chore(filter): common filter for all providers

internal/provider/nordvpn/connection.go

@@ -16,7 +16,7 @@ func (n *Nordvpn) GetConnection(selection settings.ServerSelection) (
 		protocol = constants.TCP
 	}
 
-	servers, err := n.filterServers(selection)
+	servers, err := utils.FilterServers(n.servers, selection)
 	if err != nil {
 		return connection, err
 	}

internal/provider/nordvpn/filter.go

@@ -1,36 +0,0 @@
-package nordvpn
-
-import (
-	"strconv"
-
-	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gluetun/internal/models"
-	"github.com/qdm12/gluetun/internal/provider/utils"
-)
-
-func (n *Nordvpn) filterServers(selection settings.ServerSelection) (
-	servers []models.Server, err error) {
-	selectedNumbers := make([]string, len(selection.Numbers))
-	for i := range selection.Numbers {
-		selectedNumbers[i] = strconv.Itoa(int(selection.Numbers[i]))
-	}
-
-	for _, server := range n.servers {
-		serverNumber := strconv.Itoa(int(server.Number))
-		switch {
-		case
-			utils.FilterByPossibilities(server.Region, selection.Regions),
-			utils.FilterByPossibilities(server.Hostname, selection.Hostnames),
-			utils.FilterByPossibilities(serverNumber, selectedNumbers),
-			utils.FilterByProtocol(selection, server.TCP, server.UDP):
-		default:
-			servers = append(servers, server)
-		}
-	}
-
-	if len(servers) == 0 {
-		return nil, utils.NoServerFoundError(selection)
-	}
-
-	return servers, nil
-}