Fix loading of recommended methods

lib/create/facetRecommendationsLoad.ts

@@ -0,0 +1,76 @@
+import type { MethodFacetApiSectionId } from "./customRuleFacets";
+
+export type FacetScoresBySlug = Record<string, number>;
+
+const EMPTY_SCORES: FacetScoresBySlug = {};
+
+const cache = new Map<string, FacetScoresBySlug>();
+const inFlight = new Map<string, Promise<FacetScoresBySlug>>();
+
+export function buildFacetRecommendationRequestKey(
+  section: MethodFacetApiSectionId,
+  queryString: string,
+): string {
+  return `${section}?${queryString}`;
+}
+
+export function getCachedFacetScores(
+  requestKey: string,
+): FacetScoresBySlug | undefined {
+  return cache.get(requestKey);
+}
+
+function parseScoresFromMethodsJson(json: {
+  methods?: { slug: string; matches?: { score?: number } }[];
+}): FacetScoresBySlug {
+  const scoresBySlug: FacetScoresBySlug = {};
+  for (const m of json.methods ?? []) {
+    if (typeof m.slug === "string") {
+      scoresBySlug[m.slug] = m.matches?.score ?? 0;
+    }
+  }
+  return scoresBySlug;
+}
+
+async function fetchFacetScoresFromApi(
+  section: MethodFacetApiSectionId,
+  queryString: string,
+): Promise<FacetScoresBySlug> {
+  const res = await fetch(
+    `/api/create-flow/methods?section=${section}&${queryString}`,
+    { credentials: "include" },
+  );
+  if (!res.ok) throw new Error(`status ${res.status}`);
+  const json = (await res.json()) as {
+    methods?: { slug: string; matches?: { score?: number } }[];
+  };
+  return parseScoresFromMethodsJson(json);
+}
+
+/**
+ * Loads facet recommendation scores for one method deck. Results are cached
+ * and in-flight requests are deduped so prefetch + screen hooks share work.
+ */
+export function loadFacetScores(
+  section: MethodFacetApiSectionId,
+  queryString: string,
+): Promise<FacetScoresBySlug> {
+  const requestKey = buildFacetRecommendationRequestKey(section, queryString);
+  const cached = cache.get(requestKey);
+  if (cached) return Promise.resolve(cached);
+
+  let pending = inFlight.get(requestKey);
+  if (!pending) {
+    pending = fetchFacetScoresFromApi(section, queryString)
+      .then((scores) => {
+        cache.set(requestKey, scores);
+        return scores;
+      })
+      .catch(() => EMPTY_SCORES)
+      .finally(() => {
+        inFlight.delete(requestKey);
+      });
+    inFlight.set(requestKey, pending);
+  }
+  return pending;
+}