//Created by: Zoran Jambor, twitter.com/ZoranJambor
(function(){

    //This is a first layer of de-obfuscation.
    //Basically a reversed ROT13 algorithm.
    function changeLetters(string) {
        
        //Helper variables.
        var currentLetter, 
            currentPos,
            currentString = '',
            
            //Behold! The one and only counter.
            i = 0,
            
            //We're going to loop through the obfuscated strings characters, so this will come in handy.
            stringLength = string.length - 1,
            
            //Characters that will be used when de-obfuscating email address.
            //Same as string in PHP obfuscate function (obfuscateEmail).
            characters = '123456789qwertzuiopasdfghjklyxcvbnmMNBVCXYLKJHGFDSAPOIUZTREWQ',
            charactersLength = characters.length;

        
        //Counter variable has been declared before.
        for( ; i<stringLength; i++ ) {
            
            //This letter will be de-obfuscated.
            currentLetter = string.charAt(i);
            
            //Position of the letter in our characters string.
            currentPos = characters.indexOf(currentLetter);
            
            //If character is present in our string, replace it with a character
            //30 places before (opposite from obfuscating).
            //If not, leave it as it is (because character wasn't obfuscated).
            if( currentPos > -1 ) {
            
                currentPos -= (charactersLength-1) / 2;
                currentPos = currentPos < 0 ? charactersLength + currentPos : currentPos;
                
            } else {
            
                currentString += currentLetter;
            
            }
            
            //Finally, append a character to our temp string that will be returned.
            currentString += characters.charAt(currentPos);
            
        }

        return currentString;
    
    }
    
    //Function that will handle email de-obfuscation.
    //@param element is a reference to html element that will be de-obfuscated.
    //De-obfuscation is done on text and on href attribute of the element.
    //Nevertheless, function will work well with any element you pass in, 
    //even if href attribute won't be present.
    function deObfuscateEmail( element ) {
        
        //Get the text of the element.
        var text = element.innerHTML,
            
            //Get href attribute. If there is no href attribute, set href value to be an empty string.
            //Regular expression is an IE Fix.
            //Namely, IE appends obfuscated email to the url (www.domain.com/com.liameym@em).
            //Therefore, the first part of the link needs to be removed (we grab just everything after the last forward slash '/').
            href = element.getAttribute('href').replace(/http:\/\/(.+)\//gi, '') || '',
            
            //Control variable. if the two @ symbols are present, we will perform de-obfuscation,
            //if not, the string is not obfuscated and doesn't have to be de-obfuscated.
            textReplace = text.search(/@.+@/),
            hrefReplace = href.search(/@.+@/),
            
            //This function handles the second layer of de-obfuscation.
            //It is called later in the code.
            //Letters of the email are reversed (again) and css direction returned back to ltr.
            //This is called on mouseover event.
            reverseEmails = function(){
                
                //Only if htef is obfuscated.
                if( hrefReplace > -1 ) {
                    
                    //That's the reversing part right here.
                    element.setAttribute('href', href.split('').reverse().join('') );
                    
                }
                
                //Only if text is obfuscated.
                if( textReplace > -1 ) {
                
                    //Reverse the text of the element and
                    //return the direction to normal (left to right).
                    element.innerHTML = text.split('').reverse().join('');
                    element.style.direction = 'ltr';
                    element.style.unicodeBidi = 'normal';
                    
                }
                
                
                //Letters are replaced and the event isn't needed anymore.
                if( element.removeEventListener ) {
                    
                    element.removeEventListener('mouseover', reverseEmails, false);
                    
                } else {
                
                    // IE8-
                    element.detachEvent('onmouseover', reverseEmails);
                    
                }

            
            };
            //End variables and functions definitions.
        
    
        //href has to be processed first, because of the strange 
        //IE bug that will mix the href and innerHTML values.
        if( hrefReplace > -1 ) {
            
            href = changeLetters(href);
            element.setAttribute('href', href);

        }
        
        //Change the direction of the text to show real address
        //to users, instead of a reversed one.
        if( textReplace > -1 ) {
            
            text = changeLetters( text );
            element.innerHTML = text;
            element.style.direction = 'rtl';
            element.style.unicodeBidi = 'bidi-override';
            
        }
        
        
        //Since we have a rtl text, user can't copy or click on a link.
        //Therefore we'll replace the value as soon as user hovers over the link.
        if( element.addEventListener ) {
            
            element.addEventListener('mouseover', reverseEmails, false);
            
        } else {
        
            element.attachEvent('onmouseover', reverseEmails);
        
        }
            
    }
    
    

    //We could use native getElementsByClassName in browsers that support this method,
    //but I did a few quick tests and it seems to be slower. 
    //If you have more info on performance getElementsByClassName vs getElementsByTagName + className.indexOf please let me know.
    //var obfuscatedEmails = document.getElementsByClassName('obfuscatedEmail'),
    
    //This is written to be as general as possible; you can leave this part out and just call
    //deObfuscateEmail() manually on elements that should be de-obfuscated.
    
    var obfuscatedEmails = document.getElementsByTagName('a'),
        obfuscatedEmailsLength = obfuscatedEmails.length,
        i = 0;
    
    for( ; i<obfuscatedEmailsLength; i++ ) {
    
        if( obfuscatedEmails[i].className.indexOf('obfuscatedEmail') > -1 ) {
        
            deObfuscateEmail( obfuscatedEmails[i] );
            
        }
        
    }
    
}());