cache

type Cache interface {
	ConfigWatcher

	// Fetch implements the polling method of the config cache using a non-empty request.
	Fetch(context.Context, Request) (*Response, error)

	// GetStatusInfo retrieves status information for a node ID.
	GetStatusInfo(string) StatusInfo

	// GetStatusKeys retrieves node IDs for all statuses.
	GetStatusKeys() []string
}

type CacheSettings struct {
	// Ads identifies if xDS ADS service is being useds.
	Ads bool
	// Hash is the interface for hashing an Envoy node.
	Hash NodeHash
	// Logger is the logger used to log server information.
	Logger log.Logger
	// PrioritySet priorizes the response watches that the cache creates by their TypeURL.
	PrioritySet map[int][]string
}

type ConfigWatcher interface {
	// CreateWatch returns a new open watch from a non-empty request.
	//
	// Value channel produces requested resources, once they are available.  If
	// the channel is closed prior to cancellation of the watch, an unrecoverable
	// error has occurred in the producer, and the consumer should close the
	// corresponding stream.
	//
	// Cancel is an optional function to release resources in the producer. If
	// provided, the consumer may call this function multiple times.
	CreateWatch(Request) (value chan Response, cancel func())
}

type GenericSnapshot struct {
	// contains filtered or unexported fields
}

type NilSnapshot struct{}

type NodeHash interface {
	// ID function defines a unique string identifier for the remote Envoy node.
	ID(node *envoy_config_core_v3.Node) string
}

type PriorityIndex struct {
	Priority int
	Index    uint64
}

type PrioritySortedStruct struct {
	// contains filtered or unexported fields
}

type PriorityValue interface {
	GetPriority() string
}

type Request = envoy_service_discovery_v3.DiscoveryRequest

type Resource interface {
	Self() XdsResourceReference
	ResourceProto() ResourceProto
	References() []XdsResourceReference
}

type ResourceProto = proto.Message

type Resources struct {
	// Version information.
	Version string

	// Items in the group.
	Items map[string]Resource
}

type Response struct {
	// Request is the original request.
	Request envoy_service_discovery_v3.DiscoveryRequest

	// Version of the resources as tracked by the cache for the given type.
	// Proxy responds with this version as an acknowledgement.
	Version string

	// Resources to be included in the response.
	Resources []Resource
}

type ResponseWatch struct {
	// Request is the original request for the watch.
	Request Request

	// Response is the channel to push response to.
	Response chan Response
}

type Snapshot interface {
	Consistent() error
	// MakeConsistent should never be called on a generic snapshot as it is not used for snapshots with dependent resources.
	MakeConsistent()
	GetResources(typ string) Resources
	// Clone shouldn't be called on a generic snapshot until https://github.com/solo-io/solo-kit/issues/461 is resolved.
	Clone() Snapshot
}

type SnapshotCache interface {
	Cache

	// SetSnapshot sets a response snapshot for a node. For ADS, the snapshots
	// should have distinct versions and be internally consistent (e.g. all
	// referenced resources must be included in the snapshot).
	//
	// This method will cause the server to respond to all open watches, for which
	// the version differs from the snapshot version.
	//
	// based off of https://github.com/envoyproxy/go-control-plane/blob/v0.10.1/pkg/cache/v3/simple.go#L43-L49,
	// but updated to handle errors instead of returning them so Gloo Edge control plane can ensure xds snapshot
	// is always getting updates
	SetSnapshot(node string, snapshot Snapshot)

	// GetSnapshots gets the snapshot for a node.
	GetSnapshot(node string) (Snapshot, error)

	// ClearSnapshot removes all status and snapshot information associated with a node.
	ClearSnapshot(node string)
}

type StatusInfo interface {
	// GetNode returns the node metadata.
	GetNode() *envoy_config_core_v3.Node

	// GetNumWatches returns the number of open watches.
	GetNumWatches() int

	// GetLastWatchRequestTime returns the timestamp of the last discovery watch request.
	GetLastWatchRequestTime() time.Time
}

type TypedResources map[string]Resources

type XdsResourceReference struct {
	Type string
	Name string
}