// Package replay defines the authenticated replay-reservation contract used by
// the gateway transport pipeline.
package replay

import (
	"context"
	"errors"
	"time"
)

var (
	// ErrDuplicate reports that the request identifier has already been
	// reserved for the same device session within the active replay window.
	ErrDuplicate = errors.New("replay reservation already exists")
)

// Store reserves authenticated transport request identifiers for a bounded
// replay window.
type Store interface {
	// Reserve marks the deviceSessionID and requestID pair as seen for ttl.
	// Implementations must wrap ErrDuplicate when the same pair is reserved
	// again before ttl expires.
	Reserve(ctx context.Context, deviceSessionID string, requestID string, ttl time.Duration) error
}