/************** LESS modifyVars 1.3 ***************
Copyright (c) 2012, Zoran Kenda
Licensed under the Apache 2.0 License.

Modified version of less.js is required. I tried to keep modifications at minumum to ensure future versions compatibility.
Modifications in less.js (v.1.3):
--- 
function loadStyleSheets(callback, reload) {
    less.roots = []; //modification 1 ln 3224
---
function loadStyleSheet(
...
 }).parse(data, function (e, root) {
  if (e) { return error(e, href) }
	try {
	less.roots.push({root: root, sheet : sheet}); //modification 2 ln:3267 <---
	
Usage:
var modifications= {
    "@baseRotation": function(){
        index+=3;
        return index;
    }, 
    "@headerColor": "#08c",
    "@footerColor":{value:"spin(@headerColor,150 + @baseRotation)",type:"expression"},
    "@focusImage":"focus1.png?a.h=@{baseRotation}"
}
 less.modify(modifications);  
************************************************/

(function (window, undefined) {

if(!less){ console.log("Less.js not loaded. exiting"); return; }

less.modify = function(modifications){     
     
   if(!less.roots || less.roots.length==0)
      less.refresh(true);
    
    if(!less.roots) { console.log("less.roots is null. Are you using an unmodified version of less.js?"); return; }		
      
   for(var i = 0;i<less.roots.length;i++){    
      var modified = false;
      var rootInfo = less.roots[i];
      var root = rootInfo.root;
      var sheet = rootInfo.sheet;

      for(var name in modifications){                  
          var variable =  root.variable(name);
          var valx = null; 
                     
          if(variable && variable.value){
              var value = modifications[name];              
              var type = typeof value;
              
              if(type === "function"){
                  value = value();
                  var type = typeof value;
              } //zanalasc ni else
              
              if(typeof value ==="object" && value.value && value.type){
				  type = value.type;
				  value = value.value;				  
              }
              
              console.log("modifiing var "+name +" value: "+value);         
              
              try{
                  //valx = variable.value.eval();                                               
					if(type =="number"){ 
						variable.value = getDimension(value);                      						
						modified = true;  
					} else if((type=="color" || (type == "string" && value.length>0)) && value.charAt(0)=="#"){ //barva je						 
						 variable.value = getColor(value);
						 modified = true;
					}  else if(type=="expression"){ 
						new( less.Parser)().parse("@tempExpr:"+value+";",function(e,f){
							variable.value = f.variable("@tempExpr").value;
						});					
						modified = true;
					}
					else if(type =="string"){ //barva je						 
						 variable.value = getLiteral(value);
						 modified = true;
					}					
					else{
						console.log("ni rbg, ni number, ni literal");                                                   
					}                       
              }catch(e){                
                console.log(e);                       
              }
              console.log("modified var "+name);                             
          }
      }
      if(modified)
        createCSS(root.toCSS(), sheet);                                 
  } 
}

/* values to expressions */
function getValue(val){
  return new(less.tree.Value)([new(less.tree.Expression)([val])]);
}

function getDimension(val){    
    return getValue(new(less.tree.Dimension)(val));
}

function getColor(val){
    var rgb;

    if ( (val.charAt(0) === '#') && (rgb = (/^#([a-fA-F0-9]{6}|[a-fA-F0-9]{3})/).exec(val)) ) {
       val = rgb[1];
    }    
    return getValue(new(less.tree.Color)(val));
}

function getLiteral(val){        
    return getValue(new(less.tree.Quoted)("'",val,false));
}


/******************* Slightly modified functions taken from less.js ***************/
//copied from less.js and modified a little (removed cache update code)
function createCSS(styles, sheet) {
    var css;
    // Strip the query-string
    var href = sheet.href ? sheet.href.replace(/\?.*$/, '') : '';

    // If there is no title set, use the filename, minus the extension
    var id = 'less:' + (sheet.title || extractId(href));

    // If the stylesheet doesn't exist, create a new node
    if ((css = document.getElementById(id)) === null) {
        css = document.createElement('style');
        css.type = 'text/css';
        css.media = sheet.media || 'screen';
        css.id = id;
        document.getElementsByTagName('head')[0].appendChild(css);
    }

    if (css.styleSheet) { // IE
        try {
            css.styleSheet.cssText = styles;
        } catch (e) {
            throw new(Error)("Couldn't reassign styleSheet.cssText.");
        }
    } else {
        (function (node) {
            if (css.childNodes.length > 0) {
                if (css.firstChild.nodeValue !== node.nodeValue) {
                    css.replaceChild(node, css.firstChild);
                }
            } else {
                css.appendChild(node);
            }
        })(document.createTextNode(styles));
    }
}

//copied from less.js 1.3
function extractId(href) {
    return href.replace(/^[a-z]+:\/\/?[^\/]+/, '' )  // Remove protocol & domain
               .replace(/^\//,                 '' )  // Remove root /
               .replace(/\?.*$/,               '' )  // Remove query
               .replace(/\.[^\.\/]+$/,         '' )  // Remove file extension
               .replace(/[^\.\w-]+/g,          '-')  // Replace illegal characters
               .replace(/\./g,                 ':'); // Replace dots with colons(for valid id)
}


 
})(window);