/**
 * Says where an image pasted into a text lives, and how to find it again in
 * the text. The editor uploads the image and writes a link to it into the
 * Markdown; the server binds the attachments a saved text links to that text,
 * and `Markdown` gives a private one the viewer's media token.
 *
 * @module
 */

import { UUID_RE } from "./validation.ts";

/**
 * Returned by `POST /api/attachments` to the text editor, which inserts the
 * image into the body as a link to {@link attachmentPath}.
 */
export interface AttachmentResponse {
  id: string;
}

/** Returns the API path of attachment `id`, to which the API's base is added. */
export function attachmentPath(id: string): string {
  return `/api/attachments/${id}`;
}

const ID = UUID_RE.source.slice(1, -1);
const ATTACHMENT_LINK_RE = new RegExp(`/api/attachments/(${ID})`, "g");
const ATTACHMENT_URL_RE = new RegExp(`/api/attachments/${ID}$`);

/** Returns the ids of the attachments `text` links to, in order. */
export function attachmentIdsIn(text: string): string[] {
  return [...text.matchAll(ATTACHMENT_LINK_RE)].map((m) => m[1]);
}

/** Checks whether `url` is an attachment's, with no query yet. */
export function isAttachmentUrl(url: string): boolean {
  return ATTACHMENT_URL_RE.test(url);
}