/**
 * Memory file reader — direct read of memory pipeline artifacts (persona.md,
 * scene_blocks/*.md) from object storage with STS credential management.
 *
 * Usage:
 *   const reader = createMemoryFileReader({ endpoint, apiKey, serviceId });
 *   const content = await reader.read("scene_blocks/cooking-recipes.md");
 *
 * Under the hood:
 *   1. Fetches STS temporary credentials from the platform (POST /v2/cos/secret)
 *   2. Caches credentials until they expire (auto-refresh with 2-min buffer)
 *   3. Signs a COS V5 GET request with the STS credentials
 *   4. Returns the file content as a string
 *
 * Storage backend (currently COS) is an implementation detail — the public
 * API is intentionally storage-agnostic.
 */
/** Raw response from platform `POST /v2/cos/secret`. */
export interface CosSecretResponse {
    CosUrl: string;
    TmpSecretId: string;
    TmpSecretKey: string;
    TmpToken: string;
    ExpirationTime: string;
    PathPrefix: string;
}
export declare class StsCredential {
    readonly tmpSecretId: string;
    readonly tmpSecretKey: string;
    readonly token: string;
    readonly bucket: string;
    readonly region: string;
    readonly prefix: string;
    readonly expiresAtMs: number;
    private readonly _host;
    constructor(data: CosSecretResponse);
    isValid(bufferMs?: number): boolean;
    get cosHost(): string;
}
export interface MemoryFileReaderConfig {
    endpoint: string;
    apiKey: string;
    serviceId: string;
    timeout?: number;
}
export declare class StsCredentialManager {
    private credential;
    private fetchPromise;
    private readonly bufferMs;
    private readonly endpoint;
    private readonly apiKey;
    private readonly serviceId;
    private readonly timeout;
    constructor(config: MemoryFileReaderConfig, bufferMs?: number);
    getCredential(): Promise<StsCredential>;
    invalidate(): void;
    private refresh;
}
/**
 * Generate COS V5 Authorization header for a GET request.
 * Uses Node.js crypto.
 */
export declare function cosV5Sign(secretId: string, secretKey: string, method: string, path: string, host: string, startTime?: number, endTime?: number): string;
export declare class MemoryFileReader {
    private readonly stsManager;
    private readonly timeout;
    constructor(stsManager: StsCredentialManager, timeout?: number);
    /**
     * Read a memory file (persona.md, scene_blocks/*.md, …) by relative path.
     *
     * @param path Relative path within the memory space,
     *   e.g. "scene_blocks/cooking-recipes.md" or "persona.md".
     * @returns File content as UTF-8 string.
     */
    read(path: string): Promise<string>;
    private doGet;
}
/**
 * Convenience factory: create a MemoryFileReader that fetches STS credentials
 * directly from the platform's `POST /v2/cos/secret` endpoint.
 */
export declare function createMemoryFileReader(config: MemoryFileReaderConfig, opts?: {
    bufferMs?: number;
    timeout?: number;
}): MemoryFileReader;