/*
 * 
 * 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 _curpic = $("#curpic");
    var _width = p.width;
    var _child = p.child;
    var _auto = p.auto;
    var _itv;
    var _picnum = _imgFrame.find(_child).size();

    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();
        });
        if (_curpic) {
            var _picid = new Number(_curpic.html());

            if (_picid >= _picnum)
                _picid = 1;
            else
                _picid++;
            _curpic.html(_picid);
        }
    };

    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();
        });
        if (_curpic) {
            var _picid = new Number(_curpic.html());
            if (_picid <= 1)
                _picid = _picnum;
            else
                _picid--;
            _curpic.html(_picid);
        }
    };

    _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();
};