import bigInt from "big-integer";
import { Api } from "../tl";
import type { TelegramBaseClient } from "../client/telegramBaseClient";
export interface FilePoolOptions {
    /**
     * Number of parallel MTProto sessions per DC. Each session is a separate
     * TCP connection sharing the per-DC auth key. Telegram drops connections
     * if too many open at once on the same auth key, so we open them one at
     * a time with {@link sessionStartupDelayMs} between each.
     */
    sessions: number;
    /**
     * Maximum concurrent `upload.GetFile` requests across all sessions of a
     * single DC. The download loop never schedules more than this many parts
     * in flight per DC.
     */
    inflightPerDc: number;
    /**
     * Default part size (in bytes). Must be a multiple of 4096 and ≤ 1 MB.
     */
    partSize: number;
    /**
     * When all sessions of a DC have been idle for this long, the underlying
     * connections are dropped. Set to `0` to never auto-disconnect.
     */
    idleTimeoutMs: number;
    /**
     * Per-part retry budget for transient errors (FLOOD_WAIT, TIMEOUT,
     * server-side hiccups). Hard errors propagate immediately.
     */
    requestRetries: number;
    /** Opt-in to CDN redirects. Disabled by default — most users don't need it. */
    cdnSupported: boolean;
    /**
     * Minimum gap between TCP connects to the same DC. Telegram's anti-abuse
     * drops bursts of fresh connections that share an auth key, so we space
     * them out. Set to 0 to disable the gap.
     */
    sessionStartupDelayMs: number;
}
export declare const DEFAULT_FILE_POOL_OPTIONS: FilePoolOptions;
export declare class CdnRedirectError extends Error {
    readonly redirect: Api.upload.FileCdnRedirect;
    constructor(redirect: Api.upload.FileCdnRedirect);
}
export declare class FilePoolClosedError extends Error {
    constructor();
}
export declare class FilePoolAbortError extends Error {
    constructor();
}
export declare class FilePool {
    readonly opts: FilePoolOptions;
    readonly client: TelegramBaseClient;
    private readonly _dcs;
    private _closed;
    constructor(client: TelegramBaseClient, opts?: Partial<FilePoolOptions>);
    private _dc;
    getFile(dcId: number, location: Api.TypeInputFileLocation, offset: bigInt.BigInteger, limit: number, signal?: AbortSignal): Promise<Buffer>;
    private _invokeOnSlot;
    purge(dcId?: number): Promise<void>;
    close(opts?: {
        waitMs: number;
    }): Promise<void>;
}