xds

type Callbacks interface {
	// OnStreamOpen is called once an xDS stream is opened with a stream ID and the type URL (or "" for ADS).
	// Returning an error will end processing and close the stream. OnStreamClosed will still be called.
	OnStreamOpen(context.Context, int64, string) error
	// OnStreamClosed is called immediately prior to closing an xDS stream with a stream ID.
	OnStreamClosed(int64)
	// OnStreamRequest is called once a request is received on a stream.
	// Returning an error will end processing and close the stream. OnStreamClosed will still be called.
	OnStreamRequest(int64, DiscoveryRequest) error
	// OnStreamResponse is called immediately prior to sending a response on a stream.
	OnStreamResponse(int64, DiscoveryRequest, DiscoveryResponse)
}

type DeltaCallbacks interface {
	// OnDeltaStreamOpen is called once an xDS stream is opened with a stream ID and the type URL (or "" for ADS).
	// Returning an error will end processing and close the stream. OnDeltaStreamClosed will still be called.
	OnDeltaStreamOpen(context.Context, int64, string) error
	// OnDeltaStreamClosed is called immediately prior to closing an xDS stream with a stream ID.
	OnDeltaStreamClosed(int64)
	// OnStreamDeltaRequest is called once a request is received on a stream.
	// Returning an error will end processing and close the stream. OnDeltaStreamClosed will still be called.
	OnStreamDeltaRequest(int64, DeltaDiscoveryRequest) error
	// OnStreamDeltaResponse is called immediately prior to sending a response on a stream.
	OnStreamDeltaResponse(int64, DeltaDiscoveryRequest, DeltaDiscoveryResponse)
}

type DeltaDiscoveryRequest interface {
	NodeId() string
	// Node returns either a v2 or v3 Node
	Node() interface{}
	Metadata() *structpb.Struct
	GetTypeUrl() string
	GetResponseNonce() string
	GetResourceNamesSubscribe() []string
	GetInitialResourceVersions() map[string]string
	HasErrors() bool
	ErrorMsg() string
}

type DeltaDiscoveryResponse interface {
	GetTypeUrl() string
	GetResources() []*discoveryv3.Resource
	GetRemovedResources() []string
	GetNonce() string
}

type DiscoveryRequest interface {
	NodeId() string
	// Node returns either a v2 or v3 Node
	Node() interface{}
	Metadata() *structpb.Struct
	VersionInfo() string
	GetTypeUrl() string
	GetResponseNonce() string
	GetResourceNames() []string
	HasErrors() bool
	ErrorMsg() string
}

type DiscoveryResponse interface {
	GetTypeUrl() string
	VersionInfo() string
	GetResources() []*anypb.Any
	GetNonce() string
}

type LoggingCallbacks struct {
	Log logr.Logger
}

type MultiCallbacks interface {
	Callbacks
	RestCallbacks
}

type NoopCallbacks struct{}

type RestCallbacks interface {
	// OnFetchRequest is called when a new rest request comes in.
	// Returning an error will end processing. OnFetchResponse will not be called.
	OnFetchRequest(ctx context.Context, request DiscoveryRequest) error
	// OnFetchResponse is called immediately prior to sending a rest response.
	OnFetchResponse(request DiscoveryRequest, response DiscoveryResponse)
}

type StatsCallbacks interface {
	// ConfigReadyForDelivery marks a configuration as a ready to be delivered.
	// This means that any config (EDS/CDS/DDS policies etc.) with specified version was set to a Snapshot
	// and it's scheduled to be delivered.
	ConfigReadyForDelivery(configVersion string)
	// DiscardConfig removes a configuration from being delivered.
	// This should be called when the client of xDS/DDS server disconnects.
	DiscardConfig(configVersion string)
	Callbacks
	DeltaCallbacks
}