/*
* jquery pager plugin
* version 1.0 (11/20/2010)
*/
(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) {

        // setup $pager to hold render
        var $pager = $('<ul class="pages"></ul>');

        // add in the previous and next buttons
        $pager.append(renderbutton('<<', pagenumber, pagecount, buttonclickcallback)).append(renderbutton('<', 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 = 5;

        if (pagenumber >= 5) {
            startpoint = pagenumber - 2;
            endpoint = pagenumber + 2;
        }

        if (endpoint > pagecount) {
            startpoint = pagecount - 4;
            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 末页 buttons before returning the whole rendered control back.
        $pager.append(renderbutton('>', pagenumber, pagecount, buttonclickcallback)).append(renderbutton('>>', pagenumber, pagecount, buttonclickcallback));

        return $pager;
    }

    // renders and returns a 'specialized' button, ie 'next', 'previous' etc. rather than a page number button
    function renderbutton(buttonlabel, pagenumber, pagecount, buttonclickcallback) {

        var $button = $('<li class="pgnext">' + buttonlabel + '</li>');

        var destpage = 1;

        // work out destination page for required button type
        switch (buttonlabel) {
            case "<<":
                destpage = 1;
                break;
            case "<":
                destpage = pagenumber - 1;
                break;
            case ">":
                destpage = pagenumber + 1;
                break;
            case ">>":
                destpage = pagecount;
                break;
        }

        // disable and 'grey' out buttons if not needed.
        if (buttonlabel == "<<" || buttonlabel == "<") {
            pagenumber <= 1 ? $button.addclass('pgempty') : $button.click(function() { buttonclickcallback(destpage); });
        }
        else {
            pagenumber >= pagecount ? $button.addclass('pgempty') : $button.click(function() { buttonclickcallback(destpage); });
        }

        return $button;
    }

    // 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);