Website for creating custom wordpress themes

My project is a website where a user can log in and has his own dashboard. there will be a create new template button witch will lead the user to a page that has: Drag & drop features to create a WordPress template. So lets suppose i am the user i login and i want to create a wordpress template on the drag & drop sector i select a banner and i place it on top that automatically creates me the option into the settings for that banner witch is lenght and change image. i add a navigation menu on top and i add 4 menus(ex. ABOUT, CONTACT, SERVICES, WHY US) and i choose the font/size/color etc. that automatically creates me a option to change colors,size add/remove menu etc. when i finish the drag & drop i click download and i get my custom wordpress theme downloaded and it will be ready to be uploaded into the wordpress cms the important part is whatever i added i need to automatically create options for change so that means its like creating a custom wordpress theme but not coding only drag & drop so when you download it you have your own wordpress theme created by you from scratch. Please read this short description and contact me with your ideas i want you to be prepared to answer some questions and have a kind of a plan. no automated messages. Thank you.