import { EntityInstanceId } from "./entity-instance-id";
/**
 * Represents metadata about a durable entity instance.
 *
 * @typeParam T - The type of the entity state. Defaults to `unknown`.
 *
 * @example
 * ```typescript
 * // Metadata with typed state
 * const metadata: EntityMetadata<number> = {
 *   id: new EntityInstanceId("counter", "user-123"),
 *   lastModifiedTime: new Date(),
 *   backlogQueueSize: 0,
 *   includesState: true,
 *   state: 42
 * };
 * ```
 */
export interface EntityMetadata<T = unknown> {
    /**
     * The unique identifier of the entity.
     */
    readonly id: EntityInstanceId;
    /**
     * The time when the entity was last modified.
     */
    readonly lastModifiedTime: Date;
    /**
     * The size of the backlog queue, if there is a backlog and if that metric is supported by the backend.
     */
    readonly backlogQueueSize: number;
    /**
     * The instance ID of the orchestration that has locked this entity, or undefined if the entity is not locked.
     */
    readonly lockedBy?: string;
    /**
     * Indicates whether this metadata response includes the entity state.
     *
     * Queries can exclude the state of the entity from the metadata that is retrieved.
     */
    readonly includesState: boolean;
    /**
     * The state of the entity, if {@link includesState} is true.
     *
     * @throws {Error} If accessed when {@link includesState} is false.
     */
    readonly state?: T;
}
/**
 * Creates an EntityMetadata object from raw data.
 *
 * @param id - The entity instance ID.
 * @param lastModifiedTime - The last modified time.
 * @param backlogQueueSize - The backlog queue size.
 * @param lockedBy - The orchestration instance ID holding the lock, if any.
 * @param state - The entity state, if included.
 * @returns An EntityMetadata object.
 */
export declare function createEntityMetadata<T = unknown>(id: EntityInstanceId, lastModifiedTime: Date, backlogQueueSize: number, lockedBy: string | undefined, state: T | undefined): EntityMetadata<T>;
/**
 * Creates an EntityMetadata object without state.
 *
 * @param id - The entity instance ID.
 * @param lastModifiedTime - The last modified time.
 * @param backlogQueueSize - The backlog queue size.
 * @param lockedBy - The orchestration instance ID holding the lock, if any.
 * @returns An EntityMetadata object with includesState set to false.
 */
export declare function createEntityMetadataWithoutState(id: EntityInstanceId, lastModifiedTime: Date, backlogQueueSize: number, lockedBy: string | undefined): EntityMetadata<never>;