package service

import (
	"context"
	"errors"
	"net"

	corev1 "k8s.io/api/core/v1"
	kerrors "k8s.io/apimachinery/pkg/api/errors"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"edge-infra.dev/pkg/sds/remoteaccess/constants"
)

var errExpectedOneLoadBalancerIPAddress = errors.New("load balancer has multiple IP addresses, expected one")

// Get the relay load balancer external IP address, returning unavailable if so
func GetLoadBalancerExternalIP(ctx context.Context, c client.Client) (net.IP, error) {
	key := client.ObjectKey{Namespace: constants.VPNNamespace, Name: constants.RelayName}
	lbService := &corev1.Service{}
	if err := c.Get(ctx, key, lbService); kerrors.IsNotFound(err) {
		return nil, nil
	} else if err != nil {
		return nil, err
	}

	numIPAddresses := len(lbService.Status.LoadBalancer.Ingress)
	if numIPAddresses == 0 {
		return nil, nil
	} else if numIPAddresses > 1 {
		return nil, errExpectedOneLoadBalancerIPAddress
	}

	return net.ParseIP(lbService.Status.LoadBalancer.Ingress[0].IP), nil
}