txpool

type BlockInfo struct {
	// RuntimeBlock is the runtime block.
	RuntimeBlock *block.Block

	// ConsensusBlock is the consensus light block the runtime block belongs to.
	ConsensusBlock *consensus.LightBlock

	// Epoch is the epoch the runtime block belongs to.
	Epoch beacon.EpochTime

	// ActiveDescriptor is the runtime descriptor active for the runtime block.
	ActiveDescriptor *registry.Runtime
}

type Config struct {
	MaxPoolSize          uint64
	MaxCheckTxBatchSize  uint64
	MaxLastSeenCacheSize uint64

	RepublishInterval time.Duration

	// RecheckInterval is the interval (in rounds) when any pending transactions are subject to a
	// recheck and any non-passing transactions are removed.
	RecheckInterval uint64
}

type RuntimeHostProvisioner interface {
	// WaitHostedRuntime waits for the hosted runtime to be provisioned and returns it.
	WaitHostedRuntime(ctx context.Context) (host.RichRuntime, error)
}

type TransactionMeta struct {
	// Local is a flag indicating that the transaction was obtained from a local client.
	Local bool

	// Discard is a flag indicating that the transaction should be discarded after checks.
	Discard bool

	// Recheck is a flag indicating that this transaction is already in the scheduler pool and is
	// being subject to recheck.
	Recheck bool
}

type TransactionPool interface {
	// Start starts the service.
	Start() error

	// Stop halts the service.
	Stop()

	// Quit returns a channel that will be closed when the service terminates.
	Quit() <-chan struct{}

	// Submit adds the transaction into the transaction pool, first performing checks on it by
	// invoking the runtime. This method waits for the checks to complete.
	SubmitTx(ctx context.Context, tx []byte, meta *TransactionMeta) (*protocol.CheckTxResult, error)

	// SubmitTxNoWait adds the transaction into the transaction pool and returns immediately.
	SubmitTxNoWait(ctx context.Context, tx []byte, meta *TransactionMeta) error

	// RemoveTxBatch removes a transaction batch from the transaction pool.
	RemoveTxBatch(txs []hash.Hash)

	// GetScheduledBatch returns a batch of transactions ready for scheduling.
	GetScheduledBatch(force bool) []*transaction.CheckedTransaction

	// GetPrioritizedBatch returns a batch of transactions ordered by priority but without taking
	// any weight limits into account.
	//
	// Offset specifies the transaction hash that should serve as an offset when returning
	// transactions from the pool. Transactions will be skipped until the given hash is encountered
	// and only following transactions will be returned.
	GetPrioritizedBatch(offset *hash.Hash, limit uint32) []*transaction.CheckedTransaction

	// GetKnownBatch gets a set of known transactions from the transaction pool.
	//
	// For any missing transactions nil will be returned in their place and the map of missing
	// transactions will be populated accoordingly.
	GetKnownBatch(batch []hash.Hash) ([]*transaction.CheckedTransaction, map[hash.Hash]int)

	// ProcessBlock updates the last known runtime block information.
	ProcessBlock(bi *BlockInfo) error

	// UpdateWeightLimits updates the per-batch weight limits.
	UpdateWeightLimits(limits map[transaction.Weight]uint64) error

	// WakeupScheduler explicitly notifies subscribers that they should attempt scheduling.
	WakeupScheduler()

	// Clear clears the transaction pool.
	Clear()

	// WatchScheduler subscribes to notifications about when to attempt scheduling. The emitted
	// boolean flag indicates whether the batch flush timeout expired.
	WatchScheduler() (pubsub.ClosableSubscription, <-chan bool)

	// WatchCheckedTransactions subscribes to notifications about new transactions being available
	// in the transaction pool for scheduling.
	WatchCheckedTransactions() (pubsub.ClosableSubscription, <-chan []*transaction.CheckedTransaction)

	// PendingCheckSize returns the number of transactions currently pending to be checked.
	PendingCheckSize() uint64

	// PendingScheduleSize returns the number of transactions currently pending to be scheduled.
	PendingScheduleSize() uint64
}

type TransactionPublisher interface {
	// PublishTx publishes a transaction to remote peers.
	PublishTx(ctx context.Context, tx []byte) error

	// GetMinRepublishInterval returns the minimum republish interval that needs to be respected by
	// the caller. If PublishTx is called for the same transaction more quickly, the transaction
	// may be dropped and not published.
	GetMinRepublishInterval() time.Duration
}