// Stupid jQuery table plugin.
/*
    <table>
      <thead>
        <tr>
          <th class="type-int awesome">int</th>
          <th class="type-float">float</th>
          <th class="type-string">string</th>
        </tr>
      </thead>
	$("table").stupidtable();	  
*/
// Call on a table 
// sortFns: Sort functions for your datatypes.
(function($){
  $.fn.stupidtable = function(sortFns){
    var table = this; sortFns = sortFns || {};

    // ==================================================== //
    //                  Utility functions                   //
    // ==================================================== //

    // Merge sort functions with some default sort functions.
    sortFns = $.extend({}, {
      "int":function(a,b){ return parseInt(a, 10) - parseInt(b,10); },
      "float":function(a,b){ return parseFloat(a) - parseFloat(b); },
      "string":function(a,b){ if (a<b) return -1; if (a>b) return +1; return 0;}
    }, sortFns);

    // Array comparison. See http://stackoverflow.com/a/8618383
    var arrays_equal = function(a,b) { return !!a && !!b && !(a<b || b<a);}
    
    // Return the resulting indexes of a sort so we can apply
    // this result elsewhere. This returns an array of index numbers.
    // return[0] = x means "arr's 0th element is now at x"
    var sort_map =  function(arr, sort_function){
      var sorted = arr.slice(0).sort(sort_function); 
      var map = [];
      var index = 0;
      for(var i=0; i<arr.length; i++){
        index = $.inArray(arr[i], sorted);

        // If this index is already in the map, look for the next index.
        // This handles the case of duplicate entries.
        while($.inArray(index, map) != -1){
          index++;
        }
        map.push(index);
      }
      return map;
    }

    // Apply a sort map to the array. 
    var apply_sort_map = function(arr, map){
      var clone = arr.slice(0);
      for(var i=0; i<map.length; i++){
        newIndex = map[i];
        clone[newIndex] = arr[i];
      }
      return clone;
    }

    // Returns true if array is sorted, false otherwise.
    // Checks for both ascending and descending
    var is_sorted_array = function(arr, sort_function){
      var clone = arr.slice(0);
      var reversed = arr.slice(0).reverse();
      var sorted = arr.slice(0).sort(sort_function);

      // Check if the array is sorted in either direction.
      return arrays_equal(clone, sorted) || arrays_equal(reversed, sorted);
    }

    // ==================================================== //
    //                  Begin execution!                    //
    // ==================================================== //
    // Do sorting when THs are clicked
    table.delegate("th", "click", function(){
      var trs = table.find("tbody tr");
      var i = $(this).index();
      var classes = $(this).attr("class");
      var type = null;
      if (classes){
        classes = classes.split(/\s+/);

        for(var j=0; j<classes.length; j++){
          if(classes[j].search("type-") != -1){
            type = classes[j];
            break;
          }
        }
        if(type){
          type = type.split('-')[1];
        }
        else{
          type = "string";
        }
      }
      // Don't attempt to sort if no data type
      if(!type){return false;}

      var sortMethod = sortFns[type];

      // Gather the elements for this column
      column = [];

      // Push either the value of the 'data-order-by' attribute if specified
      // or just the text() value in this column to column[] for comparison.
      trs.each(function(index,tr){
        var e = $(tr).children().eq(i);
        var order_by = e.attr('data-order-by') || e.text();
	      column.push(order_by);
      });

      // If the column is already sorted, just reverse the order. The sort
      // map is just reversing the indexes.
      if(is_sorted_array(column, sortMethod)){
        column.reverse();
        var theMap = [];
        for(var i=column.length-1; i>=0; i--){
          theMap.push(i);
        }
      }
      else{
        // Get a sort map and apply to all rows
        theMap = sort_map(column, sortMethod);
      }

      var sortedTRs = $(apply_sort_map(trs, theMap));

      // Replace the content of tbody with the sortedTRs. Strangely (and
      // conveniently!) enough, .append accomplishes this for us.
      table.find("tbody").append(sortedTRs);
    });
  }
 })(jQuery);