(function (Prism) {
  // https://freemarker.apache.org/docs/dgui_template_exp.html

  // FTL expression with 4 levels of nesting supported
  var FTL_EXPR =
    /[^<()"']|\((?:<expr>)*\)|<(?!#--)|<#--(?:[^-]|-(?!->))*-->|"(?:[^\\"]|\\.)*"|'(?:[^\\']|\\.)*'/
      .source;
  for (var i = 0; i < 2; i++) {
    FTL_EXPR = FTL_EXPR.replace(/<expr>/g, function () {
      return FTL_EXPR;
    });
  }
  FTL_EXPR = FTL_EXPR.replace(/<expr>/g, /[^\s\S]/.source);

  var ftl = {
    comment: /<#--[\s\S]*?-->/,
    string: [
      {
        // raw string
        pattern: /\br("|')(?:(?!\1)[^\\]|\\.)*\1/,
        greedy: true,
      },
      {
        pattern: RegExp(
          /("|')(?:(?!\1|\$\{)[^\\]|\\.|\$\{(?:(?!\})(?:<expr>))*\})*\1/.source.replace(
            /<expr>/g,
            function () {
              return FTL_EXPR;
            }
          )
        ),
        greedy: true,
        inside: {
          interpolation: {
            pattern: RegExp(
              /((?:^|[^\\])(?:\\\\)*)\$\{(?:(?!\})(?:<expr>))*\}/.source.replace(
                /<expr>/g,
                function () {
                  return FTL_EXPR;
                }
              )
            ),
            lookbehind: true,
            inside: {
              'interpolation-punctuation': {
                pattern: /^\$\{|\}$/,
                alias: 'punctuation',
              },
              rest: null,
            },
          },
        },
      },
    ],
    keyword: /\b(?:as)\b/,
    boolean: /\b(?:false|true)\b/,
    'builtin-function': {
      pattern: /((?:^|[^?])\?\s*)\w+/,
      lookbehind: true,
      alias: 'function',
    },
    function: /\b\w+(?=\s*\()/,
    number: /\b\d+(?:\.\d+)?\b/,
    operator:
      /\.\.[<*!]?|->|--|\+\+|&&|\|\||\?{1,2}|[-+*/%!=<>]=?|\b(?:gt|gte|lt|lte)\b/,
    punctuation: /[,;.:()[\]{}]/,
  };

  ftl.string[1].inside.interpolation.inside.rest = ftl;

  Prism.languages.ftl = {
    'ftl-comment': {
      // the pattern is shortened to be more efficient
      pattern: /^<#--[\s\S]*/,
      alias: 'comment',
    },
    'ftl-directive': {
      pattern: /^<[\s\S]+>$/,
      inside: {
        directive: {
          pattern: /(^<\/?)[#@][a-z]\w*/i,
          lookbehind: true,
          alias: 'keyword',
        },
        punctuation: /^<\/?|\/?>$/,
        content: {
          pattern: /\s*\S[\s\S]*/,
          alias: 'ftl',
          inside: ftl,
        },
      },
    },
    'ftl-interpolation': {
      pattern: /^\$\{[\s\S]*\}$/,
      inside: {
        punctuation: /^\$\{|\}$/,
        content: {
          pattern: /\s*\S[\s\S]*/,
          alias: 'ftl',
          inside: ftl,
        },
      },
    },
  };

  Prism.hooks.add('before-tokenize', function (env) {
    // eslint-disable-next-line regexp/no-useless-lazy
    var pattern = RegExp(
      /<#--[\s\S]*?-->|<\/?[#@][a-zA-Z](?:<expr>)*?>|\$\{(?:<expr>)*?\}/.source.replace(
        /<expr>/g,
        function () {
          return FTL_EXPR;
        }
      ),
      'gi'
    );
    Prism.languages['markup-templating'].buildPlaceholders(env, 'ftl', pattern);
  });

  Prism.hooks.add('after-tokenize', function (env) {
    Prism.languages['markup-templating'].tokenizePlaceholders(env, 'ftl');
  });
})(Prism);