fix(import): negative amounts for YNAB4 import when importing split transactions (#464)

Author: morremeyer

.golangci.yml

@@ -8,12 +8,19 @@ issues:
         - gocyclo
         - errcheck
         - dupl
+
       # Parsing logic has high cyclomatic complexity. This is okay.
     - path: pkg/importer/parser/ynab4/parse.go
       linters:
         - gocyclo
       text: "func `parseTransactions`"
 
+      # Parsing logic has high cyclomatic complexity. This is okay.
+    - path: pkg/importer/creator.go
+      linters:
+        - gocyclo
+      text: "func `Create`"
+
 linters:
   enable:
     - gocyclo

pkg/importer/creator.go

@@ -1,6 +1,8 @@
 package importer
 
 import (
+	"errors"
+
 	"github.com/envelope-zero/backend/pkg/importer/types"
 	"github.com/google/uuid"
 	"gorm.io/gorm"
@@ -61,6 +63,10 @@ func Create(db *gorm.DB, budgetName string, resources types.ParsedResources) err
 
 	// Create transactions
 	for _, r := range resources.Transactions {
+		if r.Model.Amount.IsNegative() {
+			return errors.New("a transaction to be imported has a negative amount, this is invalid")
+		}
+
 		transaction := r.Model
 		transaction.BudgetID = budget.ID
 		transaction.SourceAccountID = resources.Accounts[r.SourceAccount].Model.ID

pkg/importer/parser/ynab4/parse.go

@@ -319,7 +319,12 @@ func parseTransactions(resources *types.ParsedResources, transactions []Transact
 				newTransaction.Envelope = mapping.Envelope
 				newTransaction.Category = mapping.Category
 			}
-			newTransaction.Model.Amount = sub.Amount
+
+			if sub.Amount.IsPositive() {
+				newTransaction.Model.Amount = sub.Amount
+			} else {
+				newTransaction.Model.Amount = sub.Amount.Neg()
+			}
 
 			resources.Transactions = append(resources.Transactions, newTransaction)
 		}