var HTMLMixedParser = Editor.Parser = (function() {

    // tags that trigger seperate parsers
    var triggers = {
        "script": "JSParser",
        "style":    "CSSParser"
    };

    function checkDependencies() {
        var parsers = ['XMLParser'];
        for (var p in triggers) parsers.push(triggers[p]);
        for (var i in parsers) {
            if (!window[parsers[i]]) throw new Error(parsers[i] + " parser must be loaded for HTML mixed mode to work.");
        }
        XMLParser.configure({useHTMLKludges: true});
    }

    function parseMixed(stream) {
        checkDependencies();
        var htmlParser = XMLParser.make(stream), localParser = null, inTag = false;
        var iter = {next: top, copy: copy};

        function top() {
            var token = htmlParser.next();
            if (token.content == "<")
                inTag = true;
            else if (token.style == "xml-tagname" && inTag === true)
                inTag = token.content.toLowerCase();
            else if (token.content == ">") {
                if (triggers[inTag]) {
                    var parser = window[triggers[inTag]];
                    iter.next = local(parser, "</" + inTag);
                }
                inTag = false;
            }
            return token;
        }
        function local(parser, tag) {
            var baseIndent = htmlParser.indentation();
            localParser = parser.make(stream, baseIndent + indentUnit);
            return function() {
                if (stream.lookAhead(tag, false, false, true)) {
                    localParser = null;
                    iter.next = top;
                    return top();
                }

                var token = localParser.next();
                var lt = token.value.lastIndexOf("<"), sz = Math.min(token.value.length - lt, tag.length);
                if (lt != -1 && token.value.slice(lt, lt + sz).toLowerCase() == tag.slice(0, sz) &&
                        stream.lookAhead(tag.slice(sz), false, false, true)) {
                    stream.push(token.value.slice(lt));
                    token.value = token.value.slice(0, lt);
                }

                if (token.indentation) {
                    var oldIndent = token.indentation;
                    token.indentation = function(chars) {
                        if (chars == "</")
                            return baseIndent;
                        else
                            return oldIndent(chars);
                    };
                }

                return token;
            };
        }

        function copy() {
            var _html = htmlParser.copy(), _local = localParser && localParser.copy(),
                    _next = iter.next, _inTag = inTag;
            return function(_stream) {
                stream = _stream;
                htmlParser = _html(_stream);
                localParser = _local && _local(_stream);
                iter.next = _next;
                inTag = _inTag;
                return iter;
            };
        }
        return iter;
    }

    return {
        make: parseMixed,
        electricChars: "{}/:",
        configure: function(obj) {
            if (obj.triggers) triggers = obj.triggers;
        }
    };

})();
