projection

type Handler func(context.Context, messages.Message) error

type HasProjectionManager interface {
	GetProjectionManager() Manager
}

type Manager interface {
	// Create a new stream.
	Create(ctx context.Context, name string, options []ProjectorOpt) (Projector, error)

	// Delete will remove the projection from the projections store.
	Delete(ctx context.Context, projectionName string) error

	// Reset will reset the position of the stream to 0.
	Reset(ctx context.Context, projectionName string) error

	// Stop will set the status to stop, the running projection should handle this.
	Stop(ctx context.Context, projectionName string) error

	// FetchProjections grabs projections matching the filter.
	FetchProjectionNames(ctx context.Context, filter string, start, limit uint64) ([]string, error)

	// FetchPojectionStatus will return the status of a projection.
	FetchPojectionStatus(ctx context.Context, projectionName string) (Status, error)

	// FetchPojectionStreamPositions will return the status of a projection.
	FetchPojectionStreamPositions(ctx context.Context, projectionName string) (StreamPositions, error)
}

type Projector interface {
	// FromStream will limit the Projector to events from 1 stream.
	FromStream(streamName string) Projector
	// FromStreams will limit the Projector to events from many streams.
	FromStreams(streamNames []string) Projector
	// When the event with the event name is given the Handler will be called.
	When(eventName string, cb Handler) Projector
	// WhenAny event is given the Handler will be called.
	WhenAny(cb Handler) Projector
	// Stop will stop the processing of the events.
	Stop(ctx context.Context) error
	// Run will start the processing of the events.
	Run(ctx context.Context) error
}

type ProjectorOpt func(*ProjectorOpts) error

type ProjectorOpts struct {
	// Sleep how long after reading all the events should we sleep before reading more.
	Sleep time.Duration
}

type Status string

type StreamPositions map[string]uint64