/**
 * Images pasted into Markdown bodies (chat, comments, descriptions): their
 * records, and binding them to the resource whose body links them, so the
 * startup purge keeps them.
 *
 * @module
 */

import { db, transaction } from "../db/connection.ts";
import { APIErrorCode } from "../../shared/api.ts";
import { APIException } from "../lib/api-exception.ts";

/** Records the upload of attachment `id`, not yet bound to any resource. */
export function createAttachment(id: string, mime: string): void {
  db.prepare(
    "INSERT INTO attachments (id, mime, created_at) VALUES (?, ?, ?)",
  ).run(id, mime, new Date().toISOString());
}

/**
 * Returns attachment `attachmentId`'s MIME type.
 *
 * @throws {APIException} 404 when there is no such attachment.
 */
export function getAttachment(attachmentId: string): { mime: string } {
  const row = db.prepare(
    "SELECT mime FROM attachments WHERE id = ?",
  ).get(attachmentId) as { mime: string } | undefined;

  if (!row) {
    throw new APIException(
      APIErrorCode.NOT_FOUND,
      404,
      "Attachment not found",
    );
  }

  return { mime: row.mime };
}

/** An attachment URL in a Markdown body, capturing its id. */
const ATTACHMENT_RE =
  /\/api\/attachments\/([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})/g;

/**
 * Binds the unowned attachments whose URLs appear in `text` to
 * `resourceId`. Only updates rows where resource_id IS NULL so a user cannot
 * claim attachments that already belong to another resource.
 */
export function linkAttachments(text: string, resourceId: string): void {
  const ids = [...text.matchAll(ATTACHMENT_RE)].map((m) => m[1]);
  if (ids.length === 0) return;
  const update = db.prepare(
    "UPDATE attachments SET resource_id = ? WHERE id = ? AND resource_id IS NULL",
  );
  transaction(() => {
    for (const id of ids) update.run(resourceId, id);
  });
}