<!-- 
    需要根据内容自适应请写minWidth
    定义slots与width不会自适应
 -->
<template>
    <!-- 
        :auto-resize="true"//父元素变化重新计算表格
     -->
    <vxe-table
        :class="{ isNoBorder: !border }"
        :border="border"
        :data="tableData"
        :max-height="height"
        :show-header="showHeader"
        :loading="loading"
        cell-class-name="cellStyle"
        @checkbox-all="selectAllChangeEvent"
        @checkbox-change="onSelectChange"
        header-row-class-name="headerStyle"
        :span-method="mergeRowMethod"
        ref="vxeTable"
        :auto-resize="true"
    >
        <template v-for="config in headerColumn">
            <vxe-column
                :key="config.field"
                :type="config.type"
                :field="config.field"
                :title="config.title"
                :fixed="config.fixed"
                :width="config.width"
                :filters="config.filters"
                :align="config.align"
                :formatter="config.formatter"
                :min-width="config.minWidth"
                :show-overflow="config.showOverflow"
            >
                <template #header="{ row }" v-if="config.headerSlots">
                    <slot :name="config.headerSlots" :row="row"></slot>
                </template>
                <template #content="{ row, rowIndex }" v-if="config.type == 'expand'">
                    <slot :name="config.slots" :row="row" :rowIndex="rowIndex"></slot>
                </template>
                <template #default="{ row, column }" v-else-if="config.slots">
                    <slot :name="config.slots" :row="row" :column="column"></slot>
                </template>
            </vxe-column>
        </template>
    </vxe-table>
</template>

<script>
export default {
    name: 'VxeTables',
    props: {
        tableData: {
            type: Array,
            default: () => []
        },
        tableColumn: {
            type: Array,
            default: () => []
        },
        border: {
            type: Boolean,
            default: true
        },
        height: {
            type: String,
            default: 'auto'
        },
        showHeader: {
            type: Boolean,
            default: true
        },
        loading: {
            type: Boolean,
            default: false
        },
        mergeFields: {
            type: Array,
            default: () => []
        }
    },
    data() {
        return {
            headerColumn: []
        }
    },
    watch: {
        /**
         * 监控表格的数据data，自动设置表格宽度
         * @param valArr
         */
        tableData(valArr) {
            this.resetColumnWidth(valArr)
        }
    },
    methods: {
        onSelectChange({ row }) {
            const records = this.$refs.vxeTable.getCheckboxRecords()
            this.$emit('selectionChange', row, records)
        },
        selectAllChangeEvent({ records }) {
            this.$emit('selectAllChangeEvent', records)
        },
        // 通用行合并函数（将相同多列数据合并为一行）
        mergeRowMethod({ row, _rowIndex, column, visibleData }) {
            if (!this.mergeFields.length) return false
            const fields = this.mergeFields
            const cellValue = row[column.property]
            if (cellValue && fields.includes(column.property)) {
                const prevRow = visibleData[_rowIndex - 1]
                let nextRow = visibleData[_rowIndex + 1]
                if (prevRow && prevRow[column.property] === cellValue) {
                    return { rowspan: 0, colspan: 0 }
                } else {
                    let countRowspan = 1
                    while (nextRow && nextRow[column.property] === cellValue) {
                        nextRow = visibleData[++countRowspan + _rowIndex]
                    }
                    if (countRowspan > 1) {
                        return { rowspan: countRowspan, colspan: 1 }
                    }
                }
            }
        },
        getCheckboxRecords() {
            return this.$refs.vxeTable.getCheckboxRecords()
        },
        /**
         * 遍历列的所有内容，获取最宽一列的宽度
         * @param arr
         */
        getMaxLength(arr) {
            return arr.reduce((acc, item) => {
                if (item) {
                    let calcLen = this.getTextWidth(item)
                    if (acc < calcLen) {
                        acc = calcLen
                    }
                }
                return acc
            }, 0)
        },
        /**
         * 使用span标签包裹内容，然后计算span的宽度 width： px
         * @param valArr
         */
        getTextWidth(str) {
            let width = 0
            let html = document.createElement('span')
            html.innerText = str
            html.className = 'getTextWidth'
            document.querySelector('body').appendChild(html)
            width = document.querySelector('.getTextWidth').offsetWidth
            document.querySelector('.getTextWidth').remove()
            return width
        },
        resetColumnWidth(valArr) {
            const _this = this
            this.headerColumn = this.tableColumn.map(function (value) {
                // 根据最小宽去计算根据内容自适应
                if (value.minWidth) {
                    const arr = valArr.map(x => x[value.field]) // 获取每一列的所有数据
                    arr.push(value.title) // 把每列的表头也加进去算
                    value.minWidth = _this.getMaxLength(arr) + 20 // 每列内容最大的宽度 + 表格的内间距(依据实际情况而定)
                }
                return value
            })
        }
    },
    created() {
        this.resetColumnWidth(this.tableData)
    }
}
</script>

<style lang="scss" scoped>
.vxe-table {
    width: 100%;
    ::v-deep .cellStyle {
        padding: 6px 0;
        height: 48px;
        white-space: nowrap;
    }
    ::v-deep .headerStyle {
        background: #f8f9fa;
    }
    &.isNoBorder ::v-deep .vxe-table--border-line {
        border: none;
    }
}
// 展开表头样式
::v-deep .expand_wrap {
    .headerStyle {
        background: #edf2ff;
    }
    .vxe-table .vxe-table--border-line {
        border-top: 1px solid #e8eaec;
        border-left: 1px solid #e8eaec;
        border-bottom: 1px solid #e8eaec;
    }
}
</style>