refactor: move offset function to internal (#11)

* refactor: move offset function to internal

* refactor: rename function offset to getOffset

keeper.go

@@ -7,7 +7,6 @@ import (
 	"github.com/go-redsync/redsync"
 	redigo "github.com/gomodule/redigo/redis"
 	"github.com/jpillora/backoff"
-	"github.com/kumparan/go-lib/utils"
 )
 
 const (
@@ -485,7 +484,7 @@ func (k *keeper) GetAndRemoveLastListElement(name string) (value interface{}, er
 }
 
 func (k *keeper) GetList(name string, size int64, page int64) (value interface{}, err error) {
-	offset := utils.Offset(page, size)
+	offset := getOffset(page, size)
 
 	client := k.connPool.Get()
 	defer client.Close()
@@ -517,3 +516,12 @@ func (k *keeper) GetTTL(name string) (value int64, err error) {
 	value = val.(int64)
 	return
 }
+
+// getOffset to get offset from page and limit, min value for page = 1
+func getOffset(page, limit int64) int64 {
+	offset := (page - 1) * limit
+	if offset < 0 {
+		return 0
+	}
+	return offset
+}