import type { User, UsersPage } from '@admin/types/auth'
import { compareUserSortValues } from '@admin/utils/user/compare-user-sort-values'
import { getUserSortValue } from '@admin/utils/user/get-user-sort-value'
import { normalizeUserFilterValue } from '@admin/utils/user/normalize-user-filter-value'

interface GetUsersPageOptions {
  pageIndex: number
  pageSize: number
  role?: string
  search?: string
  sortDir?: 'asc' | 'desc'
  sortField?: string
  status?: string
}

const USER_SORT_FIELDS = new Set(['createdAt', 'email', 'emailVerified', 'role'])

export function getUsersPage(users: User[], options: GetUsersPageOptions): UsersPage {
  const search = normalizeUserFilterValue(options.search)
  const role = normalizeUserFilterValue(options.role)
  const status = normalizeUserFilterValue(options.status)
  const sortField =
    options.sortField && USER_SORT_FIELDS.has(options.sortField) ? options.sortField : ''
  const sortDirection = options.sortDir === 'desc' ? -1 : 1
  const filteredUsers = users.filter((user) => {
    const matchesSearch =
      !search ||
      user.email.toLowerCase().includes(search) ||
      user.name.toLowerCase().includes(search)
    const matchesRole = !role || user.role.toLowerCase() === role
    const matchesStatus =
      !status ||
      (status === 'verified' && user.emailVerified) ||
      (status === 'unverified' && !user.emailVerified)

    return matchesSearch && matchesRole && matchesStatus
  })

  if (sortField) {
    filteredUsers.sort((a, b) => {
      const comparison = compareUserSortValues(
        getUserSortValue(a, sortField),
        getUserSortValue(b, sortField)
      )

      return comparison * sortDirection
    })
  }

  const total = filteredUsers.length
  const pageSize = options.pageSize === -1 ? total : Math.max(options.pageSize, 1)
  const start = Math.max(options.pageIndex, 0) * pageSize
  const pageUsers = pageSize > 0 ? filteredUsers.slice(start, start + pageSize) : filteredUsers

  return { users: pageUsers, total }
}