/* vim:ts=4:sts=4:sw=4:
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Ajax.org Code Editor (ACE).
 *
 * The Initial Developer of the Original Code is
 * Ajax.org B.V.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *      Fabian Jakobs <fabian AT ajax DOT org>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * under the terms of either the GPL or the LGPL, and not to allow others to
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 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {
"use strict";

var TokenIterator = function(session, initialRow, initialColumn) {
    this.$session = session;
    this.$row = initialRow;
    this.$rowTokens = session.getTokens(initialRow, initialRow)[0].tokens;

    var token = session.getTokenAt(initialRow, initialColumn);
    this.$tokenIndex = token ? token.index : -1;
};

(function() {
    
    this.stepBackward = function() {
        this.$tokenIndex -= 1;
        
        while (this.$tokenIndex < 0) {
            this.$row -= 1;
            if (this.$row < 0) {
                this.$row = 0;
                return null;
            }
                
            this.$rowTokens = this.$session.getTokens(this.$row, this.$row)[0].tokens;
            this.$tokenIndex = this.$rowTokens.length - 1;
        }
            
        return this.$rowTokens[this.$tokenIndex];
    };
    
    this.stepForward = function() {
        var rowCount = this.$session.getLength();
        this.$tokenIndex += 1;
        
        while (this.$tokenIndex >= this.$rowTokens.length) {
            this.$row += 1;
            if (this.$row >= rowCount) {
                this.$row = rowCount - 1;
                return null;
            }

            this.$rowTokens = this.$session.getTokens(this.$row, this.$row)[0].tokens;
            this.$tokenIndex = 0;
        }
            
        return this.$rowTokens[this.$tokenIndex];
    };
    
    this.getCurrentToken = function () {
        return this.$rowTokens[this.$tokenIndex];
    };
    
    this.getCurrentTokenRow = function () {
        return this.$row;
    };
    
    this.getCurrentTokenColumn = function() {
        var rowTokens = this.$rowTokens;
        var tokenIndex = this.$tokenIndex;
        
        // If a column was cached by EditSession.getTokenAt, then use it
        var column = rowTokens[tokenIndex].start;
        if (column !== undefined)
            return column;
            
        column = 0;
        while (tokenIndex > 0) {
            tokenIndex -= 1;
            column += rowTokens[tokenIndex].value.length;
        }
        
        return column;  
    };
            
}).call(TokenIterator.prototype);

exports.TokenIterator = TokenIterator;
});