From f370b99fe49c443bc23cdd4e49c4ccbbc33e6d9e Mon Sep 17 00:00:00 2001
From: Peter Turi <peter.turi@openmeter.io>
Date: Tue, 21 Jan 2025 10:36:52 +0100
Subject: [PATCH] fix: split lines should not be returned for gathering
 invoices

Right now we have a sugar on gathering invoices that calculates the totals, for that
we fetch all the lines regardless of the expand settings.

This patch ensures that we are emulating the expand settings in terms of lines so that
we are not returning extra data.
---
 openmeter/billing/service/invoice.go | 30 ++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/openmeter/billing/service/invoice.go b/openmeter/billing/service/invoice.go
index a90f3f9d6..200339013 100644
--- a/openmeter/billing/service/invoice.go
+++ b/openmeter/billing/service/invoice.go
@@ -40,7 +40,7 @@ func (s *Service) ListInvoices(ctx context.Context, input billing.ListInvoicesIn
 		}
 
 		if input.Expand.GatheringTotals {
-			invoices.Items[i], err = s.recalculateGatheringInvoice(ctx, invoices.Items[i])
+			invoices.Items[i], err = s.recalculateGatheringInvoice(ctx, invoices.Items[i], input.Expand)
 			if err != nil {
 				return billing.ListInvoicesResponse{}, fmt.Errorf("error recalculating gathering invoice [%s]: %w", invoices.Items[i].ID, err)
 			}
@@ -85,12 +85,14 @@ func (s *Service) resolveStatusDetails(ctx context.Context, invoice billing.Invo
 	return invoice, nil
 }
 
-func (s *Service) recalculateGatheringInvoice(ctx context.Context, invoice billing.Invoice) (billing.Invoice, error) {
+func (s *Service) recalculateGatheringInvoice(ctx context.Context, invoice billing.Invoice, expand billing.InvoiceExpand) (billing.Invoice, error) {
 	if invoice.Status != billing.InvoiceStatusGathering {
 		return invoice, nil
 	}
 
-	if invoice.Lines.IsAbsent() {
+	wasLinesAbsent := invoice.Lines.IsAbsent()
+
+	if wasLinesAbsent {
 		// Let's load the lines, if not expanded. This can happen when we are responding to a list request, however
 		// this at least allows us to not to expand all the invoices.
 		lines, err := s.adapter.ListInvoiceLines(ctx, billing.ListInvoiceLinesAdapterInput{
@@ -123,6 +125,26 @@ func (s *Service) recalculateGatheringInvoice(ctx context.Context, invoice billi
 		return invoice, fmt.Errorf("calculating invoice: %w", err)
 	}
 
+	if wasLinesAbsent {
+		// If the original user intent was to not to receive the lines, let's not send them
+		invoice.Lines = billing.LineChildren{}
+	} else {
+		// For calulcations we fetch the split lines, but we don't want to expose them for the response
+		invoice.Lines = billing.NewLineChildren(
+			lo.Filter(invoice.Lines.OrEmpty(), func(line *billing.Line, _ int) bool {
+				if !expand.DeletedLines && line.DeletedAt != nil {
+					return false
+				}
+
+				if !expand.SplitLines && line.Status == billing.InvoiceLineStatusSplit {
+					return false
+				}
+
+				return true
+			}),
+		)
+	}
+
 	return invoice, nil
 }
 
@@ -143,7 +165,7 @@ func (s *Service) GetInvoiceByID(ctx context.Context, input billing.GetInvoiceBy
 	}
 
 	if input.Expand.GatheringTotals {
-		invoice, err = s.recalculateGatheringInvoice(ctx, invoice)
+		invoice, err = s.recalculateGatheringInvoice(ctx, invoice, input.Expand)
 		if err != nil {
 			return billing.Invoice{}, fmt.Errorf("error recalculating gathering invoice [%s]: %w", invoice.ID, err)
 		}