Interacting with a project and its references

I want to create an extension that adds a new tool window to VS 2015.

I want access to the tool window to be by right-click on a projects references node and clicking a (new) context menu entry.

When click I want to show the new tool window.

I want to display information in that tool window that is obtained by inspecting the set of references for the project so I need to somehow access the project (who's references node was clicked) and then somehow enumerate data about that project (like properties, list of references etc).

I've looked at the various MSDN docs on all this (for example this) but can't find out much about the details of how to do what I need.

Any pointers etc much appreciated!

Thx