CodeMirror.defineMode("vb", function(conf, parserConf) {
    var ERRORCLASS = 'error';

    function wordRegexp(words) {
        return new RegExp("^((" + words.join(")|(") + "))\\b", "i");
    }

    var singleOperators = new RegExp("^[\\+\\-\\*/%&\\\\|\\^~<>!]");
    var singleDelimiters = new RegExp('^[\\(\\)\\[\\]\\{\\}@,:`=;\\.]');
    var doubleOperators = new RegExp("^((==)|(<>)|(<=)|(>=)|(<>)|(<<)|(>>)|(//)|(\\*\\*))");
    var doubleDelimiters = new RegExp("^((\\+=)|(\\-=)|(\\*=)|(%=)|(/=)|(&=)|(\\|=)|(\\^=))");
    var tripleDelimiters = new RegExp("^((//=)|(>>=)|(<<=)|(\\*\\*=))");
    var identifiers = new RegExp("^[_A-Za-z][_A-Za-z0-9]*");

    var openingKeywords = ['class','module', 'sub','enum','select','while','if','function',  'get','set','property', 'try'];
    var middleKeywords = ['else','elseif','case', 'catch'];
    var endKeywords = ['next','loop'];

    var wordOperators = wordRegexp(['and', 'or', 'not', 'xor', 'in']);
    var commonkeywords = ['as', 'dim', 'break',  'continue','optional', 'then',  'until',
                          'goto', 'byval','byref','new','handles','property', 'return',
                          'const','private', 'protected', 'friend', 'public', 'shared', 'static', 'true','false'];
    var commontypes = ['integer','string','double','decimal','boolean','short','char', 'float','single'];

    var keywords = wordRegexp(commonkeywords);
    var types = wordRegexp(commontypes);
    var stringPrefixes = '"';

    var opening = wordRegexp(openingKeywords);
    var middle = wordRegexp(middleKeywords);
    var closing = wordRegexp(endKeywords);
    var doubleClosing = wordRegexp(['end']);
    var doOpening = wordRegexp(['do']);

    var indentInfo = null;




    function indent(_stream, state) {
      state.currentIndent++;
    }

    function dedent(_stream, state) {
      state.currentIndent--;
    }
    // tokenizers
    function tokenBase(stream, state) {
        if (stream.eatSpace()) {
            return null;
        }

        var ch = stream.peek();

        // Handle Comments
        if (ch === "'") {
            stream.skipToEnd();
            return 'comment';
        }


        // Handle Number Literals
        if (stream.match(/^((&H)|(&O))?[0-9\.a-f]/i, false)) {
            var floatLiteral = false;
            // Floats
            if (stream.match(/^\d*\.\d+F?/i)) { floatLiteral = true; }
            else if (stream.match(/^\d+\.\d*F?/)) { floatLiteral = true; }
            else if (stream.match(/^\.\d+F?/)) { floatLiteral = true; }

            if (floatLiteral) {
                // Float literals may be "imaginary"
                stream.eat(/J/i);
                return 'number';
            }
            // Integers
            var intLiteral = false;
            // Hex
            if (stream.match(/^&H[0-9a-f]+/i)) { intLiteral = true; }
            // Octal
            else if (stream.match(/^&O[0-7]+/i)) { intLiteral = true; }
            // Decimal
            else if (stream.match(/^[1-9]\d*F?/)) {
                // Decimal literals may be "imaginary"
                stream.eat(/J/i);
                // TODO - Can you have imaginary longs?
                intLiteral = true;
            }
            // Zero by itself with no other piece of number.
            else if (stream.match(/^0(?![\dx])/i)) { intLiteral = true; }
            if (intLiteral) {
                // Integer literals may be "long"
                stream.eat(/L/i);
                return 'number';
            }
        }

        // Handle Strings
        if (stream.match(stringPrefixes)) {
            state.tokenize = tokenStringFactory(stream.current());
            return state.tokenize(stream, state);
        }

        // Handle operators and Delimiters
        if (stream.match(tripleDelimiters) || stream.match(doubleDelimiters)) {
            return null;
        }
        if (stream.match(doubleOperators)
            || stream.match(singleOperators)
            || stream.match(wordOperators)) {
            return 'operator';
        }
        if (stream.match(singleDelimiters)) {
            return null;
        }
        if (stream.match(doOpening)) {
            indent(stream,state);
            state.doInCurrentLine = true;
            return 'keyword';
        }
        if (stream.match(opening)) {
            if (! state.doInCurrentLine)
              indent(stream,state);
            else
              state.doInCurrentLine = false;
            return 'keyword';
        }
        if (stream.match(middle)) {
            return 'keyword';
        }

        if (stream.match(doubleClosing)) {
            dedent(stream,state);
            dedent(stream,state);
            return 'keyword';
        }
        if (stream.match(closing)) {
            dedent(stream,state);
            return 'keyword';
        }

        if (stream.match(types)) {
            return 'keyword';
        }

        if (stream.match(keywords)) {
            return 'keyword';
        }

        if (stream.match(identifiers)) {
            return 'variable';
        }

        // Handle non-detected items
        stream.next();
        return ERRORCLASS;
    }

    function tokenStringFactory(delimiter) {
        var singleline = delimiter.length == 1;
        var OUTCLASS = 'string';

        return function(stream, state) {
            while (!stream.eol()) {
                stream.eatWhile(/[^'"]/);
                if (stream.match(delimiter)) {
                    state.tokenize = tokenBase;
                    return OUTCLASS;
                } else {
                    stream.eat(/['"]/);
                }
            }
            if (singleline) {
                if (parserConf.singleLineStringErrors) {
                    return ERRORCLASS;
                } else {
                    state.tokenize = tokenBase;
                }
            }
            return OUTCLASS;
        };
    }


    function tokenLexer(stream, state) {
        var style = state.tokenize(stream, state);
        var current = stream.current();

        // Handle '.' connected identifiers
        if (current === '.') {
            style = state.tokenize(stream, state);
            current = stream.current();
            if (style === 'variable') {
                return 'variable';
            } else {
                return ERRORCLASS;
            }
        }


        var delimiter_index = '[({'.indexOf(current);
        if (delimiter_index !== -1) {
            indent(stream, state );
        }
        if (indentInfo === 'dedent') {
            if (dedent(stream, state)) {
                return ERRORCLASS;
            }
        }
        delimiter_index = '])}'.indexOf(current);
        if (delimiter_index !== -1) {
            if (dedent(stream, state)) {
                return ERRORCLASS;
            }
        }

        return style;
    }

    var external = {
        electricChars:"dDpPtTfFeE ",
        startState: function() {
            return {
              tokenize: tokenBase,
              lastToken: null,
              currentIndent: 0,
              nextLineIndent: 0,
              doInCurrentLine: false


          };
        },

        token: function(stream, state) {
            if (stream.sol()) {
              state.currentIndent += state.nextLineIndent;
              state.nextLineIndent = 0;
              state.doInCurrentLine = 0;
            }
            var style = tokenLexer(stream, state);

            state.lastToken = {style:style, content: stream.current()};



            return style;
        },

        indent: function(state, textAfter) {
            var trueText = textAfter.replace(/^\s+|\s+$/g, '') ;
            if (trueText.match(closing) || trueText.match(doubleClosing) || trueText.match(middle)) return conf.indentUnit*(state.currentIndent-1);
            if(state.currentIndent < 0) return 0;
            return state.currentIndent * conf.indentUnit;
        }

    };
    return external;
});

CodeMirror.defineMIME("text/x-vb", "vb");