Display/generate the table of contents for any document while reading

We currently have a table of content macro but the author needs to add it himself. Not all documents have it.

Also, the table of content macro becomes part of the content and sometimes it's at the top, sometimes it's floating to the right, making the content wrap badly around it.

It would be really nice if the table of content was an User Interface feature for any document and that would be easily toggled (on the right, for example) to provide quick navigation inside the (possibly large) document. (We already have navigation in the wiki, but not inside a document).

This table of content would be generated on the spot for any document being viewed (using the headings structure) or, would be populated with any existing table of content (macro) explicitly set by the document editors.

The UI table of contents should be easily hidden to not affect reading, but should also easily be toggleable and should follow the scrolling (i.e. not set in a static panel that you need to scroll to get to the start of the page to read).

Again, ideally, it should be part of XWiki's UI, but it could also be developed as an extension.

Good candidate for a GSoC or hackathon project.