<template>
  <view class='layout-column'>
    <view id="parent" class="parent-view" style="width:fit-content;">
      <slot></slot>
    </view>
    <view
        :style="'width:'+slotW+';max-height: '+getListContentHei+'rpx;z-index: 9999;position: absolute;margin-top:'+slotH+';'+(isShow ? '' : 'display:none;')"
        :class="(dataList.length > 0 ? 'data-box-shadow ' : 'data-box ') + animate">
      <block v-if="dataList.length > 0">
        <view class="data-box-scroll"
              :style="'height:'+dataList.length*(itemHeight-1)+'rpx;max-height: '+max*(itemHeight-1)+'rpx;'">
          <text v-for="(item,index) in dataList" :key="item[identifier]"
                :class="'layout-row less-center list-item '+(item.enable === false ? '' : 'active')"
                :style="'color:'+(item.enable === false ? '#dedede' : (checkedIndex.indexOf(index) >= 0 ? itemSelectColor : itemColor))+';font-size:'+itemFontsize+'rpx;'"
                @click="handleListItem(index, item)">{{ item[showKey] }}
          </text>
        </view>
        <view class="layout-row opera-btns less-center" v-if="mode == 'multiple'">
          <view class="opera-cancel layout-row center" @click='handelCancel'>取消</view>
          <view class="opera-sure layout-row center" @click='handelSure'>确定</view>
        </view>
      </block>
      <view v-else :style="'width:'+slotW+';'" class='status-text'>暂无数据</view>
    </view>
    <view class="mask" v-show="isShow" @click="handelCancel"></view>
  </view>
</template>

<script>
export default {
  name: "down-select",
  props: {
    //要显示的字段
    showKey: {
      type: String,
      default: '',
    },
    mode: {
      type: String,
      default: 'single', //multiple
      // default: 'multiple'
    },
    dataList: {
      type: Array,
      default: []
    },
    //选中的列表，用作显示列表是展示已选中项
    checkedDataList: {
      type: Array,
      default: ()=>{return []}
    },
    //最多展示几项后开始滑动
    max: {
      type: Number,
      default: 4
    },
    //数据项每个item高度rpx
    itemHeight: {
      type: Number,
      default: 80
    },
    //唯一标识符字段，用来比对选中项和维持v-for列表中的key,不填此项无选中效果
    identifier: {
      type: String,
      default: ''
    },
    itemSelectColor: {
      type: String,
      default: '#00aaff'
    },
    itemColor: {
      type: String,
      default: 'black'
    },
    itemFontsize: {
      type: Number,
      default: 30
    }
  },
  computed: {
    getListContentHei() {
      let len = this.dataList.length
      let signleH = len < this.max ? this.itemHeight * len : this.itemHeight * this.max
      if (this.mode == 'single') {
        return len <= 0 ? this.itemHeight : signleH
      } else {
        return len <= 0 ? this.itemHeight : (signleH + this.itemHeight)
      }
    }
  },
  watch: {
    dataList: {
      handler: function (newVal, oldVal) {
        if (this.checkedDataList.length >= 0 && this.identifier) {
          this.checkedIndex = []
          this.checkedDataList.forEach(ele => {
            let index = newVal.findIndex(ele1 => ele[this.identifier] === ele1[this
                .identifier])
            if (index >= 0) {
              this.checkedIndex.push(index)
            }
          })
        }
      },
      immediate: true, // 组件创建时立即触发
      deep: true // 对象内部属性变化时也触发
    },
    checkedDataList: {
      handler: function (newVal, oldVal) {
        if (newVal.length >= 0 && this.identifier) {
          this.checkedIndex = []
          newVal.forEach(ele => {
            let index = this.dataList.findIndex(ele1 => ele[this.identifier] === ele1[this
                .identifier])
            if (index >= 0) {
              this.checkedIndex.push(index)
            }
          })
        }
      },
      immediate: true, // 组件创建时立即触发
      deep: true // 对象内部属性变化时也触发
    }
  },
  mounted() {
    this.$nextTick(() => {
      uni.createSelectorQuery().in(this).select('#parent').boundingClientRect(res => {
        if (res.width) {
          this.slotW = `${res.width}px`
          this.slotH = `${res.height + 5}px`
        }
      }).exec()
    })
  },
  data() {
    return {
      slotW: '0px',
      slotH: '0px',
      isShow: false,
      checkedIndex: [],
      animate: '',
      //传进来选中项，后又改成未选中并确认，多选模式生效
      checkedDels: []
    };
  },
  methods: {
    open() {
      if (this.checkedDataList.length >= 0 && this.identifier) {
        this.checkedIndex = []
        this.checkedDataList.forEach(ele => {
          let index = this.dataList.findIndex(ele1 => ele[this.identifier] === ele1[this
              .identifier])
          if (index >= 0) {
            this.checkedIndex.push(index)
          }
        })
      }
      this.isShow = true
      this.animate = 'show-animate'
    },
    close() {
      this.animate = 'hide-animate'
      this.checkedIndex = []
      this.checkedDels = []
      this.isShow = false
    },
    handleListItem(index, obj) {
      if (obj.enable === false) {
        return
      }
      if (this.mode === 'single') {
        this.checkedIndex = []
        this.checkedIndex.push(index)
        this.handelSure()
      } else {
        let sindex = this.checkedIndex.indexOf(index)
        if (sindex >= 0) {
          if (this.identifier) {
            //判断未选中的项在传进来的已选项中是否存在
            let contain = this.checkedDataList.filter(ele => ele[this.identifier] === this.dataList[index][
                this.identifier
                ])
            if (contain.length > 0) {
              //传进来的已选项中是否存在选择为未选中的内容
              let contain1 = this.checkedDels.filter(ele => ele[this.identifier] === contain[0][this
                  .identifier
                  ])
              if (contain1.length <= 0) {
                this.checkedDels.push(contain[0])
              }
            }
          }
          this.checkedIndex.splice(sindex, 1);
        } else {
          if (this.identifier) {
            let contain2 = this.checkedDels.filter(ele => ele[this.identifier] === this.dataList[index][
                this.identifier
                ])
            if (contain2.length > 0) {
              let tempIndex = this.checkedDels.findIndex(ele => ele[this.identifier] === this.dataList[
                  index][this.identifier])
              if (tempIndex >= 0) {
                this.checkedDels.splice(tempIndex, 1)
              }
            }
          }
          this.checkedIndex.push(index)
        }
      }
    },
    handelCancel() {
      this.close()
      this.$emit('cancelDimss', '')
    },
    handelSure() {
      let results = []
      if (this.checkedIndex.length <= 0) {
        uni.showToast({
          title: '请选择至少一项',
          icon: 'none'
        });
        return
      }

      this.checkedIndex.forEach(ele => {
        if (this.dataList[ele]) {
          results.push(this.dataList[ele])
        }
      })
      //将本次选中结果清除
      this.checkedIndex = []
      this.$emit('resultBack', results, this.checkedDels)
      this.close()
    }
  }
}
</script>

<style scoped>
.active {
}

.active:active {
  opacity: 0.6;
}

.layout-row {
  display: flex;
  flex-direction: row;
}

.layout-column {
  display: flex;
  flex-direction: column;
}

/* 整体方向居中 */
.center {
  align-items: center;
  justify-content: center;
}

/* 主轴方向居中 */
.main-center {
  justify-content: center;
}

/* 侧轴方向居中 */
.less-center {
  align-items: center;
}

.data-box-scroll {
  width: 100%;
  overflow-y: scroll;
}

.data-box-scroll::-webkit-scrollbar {
  display: none
}

.data-box {
  background: white;
  border-radius: 8rpx;
  box-shadow: 0px 0px 3px 1px rgba(0, 0, 0, 0.1);
  z-index: 9999;
}

.data-box-shadow {
  background: white;
  border-radius: 8rpx;
  box-shadow: 0px 0px 3px 1px rgba(0, 0, 0, 0.1);
  z-index: 9999;
}

.list-item {
  width: 100%;
  height: 80rpx;
  margin-left: 20rpx;
  margin-right: 20rpx;
  border-bottom: 1rpx solid #D8DFEC;
  text-align: right;
}

.opera-btns {
  width: 100%;
  height: 80rpx;
  justify-content: flex-end;
}

.opera-cancel {
  width: 100rpx;
  height: 50rpx;
  background-color: white;
  box-shadow: 0px 0px 3px 1px rgba(0, 0, 0, 0.1);
  border-radius: 5rpx;
  font-size: 26rpx;
}

.opera-sure {
  width: 100rpx;
  height: 50rpx;
  background-color: #58a2e4;
  box-shadow: 0px 0px 3px 1px rgba(0, 0, 0, 0.1);
  border-radius: 5rpx;
  font-size: 26rpx;
  color: white;
  margin-right: 30rpx;
  margin-left: 30rpx;
}

.status-text {
  text-align: center;
  font-size: 28rpx;
  font-weight: 600;
  color: #c2c2c2;
  padding-top: 20rpx;
  padding-bottom: 20rpx;
}

.mask {
  position: fixed;
  background: transparent;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.show-animate {
  animation-name: open;
  animation-duration: 1s;
  animation-iteration-count: 1;
}

@keyframes open {
  0% {
    height: 0rpx;
  }

  100% {
    height: 100%;
  }
}

.hide-animate {
  animation-name: close;
  animation-duration: 1s;
  animation-iteration-count: 1;
  animation-fill-mode: forwards;
}

@keyframes close {
  0% {
    height: 100%;
  }

  100% {
    height: 0rpx;
  }
}
</style>