Implement categories for new transactions

http/transaction.go

@@ -10,17 +10,48 @@ import (
 	"github.com/google/uuid"
 )
 
+func getUUID(c *gin.Context, name string) (uuid.UUID, error) {
+	value, succ := c.GetPostForm(name)
+	if !succ {
+		return uuid.UUID{}, fmt.Errorf("not set")
+	}
+
+	id, err := uuid.Parse(value)
+	if err != nil {
+		return uuid.UUID{}, fmt.Errorf("not a valid uuid: %w", err)
+	}
+
+	return id, nil
+}
+
+func getNullUUID(c *gin.Context, name string) (uuid.NullUUID, error) {
+	value, succ := c.GetPostForm(name)
+	if !succ {
+		return uuid.NullUUID{}, nil
+	}
+
+	id, err := uuid.Parse(value)
+	if err != nil {
+		return uuid.NullUUID{}, fmt.Errorf("not a valid uuid: %w", err)
+	}
+
+	return uuid.NullUUID{
+		UUID:  id,
+		Valid: true,
+	}, nil
+}
+
 func (h *Handler) newTransaction(c *gin.Context) {
 	transactionMemo, _ := c.GetPostForm("memo")
-	transactionAccount, succ := c.GetPostForm("account_id")
-	if !succ {
-		c.AbortWithError(http.StatusNotAcceptable, fmt.Errorf("account_id missing"))
+	transactionAccountID, err := getUUID(c, "account_id")
+	if err != nil {
+		c.AbortWithError(http.StatusNotAcceptable, err)
 		return
 	}
 
-	transactionAccountID, err := uuid.Parse(transactionAccount)
-	if !succ {
-		c.AbortWithError(http.StatusNotAcceptable, fmt.Errorf("account_id is not a valid uuid"))
+	transactionCategoryID, err := getNullUUID(c, "category_id")
+	if err != nil {
+		c.AbortWithError(http.StatusNotAcceptable, err)
 		return
 	}
 
@@ -50,7 +81,7 @@ func (h *Handler) newTransaction(c *gin.Context) {
 		Amount:     amount,
 		AccountID:  transactionAccountID,
 		PayeeID:    uuid.NullUUID{},
-		CategoryID: uuid.NullUUID{},
+		CategoryID: transactionCategoryID,
 	}
 	_, err = h.Service.CreateTransaction(c.Request.Context(), new)
 	if err != nil {