function wordRegexp(words) {
  return new RegExp("^((" + words.join(")|(") + "))\\b");
}
var builtinArray = [
  "Clamp",
  "Constructor",
  "EnforceRange",
  "Exposed",
  "ImplicitThis",
  "Global", "PrimaryGlobal",
  "LegacyArrayClass",
  "LegacyUnenumerableNamedProperties",
  "LenientThis",
  "NamedConstructor",
  "NewObject",
  "NoInterfaceObject",
  "OverrideBuiltins",
  "PutForwards",
  "Replaceable",
  "SameObject",
  "TreatNonObjectAsNull",
  "TreatNullAs",
    "EmptyString",
  "Unforgeable",
  "Unscopeable"
];
var builtins = wordRegexp(builtinArray);

var typeArray = [
  "unsigned", "short", "long",                  // UnsignedIntegerType
  "unrestricted", "float", "double",            // UnrestrictedFloatType
  "boolean", "byte", "octet",                   // Rest of PrimitiveType
  "Promise",                                    // PromiseType
  "ArrayBuffer", "DataView", "Int8Array", "Int16Array", "Int32Array",
  "Uint8Array", "Uint16Array", "Uint32Array", "Uint8ClampedArray",
  "Float32Array", "Float64Array",               // BufferRelatedType
  "ByteString", "DOMString", "USVString", "sequence", "object", "RegExp",
  "Error", "DOMException", "FrozenArray",       // Rest of NonAnyType
  "any",                                        // Rest of SingleType
  "void"                                        // Rest of ReturnType
];
var types = wordRegexp(typeArray);

var keywordArray = [
  "attribute", "callback", "const", "deleter", "dictionary", "enum", "getter",
  "implements", "inherit", "interface", "iterable", "legacycaller", "maplike",
  "partial", "required", "serializer", "setlike", "setter", "static",
  "stringifier", "typedef",                     // ArgumentNameKeyword except
                                                // "unrestricted"
  "optional", "readonly", "or"
];
var keywords = wordRegexp(keywordArray);

var atomArray = [
  "true", "false",                              // BooleanLiteral
  "Infinity", "NaN",                            // FloatLiteral
  "null"                                        // Rest of ConstValue
];
var atoms = wordRegexp(atomArray);

var startDefArray = ["callback", "dictionary", "enum", "interface"];
var startDefs = wordRegexp(startDefArray);

var endDefArray = ["typedef"];
var endDefs = wordRegexp(endDefArray);

var singleOperators = /^[:<=>?]/;
var integers = /^-?([1-9][0-9]*|0[Xx][0-9A-Fa-f]+|0[0-7]*)/;
var floats = /^-?(([0-9]+\.[0-9]*|[0-9]*\.[0-9]+)([Ee][+-]?[0-9]+)?|[0-9]+[Ee][+-]?[0-9]+)/;
var identifiers = /^_?[A-Za-z][0-9A-Z_a-z-]*/;
var identifiersEnd = /^_?[A-Za-z][0-9A-Z_a-z-]*(?=\s*;)/;
var strings = /^"[^"]*"/;
var multilineComments = /^\/\*.*?\*\//;
var multilineCommentsStart = /^\/\*.*/;
var multilineCommentsEnd = /^.*?\*\//;

function readToken(stream, state) {
  // whitespace
  if (stream.eatSpace()) return null;

  // comment
  if (state.inComment) {
    if (stream.match(multilineCommentsEnd)) {
      state.inComment = false;
      return "comment";
    }
    stream.skipToEnd();
    return "comment";
  }
  if (stream.match("//")) {
    stream.skipToEnd();
    return "comment";
  }
  if (stream.match(multilineComments)) return "comment";
  if (stream.match(multilineCommentsStart)) {
    state.inComment = true;
    return "comment";
  }

  // integer and float
  if (stream.match(/^-?[0-9\.]/, false)) {
    if (stream.match(integers) || stream.match(floats)) return "number";
  }

  // string
  if (stream.match(strings)) return "string";

  // identifier
  if (state.startDef && stream.match(identifiers)) return "def";

  if (state.endDef && stream.match(identifiersEnd)) {
    state.endDef = false;
    return "def";
  }

  if (stream.match(keywords)) return "keyword";

  if (stream.match(types)) {
    var lastToken = state.lastToken;
    var nextToken = (stream.match(/^\s*(.+?)\b/, false) || [])[1];

    if (lastToken === ":" || lastToken === "implements" ||
        nextToken === "implements" || nextToken === "=") {
      // Used as identifier
      return "builtin";
    } else {
      // Used as type
      return "type";
    }
  }

  if (stream.match(builtins)) return "builtin";
  if (stream.match(atoms)) return "atom";
  if (stream.match(identifiers)) return "variable";

  // other
  if (stream.match(singleOperators)) return "operator";

  // unrecognized
  stream.next();
  return null;
}
const webIDL = {
  startState: function() {
    return {
      // Is in multiline comment
      inComment: false,
      // Last non-whitespace, matched token
      lastToken: "",
      // Next token is a definition
      startDef: false,
      // Last token of the statement is a definition
      endDef: false
    };
  },
  token: function(stream, state) {
    var style = readToken(stream, state);

    if (style) {
      var cur = stream.current();
      state.lastToken = cur;
      if (style === "keyword") {
        state.startDef = startDefs.test(cur);
        state.endDef = state.endDef || endDefs.test(cur);
      } else {
        state.startDef = false;
      }
    }

    return style;
  },

  languageData: {
    autocomplete: builtinArray.concat(typeArray).concat(keywordArray).concat(atomArray)
  }
};

export { webIDL };
