/**
 * jQuery fontscale - A plugin to alter the font size of DOM elements 
 * Copyright (c) 2010 Ben Byrne - ben(at)fireflypartners(dot)com | http://www.fireflypartners.com
 * Dual licensed under MIT and GPL.
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 * Date: 07/21/2010
 * @author Ben Byrne
 * @version 0.2
 *
 */

/**
 * For complete documentation, visit http://byrnecreative.com/blog/fontscale
 * @example $("#fontgrow").fontscale("p","+");
 * @desc Bind scaling up the font size of all P elements to the element #fontgrow with default settings.
 * @example $("#fontshrink").fontscale("p","-",{unit:"percent",increment:25,useCookie:false,adjustLeading:true});
 * @desc Bind scaling down the font size of all P elements to the element #fontshrink with custom settings.
 * @example $("#reset").fontscale("p","reset");
 * @desc Eliminate all fontscale resizing 
 */
 
(function($) {
 $.fn.fontscale = function(selectors, adjustment, parameters) {

  var settings = $.extend( $.fn.fontscale.defaults, parameters);
  
  //only use cookies if we can
		if ( ! $.isFunction( $.cookie ) ) settings.useCookie = false;
		
  // if the cookie exists, we're supposed to use it, and we haven't before, then load it 
	 if (!settings.cookieLoaded && $.cookie(settings.cookieName) && settings.useCookie) {
   cookieSettings = $.fn.fontscale.readcookie( settings.cookieName );
	  //only actually apply the data from the cookie if its unit settings match!
			if (cookieSettings.unit == settings.unit && !settings.cookieLoaded) $.fn.fontscale.scale( selectors, cookieSettings.delta, settings, true );
	 }
		
  this.each( function() {

		 // bind to elements
		 $(this).bind(settings.event, function() {
    $.fn.fontscale.scale( selectors, adjustment, settings, false);
    if ($.isFunction(settings.onAfter)) settings.onAfter(selectors, adjustment, settings); //is this okay?				
		 });
		});
		
		return this;
		
 };

 $.fn.fontscale.reset = function( object, settings ) {
  
  //remove any scaling done inline (assumed to be from this plugin)
  $(object).each(function(i) {
   $(this).css('font-size','');
   if (settings.adjustLeading) $(this).css('line-height','');
  });
  
  //if we're using a cookie, reset it too
  if ( settings.useCookie ) {
   $.fn.fontscale.savecookie("delete", settings );
  }
 }

	$.fn.fontscale.scale = function( object, adj, settings, fromcookie) {
	
  //make delta an int that changes nothing to start
  var delta = 0;
	
  if (adj == "+" || adj == "up") {
   //set the delta as an increase
   delta = settings.increment;
  } else if (adj == "-" || adj == "down") {
   //set the delta as a decrease
   delta = settings.increment * -1;
  } else if (adj == "reset") {
   //remove applied changes and do nothing else
   return $.fn.fontscale.reset( object, settings );
  } else if (fromcookie) {
   //get a pre-calibrated delta from the cookie if 
   delta = parseFloat(adj);
   settings.cookieLoaded = true;
	 }
	 	 
  //change the value into a percent if we have to
  if (settings.unit == "percent" && !fromcookie) {
   delta = 1 + (delta / 100);
  }
  	 
  $(object).each(function(i) {

   var currentSize = parseInt($(this).css("font-size"));
   var currentLeading = parseInt($(this).css("line-height"));
   
   if (settings.unit == "percent") {
    $(this).css("font-size", Math.round( currentSize * delta));
    if (settings.adjustLeading) $(this).css("line-height", Math.round( currentLeading * delta));
   } else {
    $(this).css("font-size", currentSize + delta);
    if (settings.adjustLeading) $(this).css("line-height", currentLeading + delta);
   }
 
	 });

 if (settings.useCookie && !fromcookie) $.fn.fontscale.savecookie( delta, settings );
 
 return;
 
 };
 
 $.fn.fontscale.savecookie = function( delta, settings ) {

  //delete the cookie if we're performing a reset, do nothing else
  if (delta == "delete") {
   $.cookie( settings.cookieName, null, settings.cookieParams );
   return true;
  }
    
  if ($.cookie( settings.cookieName )) {
   properties = $.fn.fontscale.readcookie( settings.cookieName );
  } else {
   properties = {"delta":0}
  }
    
  //if we have a cookie that matches, just change the delta
  if (settings.unit == properties.unit) { 

   if (settings.unit == "percent") {
    properties.delta = (delta) ? properties.delta * delta : 1 ;
   } else {
    properties.delta = parseInt(properties.delta) + delta;
   }
  
   return $.cookie( settings.cookieName, "delta="+properties.delta+"&unit="+properties.unit, settings.cookieParams);
  
  //no cookie that matches, create a new   
  } else {
   $.cookie( settings.cookieName, "delta="+delta+"&unit="+settings.unit, settings.cookieParams);
   return true;
  }
   
 };
 
 $.fn.fontscale.readcookie = function( the_cookie ) {
 
  val_string = $.cookie( the_cookie );
        
  var objResult = {};
  $.each(val_string.split("&"), function() { 
   var prm=this.split("=");
   objResult[prm[0]] = prm[1]; 
  });
  return objResult;
 };

})(jQuery);

$.fn.fontscale.defaults = {
 useCookie:true,
 cookieName:'fontscale',
 cookieParams:{
  expires:30,
  path:"/"},
 increment:2,
 unit:"px",
 adjustLeading:false,
 event:"click",
 cookieLoaded:false
};