ledger

type Events struct {
	// MemPool contains all mempool related events.
	MemPool *mempool.Events

	event.Group[Events, *Events]
}

type Ledger interface {
	// Events is a dictionary for Ledger related events.
	Events() *Events

	// MemPool returns the MemPool implementation used by this ledger.
	MemPool() mempool.MemPool

	// UnspentOutputs returns the unspent outputs of the ledger state.
	UnspentOutputs() UnspentOutputs

	// StateDiffs returns the state diffs of the ledger state.
	StateDiffs() StateDiffs

	// ApplyStateDiff applies the state diff of the given slot index.
	ApplyStateDiff(slot.Index) error

	// Import imports the ledger state from the given reader.
	Import(io.ReadSeeker) error

	// Export exports the ledger state to the given writer.
	Export(io.WriteSeeker, slot.Index) error

	// Interface embeds the required methods of the module.Interface.
	module.Interface
}

type StateDiffs interface {
	// StreamCreatedOutputs streams the created outputs of the given slot index.
	StreamCreatedOutputs(slot.Index, func(*mempool.OutputWithMetadata) error) error

	// StreamSpentOutputs streams the spent outputs of the given slot index.
	StreamSpentOutputs(slot.Index, func(*mempool.OutputWithMetadata) error) error
}

type UnspentOutputs interface {
	// IDs returns the IDs of the unspent outputs.
	IDs() *ads.Set[utxo.OutputID, *utxo.OutputID]

	// Subscribe subscribes to changes in the unspent outputs.
	Subscribe(UnspentOutputsSubscriber)

	// Unsubscribe unsubscribes from changes in the unspent outputs.
	Unsubscribe(UnspentOutputsSubscriber)

	// ApplyCreatedOutput applies the given output to the unspent outputs.
	ApplyCreatedOutput(*mempool.OutputWithMetadata) error

	// BatchCommittable embeds the required methods of the BatchCommittable trait.
	traits.BatchCommittable

	// Interface embeds the required methods of the module.Interface.
	module.Interface
}

type UnspentOutputsSubscriber interface {
	// ApplyCreatedOutput is called when an output is created.
	ApplyCreatedOutput(*mempool.OutputWithMetadata) error

	// ApplySpentOutput is called when an output is spent.
	ApplySpentOutput(*mempool.OutputWithMetadata) error

	// RollbackCreatedOutput is called when a created output is rolled back.
	RollbackCreatedOutput(*mempool.OutputWithMetadata) error

	// RollbackSpentOutput is called when a spent output is rolled back.
	RollbackSpentOutput(*mempool.OutputWithMetadata) error

	// BeginBatchedStateTransition is called when a batched state transition is started.
	BeginBatchedStateTransition(slot.Index) (currentSlot slot.Index, err error)

	// CommitBatchedStateTransition is called when a batched state transition is committed.
	CommitBatchedStateTransition() context.Context
}