> I mean I want to log income, spendings, exchanges in multiple currencies (or commodities), and then be able to see reports in a single currency -

All the major PTA tools support this - perhaps the chat could help ?

> my net worth, my income over period of time, capital gains / losses.

The first two are easy, the third is more complicated but also possible - unrealized gains at least, I forget how easy realized gains are in the various tools, it might not be fully automatic.