/*
* jQuery pager plugin
* Version 1.0 (12/22/2008)
* @requires jQuery v1.2.6 or later
*
* Example at: http://jonpauldavies.github.com/JQuery/Pager/PagerDemo.html
*
* Copyright (c) 2008-2009 Jon Paul Davies
* Dual licensed under the MIT and GPL licenses:
*
*/
(function($) {
 
    $.fn.pager = function(options) {
 
        var opts = $.extend({}, $.fn.pager.defaults, options);
 
        return this.each(function() {
 
        /*empty out the destination element and then render out the pager with the supplied options*/
            $(this).empty().append(renderpager(parseInt(options.pagenumber), parseInt(options.pagecount), options.buttonClickCallback));
            
            /* specify correct cursor activity*/
            $('.pages li').mouseover(function() { document.body.style.cursor = "pointer"; }).mouseout(function() { document.body.style.cursor = "auto"; });
        });
    };
 
    /* render and return the pager with the supplied options*/
    function renderpager(pagenumber, pagecount, buttonClickCallback) {
 
        var $pager = $('<ul class="pages"></ul>');
 
        /* add in the previous and next buttons*/
        $pager.append(renderButton('首页', pagenumber, pagecount, buttonClickCallback)).append(renderButton('上一页', pagenumber, pagecount, buttonClickCallback));
 
        /* pager currently only handles 10 viewable pages ( could be easily parameterized, maybe in next version ) so handle edge cases*/
        var startPoint = 1;
        var endPoint = 9;
 
        if (pagenumber > 4) {
            startPoint = pagenumber - 4;
            endPoint = pagenumber + 4;
        }
 
        if (endPoint > pagecount) {
            startPoint = pagecount - 8;
            endPoint = pagecount;
        }
 
        if (startPoint < 1) {
            startPoint = 1;
        }
 
        /* loop thru visible pages and render buttons*/
        for (var page = startPoint; page <= endPoint; page++) {
 
            var currentButton = $('<li class="page-number">' + (page) + '</li>');
 
            page == pagenumber ? currentButton.addClass('pgCurrent') : currentButton.click(function() { buttonClickCallback(this.firstChild.data); });
            currentButton.appendTo($pager);
        }
 
       /* render in the next and last buttons before returning the whole rendered control back.*/
        $pager.append(renderButton('下一页', pagenumber, pagecount, buttonClickCallback)).append(renderButton('最后页', pagenumber, pagecount, buttonClickCallback));
        
        /* go to page*/
        $pager.append('<li class="pginput"><input type="text" name="gopage" style="width:35px; height:18px; border:none;" />');
        $pager.append(renderButton('GO', pagenumber, pagecount, buttonClickCallback))
        return $pager;
    }
 
    
    function renderButton(buttonLabel, pagenumber, pagecount, buttonClickCallback) {
 
        var $Button = $('<li class="pgNext">' + buttonLabel + '</li>');
 
        var destPage = 1;
 
       
        switch (buttonLabel) {
            case "首页":
                destPage = 1;
                break;
            case "上一页":
                destPage = pagenumber - 1;
                break;
            case "下一页":
                destPage = pagenumber + 1;
                break;
            case "最后页":
                destPage = pagecount;
                break;
        }
        
        
        if (buttonLabel == "首页" || buttonLabel == "上一页") {
            pagenumber <= 1 ? $Button.addClass('pgEmpty') : $Button.click(function() { buttonClickCallback(destPage); });
        }
        else if(buttonLabel == "GO") {
        	$Button.click(function() { goToPage(pagecount, buttonClickCallback); });
        } 
        else {
    		pagenumber >= pagecount ? $Button.addClass('pgEmpty') : $Button.click(function() { buttonClickCallback(destPage); });
    	}
 
        return $Button;
    }
    
    
    function goToPage(pagecount, buttonClickCallback) {
    	
    	var destPage = parseInt($('input[name="gopage"]').val());
    	
    	if(isNaN(destPage) == false) {
    		buttonClickCallback(destPage);
    	}
    }
 
    /* pager defaults. hardly worth bothering with in this case but used as placeholder for expansion in the next version*/
    $.fn.pager.defaults = {
        pagenumber: 1,
        pagecount: 1
    };
 
})(jQuery);