cache

type Cache interface {
	Fetcher
	services.Service
}

type CacheSet interface {
	services.Service
	Get(ctx context.Context, client Client) (Fetcher, error)
}

type Client interface {
	Fetcher
	ServerURL() string
	RawClient() pb.MercuryClient
}

type Config struct {
	// LatestReportTTL controls how "stale" we will allow a price to be e.g. if
	// set to 1s, a new price will always be fetched if the last result was
	// from more than 1 second ago.
	//
	// Another way of looking at it is such: the cache will _never_ return a
	// price that was queried from before now-LatestReportTTL.
	//
	// Setting to zero disables caching entirely.
	LatestReportTTL time.Duration
	// MaxStaleAge is that maximum amount of time that a value can be stale
	// before it is deleted from the cache (a form of garbage collection).
	//
	// This should generally be set to something much larger than
	// LatestReportTTL. Setting to zero disables garbage collection.
	MaxStaleAge time.Duration
	// LatestReportDeadline controls how long to wait for a response before
	// retrying. Setting this to zero will wait indefinitely.
	LatestReportDeadline time.Duration
}

type Fetcher interface {
	LatestReport(ctx context.Context, req *pb.LatestReportRequest) (resp *pb.LatestReportResponse, err error)
}