"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import type { Paged } from "@/lib/api";

const PAGE_SIZE = 25;

export type PagedListState<T> = {
  items: T[];
  total: number;
  page: number;
  pageSize: number;
  totalPages: number;
  loading: boolean;
  error: string | null;
  setPage: (p: number) => void;
  refresh: () => void;
};

/**
 * Shared search + offset-pagination logic for the admin list pages. `fetcher`
 * receives (limit, offset) plus whatever extra deps the caller closes over
 * (search query, status filter, report type); pass those in `deps` so a change
 * resets to page 1 and refetches. A request token guards against out-of-order
 * responses when the user types/pages quickly.
 */
export function usePagedList<T>(
  fetcher: (limit: number, offset: number) => Promise<Paged<T>>,
  deps: unknown[],
  pageSize = PAGE_SIZE,
): PagedListState<T> {
  const [items, setItems] = useState<T[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const token = useRef(0);

  // Reset to page 1 whenever the external filters change.
  // eslint-disable-next-line react-hooks/exhaustive-deps
  useEffect(() => setPage(1), deps);

  const load = useCallback(() => {
    const my = ++token.current;
    setLoading(true);
    setError(null);
    fetcher(pageSize, (page - 1) * pageSize)
      .then((res) => {
        if (my !== token.current) return;
        setItems(res.items);
        setTotal(res.total);
      })
      .catch((e) => {
        if (my !== token.current) return;
        setError(e instanceof Error ? e.message : "Could not load.");
      })
      .finally(() => {
        if (my === token.current) setLoading(false);
      });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [page, pageSize, ...deps]);

  useEffect(() => load(), [load]);

  return {
    items,
    total,
    page,
    pageSize,
    totalPages: Math.max(1, Math.ceil(total / pageSize)),
    loading,
    error,
    setPage,
    refresh: load,
  };
}