Create payment or credit when Invoice marked as 'Paid'

Overview

When an invoice is processed payments or credits need to be created again the Funds that are responsible for accounting for the invoices value.

Approach:

Current assumption is that payments will be created for all positive fund distributions and credits will be created for all negative fund distributions.

1. Determine the expected number of payments & credits.
2. Check if the payments have already been processed. If yes, go to step 5
   • use GET /finance/transactions?query=invoiceInvoiceId==<invoiceId>.
3. Create payment_summary
   • Use POST /finance/invoice-payment-summaries
4. Generate and send payments & credits for processing
   • One payment or credit for each fundDistribution for each invoiceLine (see example below)
   • Use POST /finance/payments and POST /finance/credits
5. Update invoice status to Paid.

NOTE: If any of these steps fail, an appropriate error message should be returned to the client - saying that paying the invoice failed, and they can retry.
NOTE: The transactions can happen in parallel. If needed we can look at batching these in the future but that's outside the scope of this story.

Example of Generating Payments/Credits

Invoice XYZ

• invoiceLine A
  • Fund Distro $50, USHIST
  • Fund Distro $25, HIST
• invoiceLine B
  • Fund Distro $25, LAW
  • Fund Distro $25, MATH
  • Fund Distro $25, HIST
• invoiceLine C
  • Fund Distro -$10, USHIST

InvoicePaymentSummary:

• Invoice: XYZ
• NumPayments: 6

Payments:

• $50 USHIST (Invoice: XYZ, InvoiceLine: A)
• $25 HIST (Invoice: XYZ, InvoiceLine: A)
• $25 LAW (Invoice: XYZ, InvoiceLine: B)
• $25 MATH (Invoice: XYZ, InvoiceLine: B)
• $25 HIST (Invoice: XYZ, InvoiceLine: B)

Credits:

• $10 USHIST (Invoice: XYZ, InvoiceLine: C)

Additional Background/Context/Details

See related section/flowchart on this spike page
See the wiki for additional details

Acceptance criteria:

• The business logic described above has been added
• Unit tests are updated
• API tests are updated