lume/src/app/space/components/blocks/feed.tsx

import { useInfiniteQuery } from '@tanstack/react-query';
import { useVirtualizer } from '@tanstack/react-virtual';
import { useCallback, useEffect, useRef } from 'react';

import { getNotesByAuthors } from '@libs/storage';

import { NoteKind_1, NoteKind_1063, NoteThread, Repost } from '@shared/notes';
import { NoteKindUnsupport } from '@shared/notes/kinds/unsupport';
import { NoteSkeleton } from '@shared/notes/skeleton';
import { TitleBar } from '@shared/titleBar';

import { Block, LumeEvent } from '@utils/types';

const ITEM_PER_PAGE = 10;

export function FeedBlock({ params }: { params: Block }) {
  const { status, data, fetchNextPage, hasNextPage, isFetchingNextPage } =
    useInfiniteQuery({
      queryKey: ['newsfeed', params.content],
      queryFn: async ({ pageParam = 0 }) => {
        return await getNotesByAuthors(params.content, ITEM_PER_PAGE, pageParam);
      },
      getNextPageParam: (lastPage) => lastPage.nextCursor,
    });

  const notes = data ? data.pages.flatMap((d: { data: LumeEvent[] }) => d.data) : [];

  const parentRef = useRef();
  const rowVirtualizer = useVirtualizer({
    count: hasNextPage ? notes.length + 1 : notes.length,
    getScrollElement: () => parentRef.current,
    estimateSize: () => 500,
    overscan: 2,
  });

  const itemsVirtualizer = rowVirtualizer.getVirtualItems();

  useEffect(() => {
    const [lastItem] = [...rowVirtualizer.getVirtualItems()].reverse();

    if (!lastItem) {
      return;
    }

    if (lastItem.index >= notes.length - 1 && hasNextPage && !isFetchingNextPage) {
      fetchNextPage();
    }
  }, [notes.length, fetchNextPage, rowVirtualizer.getVirtualItems()]);

  const renderItem = useCallback(
    (index: string | number) => {
      const note: LumeEvent = notes[index];
      if (!note) return;
      switch (note.kind) {
        case 1: {
          const root = note.tags.find((el) => el[3] === 'root')?.[1];
          const reply = note.tags.find((el) => el[3] === 'reply')?.[1];
          if (root || reply) {
            return (
              <div
                key={note.event_id || note.id}
                data-index={index}
                ref={rowVirtualizer.measureElement}
              >
                <NoteThread event={note} root={root} reply={reply} />
              </div>
            );
          } else {
            return (
              <div
                key={note.event_id || note.id}
                data-index={index}
                ref={rowVirtualizer.measureElement}
              >
                <NoteKind_1 event={note} skipMetadata={false} />
              </div>
            );
          }
        }
        case 6:
          return (
            <div
              key={note.event_id || note.id}
              data-index={index}
              ref={rowVirtualizer.measureElement}
            >
              <Repost key={note.event_id} event={note} />
            </div>
          );
        case 1063:
          return (
            <div
              key={note.event_id || note.id}
              data-index={index}
              ref={rowVirtualizer.measureElement}
            >
              <NoteKind_1063 key={note.event_id} event={note} />
            </div>
          );
        default:
          return (
            <div
              key={note.event_id || note.id}
              data-index={index}
              ref={rowVirtualizer.measureElement}
            >
              <NoteKindUnsupport key={note.event_id} event={note} />
            </div>
          );
      }
    },
    [notes]
  );

  return (
    <div
      ref={parentRef}
      className="scrollbar-hide relative h-full w-[400px] shrink-0 overflow-y-auto bg-white/10 pb-20"
    >
      <TitleBar id={params.id} title={params.title} />
      <div className="h-full">
        {status === 'loading' ? (
          <div className="px-3 py-1.5">
            <div className="rounded-xl border-t border-zinc-800/50 bg-zinc-900 px-3 py-3">
              <NoteSkeleton />
            </div>
          </div>
        ) : itemsVirtualizer.length === 0 ? (
          <div className="px-3 py-1.5">
            <div className="rounded-xl border-t border-zinc-800/50 bg-zinc-900 px-3 py-6">
              <div className="flex flex-col items-center gap-4">
                <p className="text-center text-sm text-zinc-300">
                  Not found any posts from last 48 hours
                </p>
              </div>
            </div>
          </div>
        ) : (
          <div
            className="relative w-full"
            style={{
              height: `${rowVirtualizer.getTotalSize()}px`,
            }}
          >
            <div
              className="absolute left-0 top-0 w-full"
              style={{
                transform: `translateY(${
                  itemsVirtualizer[0].start - rowVirtualizer.options.scrollMargin
                }px)`,
              }}
            >
              {itemsVirtualizer.map((virtualRow) => renderItem(virtualRow.index))}
            </div>
          </div>
        )}
        {isFetchingNextPage && (
          <div className="px-3 py-1.5">
            <div className="rounded-xl border-t border-zinc-800/50 bg-zinc-900 px-3 py-3">
              <NoteSkeleton />
            </div>
          </div>
        )}
      </div>
    </div>
  );
}