Time management app

I want to create a program for time management for my law firm. Much work is done via gmail and I want to make a program that 1. lists all emails to and from a client, with a timestamp. 2. The program should be a widget to gmail or at least be able to use the emails that are downloadable via e.g. CloudHQ. 3. Shows the amount of words in each email to and from the client 4. Shows attachment(s) with names of (files) 5. Calculates billable time 1. every email is billable as minimum 30 minutes work 2. emails sent as a reply within these 30 minutes are not billed separately but within this 30 minute timeframe. If there is a better idea than to create a gmail widget - I welcome your idea. Perhaps an app would be better with all communication with the client - with time calculated in real time so the clien