lume/apps/desktop2/src/routes/topic.tsx

import { Conversation } from "@/components/conversation";
import { Quote } from "@/components/quote";
import { RepostNote } from "@/components/repost";
import { TextNote } from "@/components/text";
import { ArrowRightCircleIcon } from "@lume/icons";
import { type LumeEvent, NostrQuery } from "@lume/system";
import { type ColumnRouteSearch, Kind } from "@lume/types";
import { Spinner } from "@lume/ui";
import * as ScrollArea from "@radix-ui/react-scroll-area";
import { useInfiniteQuery } from "@tanstack/react-query";
import { createFileRoute, redirect } from "@tanstack/react-router";
import { useCallback, useRef } from "react";
import { Virtualizer } from "virtua";

type Topic = {
	content: string[];
};

export const Route = createFileRoute("/topic")({
	validateSearch: (search: Record<string, string>): ColumnRouteSearch => {
		return {
			account: search.account,
			label: search.label,
			name: search.name,
		};
	},
	beforeLoad: async ({ search }) => {
		const key = `lume:topic:${search.label}`;
		const topics: Topic[] = await NostrQuery.getNstore(key);
		const settings = await NostrQuery.getUserSettings();

		if (!topics?.length) {
			throw redirect({
				to: "/create-topic",
				search: {
					...search,
					redirect: "/topic",
				},
			});
		}

		const hashtags: string[] = [];

		for (const topic of topics) {
			hashtags.push(...topic.content);
		}

		return { settings, hashtags };
	},
	component: Screen,
});

export function Screen() {
	const { label, account } = Route.useSearch();
	const { hashtags } = Route.useRouteContext();
	const {
		data,
		isLoading,
		isFetching,
		isFetchingNextPage,
		hasNextPage,
		fetchNextPage,
	} = useInfiniteQuery({
		queryKey: [label, account],
		initialPageParam: 0,
		queryFn: async ({ pageParam }: { pageParam: number }) => {
			const events = NostrQuery.getHashtagEvents(hashtags, pageParam);
			return events;
		},
		getNextPageParam: (lastPage) => lastPage?.at(-1)?.created_at - 1,
		select: (data) => data?.pages.flat(),
		refetchOnWindowFocus: false,
	});

	const ref = useRef<HTMLDivElement>(null);

	const renderItem = useCallback(
		(event: LumeEvent) => {
			if (!event) return;
			switch (event.kind) {
				case Kind.Repost:
					return <RepostNote key={event.id} event={event} className="mb-3" />;
				default: {
					if (event.isConversation) {
						return (
							<Conversation key={event.id} className="mb-3" event={event} />
						);
					}
					if (event.isQuote) {
						return <Quote key={event.id} event={event} className="mb-3" />;
					}
					return <TextNote key={event.id} event={event} className="mb-3" />;
				}
			}
		},
		[data],
	);

	return (
		<ScrollArea.Root
			type={"scroll"}
			scrollHideDelay={300}
			className="overflow-hidden size-full"
		>
			<ScrollArea.Viewport ref={ref} className="h-full px-3 pb-3">
				<Virtualizer scrollRef={ref}>
					{isFetching && !isLoading && !isFetchingNextPage ? (
						<div className="flex items-center justify-center w-full mb-3 h-11 bg-black/10 dark:bg-white/10 backdrop-blur-lg rounded-xl shadow-primary dark:ring-1 ring-neutral-800/50">
							<div className="flex items-center justify-center gap-2">
								<Spinner className="size-5" />
								<span className="text-sm font-medium">
									Fetching new notes...
								</span>
							</div>
						</div>
					) : null}
					{isLoading ? (
						<div className="flex items-center justify-center w-full h-16 gap-2">
							<Spinner className="size-5" />
							<span className="text-sm font-medium">Loading...</span>
						</div>
					) : !data.length ? (
						<div className="flex items-center justify-center">
							Yo. You're catching up on all the things happening around you.
						</div>
					) : (
						data.map((item) => renderItem(item))
					)}
					{data?.length && hasNextPage ? (
						<div>
							<button
								type="button"
								onClick={() => fetchNextPage()}
								disabled={isFetchingNextPage || isLoading}
								className="inline-flex items-center justify-center w-full gap-2 px-3 font-medium h-9 rounded-xl bg-black/5 hover:bg-black/10 focus:outline-none dark:bg-white/10 dark:hover:bg-white/20"
							>
								{isFetchingNextPage ? (
									<Spinner className="size-5" />
								) : (
									<>
										<ArrowRightCircleIcon className="size-5" />
										Load more
									</>
								)}
							</button>
						</div>
					) : null}
				</Virtualizer>
			</ScrollArea.Viewport>
			<ScrollArea.Scrollbar
				className="flex select-none touch-none p-0.5 duration-[160ms] ease-out data-[orientation=vertical]:w-2"
				orientation="vertical"
			>
				<ScrollArea.Thumb className="flex-1 bg-black/10 dark:bg-white/10 rounded-full relative before:content-[''] before:absolute before:top-1/2 before:left-1/2 before:-translate-x-1/2 before:-translate-y-1/2 before:w-full before:h-full before:min-w-[44px] before:min-h-[44px]" />
			</ScrollArea.Scrollbar>
			<ScrollArea.Corner className="bg-transparent" />
		</ScrollArea.Root>
	);
}