Refactor (#174)

- Goal was to simplify main.go complexity
- Use common structures and interfaces for all vpn providers
- Moved files around
- Removed some alias models

internal/provider/provider.go

@@ -0,0 +1,38 @@
+package provider
+
+import (
+	"context"
+
+	"github.com/qdm12/golibs/files"
+	"github.com/qdm12/golibs/logging"
+	"github.com/qdm12/golibs/network"
+	"github.com/qdm12/private-internet-access-docker/internal/constants"
+	"github.com/qdm12/private-internet-access-docker/internal/firewall"
+	"github.com/qdm12/private-internet-access-docker/internal/models"
+)
+
+// Provider contains methods to read and modify the openvpn configuration to connect as a client
+type Provider interface {
+	GetOpenVPNConnections(selection models.ServerSelection) (connections []models.OpenVPNConnection, err error)
+	BuildConf(connections []models.OpenVPNConnection, verbosity, uid, gid int, root bool, cipher, auth string, extras models.ExtraConfigOptions) (err error)
+	GetPortForward() (port uint16, err error)
+	WritePortForward(filepath models.Filepath, port uint16, uid, gid int) (err error)
+	AllowPortForwardFirewall(ctx context.Context, device models.VPNDevice, port uint16) (err error)
+}
+
+func New(provider models.VPNProvider, logger logging.Logger, client network.Client, fileManager files.FileManager, firewall firewall.Configurator) Provider {
+	switch provider {
+	case constants.PrivateInternetAccess:
+		return newPrivateInternetAccess(client, fileManager, firewall)
+	case constants.Mullvad:
+		return newMullvad(fileManager, logger)
+	case constants.Windscribe:
+		return newWindscribe(fileManager)
+	case constants.Surfshark:
+		return newSurfshark(fileManager)
+	case constants.Cyberghost:
+		return newCyberghost(fileManager)
+	default:
+		return nil // should never occur
+	}
+}