need a basic app - 4 questions - generate pdf invoice with line items

We are looking for an app to help us achieve the following: each day when a user logs in, there will be a todo list for each day / week / month that can be generated by the user or by admin for the user. there will be a library of clients that can be added by user or admin, and a library of open projects for each client that can also be added by user or admin. each day the todo list will be linked to client and to project. user or admin can add tasks to the todo list. by clicking a down arrow with first clients in the library > then projects in the library. (if the task is not already in the library, it can be added by user or admin) Once the user or admin adds the client, then the project... then we want the app to ask the user or admin what type of billing we will use [ 2 options - 1. hourly and 2. project ] user or admin will pick one of the two options, then the app will ask: how many hours will it take? (if they pick hours) and: how much is the project price? (if its a project) Then once the user or admin completes the project, they can click the app dashboard for running projects and they can mark it as completed. Once this is done, I want it to be moved to a running invoice for the month for that client as a line item and added to a list of amounts that are being billed. so in essence we want to make billing easier as a daily task of just small data entries but it adds up for all clients invoices at the end of the month that are automatically generated by the app. Make sense? let me know if you have any questions or suggestions to help us achieve this? Thanks!!