flnxi-Wu/app/admin/_hooks/usePermissions.ts

'use client'

import { useCallback, useMemo } from 'react'
import { buildDepartmentDescendants, isDepartmentWithinScope } from '@/lib/departments'
import type { Department, User } from '../_components/types'

interface UsePermissionsOptions {
  sessionUser?: Record<string, any> | null
  users: User[]
  departments: Department[]
}

export default function usePermissions({
  sessionUser,
  users,
  departments,
}: UsePermissionsOptions) {
  const currentUserId = sessionUser?.id as string | undefined

  const currentUserRecord = useMemo(
    () => (currentUserId ? users.find((user) => user.id === currentUserId) : undefined),
    [currentUserId, users],
  )

  const currentIsSuperAdmin = useMemo(
    () => Boolean(currentUserRecord?.isSuperAdmin ?? sessionUser?.isSuperAdmin),
    [currentUserRecord, sessionUser],
  )

  const currentRole = (sessionUser?.role ?? currentUserRecord?.role) as
    | 'ADMIN'
    | 'USER'
    | undefined

  const currentIsAdminRole = useMemo(
    () => currentIsSuperAdmin || currentRole === 'ADMIN' || currentUserRecord?.role === 'ADMIN',
    [currentIsSuperAdmin, currentRole, currentUserRecord?.role],
  )

  const currentManagedDepartment = useMemo(
    () => currentUserRecord?.managedDepartment ?? sessionUser?.managedDepartment,
    [currentUserRecord?.managedDepartment, sessionUser?.managedDepartment],
  )

  const currentDepartmentScope = useMemo(() => {
    const fallback = (currentUserRecord?.department || '').trim() || undefined
    return currentManagedDepartment || fallback
  }, [currentManagedDepartment, currentUserRecord?.department])

  const departmentDescendantsMap = useMemo(
    () => buildDepartmentDescendants(departments),
    [departments],
  )

  const canManageUser = useCallback(
    (target: User) => {
      if (!currentUserId) return false
      if (currentIsSuperAdmin) return true
      if (target.isSuperAdmin) return false

      const targetDept = (target.department || '').trim()
      if (!targetDept && currentIsAdminRole) {
        return true
      }

      if (currentDepartmentScope) {
        return isDepartmentWithinScope(
          currentDepartmentScope,
          target.department,
          departmentDescendantsMap,
        )
      }

      return target.id === currentUserId
    },
    [
      currentDepartmentScope,
      currentIsAdminRole,
      currentIsSuperAdmin,
      currentUserId,
      departmentDescendantsMap,
    ],
  )

  return {
    currentUserId,
    currentIsSuperAdmin,
    canManageUser,
  }
}