Custom Wordpress Invoice Plugin

Deliverables: 1. Custom Wordpress Invoice Plugin (Compatible with most recent version as updates are regular) All code required. Project Specs: Plugin will need a section in the WP Admin. Administrators/Editors privileges can create and save invoices based on the following: Line Item Input Data (unlimited items): 1. Item Name 2. Description 3. if Option A: Hourly rate (as input for each item; ex: $45.00[usd]) if Option B: Flat rate (as input for each item; ex: $250.00[usd]) 4. if Option A: Number of hours (to hundredth of hour; ex: 2.25 hrs) if Option B: Number of items (as input for each item; ex: 2.0 items) 5. Perform calculation based on if Option A (hourly rate) or B (flat rate). Maybe overridden by user input. Invoice Total Calculations: 1. Total Line Items 2. Total Hours 3. Total Due (in USD) Invoice Actions: 1. Save as a draft (mark as draft) 2. Save/Send to recipient as pdf via email (mark as sent; Timestamp and mark due at NET15) 3. Record a payment with details (mark as paid) Need to be able to view invoices independently by status: 1. Drafts 2. Sent 3. Paid (Archive) This should be a good overview of the project. Of course, it will need to look good too. No special design is required. It can just be styled to blend with the Default Wordpress Admin. Integration of AJAX technologies would be great, but not required. No payment processing or gateway integration is required of this project.