chore(all): return concrete types, accept interfaces

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

internal/healthcheck/openvpn.go

@@ -5,11 +5,10 @@ import (
 	"time"
 
 	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/gluetun/internal/vpn"
 )
 
 type vpnHealth struct {
-	looper       vpn.Looper
+	loop         StatusApplier
 	healthyWait  time.Duration
 	healthyTimer *time.Timer
 }
@@ -17,8 +16,8 @@ type vpnHealth struct {
 func (s *Server) onUnhealthyVPN(ctx context.Context) {
 	s.logger.Info("program has been unhealthy for " +
 		s.vpn.healthyWait.String() + ": restarting VPN")
-	_, _ = s.vpn.looper.ApplyStatus(ctx, constants.Stopped)
-	_, _ = s.vpn.looper.ApplyStatus(ctx, constants.Running)
+	_, _ = s.vpn.loop.ApplyStatus(ctx, constants.Stopped)
+	_, _ = s.vpn.loop.ApplyStatus(ctx, constants.Running)
 	s.vpn.healthyWait += *s.config.VPN.Addition
 	s.vpn.healthyTimer = time.NewTimer(s.vpn.healthyWait)
 }