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 * Distributed under the BSD license:
 *
 * Copyright (c) 2010, Ajax.org B.V.
 * All rights reserved.
 * 
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 * modification, are permitted provided that the following conditions are met:
 *     * 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
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 * ***** END LICENSE BLOCK ***** */

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, optionalEndTags) {
    BaseFoldMode.call(this);
    this.voidElements = voidElements || {};
    this.optionalEndTags = oop.mixin({}, this.voidElements);
    if (optionalEndTags)
        oop.mixin(this.optionalEndTags, optionalEndTags);
    
};
oop.inherits(FoldMode, BaseFoldMode);

var Tag = function() {
    this.tagName = "";
    this.closing = false;
    this.selfClosing = false;
    this.start = {row: 0, column: 0};
    this.end = {row: 0, column: 0};
};

function is(token, type) {
    return token.type.lastIndexOf(type + ".xml") > -1;
}

(function() {

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

        if (!tag)
            return this.getCommentFoldWidget(session, row);

        if (tag.closing || (!tag.tagName && tag.selfClosing))
            return foldStyle == "markbeginend" ? "end" : "";

        if (!tag.tagName || tag.selfClosing || this.voidElements.hasOwnProperty(tag.tagName.toLowerCase()))
            return "";

        if (this._findEndTagInLine(session, row, tag.tagName, tag.end.column))
            return "";

        return "start";
    };
    
    this.getCommentFoldWidget = function(session, row) {
        if (/comment/.test(session.getState(row)) && /<!-/.test(session.getLine(row)))
            return "start";
        return "";
    };

    /*
     * returns a first tag (or a fragment) in a line
     */
    this._getFirstTagInLine = function(session, row) {
        var tokens = session.getTokens(row);
        var tag = new Tag();

        for (var i = 0; i < tokens.length; i++) {
            var token = tokens[i];
            if (is(token, "tag-open")) {
                tag.end.column = tag.start.column + token.value.length;
                tag.closing = is(token, "end-tag-open");
                token = tokens[++i];
                if (!token)
                    return null;
                tag.tagName = token.value;
                tag.end.column += token.value.length;
                for (i++; i < tokens.length; i++) {
                    token = tokens[i];
                    tag.end.column += token.value.length;
                    if (is(token, "tag-close")) {
                        tag.selfClosing = token.value == '/>';
                        break;
                    }
                }
                return tag;
            } else if (is(token, "tag-close")) {
                tag.selfClosing = token.value == '/>';
                return tag;
            }
            tag.start.column += token.value.length;
        }

        return null;
    };

    this._findEndTagInLine = function(session, row, tagName, startColumn) {
        var tokens = session.getTokens(row);
        var column = 0;
        for (var i = 0; i < tokens.length; i++) {
            var token = tokens[i];
            column += token.value.length;
            if (column < startColumn)
                continue;
            if (is(token, "end-tag-open")) {
                token = tokens[i + 1];
                if (token && token.value == tagName)
                    return true;
            }
        }
        return false;
    };

    /*
     * reads a full tag and places the iterator after the tag
     */
    this._readTagForward = function(iterator) {
        var token = iterator.getCurrentToken();
        if (!token)
            return null;

        var tag = new Tag();
        do {
            if (is(token, "tag-open")) {
                tag.closing = is(token, "end-tag-open");
                tag.start.row = iterator.getCurrentTokenRow();
                tag.start.column = iterator.getCurrentTokenColumn();
            } else if (is(token, "tag-name")) {
                tag.tagName = token.value;
            } else if (is(token, "tag-close")) {
                tag.selfClosing = token.value == "/>";
                tag.end.row = iterator.getCurrentTokenRow();
                tag.end.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 tag = new Tag();
        do {
            if (is(token, "tag-open")) {
                tag.closing = is(token, "end-tag-open");
                tag.start.row = iterator.getCurrentTokenRow();
                tag.start.column = iterator.getCurrentTokenColumn();
                iterator.stepBackward();
                return tag;
            } else if (is(token, "tag-name")) {
                tag.tagName = token.value;
            } else if (is(token, "tag-close")) {
                tag.selfClosing = token.value == "/>";
                tag.end.row = iterator.getCurrentTokenRow();
                tag.end.column = iterator.getCurrentTokenColumn() + token.value.length;
            }
        } 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.optionalEndTags.hasOwnProperty(top.tagName)) {
                stack.pop();
                continue;
            } else {
                return null;
            }
        }
    };
    
    this.getFoldWidgetRange = function(session, foldStyle, row) {
        var firstTag = this._getFirstTagInLine(session, row);
        
        if (!firstTag) {
            return this.getCommentFoldWidget(session, row)
                && session.getCommentFoldRange(row, session.getLine(row).length);
        }
        
        var isBackward = firstTag.closing || firstTag.selfClosing;
        var stack = [];
        var tag;
        
        if (!isBackward) {
            var iterator = new TokenIterator(session, row, firstTag.start.column);
            var start = {
                row: row,
                column: firstTag.start.column + firstTag.tagName.length + 2
            };
            if (firstTag.start.row == firstTag.end.row)
                start.column = firstTag.end.column;
            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.end.column);
            var end = {
                row: row,
                column: firstTag.start.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;
                        if (tag.start.row == tag.end.row && tag.start.column < tag.end.column)
                            tag.start.column = tag.end.column;
                        return Range.fromPoints(tag.start, end);
                    }
                }
                else {
                    stack.push(tag);
                }
            }
        }
        
    };

}).call(FoldMode.prototype);

});