/**
 * Points at the instance an account from another gerbeur comes from, its
 * home, where its password, email, avatar and name are changed. Such a user's
 * handle here is `name@host` (`splitHandle`); the profile, the settings and
 * the `/authorize` page read it through these.
 *
 * @module
 */

import { API_URL } from "../../config/api.ts";
import { splitHandle } from "../../../shared/validation.ts";

/**
 * Checks whether `host`, as a handle writes it, is this instance's: its API's,
 * which handles carry, or its pages'. Another instance writes this one's users
 * with it.
 */
export function isSelfHost(host: string): boolean {
  const h = host.toLowerCase();
  return h === new URL(API_URL || location.origin).host ||
    h === location.host;
}

/**
 * Returns the host of `handle`'s home instance, or undefined for a local
 * user.
 */
export function homeHost(handle: string): string | undefined {
  return splitHandle(handle).host;
}

/**
 * Returns a link to `path` on `handle`'s home instance, their profile there
 * by default, or null for a local user. The host in a handle is the home's
 * API, not necessarily its pages, so the link goes through
 * `GET /api/users/:key/home`, which redirects to them.
 */
export function homeUrl(handle: string, path?: string): string | null {
  if (!homeHost(handle)) return null;
  const query = path ? `?path=${encodeURIComponent(path)}` : "";
  return `${API_URL}/api/users/@${encodeURIComponent(handle)}/home${query}`;
}