/* listfilter js
----------------------------------------------------------

@package:	Zotonic 2009	
@Author: 	Tim Benniks <tim@timbenniks.nl>

Copyright 2009 Tim Benniks

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
http://www.apache.org/licenses/LICENSE-2.0
 
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

qs_score - Quicksilver Score

A port of the Quicksilver string ranking algorithm

"hello world".score("axl") //=> 0.0
"hello world".score("ow") //=> 0.6
"hello world".score("hello world") //=> 1.0

---------------------------------------------------------- */

String.prototype.score = function(abbreviation,offset) {
  offset = offset || 0 // TODO: I think this is unused... remove
 
  if(abbreviation.length == 0) return 0.9
  if(abbreviation.length > this.length) return 0.0

  for (var i = abbreviation.length; i > 0; i--) {
	var sub_abbreviation = abbreviation.substring(0,i)
	var index = this.indexOf(sub_abbreviation)


	if(index < 0) continue;
	if(index + abbreviation.length > this.length + offset) continue;

	var next_string		  = this.substring(index+sub_abbreviation.length)
	var next_abbreviation = null

	if(i >= abbreviation.length)
	  next_abbreviation = ''
	else
	  next_abbreviation = abbreviation.substring(i)
 
	var remaining_score	  = next_string.score(next_abbreviation,offset+index)
 
	if (remaining_score > 0) {
	  var score = this.length-next_string.length;

	  if(index != 0) {
		var j = 0;

		var c = this.charCodeAt(index-1)
		if(c==32 || c == 9) {
		  for(var j=(index-2); j >= 0; j--) {
			c = this.charCodeAt(j)
			score -= ((c == 32 || c == 9) ? 1 : 0.15)
		  }
		} else {
		  score -= index
		}
	  }
   
	  score += remaining_score * next_string.length
	  score /= this.length;
	  return score
	}
  }
  return 0.0
}

jQuery.fn.listfilter = function(options)
{
	list = jQuery(options.list);

	if(list.length) 
	{
		var rows = list.children()
		var cache = rows.map(function()
		{
			return $(this).text().toLowerCase();
		});
			
		this.keyup(filter).keyup().parents('form').submit(function()
		{
			return false;
		});
	}
		
	return this;
		
	function filter()
	{
		var term = jQuery.trim(jQuery(this).val().toLowerCase()), scores = [];
		
		if(!term) 
		{
			rows.show();
		}
		else
		{
			rows.hide();

			cache.each(function(i)
			{
				var score = this.score(term);
				if(score > 0)
				{
					scores.push([score, i]); 
				}
			});

			jQuery.each(scores.sort(function(a, b){return b[0] - a[0];}), function()
			{
				jQuery(rows[ this[1] ]).show();
			});
		}
	}
};