Add endpoint for updating link

link/repository.go

@@ -16,6 +16,7 @@ type Repository interface {
 	Save(link *Link) error
 	FindById(id string) (*Link, error)
 	FindAll(limit int, offset int) (Links, error)
+	Update(link *Link) error
 	DeleteById(id string) error
 }
 
@@ -135,6 +136,38 @@ func (r *PgRepository) FindAll(limit int, offset int) (Links, error) {
 	return links, nil
 }
 
+func (r *PgRepository) Update(link *Link) error {
+	if link.Id == "" {
+		return errors.New("link ID must not be empty")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	tx, err := r.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+
+	sql := `
+		UPDATE links
+		SET name = $1, redirect_url = $2
+		WHERE id = $3
+	`
+
+	_, err = tx.Exec(ctx, sql, link.Name, link.RedirectURL.String(), link.Id)
+	if err != nil {
+		_ = tx.Rollback(ctx)
+		return err
+	}
+
+	if err = tx.Commit(ctx); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (r *PgRepository) DeleteById(id string) error {
 	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
 	defer cancel()