chore(all): return concrete types, accept interfaces

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

internal/publicip/interfaces.go

@@ -0,0 +1,28 @@
+package publicip
+
+import (
+	"context"
+	"net"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/models"
+	publicipmodels "github.com/qdm12/gluetun/internal/publicip/models"
+)
+
+type statusManager interface {
+	GetStatus() (status models.LoopStatus)
+	SetStatus(status models.LoopStatus)
+	ApplyStatus(ctx context.Context, status models.LoopStatus) (
+		outcome string, err error)
+}
+
+type stateManager interface {
+	GetData() (data publicipmodels.IPInfoData)
+	SetData(data publicipmodels.IPInfoData)
+	GetSettings() (settings settings.PublicIP)
+	SetSettings(ctx context.Context, settings settings.PublicIP) (outcome string)
+}
+
+type fetcher interface {
+	FetchPublicIP(ctx context.Context) (ip net.IP, err error)
+}