How to build online web site builder like wix?

I have assigned to create a web application like wix. I know PHP and I would like to create it by using it. Is there any code helper to build that application?

It should have all the features like in the wix web application. Like tools, drag and drop, resize the objects on the stage and change their properties.

Can any one suggest me if any code help site to build the web app?

Thanks, Guru