/**
 * Sometimes for quick navigation, it can be useful to allow an end user to
 * enter which page they wish to jump to manually. This paging control uses a
 * text input box to accept new paging numbers (arrow keys are also allowed
 * for), and four standard navigation buttons are also presented to the end
 * user.
 *
 *  @name Navigation with text input
 *  @summary Shows an input element into which the user can type a page number
 *  @author [Allan Jardine](http://sprymedia.co.uk)
 *  @author [Gordey Doronin](http://github.com/GDoronin)
 *
 *  @example
 *    $(document).ready(function() {
 *        $('#example').dataTable( {
 *            "pagingType": "input"
 *        } );
 *    } );
 */

(function ($) {
  function calcDisableClasses(oSettings) {
    var start = oSettings._iDisplayStart;
    var length = oSettings._iDisplayLength;
    var visibleRecords = oSettings.fnRecordsDisplay();
    var all = length === -1;

    // Gordey Doronin: Re-used this code from main jQuery.dataTables source code. To be consistent.
    var page = all ? 0 : Math.ceil(start / length);
    var pages = all ? 1 : Math.ceil(visibleRecords / length);

    var disableFirstPrevClass = (page > 0 ? '' : oSettings.oClasses.sPageButtonDisabled);
    var disableNextLastClass = (page < pages - 1 ? '' : oSettings.oClasses.sPageButtonDisabled);

    return {
      'first': disableFirstPrevClass,
      'previous': disableFirstPrevClass,
      'next': disableNextLastClass,
      'last': disableNextLastClass
    };
  }

  function calcCurrentPage(oSettings) {
    return Math.ceil(oSettings._iDisplayStart / oSettings._iDisplayLength) + 1;
  }

  function calcPages(oSettings) {
    return Math.ceil(oSettings.fnRecordsDisplay() / oSettings._iDisplayLength);
  }

  var firstClassName = 'first';
  var previousClassName = 'previous';
  var nextClassName = 'next';
  var lastClassName = 'last';

  var paginateClassName = 'paginate';
  var paginatePageClassName = 'paginate_page';
  var paginateInputClassName = 'paginate_input';
  var paginateTotalClassName = 'paginate_total';

  $.fn.dataTableExt.oPagination.input = {
    'fnInit': function (oSettings, nPaging, fnCallbackDraw) {
      var nFirst = document.createElement('span');
      var nPrevious = document.createElement('span');
      var nNext = document.createElement('span');
      var nLast = document.createElement('span');
      var nInput = document.createElement('input');
      var nTotal = document.createElement('span');
      var nInfo = document.createElement('span');

      var language = oSettings.oLanguage.oPaginate;
      var classes = oSettings.oClasses;
      var info = language.info || 'Page _INPUT_ of _TOTAL_';

      nFirst.innerHTML = language.sFirst;
      nPrevious.innerHTML = language.sPrevious;
      nNext.innerHTML = language.sNext;
      nLast.innerHTML = language.sLast;

      nFirst.className = firstClassName + ' ' + classes.sPageButton;
      nPrevious.className = previousClassName + ' ' + classes.sPageButton;
      nNext.className = nextClassName + ' ' + classes.sPageButton;
      nLast.className = lastClassName + ' ' + classes.sPageButton;

      nInput.className = paginateInputClassName;
      nTotal.className = paginateTotalClassName;

      if (oSettings.sTableId !== '') {
        nPaging.setAttribute('id', oSettings.sTableId + '_' + paginateClassName);
        nFirst.setAttribute('id', oSettings.sTableId + '_' + firstClassName);
        nPrevious.setAttribute('id', oSettings.sTableId + '_' + previousClassName);
        nNext.setAttribute('id', oSettings.sTableId + '_' + nextClassName);
        nLast.setAttribute('id', oSettings.sTableId + '_' + lastClassName);
      }

      nInput.type = 'text';

      info = info.replace(/_INPUT_/g, '</span>' + nInput.outerHTML + '<span>');
      info = info.replace(/_TOTAL_/g, '</span>' + nTotal.outerHTML + '<span>');
      nInfo.innerHTML = '<span>' + info + '</span>';

      nPaging.appendChild(nFirst);
      nPaging.appendChild(nPrevious);
      $(nInfo).children().each(function (i, n) {
        nPaging.appendChild(n);
      });
      nPaging.appendChild(nNext);
      nPaging.appendChild(nLast);

      $(nFirst).click(function () {
        var iCurrentPage = calcCurrentPage(oSettings);
        if (iCurrentPage !== 1) {
          oSettings.oApi._fnPageChange(oSettings, 'first');
          fnCallbackDraw(oSettings);
        }
      });

      $(nPrevious).click(function () {
        var iCurrentPage = calcCurrentPage(oSettings);
        if (iCurrentPage !== 1) {
          oSettings.oApi._fnPageChange(oSettings, 'previous');
          fnCallbackDraw(oSettings);
        }
      });

      $(nNext).click(function () {
        var iCurrentPage = calcCurrentPage(oSettings);
        if (iCurrentPage !== calcPages(oSettings)) {
          oSettings.oApi._fnPageChange(oSettings, 'next');
          fnCallbackDraw(oSettings);
        }
      });

      $(nLast).click(function () {
        var iCurrentPage = calcCurrentPage(oSettings);
        if (iCurrentPage !== calcPages(oSettings)) {
          oSettings.oApi._fnPageChange(oSettings, 'last');
          fnCallbackDraw(oSettings);
        }
      });

      $(nPaging).find('.' + paginateInputClassName).keyup(function (e) {
        // 38 = up arrow, 39 = right arrow
        if (e.which === 38 || e.which === 39) {
          this.value++;
        }
        // 37 = left arrow, 40 = down arrow
        else if ((e.which === 37 || e.which === 40) && this.value > 1) {
          this.value--;
        }

        if (this.value === '' || this.value.match(/[^0-9]/)) {
          /* Nothing entered or non-numeric character */
          this.value = this.value.replace(/[^\d]/g, ''); // don't even allow anything but digits
          return;
        }

        var iNewStart = oSettings._iDisplayLength * (this.value - 1);
        if (iNewStart < 0) {
          iNewStart = 0;
        }
        if (iNewStart >= oSettings.fnRecordsDisplay()) {
          iNewStart = (Math.ceil((oSettings.fnRecordsDisplay()) / oSettings._iDisplayLength) - 1) * oSettings._iDisplayLength;
        }

        oSettings._iDisplayStart = iNewStart;
        fnCallbackDraw(oSettings);
      });

      // Take the brutal approach to cancelling text selection.
      $('span', nPaging).bind('mousedown', function () { return false; });
      $('span', nPaging).bind('selectstart', function () { return false; });

      // If we can't page anyway, might as well not show it.
      var iPages = calcPages(oSettings);
      if (iPages <= 1) {
        $(nPaging).hide();
      }
    },

    'fnUpdate': function (oSettings) {
      if (!oSettings.aanFeatures.p) {
        return;
      }

      var iPages = calcPages(oSettings);
      var iCurrentPage = calcCurrentPage(oSettings);

      var an = oSettings.aanFeatures.p;
      if (iPages <= 1) // hide paging when we can't page
      {
        $(an).hide();
        return;
      }

      var disableClasses = calcDisableClasses(oSettings);

      $(an).show();

      // Enable/Disable `first` button.
      $(an).children('.' + firstClassName)
        .removeClass(oSettings.oClasses.sPageButtonDisabled)
        .addClass(disableClasses[firstClassName]);

      // Enable/Disable `prev` button.
      $(an).children('.' + previousClassName)
        .removeClass(oSettings.oClasses.sPageButtonDisabled)
        .addClass(disableClasses[previousClassName]);

      // Enable/Disable `next` button.
      $(an).children('.' + nextClassName)
        .removeClass(oSettings.oClasses.sPageButtonDisabled)
        .addClass(disableClasses[nextClassName]);

      // Enable/Disable `last` button.
      $(an).children('.' + lastClassName)
        .removeClass(oSettings.oClasses.sPageButtonDisabled)
        .addClass(disableClasses[lastClassName]);

      // Paginate of N pages text
      $(an).find('.' + paginateTotalClassName).html(iPages);

      // Current page number input value
      $(an).find('.' + paginateInputClassName).val(iCurrentPage);
    }
  };
})(jQuery);