chore(all): return concrete types, accept interfaces

- Remove exported interfaces unused locally
- Define interfaces to accept arguments
- Return concrete types, not interfaces

internal/updater/interfaces.go

@@ -0,0 +1,33 @@
+package updater
+
+import (
+	"context"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider"
+)
+
+type Providers interface {
+	Get(providerName string) provider.Provider
+}
+
+type Storage interface {
+	SetServers(provider string, servers []models.Server) (err error)
+	GetServersCount(provider string) (count int)
+	ServersAreEqual(provider string, servers []models.Server) (equal bool)
+	// Extra methods to match the provider.New storage interface
+	FilterServers(provider string, selection settings.ServerSelection) (filtered []models.Server, err error)
+	GetServerByName(provider string, name string) (server models.Server, ok bool)
+}
+
+type Unzipper interface {
+	FetchAndExtract(ctx context.Context, url string) (
+		contents map[string][]byte, err error)
+}
+
+type Logger interface {
+	Info(s string)
+	Warn(s string)
+	Error(s string)
+}