(function (Prism) {
  // https://yaml.org/spec/1.2/spec.html#c-ns-anchor-property
  // https://yaml.org/spec/1.2/spec.html#c-ns-alias-node
  var anchorOrAlias = /[*&][^\s[\]{},]+/;
  // https://yaml.org/spec/1.2/spec.html#c-ns-tag-property
  var tag =
    /!(?:<[\w\-%#;/?:@&=+$,.!~*'()[\]]+>|(?:[a-zA-Z\d-]*!)?[\w\-%#;/?:@&=+$.~*'()]+)?/;
  // https://yaml.org/spec/1.2/spec.html#c-ns-properties(n,c)
  var properties =
    '(?:' +
    tag.source +
    '(?:[ \t]+' +
    anchorOrAlias.source +
    ')?|' +
    anchorOrAlias.source +
    '(?:[ \t]+' +
    tag.source +
    ')?)';
  // https://yaml.org/spec/1.2/spec.html#ns-plain(n,c)
  // This is a simplified version that doesn't support "#" and multiline keys
  // All these long scarry character classes are simplified versions of YAML's characters
  var plainKey =
    /(?:[^\s\x00-\x08\x0e-\x1f!"#%&'*,\-:>?@[\]`{|}\x7f-\x84\x86-\x9f\ud800-\udfff\ufffe\uffff]|[?:-]<PLAIN>)(?:[ \t]*(?:(?![#:])<PLAIN>|:<PLAIN>))*/.source.replace(
      /<PLAIN>/g,
      function () {
        return /[^\s\x00-\x08\x0e-\x1f,[\]{}\x7f-\x84\x86-\x9f\ud800-\udfff\ufffe\uffff]/
          .source;
      }
    );
  var string = /"(?:[^"\\\r\n]|\\.)*"|'(?:[^'\\\r\n]|\\.)*'/.source;

  /**
   *
   * @param {string} value
   * @param {string} [flags]
   * @returns {RegExp}
   */
  function createValuePattern(value, flags) {
    flags = (flags || '').replace(/m/g, '') + 'm'; // add m flag
    var pattern =
      /([:\-,[{]\s*(?:\s<<prop>>[ \t]+)?)(?:<<value>>)(?=[ \t]*(?:$|,|\]|\}|(?:[\r\n]\s*)?#))/.source
        .replace(/<<prop>>/g, function () {
          return properties;
        })
        .replace(/<<value>>/g, function () {
          return value;
        });
    return RegExp(pattern, flags);
  }

  Prism.languages.yaml = {
    scalar: {
      pattern: RegExp(
        /([\-:]\s*(?:\s<<prop>>[ \t]+)?[|>])[ \t]*(?:((?:\r?\n|\r)[ \t]+)\S[^\r\n]*(?:\2[^\r\n]+)*)/.source.replace(
          /<<prop>>/g,
          function () {
            return properties;
          }
        )
      ),
      lookbehind: true,
      alias: 'string',
    },
    comment: /#.*/,
    key: {
      pattern: RegExp(
        /((?:^|[:\-,[{\r\n?])[ \t]*(?:<<prop>>[ \t]+)?)<<key>>(?=\s*:\s)/.source
          .replace(/<<prop>>/g, function () {
            return properties;
          })
          .replace(/<<key>>/g, function () {
            return '(?:' + plainKey + '|' + string + ')';
          })
      ),
      lookbehind: true,
      greedy: true,
      alias: 'atrule',
    },
    directive: {
      pattern: /(^[ \t]*)%.+/m,
      lookbehind: true,
      alias: 'important',
    },
    datetime: {
      pattern: createValuePattern(
        /\d{4}-\d\d?-\d\d?(?:[tT]|[ \t]+)\d\d?:\d{2}:\d{2}(?:\.\d*)?(?:[ \t]*(?:Z|[-+]\d\d?(?::\d{2})?))?|\d{4}-\d{2}-\d{2}|\d\d?:\d{2}(?::\d{2}(?:\.\d*)?)?/
          .source
      ),
      lookbehind: true,
      alias: 'number',
    },
    boolean: {
      pattern: createValuePattern(/false|true/.source, 'i'),
      lookbehind: true,
      alias: 'important',
    },
    null: {
      pattern: createValuePattern(/null|~/.source, 'i'),
      lookbehind: true,
      alias: 'important',
    },
    string: {
      pattern: createValuePattern(string),
      lookbehind: true,
      greedy: true,
    },
    number: {
      pattern: createValuePattern(
        /[+-]?(?:0x[\da-f]+|0o[0-7]+|(?:\d+(?:\.\d*)?|\.\d+)(?:e[+-]?\d+)?|\.inf|\.nan)/
          .source,
        'i'
      ),
      lookbehind: true,
    },
    tag: tag,
    important: anchorOrAlias,
    punctuation: /---|[:[\]{}\-,|>?]|\.\.\./,
  };

  Prism.languages.yml = Prism.languages.yaml;
})(Prism);