Add functionality to post editor

Question

I can't find any documentation to add a functionality to the post editor. I've got this so far:

http://www.wpbeginner.com/wp-tutorials/how-to-add-custom-styles-to-wordpress-visual-editor/

But I would like a popup with fields (meta boxes) just like when you select some text, and insert a link.

Answer 1

I have found an url which explains it all, just adding some javascript, php and css to TinyMCE by some hooks and you got it up and running. http://codex.wordpress.org/Plugin_API/Filter_Reference/mce_external_plugins