MZC/KnowMathBot/frontend/node_modules/micromark-core-commonmark/lib/autolink.js

/**
 * @import {
 *   Construct,
 *   State,
 *   TokenizeContext,
 *   Tokenizer
 * } from 'micromark-util-types'
 */

import { asciiAlphanumeric, asciiAlpha, asciiAtext, asciiControl } from 'micromark-util-character';
/** @type {Construct} */
export const autolink = {
  name: 'autolink',
  tokenize: tokenizeAutolink
};

/**
 * @this {TokenizeContext}
 *   Context.
 * @type {Tokenizer}
 */
function tokenizeAutolink(effects, ok, nok) {
  let size = 0;
  return start;

  /**
   * Start of an autolink.
   *
   * ```markdown
   * > | a<https://example.com>b
   *      ^
   * > | a<user@example.com>b
   *      ^
   * ```
   *
   * @type {State}
   */
  function start(code) {
    effects.enter("autolink");
    effects.enter("autolinkMarker");
    effects.consume(code);
    effects.exit("autolinkMarker");
    effects.enter("autolinkProtocol");
    return open;
  }

  /**
   * After `<`, at protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *       ^
   * > | a<user@example.com>b
   *       ^
   * ```
   *
   * @type {State}
   */
  function open(code) {
    if (asciiAlpha(code)) {
      effects.consume(code);
      return schemeOrEmailAtext;
    }
    if (code === 64) {
      return nok(code);
    }
    return emailAtext(code);
  }

  /**
   * At second byte of protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *        ^
   * > | a<user@example.com>b
   *        ^
   * ```
   *
   * @type {State}
   */
  function schemeOrEmailAtext(code) {
    // ASCII alphanumeric and `+`, `-`, and `.`.
    if (code === 43 || code === 45 || code === 46 || asciiAlphanumeric(code)) {
      // Count the previous alphabetical from `open` too.
      size = 1;
      return schemeInsideOrEmailAtext(code);
    }
    return emailAtext(code);
  }

  /**
   * In ambiguous protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *        ^
   * > | a<user@example.com>b
   *        ^
   * ```
   *
   * @type {State}
   */
  function schemeInsideOrEmailAtext(code) {
    if (code === 58) {
      effects.consume(code);
      size = 0;
      return urlInside;
    }

    // ASCII alphanumeric and `+`, `-`, and `.`.
    if ((code === 43 || code === 45 || code === 46 || asciiAlphanumeric(code)) && size++ < 32) {
      effects.consume(code);
      return schemeInsideOrEmailAtext;
    }
    size = 0;
    return emailAtext(code);
  }

  /**
   * After protocol, in URL.
   *
   * ```markdown
   * > | a<https://example.com>b
   *             ^
   * ```
   *
   * @type {State}
   */
  function urlInside(code) {
    if (code === 62) {
      effects.exit("autolinkProtocol");
      effects.enter("autolinkMarker");
      effects.consume(code);
      effects.exit("autolinkMarker");
      effects.exit("autolink");
      return ok;
    }

    // ASCII control, space, or `<`.
    if (code === null || code === 32 || code === 60 || asciiControl(code)) {
      return nok(code);
    }
    effects.consume(code);
    return urlInside;
  }

  /**
   * In email atext.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *              ^
   * ```
   *
   * @type {State}
   */
  function emailAtext(code) {
    if (code === 64) {
      effects.consume(code);
      return emailAtSignOrDot;
    }
    if (asciiAtext(code)) {
      effects.consume(code);
      return emailAtext;
    }
    return nok(code);
  }

  /**
   * In label, after at-sign or dot.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *                 ^       ^
   * ```
   *
   * @type {State}
   */
  function emailAtSignOrDot(code) {
    return asciiAlphanumeric(code) ? emailLabel(code) : nok(code);
  }

  /**
   * In label, where `.` and `>` are allowed.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *                   ^
   * ```
   *
   * @type {State}
   */
  function emailLabel(code) {
    if (code === 46) {
      effects.consume(code);
      size = 0;
      return emailAtSignOrDot;
    }
    if (code === 62) {
      // Exit, then change the token type.
      effects.exit("autolinkProtocol").type = "autolinkEmail";
      effects.enter("autolinkMarker");
      effects.consume(code);
      effects.exit("autolinkMarker");
      effects.exit("autolink");
      return ok;
    }
    return emailValue(code);
  }

  /**
   * In label, where `.` and `>` are *not* allowed.
   *
   * Though, this is also used in `emailLabel` to parse other values.
   *
   * ```markdown
   * > | a<user.name@ex-ample.com>b
   *                    ^
   * ```
   *
   * @type {State}
   */
  function emailValue(code) {
    // ASCII alphanumeric or `-`.
    if ((code === 45 || asciiAlphanumeric(code)) && size++ < 63) {
      const next = code === 45 ? emailValue : emailLabel;
      effects.consume(code);
      return next;
    }
    return nok(code);
  }
}