import { useState } from "react"

import { PaginationMeta } from "@/types/common"

/**
 * Pages an already-loaded list in the browser, producing the same `PaginationMeta` shape the
 * server-paged lists use so it plugs straight into `PaginationFooter`.
 *
 * `resetKey` (e.g. the selected date) sends the list back to page 1 when it changes. It's a key
 * rather than the array itself because callers often pass `data ?? []`, a new array every render.
 */
export function useClientPagination<T>(rows: T[], resetKey: unknown, initialPageSize = 10) {
  const [page, setPage] = useState(1)
  const [pageSize, setPageSizeState] = useState(initialPageSize)
  const [prevKey, setPrevKey] = useState(resetKey)

  // Reset during render (React's "adjust state when a prop changes" pattern) — no effect needed.
  if (!Object.is(prevKey, resetKey)) {
    setPrevKey(resetKey)
    setPage(1)
  }

  const totalItems = rows.length
  const totalPages = Math.max(1, Math.ceil(totalItems / pageSize))
  // Clamped, so shrinking the list (or a bigger page size) never leaves an empty page showing.
  const current = Math.min(page, totalPages)
  const pageRows = rows.slice((current - 1) * pageSize, current * pageSize)
  const pagination: PaginationMeta = { page: current, pageSize, totalItems, totalPages }

  function setPageSize(size: number) {
    setPageSizeState(size)
    setPage(1)
  }

  return { pageRows, pagination, setPage, setPageSize }
}