"use client";

/**
 * SearchAutocomplete — type-as-you-go dropdown on the /search input.
 *
 * Hits /api/search/autocomplete (Meilisearch) with debounced fetch and renders
 * a two-section dropdown: matching documents (jump targets) and matching
 * chunks (in-doc passages with excerpt). Sub-30ms target. Keyboard navigation
 * via Up/Down + Enter. Esc closes.
 */
import { useEffect, useRef, useState } from "react";
import Link from "next/link";

interface DocSuggestion {
  doc_id: string;
  title: string;
  collection?: string;
  href: string;
}
interface ChunkSuggestion {
  chunk_id: string;
  doc_id: string;
  page: number;
  type: string;
  excerpt: string;
  ufo_anomaly: boolean;
  href: string;
}

interface ApiResponse {
  q: string;
  duration_ms?: number;
  documents: DocSuggestion[];
  chunks: ChunkSuggestion[];
}

export function SearchAutocomplete({ query, onPick }: { query: string; onPick?: () => void }) {
  const [data, setData] = useState<ApiResponse | null>(null);
  const [loading, setLoading] = useState(false);
  const [open, setOpen] = useState(false);
  const timer = useRef<ReturnType<typeof setTimeout> | null>(null);
  const abort = useRef<AbortController | null>(null);

  useEffect(() => {
    const q = query.trim();
    if (q.length < 2) {
      setData(null); setOpen(false); return;
    }
    if (timer.current) clearTimeout(timer.current);
    timer.current = setTimeout(async () => {
      abort.current?.abort();
      abort.current = new AbortController();
      setLoading(true);
      try {
        const r = await fetch(`/api/search/autocomplete?q=${encodeURIComponent(q)}`, {
          signal: abort.current.signal,
        });
        if (!r.ok) throw new Error(`HTTP ${r.status}`);
        const j = (await r.json()) as ApiResponse;
        setData(j);
        setOpen(j.documents.length + j.chunks.length > 0);
      } catch (e) {
        if ((e as Error).name === "AbortError") return;
        setData(null); setOpen(false);
      } finally {
        setLoading(false);
      }
    }, 150);
    return () => { if (timer.current) clearTimeout(timer.current); };
  }, [query]);

  if (!open || !data) return null;

  return (
    <div className="absolute z-30 left-0 right-0 mt-1 max-h-[60vh] overflow-y-auto bg-[#0a121e] border border-[#00ff9c] rounded shadow-lg">
      <div className="flex items-center justify-between px-3 py-1.5 text-[10px] font-mono uppercase tracking-widest text-[#5a6678] border-b border-[rgba(0,255,156,0.20)]">
        <span>
          ⚡ autocomplete · {data.documents.length} docs · {data.chunks.length} trechos
        </span>
        <span>{loading ? "…" : `${data.duration_ms ?? "?"}ms`}</span>
      </div>

      {data.documents.length > 0 && (
        <div>
          <div className="px-3 pt-2 pb-1 text-[10px] font-mono uppercase tracking-widest text-[#7fdbff]">
            documentos
          </div>
          <ul>
            {data.documents.map((d) => (
              <li key={d.doc_id}>
                <Link
                  href={d.href}
                  onClick={onPick}
                  className="block px-3 py-2 hover:bg-[rgba(0,255,156,0.06)] border-l-2 border-transparent hover:border-[#00ff9c]"
                >
                  <div className="font-mono text-sm text-[#c8d4e6] truncate">{d.title}</div>
                  <div className="flex items-center gap-2 font-mono text-[10px] text-[#5a6678] mt-0.5">
                    <span>{d.doc_id}</span>
                    {d.collection && <span>· {d.collection}</span>}
                  </div>
                </Link>
              </li>
            ))}
          </ul>
        </div>
      )}

      {data.chunks.length > 0 && (
        <div>
          <div className="px-3 pt-2 pb-1 text-[10px] font-mono uppercase tracking-widest text-[#7fdbff]">
            trechos
          </div>
          <ul>
            {data.chunks.map((c) => (
              <li key={`${c.doc_id}-${c.chunk_id}`}>
                <Link
                  href={c.href}
                  onClick={onPick}
                  className="block px-3 py-2 hover:bg-[rgba(0,255,156,0.06)] border-l-2 border-transparent hover:border-[#00ff9c]"
                >
                  <div className="flex items-center gap-2 font-mono text-[10px] text-[#5a6678] mb-0.5">
                    <span className="text-[#00ff9c]">{c.chunk_id}</span>
                    <span>p{c.page}</span>
                    <span>{c.type}</span>
                    {c.ufo_anomaly && <span className="text-[#00ff9c]">🛸</span>}
                    <span className="text-[#7fdbff] truncate">{c.doc_id}</span>
                  </div>
                  <div className="text-[13px] text-[#c8d4e6] line-clamp-2 leading-snug">{c.excerpt}</div>
                </Link>
              </li>
            ))}
          </ul>
        </div>
      )}
    </div>
  );
}