core

type Event struct {
	AggregateID   string
	Version       Version
	GlobalVersion Version
	AggregateType string
	Timestamp     time.Time
	Reason        string // based on the Data type
	Data          []byte // interface{} on the external Event type
	Metadata      []byte // map[string]interface{} on the external Event type
}

type EventStore interface {
	Save(events []Event) error
	Get(ctx context.Context, id string, aggregateType string, afterVersion Version) (Iterator, error)
}

type Fetcher func() (Iterator, error)

type Iterator interface {
	Next() bool
	Value() (Event, error)
	Close()
}

type Snapshot struct {
	ID            string
	Type          string
	Version       Version
	GlobalVersion Version
	State         []byte
}

type SnapshotStore interface {
	Save(snapshot Snapshot) error
	Get(ctx context.Context, id, aggregateType string) (Snapshot, error)
}

type Version uint64