"use client";

import { useEffect, useState } from "react";
import useSWR from "swr";
import { fetcher } from "@/lib/fetcher";

export interface SearchHit {
  slug: string;
  title: string;
  section: string;
  score: number;
  snippet: string;
}

export type SearchMode = "hybrid" | "keyword" | "semantic";

function useDebounced<T>(value: T, delayMs: number): T {
  const [debounced, setDebounced] = useState(value);
  useEffect(() => {
    const t = setTimeout(() => setDebounced(value), delayMs);
    return () => clearTimeout(t);
  }, [value, delayMs]);
  return debounced;
}

export function useSearch(q: string, mode: SearchMode = "hybrid", limit = 30) {
  const debouncedQ = useDebounced(q, 180);
  const trimmed = debouncedQ.trim();
  const key = trimmed ? `/api/search?q=${encodeURIComponent(trimmed)}&mode=${mode}&limit=${limit}` : null;

  const swr = useSWR<{ results: SearchHit[] }>(key, fetcher, {
    keepPreviousData: true,
    revalidateOnFocus: false,
    dedupingInterval: 2_000,
  });

  return {
    ...swr,
    hits: swr.data?.results ?? [],
    isSearching: !!trimmed && swr.isLoading,
  };
}