
  data() {
   return {
    value: '',
    showPicker: false,
    minDate: new Date(2010, 5, 15),
    maxDate: new Date(2025, 10, 15),
    currentDate: new Date(),
    startDate: '',
    endDate: '',
   };
  },

  mounted() {

  },

  methods: {
   onConfirm(value, index) {
    console.log(`当前值：${value}, 当前索引：${index}`);
    this.startDate = value.slice(0,3).join('-');
    this.endDate = value.slice(4,7).join('-');
    this.value = this.startDate + '至' + this.endDate;
    this.showPicker = false
   },

   onChange(picker, value, index) {
    console.log(`当前值：${value}, 当前索引：${index}`);
   },
  },
 }
</script>

<style scoped>

</style>