'use client';

import { useEffect, useRef, useState } from 'react';
import Link from 'next/link';
import { formatMinutes } from '@/lib/steam';

interface MapSummary {
  map_name: string;
  times_played: number;
  last_played: string;
  total_minutes: number;
}

export default function MapSearch() {
  const [q, setQ] = useState('');
  const [maps, setMaps] = useState<MapSummary[]>([]);
  const [loading, setLoading] = useState(true);
  const [loadingMore, setLoadingMore] = useState(false);
  const [hasMore, setHasMore] = useState(true);

  const offsetRef = useRef(0);
  const loadingMoreRef = useRef(false);
  const sentinelRef = useRef<HTMLDivElement>(null);

  async function fetchPage(searchQ: string, offset: number) {
    const params = new URLSearchParams({ q: searchQ, offset: String(offset) });
    const res = await fetch(`/api/maps?${params.toString()}`);
    return res.json() as Promise<{ maps: MapSummary[]; hasMore: boolean }>;
  }

  useEffect(() => {
    const handle = setTimeout(async () => {
      setLoading(true);
      offsetRef.current = 0;
      const data = await fetchPage(q, 0);
      setMaps(data.maps);
      setHasMore(data.hasMore);
      offsetRef.current = data.maps.length;
      setLoading(false);
    }, 250);

    return () => clearTimeout(handle);
  }, [q]);

  async function loadMore() {
    if (loadingMoreRef.current || !hasMore || loading) return;
    loadingMoreRef.current = true;
    setLoadingMore(true);
    const data = await fetchPage(q, offsetRef.current);
    setMaps((prev) => [...prev, ...data.maps]);
    setHasMore(data.hasMore);
    offsetRef.current += data.maps.length;
    setLoadingMore(false);
    loadingMoreRef.current = false;
  }

  useEffect(() => {
    const el = sentinelRef.current;
    if (!el) return;
    const observer = new IntersectionObserver(
      (entries) => {
        if (entries[0].isIntersecting) loadMore();
      },
      { rootMargin: '400px' },
    );
    observer.observe(el);
    return () => observer.disconnect();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [hasMore, loading, q]);

  return (
    <div className="space-y-4">
      <input
        type="text"
        placeholder="Search by map name…"
        value={q}
        onChange={(e) => setQ(e.target.value)}
        className="w-full bg-base-panel border border-base-border rounded-lg px-4 py-3 text-ink placeholder:text-ink-faint focus:border-accent/50 transition-colors"
      />

      <div className="panel row-divide">
        {loading ? (
          <div className="p-4 text-sm text-ink-faint font-mono">loading…</div>
        ) : maps.length === 0 ? (
          <div className="p-4 text-sm text-ink-muted">No maps found.</div>
        ) : (
          maps.map((m) => (
            <Link
              key={m.map_name}
              href={`/maps/${encodeURIComponent(m.map_name)}`}
              className="group flex items-center justify-between px-4 py-3 hover:bg-base transition-colors"
            >
              <div className="text-ink text-sm">{m.map_name}</div>
              <div className="flex items-center gap-4">
                <div className="flex flex-col items-end text-xs text-ink-faint font-mono gap-0.5">
                  <span>{m.times_played}× played · {formatMinutes(m.total_minutes)} total</span>
                  <span>last played {new Date(m.last_played.replace(' ', 'T')).toLocaleString()}</span>
                </div>
                <svg
                  width="16"
                  height="16"
                  viewBox="0 0 24 24"
                  fill="none"
                  stroke="currentColor"
                  strokeWidth="2"
                  className="text-ink-faint group-hover:text-accent group-hover:translate-x-0.5 transition-all shrink-0"
                >
                  <path d="M9 6l6 6-6 6" strokeLinecap="round" strokeLinejoin="round" />
                </svg>
              </div>
            </Link>
          ))
        )}

        {!loading && maps.length > 0 && (
          <div ref={sentinelRef} className="p-4 text-center">
            {loadingMore ? (
              <span className="text-xs text-ink-faint font-mono">loading more…</span>
            ) : !hasMore ? (
              <span className="text-xs text-ink-faint">— end of list —</span>
            ) : null}
          </div>
        )}
      </div>
    </div>
  );
}