import { API_URL, ApiError } from "../../lib/api-client";
import { getSessionToken } from "../../lib/session-token";

/**
 * Binary download for GET /files/items/:itemId/download. This cannot use
 * `apiFetch` (it parses JSON) or a bare anchor (the endpoint needs the
 * Authorization header, which anchors cannot send), so it replays the client's
 * auth rules: same base URL, Bearer token, cookie credentials — then streams
 * the body into a Blob and clicks a temporary anchor.
 */
export async function downloadGroupFile(itemId: string, fileName: string): Promise<void> {
  const token = getSessionToken();
  const response = await fetch(`${API_URL}/files/items/${encodeURIComponent(itemId)}/download`, {
    credentials: "include",
    headers: token === null ? {} : { Authorization: `Bearer ${token}` },
  });
  if (!response.ok) {
    if (response.status === 401) throw new ApiError(401, "Your session expired — sign in again.", null);
    throw new ApiError(response.status, `Download failed (HTTP ${response.status})`, null);
  }
  const blob = await response.blob();
  const url = URL.createObjectURL(blob);
  const anchor = document.createElement("a");
  anchor.href = url;
  anchor.download = fileName;
  document.body.append(anchor);
  anchor.click();
  anchor.remove();
  URL.revokeObjectURL(url);
}

/**
 * Derive the share id from a public tokenUrl of the form
 * `/files/shares/:token/download`, used for DELETE /files/shares/:shareId when
 * the POST response omits an explicit shareId.
 */
export function shareIdFromUrl(tokenUrl: string): string | null {
  const match = /\/files\/shares\/([^/?#]+)/.exec(tokenUrl);
  return match?.[1] !== undefined && match[1] !== "" ? match[1] : null;
}