/// <reference types="remark-parse" />
/// <reference types="remark-stringify" />

/**
 * @typedef {import('mdast').Root} Root
 * @typedef {import('mdast-util-gfm').Options} MdastOptions
 * @typedef {import('micromark-extension-gfm').Options} MicromarkOptions
 * @typedef {import('unified').Processor<Root>} Processor
 */

/**
 * @typedef {MicromarkOptions & MdastOptions} Options
 *   Configuration.
 */

import {gfmFromMarkdown, gfmToMarkdown} from 'mdast-util-gfm'
import {gfm} from 'micromark-extension-gfm'

/** @type {Options} */
const emptyOptions = {}

/**
 * Add support GFM (autolink literals, footnotes, strikethrough, tables,
 * tasklists).
 *
 * @param {Options | null | undefined} [options]
 *   Configuration (optional).
 * @returns {undefined}
 *   Nothing.
 */
export default function remarkGfm(options) {
  // @ts-expect-error: TS is wrong about `this`.
  // eslint-disable-next-line unicorn/no-this-assignment
  const self = /** @type {Processor} */ (this)
  const settings = options || emptyOptions
  const data = self.data()

  const micromarkExtensions =
    data.micromarkExtensions || (data.micromarkExtensions = [])
  const fromMarkdownExtensions =
    data.fromMarkdownExtensions || (data.fromMarkdownExtensions = [])
  const toMarkdownExtensions =
    data.toMarkdownExtensions || (data.toMarkdownExtensions = [])

  micromarkExtensions.push(gfm(settings))
  fromMarkdownExtensions.push(gfmFromMarkdown())
  toMarkdownExtensions.push(gfmToMarkdown(settings))
}