/**
 * `useManifest` — the structure feed. Fetches `.nwire/manifest.json` (the deep
 * manifest) via TanStack Query and exposes a tolerant native view. Re-keys per
 * project so a switch refetches.
 */
import { computed, toValue, type MaybeRefOrGetter } from "vue";
import { useQuery } from "@tanstack/vue-query";
import { manifestView, type Manifest, type ManifestView } from "../lib/manifest";

const MANIFEST_URL = "/__nwire/manifest.json";

export function useManifest(project?: MaybeRefOrGetter<string | undefined | null>) {
  const key = computed(() => ["manifest", toValue(project) ?? "active"] as const);

  const query = useQuery({
    queryKey: key,
    queryFn: async (): Promise<Manifest> => {
      // The global fetch shim appends `?project=<active cwd>`.
      const res = await fetch(MANIFEST_URL);
      if (!res.ok) {
        throw new Error(`Manifest fetch failed (${res.status}). Run \`nwire cache\` to build it.`);
      }
      return (await res.json()) as Manifest;
    },
    staleTime: 5_000,
    // keepPreviousData: smooth refresh, no flash while a refetch is in flight.
    placeholderData: (prev) => prev,
  });

  const view = computed<ManifestView | null>(() =>
    query.data.value ? manifestView(query.data.value) : null,
  );

  return {
    manifest: query.data,
    view,
    isLoading: query.isLoading,
    isFetching: query.isFetching,
    isError: query.isError,
    error: computed(() => (query.error.value as Error | null)?.message ?? null),
    refetch: query.refetch,
  };
}