Need Chrome Extension with Reddit API -- 2

I need a simple desktop Chrome browser extension. It will also use Reddit.com API . When I browse a subreddit page or post, it will scan the page to get all user IDs on the page and then check if any of them are already in my database. If so, then all usernames of user's in database will be highlighted on the page. If I hover the mouse over a username, it will open a popup and display all comments between me and that user. If I reply to a comment or send a private message, then add that user's ID in the database if not already in there.