<template>
  <view v-if="value" class="tn-select-class tn-select">
    <tn-popup
        v-model="value"
        mode="bottom"
        :popup="false"
        length="auto"
        :safeAreaInsetBottom="safeAreaInsetBottom"
        :maskCloseable="maskCloseable"
        :zIndex="elZIndex"
        @close="close"
    >
      <view class="tn-select__content">
        <!-- 头部 -->
        <view class="tn-select__content__header" @touchmove.stop.prevent>
          <view
              class="tn-select__content__header__btn tn-select__content__header--cancel"
              :style="{ color: cancelColor }"
              hover-class="tn-hover-class"
              hover-stay-time="150"
              @tap="getResult('cancel')"
          >{{ cancelText }}</view>
          <view class="tn-select__content__header__title">{{ title }}</view>
          <view
              class="tn-select__content__header__btn tn-select__content__header--confirm"
              :style="{ color: confirmColor }"
              hover-class="tn-hover-class"
              hover-stay-time="150"
              @tap="getResult('confirm')"
          >{{ confirmText }}</view>
        </view>
        <!-- 列表内容 -->

        <view class="tn-select__content__body">
          <view v-if="searchShow && mode==='single'">
            <view class="tn-flex tn-select__content__body__search">
              <view class="tn-icon-search tn-padding-sm" ></view>
              <input class="tn-select__content__body__search__input" :placeholder="searchPlaceholder" maxlength="255" confirm-type="search" @input="searchInput" @confirm="search"  >
            </view>
          </view>
          <picker-view
              class="tn-select__content__body__view"
              :value="defaultSelector"
              @pickstart="pickStart"
              @pickend="pickEnd"
              @change="columnChange"
          >

            <picker-view-column v-for="(item, index) in columnData" :key="index">
              <view class="tn-select__content__body__item" v-for="(sub_item, sub_index) in item" :key="sub_index">
                <view class="tn-text-ellipsis">
                  {{ sub_item[labelName] }}
                </view>
              </view>
            </picker-view-column>
          </picker-view>
        </view>
      </view>
    </tn-popup>
  </view>
</template>

<script>
export default {
  name: 'tn-select',
  props: {
    value: {
      type: Boolean,
      default: false
    },
    // 列表模式
    // single 单列 multi 多列 multi-auto 多列联动
    mode: {
      type: String,
      default: 'single'
    },
    // 列数据
    list: {
      type: Array,
      default() {
        return []
      }
    },
    // value属性名
    valueName: {
      type: String,
      default: 'value'
    },
    // label属性名
    labelName: {
      type: String,
      default: 'label'
    },
    // 当mode=multi-auto时，children的属性名
    childName: {
      type: String,
      default: 'children'
    },
    // 默认值
    defaultValue: {
      type: Array,
      default() {
        return [0]
      }
    },
    // 顶部标题
    title: {
      type: String,
      default: ''
    },
    // 取消按钮文字
    cancelText: {
      type: String,
      default: '取消'
    },
    // 取消按钮文字颜色
    cancelColor: {
      type: String,
      default: ''
    },
    // 确认按钮文字
    confirmText: {
      type: String,
      default: '确认'
    },
    // 确认按钮文字颜色
    confirmColor: {
      type: String,
      default: ''
    },
    // 点击遮罩关闭
    maskCloseable: {
      type: Boolean,
      default: true
    },
    // 预留安全区域
    safeAreaInsetBottom: {
      type: Boolean,
      default: false
    },
    // zIndex
    zIndex: {
      type: Number,
      default: 0
    },
    // 是否开启模糊搜索(只在单列模式生效)
    searchShow:{
      type:Boolean,
      default:true
    },
    //搜索框placeholder
    searchPlaceholder:{
      type:String,
      default:'搜索'
    }
  },
  computed: {
    elZIndex() {
      return this.zIndex ? this.zIndex : this.$tn.zIndex.popup
    }
  },
  data() {
    return {
      // 列是否还在滑动中，微信小程序如果在滑动中就点确定，结果可能不准确
      moving: false,
      // 用户保存当前列的索引，用于判断下一次变化时改变的列
      defaultSelector: [0],
      // picker-view数据
      columnData: [],
      // 保存用户选择的结果
      selectValue: [],
      // 上一次改变时的index
      lastSelectIndex: [],
      // 列数
      columnNum: 0,

    }
  },
  watch: {
    // 在select弹起的时候，重新初始化所有数据
    value: {
      handler(val) {
        if (val) setTimeout(() => this.init(), 10)
      },
      immediate: true
    }
  },
  methods: {
    //搜索输入监听
    searchInput(e){
      console.log(e.detail.value);
      this.searchResult(e.detail.value)
    },
    //搜索完成监听
    search(e){
      console.log(e.detail.value)
      this.searchResult(e.detail.value)
    },
    //执行搜索方法
    searchResult(value) {
      let result = [];
      // console.log(this.list)
      let data = this.list.filter(item => item.label.indexOf(value) > -1);
      if (data.length > 0) {
        result.push(data
        );
      }
      // console.log(result)
      this.columnData = result;
      this.selectValue=[]
      if (this.columnData.length>0){
        this.setSelectValue()
      }
    },

    // 标识滑动开始，只有微信小程序才有这样的事件
    pickStart() {
      // #ifdef MP-WEIXIN
      this.moving = true;
      // #endif
    },
    // 标识滑动结束
    pickEnd() {
      // #ifdef MP-WEIXIN
      this.moving = false;
      // #endif
    },
    init() {
      this.setColumnNum()
      this.setDefaultSelector()
      this.setColumnData()
      this.setSelectValue()
    },
    // 获取默认选中列下标
    setDefaultSelector() {
      // 如果没有传入默认值，生成用0填充长度为columnNum的数组
      this.defaultSelector = this.defaultValue.length === this.columnNum ? this.defaultValue : Array(this.columnNum).fill(0)
      this.lastSelectIndex = this.$tn.deepClone(this.defaultSelector)
    },
    // 计算列数
    setColumnNum() {
      // 单列的数量为1
      if (this.mode === 'single') this.columnNum = 1
      // 多列时取list的长度
      else if (this.mode === 'multi') this.columnNum = this.list.length
      // 多列联动时，通过遍历list的第一个元素，得出有多少列
      else if (this.mode === 'multi-auto') {
        let num = 1
        let column = this.list
        // 如果存在children属性，再次遍历
        while (column[0][this.childName]) {
          column = column[0] ? column[0][this.childName] : {},
              num++
        }
        this.columnNum = num
      }
    },
    // 获取需要展示在picker中的列数据
    setColumnData() {
      let data = []
      this.selectValue = []
      if (this.mode === 'multi-auto') {
        // 获取所有数据中的第一个元素
        let column = this.list[this.defaultSelector.length ? this.defaultSelector[0] : 0]
        // 通过循环所有列数，再根据设定列的数组，得出当前需要渲染的整个列数组
        for (let i = 0; i < this.columnNum; i++) {
          // 第一列默认为整个list数组
          if (i === 0) {
            data[i] = this.list
            column = column[this.childName]
          } else {
            // 大于第一列时，判断是否有默认选中的，如果没有就用该列的第一项
            data[i] = column
            column = column[this.defaultSelector[i]][this.childName]
          }
        }
      } else if (this.mode === 'single') {
        data[0] = this.list
      } else {
        data = this.list
      }
      this.columnData = data
    },
    // 获取默认选中的值，如果没有设置，则默认选中第一项
    setSelectValue() {
      let tmp = null
      for (let i = 0; i < this.columnNum; i++) {
        tmp = this.columnData[i][this.defaultSelector[i]]
        let data = {
          value: tmp ? tmp[this.valueName] : null,
          label: tmp ? tmp[this.labelName] : null
        }
        // 判断是否存在额外的参数
        if (tmp && tmp.extra) data.extra = tmp.extra
        this.selectValue.push(data)
      }
      // console.log("默认",this.selectValue)
    },
    // 列选项
    columnChange(event) {
      let index = null
      let columnIndex = event.detail.value

      this.selectValue = []
      if (this.mode === 'multi-auto') {
        // 对比前后两个数组，判断变更的是那一列
        this.lastSelectIndex.map((v, idx) => {
          if (v != columnIndex[idx]) index = idx
        })
        this.defaultSelector = columnIndex
        // 当前变化列的下一列的数据，需要获取上一列的数据，同时需要指定是上一列的第几个的children，再往后的
        // 默认是队列的第一个为默认选项
        for (let i = index + 1; i < this.columnNum; i++) {
          this.columnData[i] = this.columnData[i - 1][i - 1 == index ? columnIndex[index] : 0][this.childName]
          this.defaultSelector[i] = 0
        }
        // 在历遍的过程中，可能由于上一步修改this.columnData，导致产生连锁反应，程序触发columnChange，会有多次调用
        // 只有在最后一次数据稳定后的结果是正确的，此前的历遍中，可能会产生undefined，故需要判断
        columnIndex.map((item, index) => {
          let data = this.columnData[index][columnIndex[index]]
          let tmp = {
            value: data ? data[this.valueName] : null,
            label: data ? data[this.labelName] : null
          }
          if (data && data.extra !== undefined) tmp.extra = data.extra
          this.selectValue.push(tmp)
        })
        this.lastSelectIndex = columnIndex
      } else if (this.mode === 'single') {
        let data = this.columnData[0][columnIndex[0]]
        let tmp = {
          value: data ? data[this.valueName] : null,
          label: data ? data[this.labelName] : null
        }
        if (data && data.extra !== undefined) tmp.extra = data.extra
        this.selectValue.push(tmp)
      } else if (this.mode === 'multi') {
        columnIndex.map((item, index) => {
          let data = this.columnData[index][columnIndex[index]]
          let tmp = {
            value: data ? data[this.valueName] : null,
            label: data ? data[this.labelName] : null
          }
          if (data && data.extra !== undefined) tmp.extra = data.extra
          this.selectValue.push(tmp)
        })
      }
    },
    close() {
      this.$emit('input', false)
    },
    getResult(event = null) {
      // #ifdef MP-WEIXIN
      if (this.moving) return;
      // #endif
      if (event) this.$emit(event, this.selectValue)
      this.close()
    }
  }
}
</script>

<style lang="scss" scoped>

.tn-select {

  &__content {
    position: relative;

    &__header {
      position: relative;
      display: flex;
      flex-direction: row;
      width: 100%;
      height: 90rpx;
      padding: 0 40rpx;
      align-items: center;
      justify-content: space-between;
      box-sizing: border-box;
      font-size: 30rpx;
      background-color: #FFFFFF;

      &__btn {
        padding: 16rpx;
        box-sizing: border-box;
        text-align: center;
        text-decoration: none;
      }

      &__title {
        color: #080808;
      }

      &--cancel {
        color: #AAAAAA;
      }

      &--confirm {
        color: #01BEFF;
      }
    }

    &__body {
      width: 100%;
      height: 500rpx;
      overflow: hidden;
      background-color: #FFFFFF;

      &__search{
        z-index: 5;
        align-items: center;
        border-radius: 19px;
        background: #f8f8f8;
        width: calc(100% - 60rpx);
        margin: 0 auto;
        position: relative;
        top: 15px;

        &__input{
          width: 600rpx;
        }
      }

      &__view {
        height: 100%;
        box-sizing: border-box;
      }

      &__item {
        display: flex;
        flex-direction: row;
        align-items: center;
        justify-content: center;
        font-size: 32rpx;
        color: #080808;
        padding: 0 8rpx;
      }
    }
  }

}
</style>
