Plagiarism Detection Server Side Script

Write a server side script that will detect plagiarism using google API. This will allow admin to check what members upload (automatically, NOT be posted manually in a box) that has been published online. We want a pop up box that appears to tell the user that it will be checked before published. The code will return the amount of plagiarised text as a percentage, as well as highlighting plagiarised phrases (similar to turnitin, grammarly, etc). The code will also need to check spelling and grammar then notify the member. Once it has been modified by the member then checked again to be classed as not plagiarism, it will have not highlights of plagiarised text.