/*
* 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:
* http://www.opensource.org/licenses/mit-license.php
* http://www.gnu.org/licenses/gpl.html
* 
* Read the related blog post and contact the author at http://www.j-dee.com/2008/12/22/jquery-pager-plugin/
*
* This version is far from perfect and doesn't manage it's own state, therefore contributions are more than welcome!
*
* Usage: .pager({ pagenumber: 1, pagecount: 15, buttonClickCallback: PagerClickTest });
*
* Where pagenumber is the visible page number
*       pagecount is the total number of pages to display
*       buttonClickCallback is the method to fire when a pager button is clicked.
*
* buttonClickCallback signiture is PagerClickTest = function(pageclickednumber) 
* Where pageclickednumber is the number of the page clicked in the control.
*
* The included Pager.CSS file is a dependancy but can obviously tweaked to your wishes
* Tested in IE6 IE7 Firefox & Safari. Any browser strangeness, please report.
*/
(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 = 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('>', 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);