// src/pages/agent-office/hooks/useActivityFeed.js
import { useState, useEffect, useCallback, useRef } from 'react';
import { agentActivity } from '../../../api';

const PAGE_SIZE = 30;

export function useActivityFeed(filters, refreshTrigger = 0) {
  const [items, setItems] = useState([]);
  const [total, setTotal] = useState(0);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);

  const offsetRef = useRef(0);
  const loadingRef = useRef(false);
  const filtersRef = useRef(filters);
  filtersRef.current = filters;

  const filterKey = JSON.stringify(filters);

  const fetchPage = useCallback(async (offset, replace) => {
    if (loadingRef.current) return;
    loadingRef.current = true;
    setLoading(true);
    setError(null);
    try {
      const data = await agentActivity({ ...filtersRef.current, limit: PAGE_SIZE, offset });
      const newItems = Array.isArray(data?.items) ? data.items : [];
      setTotal(data?.total || 0);
      setItems(prev => (replace ? newItems : [...prev, ...newItems]));
      offsetRef.current = offset + newItems.length;
    } catch (e) {
      setError(e.message || '불러오기 실패');
    } finally {
      loadingRef.current = false;
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    offsetRef.current = 0;
    fetchPage(0, true);
  }, [filterKey, refreshTrigger, fetchPage]);

  const loadMore = useCallback(() => {
    if (loadingRef.current) return;
    if (offsetRef.current >= total) return;
    fetchPage(offsetRef.current, false);
  }, [fetchPage, total]);

  const retry = useCallback(() => {
    offsetRef.current = 0;
    fetchPage(0, true);
  }, [fetchPage]);

  const hasMore = items.length < total;
  return { items, total, loading, error, hasMore, loadMore, retry };
}