wip: improve invoice generation logic

internal/models/invoice.go

@@ -1,6 +1,7 @@
 package models
 
 import (
+	"errors"
 	"time"
 
 	"github.com/google/uuid"
@@ -170,6 +171,24 @@ func (db *DB) UpdateInvoice(userId, id uuid.UUID, body types.UpdateInvoiceReques
 	return nil
 }
 
+func (db *DB) UpdateInvoicePDF(userId, id uuid.UUID, pdf string, invoice *types.Invoice) error {
+	if pdf == "" {
+		return errors.New("PDF path is empty!")
+	}
+
+	result := db.instance.Where("user_id = ?", userId).Where("id = ?", id).First(invoice)
+
+	if result.Error != nil {
+		return result.Error
+	}
+
+	result = db.instance.Model(invoice).Updates(types.Invoice{
+		PDF:    pdf,
+	})
+
+	return nil
+}
+
 func (db *DB) DeleteItem(userId, id uuid.UUID) error {
 	result := db.instance.Unscoped().Where("user_id = ?", userId).Where("id = ?", id).Delete(&types.Item{})