netutils "k8s.io/utils/net"
)

// addrTypePortMapKey is used to uniquely identify groups of endpoint ports and
// address types.
type addrTypePortMapKey string

// newAddrTypePortMapKey generates a PortMapKey from endpoint ports.
func newAddrTypePortMapKey(endpointPorts []discovery.EndpointPort, addrType discovery.AddressType) addrTypePortMapKey {
	pmk := fmt.Sprintf("%s-%s", addrType, endpointsliceutil.NewPortMapKey(endpointPorts))

	addrTypes := []discovery.AddressType{discovery.AddressTypeIPv4, discovery.AddressTypeIPv6}
	multiKey := multiAddrTypePortMapKey{}

	for _, addrType := range addrTypes {
		multiKey[addrType] = newAddrTypePortMapKey(endpointPorts, addrType)
		if _, ok := d.endpointsByKey[multiKey[addrType]]; !ok {
			d.endpointsByKey[multiKey[addrType]] = endpointsliceutil.EndpointSet{}
		}
		d.portsByKey[multiKey[addrType]] = endpointPorts
	}

	slicesByKey := map[addrTypePortMapKey][]*discovery.EndpointSlice{}
	for _, existingSlice := range existingSlices {
		epKey := newAddrTypePortMapKey(existingSlice.Ports, existingSlice.AddressType)
		slicesByKey[epKey] = append(slicesByKey[epKey], existingSlice)
	}
	return slicesByKey
}