/**
 * 列头动态 facet（搜选项 + 勾选）选项加载。
 * 与 useServerColumnFilters 配合：defs 中目标列 type=enum，打开漏斗时拉去重可选值。
 * 可选 getContextParams：附带列表上下文（固定条件 + 顶部筛选 + 列头），并排除本列条件（Excel 级联）。
 */
import { reactive } from 'vue'
import { ElMessage } from 'element-plus'
import type { ColumnFilterDef } from '@/composables/useClientColumnFilters'
import { stripSelfColumnParams } from '@/composables/columnFacetContext'

export type FacetOption = { value: string; label: string; count: number }

export function useColumnFacetOptions(options: {
  /** 需要动态拉可选值的列 prop（与 defs.prop 一致，亦作为 field 传给接口） */
  facetFields: string[]
  /** 请求可选值；应返回 { list: FacetOption[] } 或已解包的 list 结构 */
  fetchFacet: (payload: {
    field: string
    keyword?: string
    limit?: number
    [key: string]: unknown
  }) => Promise<unknown>
  /** 非 facet 的静态 enum（字典等）回退；亦用于剥离本列 query 键 */
  columnFilterDefs?: ColumnFilterDef[]
  /** 当前列表查询上下文（固定条件 + 顶部筛选 + 列头）；打开漏斗时会排除本列键 */
  getContextParams?: () => Record<string, unknown>
  limit?: number
}) {
  const facetFieldSet = new Set(options.facetFields)
  const facetOptionsMap = reactive<Record<string, FacetOption[]>>({})
  const facetLoadingMap = reactive<Record<string, boolean>>({})
  const limit = options.limit ?? 500

  function enumOptionsFor(prop: string): FacetOption[] {
    if (Object.prototype.hasOwnProperty.call(facetOptionsMap, prop)) {
      return facetOptionsMap[prop]
    }
    const def = options.columnFilterDefs?.find((d) => d.prop === prop)
    return (def?.enumOptions || []).map((o) => ({
      value: String(o.value),
      label: o.label,
      count: (o as any).count ?? 0
    }))
  }

  function optionsLoadingFor(prop: string) {
    return Boolean(facetLoadingMap[prop])
  }

  async function onFilterOpen(prop: string) {
    if (!facetFieldSet.has(prop)) return
    facetLoadingMap[prop] = true
    // 上下文（含审批 scope）变化时避免短暂展示上一轮可选值
    facetOptionsMap[prop] = []
    try {
      const rawContext = options.getContextParams?.() || {}
      const context = options.columnFilterDefs?.length
        ? stripSelfColumnParams(rawContext, prop, options.columnFilterDefs)
        : { ...rawContext }
      // 排序与导出无关字段不传给 facet
      delete context.sortField
      delete context.sortOrder
      delete context.includeDocumentAttachments
      delete context.includeArrangeCopyFlags
      delete context.exportFormat
      delete context.page
      delete context.pageSize

      const res = await options.fetchFacet({ ...context, field: prop, limit })
      const data = (res as any)?.list ? res : (res as any)?.data || res || {}
      const list = (data as any).list || []
      facetOptionsMap[prop] = (Array.isArray(list) ? list : []).map((item: any) => ({
        value: String(item?.value ?? ''),
        label: String(item?.label ?? item?.value ?? ''),
        count: Number(item?.count ?? 0)
      }))
    } catch (e: any) {
      facetOptionsMap[prop] = []
      ElMessage.error(e?.message || '加载可选值失败')
    } finally {
      facetLoadingMap[prop] = false
    }
  }

  return {
    facetOptionsMap,
    facetLoadingMap,
    enumOptionsFor,
    optionsLoadingFor,
    onFilterOpen,
    isFacetField: (prop: string) => facetFieldSet.has(prop)
  }
}