Hello,
I am currently working on a project like that for myself. I'm building an inventory with charts that shows the sales, distribution and the amount added/removed from the stock. It has logs and it has search functions for a given day, month and a year.
The invoicing system will be built on top of it and will be directly connected to the stock, so the moment you create the invoice with certain products it will automatically deduct the given amount from the stock.
What else do you need configured?
Let me know what you think, and if you are interested, lets continue.