// Duenner Client fuer DOC-10s Backend-Voraussetzung
// (dms/internal/folderapi) — enthaelt keine eigene Baum-/Sortierlogik.

function apiBase(): string {
  const base = process.env.NEXT_PUBLIC_FOLDER_API_URL;
  if (!base) {
    throw new Error("NEXT_PUBLIC_FOLDER_API_URL ist nicht gesetzt (Umgebungsvariable erforderlich)");
  }
  return base;
}

export interface FolderDTO {
  id: string;
  parent_folder_id: string | null;
  name: string;
}

export interface DocumentDTO {
  id: string;
  title: string;
  size_bytes: number | null;
  created_at: string;
}

async function get<T>(path: string): Promise<T> {
  const res = await fetch(`${apiBase()}${path}`);
  if (!res.ok) {
    throw new Error(`Anfrage fehlgeschlagen (${res.status})`);
  }
  return res.json();
}

export function fetchChildren(folderID: string | null): Promise<FolderDTO[]> {
  return get(folderID ? `/folders/${encodeURIComponent(folderID)}/children` : "/folders/children");
}

export function fetchBreadcrumb(folderID: string): Promise<FolderDTO[]> {
  return get(`/folders/${encodeURIComponent(folderID)}/breadcrumb`);
}

export interface DocumentSort {
  sort?: "title" | "created_at" | "size";
  order?: "asc" | "desc";
}

export function fetchDocuments(folderID: string | null, sort?: DocumentSort): Promise<DocumentDTO[]> {
  const params = new URLSearchParams();
  if (sort?.sort) params.set("sort", sort.sort);
  if (sort?.order) params.set("order", sort.order);
  const query = params.toString() ? `?${params.toString()}` : "";
  const base = folderID ? `/folders/${encodeURIComponent(folderID)}/documents` : "/folders/documents";
  return get(base + query);
}