credit

type BalanceConnector interface {
	// GetBalanceSinceSnapshot returns the result of the engine.Run since a given snapshot.
	GetBalanceSinceSnapshot(ctx context.Context, ownerID models.NamespacedID, snap balance.Snapshot, at time.Time) (engine.RunResult, error)
	// GetBalanceAt returns the result of the engine.Run at a given time.
	// It tries to minimize execution cost by calculating from the latest valid snapshot, thus the length of the returned history WILL NOT be deterministic.
	GetBalanceAt(ctx context.Context, ownerID models.NamespacedID, at time.Time) (engine.RunResult, error)
	// GetBalanceForPeriod returns the result of the engine.Run for the provided period.
	// The returned history will exactly match the provided period.
	GetBalanceForPeriod(ctx context.Context, ownerID models.NamespacedID, period timeutil.Period) (engine.RunResult, error)
	// ResetUsageForOwner resets the usage for an owner at a given time.
	ResetUsageForOwner(ctx context.Context, ownerID models.NamespacedID, params ResetUsageForOwnerParams) (balanceAfterReset *balance.Snapshot, err error)
	// GetLastValidSnapshotAt fetches the last valid snapshot for an owner.
	GetLastValidSnapshotAt(ctx context.Context, owner models.NamespacedID, at time.Time) (balance.Snapshot, error)
}

type CreateGrantInput struct {
	Amount           float64
	Priority         uint8
	EffectiveAt      time.Time
	Expiration       grant.ExpirationPeriod
	Metadata         map[string]string
	ResetMaxRollover float64
	ResetMinRollover float64
	Recurrence       *timeutil.Recurrence
}

type CreditConnector interface {
	BalanceConnector
	GrantConnector
}

type CreditConnectorConfig struct {
	// services
	GrantRepo              grant.Repo
	BalanceSnapshotService balance.SnapshotService
	OwnerConnector         grant.OwnerConnector
	StreamingConnector     streaming.Connector
	Logger                 *slog.Logger
	Tracer                 trace.Tracer
	Publisher              eventbus.Publisher
	TransactionManager     transaction.Creator
	// configuration
	Granularity         time.Duration
	SnapshotGracePeriod isodate.Period
}

type GrantConnector interface {
	CreateGrant(ctx context.Context, owner models.NamespacedID, grant CreateGrantInput) (*grant.Grant, error)
	VoidGrant(ctx context.Context, grantID models.NamespacedID) error
}

type GrantNotFoundError struct {
	GrantID string
}

type ResetUsageForOwnerParams struct {
	At              time.Time
	RetainAnchor    bool
	PreserveOverage bool
}