client/src/hooks/useRecommend.js

/**
 * Custom hook — wraps the /api/recommend call with loading + error state.
 */

import { useState, useCallback } from "react";

export function useRecommend() {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);

  const fetchRecommendations = useCallback(async (profile) => {
    setLoading(true);
    setError(null);
    setData(null);

    try {
      const res = await fetch("/api/recommend", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(profile),
      });

      if (!res.ok) {
        const body = await res.json().catch(() => ({}));
        throw new Error(body.error || `Server returned ${res.status}`);
      }

      const result = await res.json();
      setData(result);
      return result;
    } catch (err) {
      setError(err.message);
      return null;
    } finally {
      setLoading(false);
    }
  }, []);

  return { data, loading, error, fetchRecommendations };
}