import { projectRef } from "@/lib/projects";
import { articleTarget, projectTargetFor, TargetError } from "./targets.mjs";

// The app's side of lib/annotations/targets.mjs: a request's `article` or
// `project` parameter to a target, using the app's memoised project walk.
// Everything about WHERE a note may be written is decided in targets.mjs.

export type Target = Awaited<ReturnType<typeof articleTarget>> | Awaited<ReturnType<typeof projectTargetFor>>;

export async function targetFrom(params: { article?: string | null; project?: string | null }): Promise<Target> {
  if (params.article && params.project) throw new TargetError("pass article or project, not both");
  if (params.article) return articleTarget(params.article);
  if (params.project) {
    const p = await projectRef(params.project);
    if (!p) throw new TargetError(`no project ${params.project}`, 404);
    return projectTargetFor(p);
  }
  throw new TargetError("pass ?article=<site>/<report> or ?project=<id>");
}

/** A thrown error as a response: typed refusals keep their status, the rest are 500s. */
export function errorResponse(err: unknown): Response {
  const status = typeof (err as { status?: unknown })?.status === "number" ? (err as { status: number }).status : null;
  const name = (err as Error)?.name;
  const code = status ?? (name === "NoteError" ? 400 : 500);
  return Response.json({ error: err instanceof Error ? err.message : String(err) }, { status: code });
}