<template>
    <el-table-v2 :columns="columns" :data="tableData" :fixed-data="fixedData" :width="700" :height="400" :row-class="rowClass" fixed @scroll="onScroll" />
</template>

<script lang="ts" setup>
import { computed, ref } from 'vue'

const generateColumns = (length = 10, prefix = 'column-', props?: any) =>
    Array.from({ length }).map((_, columnIndex) => ({
        ...props,
        key: `${prefix}${columnIndex}`,
        dataKey: `${prefix}${columnIndex}`,
        title: `Column ${columnIndex}`,
        width: 150,
    }))

const generateData = (columns: ReturnType<typeof generateColumns>, length = 200, prefix = 'row-') =>
    Array.from({ length }).map((_, rowIndex) => {
        return columns.reduce(
            (rowData, column, columnIndex) => {
                rowData[column.dataKey] = `Row ${rowIndex} - Col ${columnIndex}`
                return rowData
            },
            {
                id: `${prefix}${rowIndex}`,
                parentId: null,
            }
        )
    })

const columns = generateColumns(10)
const data = generateData(columns, 200)

const rowClass = ({ rowIndex }) => {
    if (rowIndex < 0 || (rowIndex + 1) % 5 === 0) return 'sticky-row'
}

const stickyIndex = ref(0)

const fixedData = computed(() => data.slice(stickyIndex.value, stickyIndex.value + 1))

const tableData = computed(() => {
    return data.slice(1)
})

const onScroll = ({ scrollTop }) => {
    stickyIndex.value = Math.floor(scrollTop / 250) * 5
}
</script>

<style>
.el-el-table-v2__fixed-header-row {
    background-color: var(--el-color-primary-light-5);
    font-weight: bold;
}
</style>
