common

type AcceptedFrontierHandler interface {
	// Notify this engine of an accepted frontier.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is in response to a GetAcceptedFrontier message, is
	// utilizing a unique requestID, or that the containerIDs from a valid
	// frontier.
	AcceptedFrontier(
		validatorID ids.NodeID,
		requestID uint32,
		containerIDs []ids.ID,
	) error

	// Notify this engine that a get accepted frontier request it issued has
	// failed.
	//
	// This function will be called if the engine sent a GetAcceptedFrontier
	// message that is not anticipated to be responded to. This could be because
	// the recipient of the message is unknown or if the message request has
	// timed out.
	//
	// The validatorID, and requestID, are assumed to be the same as those sent
	// in the GetAcceptedFrontier message.
	GetAcceptedFrontierFailed(validatorID ids.NodeID, requestID uint32) error
}

type AcceptedHandler interface {
	// Notify this engine of a set of accepted vertices.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is in response to a GetAccepted message, is utilizing a
	// unique requestID, or that the containerIDs are a subset of the
	// containerIDs from a GetAccepted message.
	Accepted(
		validatorID ids.NodeID,
		requestID uint32,
		containerIDs []ids.ID,
	) error

	// Notify this engine that a get accepted request it issued has failed.
	//
	// This function will be called if the engine sent a GetAccepted message
	// that is not anticipated to be responded to. This could be because the
	// recipient of the message is unknown or if the message request has timed
	// out.
	//
	// The validatorID, and requestID, are assumed to be the same as those sent
	// in the GetAccepted message.
	GetAcceptedFailed(validatorID ids.NodeID, requestID uint32) error
}

type AcceptedSender interface {
	// SendGetAccepted requests that every node in [nodeIDs] sends an Accepted
	// message with all the IDs in [containerIDs] that the node thinks are
	// accepted.
	SendGetAccepted(
		nodeIDs ids.NodeIDSet,
		requestID uint32,
		containerIDs []ids.ID,
	)

	// SendAccepted responds to a GetAccepted message with a set of IDs of
	// containers that are accepted.
	SendAccepted(nodeID ids.NodeID, requestID uint32, containerIDs []ids.ID)
}

type AcceptedStateSummaryHandler interface {
	// Notify this engine of a set of state summaries.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is in response to a GetAcceptedStateSummary message,
	// is utilizing a unique requestID, or that the summaryIDs are a subset of the
	// state summaries requested by key from a GetAcceptedStateSummary message.
	AcceptedStateSummary(validatorID ids.NodeID, requestID uint32, summaryIDs []ids.ID) error

	// Notify this engine that a get accepted state summary request it issued has
	// failed.
	//
	// This function will be called if the engine sent a GetAcceptedStateSummary
	// message that is not anticipated to be responded to. This could be because
	// the recipient of the message is unknown or if the message request has
	// timed out.
	//
	// The validatorID, and requestID, are assumed to be the same as those sent
	// in the GetAcceptedStateSummary message.
	GetAcceptedStateSummaryFailed(validatorID ids.NodeID, requestID uint32) error
}

type AcceptedStateSummarySender interface {
	// SendGetAcceptedStateSummary requests that every node in [nodeIDs] sends an
	// AcceptedStateSummary message with all the state summary IDs referenced by [heights]
	// that the node thinks are accepted.
	SendGetAcceptedStateSummary(nodeIDs ids.NodeIDSet, requestID uint32, heights []uint64)

	// SendAcceptedStateSummary responds to a AcceptedStateSummary message with a
	// set of summary ids that are accepted.
	SendAcceptedStateSummary(nodeID ids.NodeID, requestID uint32, summaryIDs []ids.ID)
}

type AllGetsServer interface {
	GetStateSummaryFrontierHandler
	GetAcceptedStateSummaryHandler
	GetAcceptedFrontierHandler
	GetAcceptedHandler
	GetAncestorsHandler
	GetHandler
}

type AncestorsHandler interface {
	// Notify this engine of multiple containers.
	//
	// Each element of [containers] is the byte representation of a container.
	//
	// This should only be called during bootstrapping, in response to a
	// GetAncestors message to [validatorID] with request ID [requestID].
	//
	// This call should contain the container requested in that message, along
	// with ancestors. The containers should be in BFS order (ie the first
	// container must be the container requested in the GetAncestors message and
	// further back ancestors are later in [containers]
	//
	// It is not safe to assume this message is in response to a GetAncestor
	// message, that this message has a unique requestID or that any of the
	// containers in [containers] are valid.
	Ancestors(
		validatorID ids.NodeID,
		requestID uint32,
		containers [][]byte,
	) error

	// Notify this engine that a GetAncestors request it issued has failed.
	//
	// This function will be called if the engine sent a GetAncestors message
	// that is not anticipated to be responded to. This could be because the
	// recipient of the message is unknown or if the message request has timed
	// out.
	//
	// The validatorID and requestID are assumed to be the same as those sent in
	// the GetAncestors message.
	GetAncestorsFailed(validatorID ids.NodeID, requestID uint32) error
}

type AppHandler interface {
	// Notify this engine of a request for data from [nodeID].
	//
	// The meaning of [request], and what should be sent in response to it, is
	// application (VM) specific.
	//
	// It is not guaranteed that:
	// * [request] is well-formed/valid.
	//
	// This node should typically send an AppResponse to [nodeID] in response to
	// a valid message using the same request ID before the deadline. However,
	// the VM may arbitrarily choose to not send a response to this request.
	AppRequest(nodeID ids.NodeID, requestID uint32, deadline time.Time, request []byte) error

	// Notify this engine that an AppRequest message it sent to [nodeID] with
	// request ID [requestID] failed.
	//
	// This may be because the request timed out or because the message couldn't
	// be sent to [nodeID].
	//
	// It is guaranteed that:
	// * This engine sent a request to [nodeID] with ID [requestID].
	// * AppRequestFailed([nodeID], [requestID]) has not already been called.
	// * AppResponse([nodeID], [requestID]) has not already been called.
	AppRequestFailed(nodeID ids.NodeID, requestID uint32) error

	// Notify this engine of a response to the AppRequest message it sent to
	// [nodeID] with request ID [requestID].
	//
	// The meaning of [response] is application (VM) specifc.
	//
	// It is guaranteed that:
	// * This engine sent a request to [nodeID] with ID [requestID].
	// * AppRequestFailed([nodeID], [requestID]) has not already been called.
	// * AppResponse([nodeID], [requestID]) has not already been called.
	//
	// It is not guaranteed that:
	// * [response] contains the expected response
	// * [response] is well-formed/valid.
	//
	// If [response] is invalid or not the expected response, the VM chooses how
	// to react. For example, the VM may send another AppRequest, or it may give
	// up trying to get the requested information.
	AppResponse(nodeID ids.NodeID, requestID uint32, response []byte) error

	// Notify this engine of a gossip message from [nodeID].
	//
	// The meaning of [msg] is application (VM) specific, and the VM defines how
	// to react to this message.
	//
	// This message is not expected in response to any event, and it does not
	// need to be responded to.
	//
	// A node may gossip the same message multiple times. That is,
	// AppGossip([nodeID], [msg]) may be called multiple times.
	AppGossip(nodeID ids.NodeID, msg []byte) error
}

type AppSender interface {
	// Send an application-level request.
	// A nil return value guarantees that for each nodeID in [nodeIDs],
	// the VM corresponding to this AppSender eventually receives either:
	// * An AppResponse from nodeID with ID [requestID]
	// * An AppRequestFailed from nodeID with ID [requestID]
	// Exactly one of the above messages will eventually be received per nodeID.
	// A non-nil error should be considered fatal.
	SendAppRequest(nodeIDs ids.NodeIDSet, requestID uint32, appRequestBytes []byte) error
	// Send an application-level response to a request.
	// This response must be in response to an AppRequest that the VM corresponding
	// to this AppSender received from [nodeID] with ID [requestID].
	// A non-nil error should be considered fatal.
	SendAppResponse(nodeID ids.NodeID, requestID uint32, appResponseBytes []byte) error
	// Gossip an application-level message.
	// A non-nil error should be considered fatal.
	SendAppGossip(appGossipBytes []byte) error
	SendAppGossipSpecific(nodeIDs ids.NodeIDSet, appGossipBytes []byte) error
}

type Bootstrapable interface {
	// Force the provided containers to be accepted. Only returns fatal errors
	// if they occur.
	ForceAccepted(acceptedContainerIDs []ids.ID) error

	// Clear removes all containers to be processed upon bootstrapping
	Clear() error
}

type BootstrapableEngine interface {
	Bootstrapable
	Engine
}

type BootstrapableTest struct {
	T *testing.T

	CantForceAccepted, CantClear bool

	ClearF         func() error
	ForceAcceptedF func(acceptedContainerIDs []ids.ID) error
}

type Bootstrapper interface {
	AcceptedFrontierHandler
	AcceptedHandler
	Haltable
	Startup() error
	Restart(reset bool) error
}

type BootstrapperTest struct {
	BootstrapableTest
	EngineTest
}

type ChitsHandler interface {
	// Notify this engine of the specified validators preferences.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is in response to a PullQuery or a PushQuery message.
	// However, the validatorID is assumed to be authenticated.
	Chits(validatorID ids.NodeID, requestID uint32, containerIDs []ids.ID) error

	// Notify this engine that a query it issued has failed.
	//
	// This function will be called if the engine sent a PullQuery or PushQuery
	// message that is not anticipated to be responded to. This could be because
	// the recipient of the message is unknown or if the message request has
	// timed out.
	//
	// The validatorID and the requestID are assumed to be the same as those
	// sent in the Query message.
	QueryFailed(validatorID ids.NodeID, requestID uint32) error
}

type Config struct {
	Ctx        *snow.ConsensusContext
	Validators validators.Set
	Beacons    validators.Set

	SampleK        int
	Alpha          uint64
	StartupTracker tracker.Startup
	Sender         Sender
	Bootstrapable  Bootstrapable
	Subnet         Subnet
	Timer          Timer

	// Should Bootstrap be retried
	RetryBootstrap bool

	// Max number of times to retry bootstrap before warning the node operator
	RetryBootstrapWarnFrequency int

	// Max time to spend fetching a container and its ancestors when responding
	// to a GetAncestors
	MaxTimeGetAncestors time.Duration

	// Max number of containers in an ancestors message sent by this node.
	AncestorsMaxContainersSent int

	// This node will only consider the first [AncestorsMaxContainersReceived]
	// containers in an ancestors message it receives.
	AncestorsMaxContainersReceived int

	SharedCfg *SharedConfig
}

type Engine interface {
	Handler

	// Return the context of the chain this engine is working on
	Context() *snow.ConsensusContext

	// Start engine operations from given request ID
	Start(startReqID uint32) error

	// Returns nil if the engine is healthy.
	// Periodically called and reported through the health API
	health.Checker

	// GetVM returns this engine's VM
	GetVM() VM
}

type EngineTest struct {
	T *testing.T

	CantStart,

	CantIsBootstrapped,
	CantTimeout,
	CantGossip,
	CantHalt,
	CantShutdown,

	CantContext,

	CantNotify,

	CantGetStateSummaryFrontier,
	CantGetStateSummaryFrontierFailed,
	CantStateSummaryFrontier,

	CantGetAcceptedStateSummary,
	CantGetAcceptedStateSummaryFailed,
	CantAcceptedStateSummary,

	CantGetAcceptedFrontier,
	CantGetAcceptedFrontierFailed,
	CantAcceptedFrontier,

	CantGetAccepted,
	CantGetAcceptedFailed,
	CantAccepted,

	CantGet,
	CantGetAncestors,
	CantGetFailed,
	CantGetAncestorsFailed,
	CantPut,
	CantAncestors,

	CantPushQuery,
	CantPullQuery,
	CantQueryFailed,
	CantChits,

	CantConnected,
	CantDisconnected,

	CantHealth,

	CantAppRequest,
	CantAppResponse,
	CantAppGossip,
	CantAppRequestFailed,

	CantGetVM bool

	StartF                                             func(startReqID uint32) error
	IsBootstrappedF                                    func() bool
	ContextF                                           func() *snow.ConsensusContext
	HaltF                                              func()
	TimeoutF, GossipF, ShutdownF                       func() error
	NotifyF                                            func(Message) error
	GetF, GetAncestorsF, PullQueryF                    func(nodeID ids.NodeID, requestID uint32, containerID ids.ID) error
	PutF, PushQueryF                                   func(nodeID ids.NodeID, requestID uint32, container []byte) error
	AncestorsF                                         func(nodeID ids.NodeID, requestID uint32, containers [][]byte) error
	AcceptedFrontierF, GetAcceptedF, AcceptedF, ChitsF func(nodeID ids.NodeID, requestID uint32, containerIDs []ids.ID) error
	GetStateSummaryFrontierF, GetStateSummaryFrontierFailedF, GetAcceptedStateSummaryFailedF,
	GetAcceptedFrontierF, GetFailedF, GetAncestorsFailedF,
	QueryFailedF, GetAcceptedFrontierFailedF, GetAcceptedFailedF, AppRequestFailedF func(nodeID ids.NodeID, requestID uint32) error
	StateSummaryFrontierF     func(nodeID ids.NodeID, requestID uint32, summary []byte) error
	GetAcceptedStateSummaryF  func(nodeID ids.NodeID, requestID uint32, keys []uint64) error
	AcceptedStateSummaryF     func(nodeID ids.NodeID, requestID uint32, summaryIDs []ids.ID) error
	ConnectedF                func(nodeID ids.NodeID, nodeVersion version.Application) error
	DisconnectedF             func(nodeID ids.NodeID) error
	HealthF                   func() (interface{}, error)
	GetVMF                    func() VM
	AppRequestF, AppResponseF func(nodeID ids.NodeID, requestID uint32, msg []byte) error
	AppGossipF                func(nodeID ids.NodeID, msg []byte) error
}

type FetchSender interface {
	// Request that the specified node send the specified container to this
	// node.
	SendGet(nodeID ids.NodeID, requestID uint32, containerID ids.ID)

	// SendGetAncestors requests that node [nodeID] send container [containerID]
	// and its ancestors.
	SendGetAncestors(nodeID ids.NodeID, requestID uint32, containerID ids.ID)

	// Tell the specified node that the container whose ID is [containerID] has
	// body [container].
	SendPut(
		nodeID ids.NodeID,
		requestID uint32,
		containerID ids.ID,
		container []byte,
	)

	// Give the specified node several containers at once. Should be in response
	// to a GetAncestors message with request ID [requestID] from the node.
	SendAncestors(nodeID ids.NodeID, requestID uint32, containers [][]byte)
}

type Fetcher struct {
	// tracks which validators were asked for which containers in which requests
	OutstandingRequests Requests

	// Called when bootstrapping is done on a specific chain
	OnFinished func(lastReqID uint32) error
}

type FrontierSender interface {
	// SendGetAcceptedFrontier requests that every node in [nodeIDs] sends an
	// AcceptedFrontier message.
	SendGetAcceptedFrontier(nodeIDs ids.NodeIDSet, requestID uint32)

	// SendAcceptedFrontier responds to a AcceptedFrontier message with this
	// engine's current accepted frontier.
	SendAcceptedFrontier(
		nodeID ids.NodeID,
		requestID uint32,
		containerIDs []ids.ID,
	)
}

type Fx struct {
	ID ids.ID
	Fx interface{}
}

type GetAcceptedFrontierHandler interface {
	// Notify this engine of a request for the accepted frontier of vertices.
	//
	// The accepted frontier is the set of accepted vertices that do not have
	// any accepted descendants.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID.
	//
	// This engine should respond with an AcceptedFrontier message with the same
	// requestID, and the engine's current accepted frontier.
	GetAcceptedFrontier(validatorID ids.NodeID, requestID uint32) error
}

type GetAcceptedHandler interface {
	// Notify this engine of a request to filter non-accepted vertices.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID. However, the validatorID is
	// assumed to be authenticated.
	//
	// This engine should respond with an Accepted message with the same
	// requestID, and the subset of the containerIDs that this node has decided
	// are accepted.
	GetAccepted(
		validatorID ids.NodeID,
		requestID uint32,
		containerIDs []ids.ID,
	) error
}

type GetAcceptedStateSummaryHandler interface {
	// Notify this engine of a request to return state summary IDs referenced by
	// the provided keys.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID. However, the validatorID is
	// assumed to be authenticated.
	//
	// This engine should respond with an AcceptedStateSummary message with the
	// same requestID, and the subset of the state summaries that this node has
	// locally available.
	GetAcceptedStateSummary(validatorID ids.NodeID, requestID uint32, keys []uint64) error
}

type GetAncestorsHandler interface {
	// Notify this engine of a request for a container and its ancestors.
	//
	// The request is from validator [validatorID]. The requested container is
	// [containerID].
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID. It is also not safe to
	// assume the requested containerID exists.
	//
	// This engine should respond with an Ancestors message with the same
	// requestID, which contains [containerID] as well as its ancestors. See
	// Ancestors's documentation.
	//
	// If this engine doesn't have some ancestors, it should reply with its best
	// effort attempt at getting them. If this engine doesn't have [containerID]
	// it can ignore this message.
	GetAncestors(validatorID ids.NodeID, requestID uint32, containerID ids.ID) error
}

type GetHandler interface {
	// Notify this engine of a request for a container.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID. It is also not safe to
	// assume the requested containerID exists.
	//
	// There should never be a situation where a virtuous node sends a Get
	// request to another virtuous node that does not have the requested
	// container.
	//
	// This engine should respond with a Put message with the same requestID if
	// the container was locally available. Otherwise, the message can be safely
	// dropped.
	Get(validatorID ids.NodeID, requestID uint32, containerID ids.ID) error
}

type GetStateSummaryFrontierHandler interface {
	// Notify this engine of a request for the frontier of state summaries.
	//
	// The accepted frontier is the last state summary available locally.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID.
	//
	// This engine should respond with an StateSummaryFrontier message with the
	// same requestID, and the engine's current state summary frontier.
	GetStateSummaryFrontier(validatorID ids.NodeID, requestID uint32) error
}

type Gossiper interface {
	// Gossip the provided container throughout the network
	SendGossip(containerID ids.ID, container []byte)
}

type HTTPHandler struct {
	LockOptions LockOption
	Handler     http.Handler
}

type Haltable interface {
	Halt()
	Halted() bool
}

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

type Handler interface {
	AllGetsServer
	StateSummaryFrontierHandler
	AcceptedStateSummaryHandler
	AcceptedFrontierHandler
	AcceptedHandler
	AncestorsHandler
	PutHandler
	QueryHandler
	ChitsHandler
	AppHandler
	InternalHandler
}

type InternalHandler interface {
	// Notify this engine of peer changes.
	validators.Connector

	// Notify this engine that a registered timeout has fired.
	Timeout() error

	// Gossip to the network a container on the accepted frontier
	Gossip() error

	// Halt this engine.
	//
	// This function will be called before the environment starts exiting. This
	// function is slightly special, in that it does not expect the chain's
	// context lock to be held before calling this function.
	Halt()

	// Shutdown this engine.
	//
	// This function will be called when the environment is exiting.
	Shutdown() error

	// Notify this engine of a message from the virtual machine.
	Notify(Message) error
}

type LockOption uint32

type Message uint32

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

type PutHandler interface {
	// Notify this engine of a container.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID.
	Put(
		validatorID ids.NodeID,
		requestID uint32,
		container []byte,
	) error

	// Notify this engine that a get request it issued has failed.
	//
	// This function will be called if the engine sent a Get message that is not
	// anticipated to be responded to. This could be because the recipient of
	// the message is unknown or if the message request has timed out.
	//
	// The validatorID and requestID are assumed to be the same as those sent in
	// the Get message.
	GetFailed(validatorID ids.NodeID, requestID uint32) error
}

type QueryHandler interface {
	// Notify this engine of a request for our preferences.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID. However, the validatorID is
	// assumed to be authenticated.
	//
	// If the container or its ancestry is incomplete, this engine is expected
	// to request the missing containers from the validator. Once the ancestry
	// is complete, this engine should send this validator the current
	// preferences in a Chits message. The Chits message should have the same
	// requestID that was passed in here.
	PullQuery(
		validatorID ids.NodeID,
		requestID uint32,
		containerID ids.ID,
	) error

	// Notify this engine of a request for our preferences.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is utilizing a unique requestID.
	//
	// This function is meant to behave the same way as PullQuery, except the
	// container is optimistically provided to potentially remove the need for
	// a series of Get/Put messages.
	//
	// If the ancestry of the container is incomplete, this engine is expected
	// to request the ancestry from the validator. Once the ancestry is
	// complete, this engine should send this validator the current preferences
	// in a Chits message. The Chits message should have the same requestID that
	// was passed in here.
	PushQuery(
		validatorID ids.NodeID,
		requestID uint32,
		container []byte,
	) error
}

type QuerySender interface {
	// Request from the specified nodes their preferred frontier, given the
	// existence of the specified container.
	// This is the same as PullQuery, except that this message includes not only
	// the ID of the container but also its body.
	SendPushQuery(
		nodeIDs ids.NodeIDSet,
		requestID uint32,
		containerID ids.ID,
		container []byte,
	)

	// Request from the specified nodes their preferred frontier, given the
	// existence of the specified container.
	SendPullQuery(nodeIDs ids.NodeIDSet, requestID uint32, containerID ids.ID)

	// Send chits to the specified node
	SendChits(nodeID ids.NodeID, requestID uint32, votes []ids.ID)
}

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

type Sender interface {
	snow.Acceptor

	StateSummarySender
	AcceptedStateSummarySender
	FrontierSender
	AcceptedSender
	FetchSender
	QuerySender
	Gossiper
	AppSender
}

type SenderTest struct {
	T *testing.T

	CantAccept,
	CantSendGetStateSummaryFrontier, CantSendStateSummaryFrontier,
	CantSendGetAcceptedStateSummary, CantSendAcceptedStateSummary,
	CantSendGetAcceptedFrontier, CantSendAcceptedFrontier,
	CantSendGetAccepted, CantSendAccepted,
	CantSendGet, CantSendGetAncestors, CantSendPut, CantSendAncestors,
	CantSendPullQuery, CantSendPushQuery, CantSendChits,
	CantSendGossip,
	CantSendAppRequest, CantSendAppResponse, CantSendAppGossip, CantSendAppGossipSpecific bool

	AcceptF                      func(*snow.ConsensusContext, ids.ID, []byte) error
	SendGetStateSummaryFrontierF func(ids.NodeIDSet, uint32)
	SendStateSummaryFrontierF    func(ids.NodeID, uint32, []byte)
	SendGetAcceptedStateSummaryF func(ids.NodeIDSet, uint32, []uint64)
	SendAcceptedStateSummaryF    func(ids.NodeID, uint32, []ids.ID)
	SendGetAcceptedFrontierF     func(ids.NodeIDSet, uint32)
	SendAcceptedFrontierF        func(ids.NodeID, uint32, []ids.ID)
	SendGetAcceptedF             func(ids.NodeIDSet, uint32, []ids.ID)
	SendAcceptedF                func(ids.NodeID, uint32, []ids.ID)
	SendGetF                     func(ids.NodeID, uint32, ids.ID)
	SendGetAncestorsF            func(ids.NodeID, uint32, ids.ID)
	SendPutF                     func(ids.NodeID, uint32, ids.ID, []byte)
	SendAncestorsF               func(ids.NodeID, uint32, [][]byte)
	SendPushQueryF               func(ids.NodeIDSet, uint32, ids.ID, []byte)
	SendPullQueryF               func(ids.NodeIDSet, uint32, ids.ID)
	SendChitsF                   func(ids.NodeID, uint32, []ids.ID)
	SendGossipF                  func(ids.ID, []byte)
	SendAppRequestF              func(ids.NodeIDSet, uint32, []byte) error
	SendAppResponseF             func(ids.NodeID, uint32, []byte) error
	SendAppGossipF               func([]byte) error
	SendAppGossipSpecificF       func(ids.NodeIDSet, []byte) error
}

type SharedConfig struct {
	// Tracks the last requestID that was used in a request
	RequestID uint32

	// True if RestartBootstrap has been called at least once
	Restarted bool
}

type StateSummaryFrontierHandler interface {
	// Notify this engine of a state summary frontier.
	//
	// This function can be called by any validator. It is not safe to assume
	// this message is in response to a GetStateSummaryFrontier message, is
	// utilizing a unique requestID, or that the summary bytes are from a valid
	// state summary.
	StateSummaryFrontier(validatorID ids.NodeID, requestID uint32, summary []byte) error

	// Notify this engine that a get state summary frontier request it issued
	// has failed.
	//
	// This function will be called if the engine sent a GetStateSummaryFrontier
	// message that is not anticipated to be responded to. This could be because
	// the recipient of the message is unknown or if the message request has
	// timed out.
	//
	// The validatorID, and requestID, are assumed to be the same as those sent
	// in the GetStateSummaryFrontier message.
	GetStateSummaryFrontierFailed(validatorID ids.NodeID, requestID uint32) error
}

type StateSummarySender interface {
	// SendGetStateSummaryFrontier requests that every node in [nodeIDs] sends a
	// StateSummaryFrontier message.
	SendGetStateSummaryFrontier(nodeIDs ids.NodeIDSet, requestID uint32)

	// SendStateSummaryFrontier responds to a StateSummaryFrontier message with this
	// engine's current state summary frontier.
	SendStateSummaryFrontier(nodeID ids.NodeID, requestID uint32, summary []byte)
}

type StateSyncer interface {
	Engine

	// IsEnabled returns true if the underlying VM wants to perform state sync.
	// Any returned error will be considered fatal.
	IsEnabled() (bool, error)
}

type Subnet interface {
	// Returns true iff the subnet is done bootstrapping
	IsBootstrapped() bool

	// Bootstrapped marks the named chain as being bootstrapped
	Bootstrapped(chainID ids.ID)
}

type SubnetTest struct {
	T *testing.T

	CantIsBootstrapped, CantBootstrapped bool

	IsBootstrappedF func() bool
	BootstrappedF   func(ids.ID)
}

type SubnetTracker interface {
	// TracksSubnet returns true if [nodeID] tracks [subnetID]
	TracksSubnet(nodeID ids.NodeID, subnetID ids.ID) bool
}

type TestVM struct {
	T *testing.T

	CantInitialize, CantSetState,
	CantShutdown, CantCreateHandlers, CantCreateStaticHandlers,
	CantHealthCheck, CantConnected, CantDisconnected, CantVersion,
	CantAppRequest, CantAppResponse, CantAppGossip, CantAppRequestFailed bool

	InitializeF           func(*snow.Context, manager.Manager, []byte, []byte, []byte, chan<- Message, []*Fx, AppSender) error
	SetStateF             func(snow.State) error
	ShutdownF             func() error
	CreateHandlersF       func() (map[string]*HTTPHandler, error)
	CreateStaticHandlersF func() (map[string]*HTTPHandler, error)
	ConnectedF            func(nodeID ids.NodeID, nodeVersion version.Application) error
	DisconnectedF         func(nodeID ids.NodeID) error
	HealthCheckF          func() (interface{}, error)
	AppRequestF           func(nodeID ids.NodeID, requestID uint32, deadline time.Time, msg []byte) error
	AppResponseF          func(nodeID ids.NodeID, requestID uint32, msg []byte) error
	AppGossipF            func(nodeID ids.NodeID, msg []byte) error
	AppRequestFailedF     func(nodeID ids.NodeID, requestID uint32) error
	VersionF              func() (string, error)
}

type Timer interface {
	// RegisterTimeout specifies how much time to delay the next timeout message
	// by. If the subnet has been bootstrapped, the timeout will fire
	// immediately.
	RegisterTimeout(time.Duration)
}

type TimerTest struct {
	T *testing.T

	CantRegisterTimout bool

	RegisterTimeoutF func(time.Duration)
}

type VM interface {
	AppHandler

	// Returns nil if the VM is healthy.
	// Periodically called and reported via the node's Health API.
	health.Checker

	// Connector represents a handler that is called on connection connect/disconnect
	validators.Connector

	// Initialize this VM.
	// [ctx]: Metadata about this VM.
	//     [ctx.networkID]: The ID of the network this VM's chain is running on.
	//     [ctx.chainID]: The unique ID of the chain this VM is running on.
	//     [ctx.Log]: Used to log messages
	//     [ctx.NodeID]: The unique staker ID of this node.
	//     [ctx.Lock]: A Read/Write lock shared by this VM and the consensus
	//                 engine that manages this VM. The write lock is held
	//                 whenever code in the consensus engine calls the VM.
	// [dbManager]: The manager of the database this VM will persist data to.
	// [genesisBytes]: The byte-encoding of the genesis information of this
	//                 VM. The VM uses it to initialize its state. For
	//                 example, if this VM were an account-based payments
	//                 system, `genesisBytes` would probably contain a genesis
	//                 transaction that gives coins to some accounts, and this
	//                 transaction would be in the genesis block.
	// [toEngine]: The channel used to send messages to the consensus engine.
	// [fxs]: Feature extensions that attach to this VM.
	Initialize(
		ctx *snow.Context,
		dbManager manager.Manager,
		genesisBytes []byte,
		upgradeBytes []byte,
		configBytes []byte,
		toEngine chan<- Message,
		fxs []*Fx,
		appSender AppSender,
	) error

	// SetState communicates to VM its next state it starts
	SetState(state snow.State) error

	// Shutdown is called when the node is shutting down.
	Shutdown() error

	// Version returns the version of the VM this node is running.
	Version() (string, error)

	// Creates the HTTP handlers for custom VM network calls.
	//
	// This exposes handlers that the outside world can use to communicate with
	// a static reference to the VM. Each handler has the path:
	// [Address of node]/ext/VM/[VM ID]/[extension]
	//
	// Returns a mapping from [extension]s to HTTP handlers.
	//
	// Each extension can specify how locking is managed for convenience.
	//
	// For example, it might make sense to have an extension for creating
	// genesis bytes this VM can interpret.
	CreateStaticHandlers() (map[string]*HTTPHandler, error)

	// Creates the HTTP handlers for custom chain network calls.
	//
	// This exposes handlers that the outside world can use to communicate with
	// the chain. Each handler has the path:
	// [Address of node]/ext/bc/[chain ID]/[extension]
	//
	// Returns a mapping from [extension]s to HTTP handlers.
	//
	// Each extension can specify how locking is managed for convenience.
	//
	// For example, if this VM implements an account-based payments system,
	// it have an extension called `accounts`, where clients could get
	// information about their accounts.
	CreateHandlers() (map[string]*HTTPHandler, error)
}