You may also want to check out Ledger (http://ledger-cli.org/ http://ledger-cli.org/). It's text based, but it would seem doable to use the powerful underlying

You may also want to check out Ledger (http://ledger-cli.org/ http://ledger-cli.org/). It's text based, but it would seem doable to use the powerful underlying engine in your project (it's open source).