'use client';

import { useCallback, useState } from 'react';
import { fetchApi } from '@/lib/utils/client';
import type { LiveChannelItem, LiveChannelListResponse } from '@/types/response/channel/live-list';
import LiveChannelCard from './LiveChannelCard';
import LiveChannelEmpty from './LiveChannelEmpty';

type Props = {
	initialChannels: LiveChannelItem[];
	initialTotal: number;
	pageSize: number;
};

export default function LiveChannelGrid({ initialChannels, initialTotal, pageSize }: Props)
{
	const [channels, setChannels] = useState<LiveChannelItem[]>(initialChannels);
	const [total, setTotal] = useState(initialTotal);
	const [loading, setLoading] = useState(false);
	const [error, setError] = useState<string|null>(null);

	const hasMore = channels.length < total;

	const handleLoadMore = useCallback(async () => {
		if (loading || !hasMore) {
			return;
		}

		setLoading(true);
		setError(null);

		try {
			const res = await fetchApi<LiveChannelListResponse>(`/api/channel/live-list?limit=${pageSize}&offset=${channels.length}`, { silent: true });
			if (res.success && res.data) {
				setChannels(prev => [...prev, ...res.data!.channels]);
				setTotal(res.data.total);
			} else {
				setError('목록을 불러오지 못했습니다.');
			}
		} catch {
			setError('목록을 불러오지 못했습니다.');
		} finally {
			setLoading(false);
		}
	}, [channels.length, hasMore, loading, pageSize]);

	if (channels.length === 0) {
		return <LiveChannelEmpty />;
	}

	return (
		<section className="home__live" aria-labelledby="home-live-heading">
			<header className="home__section-head">
				<h2 id="home-live-heading" className="home__section-title">
					라이브 방송 중
					<span className="home__section-count" aria-label={`총 ${total}개 채널`}>
						{total.toLocaleString()}
					</span>
				</h2>
			</header>

			<div className="live-grid" role="list">
				{channels.map((ch, idx) => (
					<div key={ch.channelSID} role="listitem" className="live-grid__item">
						<LiveChannelCard channel={ch} priority={idx < 4} />
					</div>
				))}
			</div>

			{hasMore && (
				<div className="home__load-more">
					<button
						type="button"
						onClick={handleLoadMore}
						disabled={loading}
						className="home__load-more-btn"
						aria-label={loading ? '불러오는 중' : '더 보기'}
					>
						{loading ? '불러오는 중...' : '더 보기'}
					</button>
				</div>
			)}

			{error && (
				<div role="alert" className="home__error">{error}</div>
			)}
		</section>
	);
}