import { computed } from 'vue'
class TableHeightCalculator {
  constructor(options) {
    this.options = options
  }
  /**
   * 计算容器高度
   */
  calculate() {
    const offset = this.calculateOffset()
    return {
      height: offset === 0 ? '100%' : `calc(100% - ${offset}px)`
    }
  }
  /**
   * 计算偏移量
   */
  calculateOffset() {
    if (!this.options.showTableHeader.value) {
      return this.calculatePaginationOffset()
    }
    const headerHeight = this.getHeaderHeight()
    const paginationOffset = this.calculatePaginationOffset()
    return headerHeight + paginationOffset + TableHeightCalculator.TABLE_HEADER_SPACING
  }
  /**
   * 获取表格头部高度
   */
  getHeaderHeight() {
    return this.options.tableHeaderHeight.value || TableHeightCalculator.DEFAULT_TABLE_HEADER_HEIGHT
  }
  /**
   * 计算分页器偏移量
   */
  calculatePaginationOffset() {
    const { paginationHeight, paginationSpacing } = this.options
    return paginationHeight.value === 0 ? 0 : paginationHeight.value + paginationSpacing.value
  }
}

TableHeightCalculator.DEFAULT_TABLE_HEADER_HEIGHT = 44
TableHeightCalculator.TABLE_HEADER_SPACING = 12

function useTableHeight(options) {
  const containerHeight = computed(() => {
    const calculator = new TableHeightCalculator(options)
    return calculator.calculate()
  })
  return {
    /** 容器高度样式对象 */
    containerHeight
  }
}
export { useTableHeight }