help with git query

Hi,

I'd like to generate the following report from git:

for each branch:
  - info about the latest commit on that branch (date and time, message, etc.)
  - info about the last time it was merged into master

What commands can I run to figure this out? I think I can figure out
the first one - it's the second one I'm having trouble with.

And if it would easier to do it from the C API (or something like the
perl Git::PurePerl module) I'd be interested in knowing that, too.

Thanks,
ER