/*
 * 
 * ImageScroller - a Image Horizental Scroll Viewer 
 * Version 0.1
 * @requires jQuery v1.2.1
 * 
 * Copyright (c) 2007 Luan
 * Email verycss-ok@yahoo.com.cn 
 * 
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Example:
 *   #viewer {height:100px; width:300px; clear:both; overflow:hidden; border:3px solid #e5e5e5;}
 *   #viewerFrame {width:505px; clear:both; padding:0;}
 *   #viewer img {width:90px; height:90px; margin:5px; display:inline; border:0;}
 *   #viewer a {display:block; float:left; width:100px; height:100px;}
 *   <script type="text/javascript">
 *   $(function(){
 *       $("#viewer").imageScroller({
 *       next:"btn1",
 *       prev:"btn2",
 *       frame:"viewerFrame",
 *       width:100, 
 *       child:"a",
 *       auto:true
 *       });     
 *   });
 *   </script>
 *   <div id="viewer"><div id="viewerFrame">
 *   <a href=""><img src="pre1.jpg"></a>
 *   <a href=""><img src="pre2.jpg"></a>
 *   <a href=""><img src="pre3.jpg"></a>
 *   <a href=""><img src="pre4.jpg"></a>
 *   <a href=""><img src="pre5.jpg"></a>
 *   </div></div>
 *   <span id="btn1">prev</span><br/><span id="btn2">next</span>   
*/

jQuery.fn.imageScroller = function(params){
    var p = params || {
        next:"buttonNext",
        prev:"buttonPrev",
        frame:"viewerFrame",
        width:100,
        child:"a",
        auto:true
    }; 
    var _btnNext = $("#"+ p.next);
    var _btnPrev = $("#"+ p.prev);
    var _imgFrame = $("#"+ p.frame);
    var _width = p.width;
    var _child = p.child;
    var _auto = p.auto;
    var _itv;
    
    var turnLeft = function(){
        _btnPrev.unbind("click",turnLeft);
        if(_auto) autoStop();
        _imgFrame.animate( {marginLeft:-_width}, 'fast', '', function(){
            _imgFrame.find(_child+":first").appendTo( _imgFrame );
            _imgFrame.css("marginLeft",0);
            _btnPrev.bind("click",turnLeft);
            if(_auto) autoPlay();
        });
    };
    
    var turnRight = function(){
        _btnNext.unbind("click",turnRight);
        if(_auto) autoStop();
        _imgFrame.find(_child+":last").clone().show().prependTo( _imgFrame );
        _imgFrame.css("marginLeft",-_width);
        _imgFrame.animate( {marginLeft:0}, 'fast' ,'', function(){
            _imgFrame.find(_child+":last").remove();
            _btnNext.bind("click",turnRight);
            if(_auto) autoPlay(); 
        });
    };
    
    _btnNext.css("cursor","hand").click( turnRight );
    _btnPrev.css("cursor","hand").click( turnLeft );
    
    var autoPlay = function(){
      _itv = window.setInterval(turnLeft, 3000);
    };
    var autoStop = function(){
        window.clearInterval(_itv);
    };
    if(_auto)    autoPlay();
};