myYouTube/frontend/src/pages/ChannelVideos.tsx

import { useInfiniteQuery, useQuery } from '@tanstack/react-query'
import { Link, useParams } from 'react-router-dom'
import { getChannel, getFeed } from '../api/client'
import Icon from '../components/Icon'
import VideoCard from '../components/VideoCard'
import { formatSubscriberCount } from '../utils/format'

function ChannelVideos() {
  const { channelId } = useParams<{ channelId: string }>()
  const id = Number(channelId)
  const valid = Number.isInteger(id) && id > 0
  const channelQuery = useQuery({ queryKey: ['channel', id], queryFn: () => getChannel(id), enabled: valid })
  const feedQuery = useInfiniteQuery({ queryKey: ['feed', 'channel', id], queryFn: ({ pageParam }) => getFeed({ channelId: id, limit: 20, cursor: pageParam }), initialPageParam: undefined as string | undefined, getNextPageParam: (lastPage) => lastPage.next_cursor ?? undefined, enabled: valid })
  const items = feedQuery.data?.pages.flatMap((page) => page.items) ?? []
  const subscriberLabel = channelQuery.data ? formatSubscriberCount(channelQuery.data.subscriber_count) : null
  return <section className="page">
    <Link to="/channels" className="back-link"><Icon name="arrow" size={17} /> Каналы</Link>
    <div className="page-heading"><div><p className="eyebrow">Видео канала</p><h1>{channelQuery.data?.title ?? 'Канал'}</h1><p className="page-subtitle">{subscriberLabel ?? 'Последние ролики из твоих подписок.'}</p></div></div>
    {(channelQuery.isError || feedQuery.isError || !valid) && <div className="empty-state" role="alert"><h2>Не удалось открыть канал</h2><Link to="/channels" className="button-primary">К списку каналов</Link></div>}
    {feedQuery.isLoading && <div className="video-grid">{Array.from({ length: 6 }, (_, index) => <div className="video-card" key={index}><div className="skeleton-thumbnail" /><div className="video-info"><div className="skeleton-line wide" /><div className="skeleton-line" /></div></div>)}</div>}
    {!feedQuery.isLoading && !feedQuery.isError && items.length > 0 && <ul className="video-grid">{items.map((video) => <VideoCard key={video.youtube_video_id} video={video} />)}</ul>}
    {!feedQuery.isLoading && !feedQuery.isError && items.length === 0 && <div className="empty-state"><h2>Пока нет видео</h2><p>Обнови ленту, чтобы получить новые ролики канала.</p></div>}
    {feedQuery.hasNextPage && <button className="button-secondary load-more" onClick={() => feedQuery.fetchNextPage()} disabled={feedQuery.isFetchingNextPage}>{feedQuery.isFetchingNextPage ? 'Загрузка…' : 'Показать ещё'}</button>}
  </section>
}
export default ChannelVideos