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 *
 * Copyright (c) 2010, Ajax.org B.V.
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 * 
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 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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define(function(require, exports, module) {
"use strict";

var oop = require("../../lib/oop");
var lang = require("../../lib/lang");
var Range = require("../../range").Range;
var BaseFoldMode = require("./fold_mode").FoldMode;
var TokenIterator = require("../../token_iterator").TokenIterator;

var FoldMode = exports.FoldMode = function(voidElements) {
    BaseFoldMode.call(this);
    this.voidElements = voidElements || {};
};
oop.inherits(FoldMode, BaseFoldMode);

(function() {

    this.getFoldWidget = function(session, foldStyle, row) {
        var tag = this._getFirstTagInLine(session, row);

        if (tag.closing)
            return foldStyle == "markbeginend" ? "end" : "";

        if (!tag.tagName || this.voidElements[tag.tagName.toLowerCase()])
            return "";

        if (tag.selfClosing)
            return "";

        if (tag.value.indexOf("/" + tag.tagName) !== -1)
            return "";

        return "start";
    };
    
    this._getFirstTagInLine = function(session, row) {
        var tokens = session.getTokens(row);
        var value = "";
        for (var i = 0; i < tokens.length; i++) {
            var token = tokens[i];
            if (token.type.indexOf("meta.tag") === 0)
                value += token.value;
            else
                value += lang.stringRepeat(" ", token.value.length);
        }
        
        return this._parseTag(value);
    };

    this.tagRe = /^(\s*)(<?(\/?)([-_a-zA-Z0-9:!]*)\s*(\/?)>?)/;
    this._parseTag = function(tag) {
        
        var match = this.tagRe.exec(tag);
        var column = this.tagRe.lastIndex || 0;
        this.tagRe.lastIndex = 0;

        return {
            value: tag,
            match: match ? match[2] : "",
            closing: match ? !!match[3] : false,
            selfClosing: match ? !!match[5] || match[2] == "/>" : false,
            tagName: match ? match[4] : "",
            column: match[1] ? column + match[1].length : column
        };
    };
    
    /*
     * reads a full tag and places the iterator after the tag
     */
    this._readTagForward = function(iterator) {
        var token = iterator.getCurrentToken();
        if (!token)
            return null;
            
        var value = "";
        var start;
        
        do {
            if (token.type.indexOf("meta.tag") === 0) {
                if (!start) {
                    var start = {
                        row: iterator.getCurrentTokenRow(),
                        column: iterator.getCurrentTokenColumn()
                    };
                }
                value += token.value;
                if (value.indexOf(">") !== -1) {
                    var tag = this._parseTag(value);
                    tag.start = start;
                    tag.end = {
                        row: iterator.getCurrentTokenRow(),
                        column: iterator.getCurrentTokenColumn() + token.value.length
                    };
                    iterator.stepForward();
                    return tag;
                }
            }
        } while(token = iterator.stepForward());
        
        return null;
    };
    
    this._readTagBackward = function(iterator) {
        var token = iterator.getCurrentToken();
        if (!token)
            return null;
            
        var value = "";
        var end;

        do {
            if (token.type.indexOf("meta.tag") === 0) {
                if (!end) {
                    end = {
                        row: iterator.getCurrentTokenRow(),
                        column: iterator.getCurrentTokenColumn() + token.value.length
                    };
                }
                value = token.value + value;
                if (value.indexOf("<") !== -1) {
                    var tag = this._parseTag(value);
                    tag.end = end;
                    tag.start = {
                        row: iterator.getCurrentTokenRow(),
                        column: iterator.getCurrentTokenColumn()
                    };
                    iterator.stepBackward();
                    return tag;
                }
            }
        } while(token = iterator.stepBackward());
        
        return null;
    };
    
    this._pop = function(stack, tag) {
        while (stack.length) {
            
            var top = stack[stack.length-1];
            if (!tag || top.tagName == tag.tagName) {
                return stack.pop();
            }
            else if (this.voidElements[tag.tagName]) {
                return;
            }
            else if (this.voidElements[top.tagName]) {
                stack.pop();
                continue;
            } else {
                return null;
            }
        }
    };
    
    this.getFoldWidgetRange = function(session, foldStyle, row) {
        var firstTag = this._getFirstTagInLine(session, row);
        
        if (!firstTag.match)
            return null;
        
        var isBackward = firstTag.closing || firstTag.selfClosing;
        var stack = [];
        var tag;
        
        if (!isBackward) {
            var iterator = new TokenIterator(session, row, firstTag.column);
            var start = {
                row: row,
                column: firstTag.column + firstTag.tagName.length + 2
            };
            while (tag = this._readTagForward(iterator)) {
                if (tag.selfClosing) {
                    if (!stack.length) {
                        tag.start.column += tag.tagName.length + 2;
                        tag.end.column -= 2;
                        return Range.fromPoints(tag.start, tag.end);
                    } else
                        continue;
                }
                
                if (tag.closing) {
                    this._pop(stack, tag);
                    if (stack.length == 0)
                        return Range.fromPoints(start, tag.start);
                }
                else {
                    stack.push(tag)
                }
            }
        }
        else {
            var iterator = new TokenIterator(session, row, firstTag.column + firstTag.match.length);
            var end = {
                row: row,
                column: firstTag.column
            };
            
            while (tag = this._readTagBackward(iterator)) {
                if (tag.selfClosing) {
                    if (!stack.length) {
                        tag.start.column += tag.tagName.length + 2;
                        tag.end.column -= 2;
                        return Range.fromPoints(tag.start, tag.end);
                    } else
                        continue;
                }
                
                if (!tag.closing) {
                    this._pop(stack, tag);
                    if (stack.length == 0) {
                        tag.start.column += tag.tagName.length + 2;
                        return Range.fromPoints(tag.start, end);
                    }
                }
                else {
                    stack.push(tag)
                }
            }
        }
        
    };

}).call(FoldMode.prototype);

});
