import GRPCClient from "./GRPCClient";
import IClientMetadata from "../../../interfaces/Client/IClientMetadata";
import { GetMetadataResponse as GetMetadataResponseResult } from "../../../types/metadata/GetMetadataResponse";
/**
 * gRPC-based metadata building block implementation.
 *
 * Provides access to Dapr sidecar metadata including runtime info, active actors,
 * registered components, and extended metadata. Also allows setting custom metadata key-value pairs.
 *
 * @implements {IClientMetadata}
 * @see {@link https://docs.dapr.io/reference/api/metadata_api} Dapr Metadata API
 * @see {@link DaprClient.metadata} for unified API
 *
 * @internal
 */
export default class GRPCClientMetadata implements IClientMetadata {
    /**
     * Reference to the underlying gRPC client.
     */
    client: GRPCClient;
    /**
     * Creates a gRPC metadata building block.
     *
     * @param client - The gRPC client instance
     */
    constructor(client: GRPCClient);
    /**
     * Retrieves metadata about the Dapr runtime and sidecar configuration.
     *
     * Returns sidecar ID, active actor counts, registered components, and extended metadata.
     * This is useful for introspection and debugging the Dapr environment.
     *
     * @returns Promise resolving to metadata response containing:
     *          - id: Dapr runtime ID
     *          - actors: Array of active actor types with counts
     *          - components: Array of registered components (state, pub/sub, bindings, etc.)
     *          - extended: Extended metadata key-value pairs
     *
     * @throws Rejects if metadata retrieval fails
     *
     * @example
     * ```typescript
     * const metadata = await client.metadata.get();
     * console.log("Dapr ID:", metadata.id);
     * console.log("Active actors:", metadata.actors); // [{ type: "timer", count: 5 }]
     * console.log("Components:", metadata.components); // [{ name: "statestore", type: "state", ...}]
     * ```
     *
     * @see {@link https://docs.dapr.io/reference/api/metadata_api/#getting-metadata}
     */
    get(): Promise<GetMetadataResponseResult>;
    /**
     * Sets custom metadata on the Dapr sidecar.
     *
     * Stores a key-value pair in the sidecar's extended metadata dictionary.
     * Useful for runtime configuration and passing data between services.
     *
     * @param key - Metadata key
     * @param value - Metadata value (string)
     *
     * @returns Promise resolving to true if successful, false if set fails
     *
     * @example
     * ```typescript
     * const success = await client.metadata.set("deployment-version", "1.2.3");
     * if (success) {
     *   console.log("Metadata updated");
     * }
     * ```
     *
     * @see {@link get}
     */
    set(key: string, value: string): Promise<boolean>;
}