import LRU from 'quick-lru';
import { CacheSemantics, ChunkResponse } from './cacheSemantics';
import AggregatingFetcher from './aggregatingFetcher';
/**
 * smart cache that fetches chunks of remote files.
 * caches chunks in an LRU cache, and aggregates upstream fetches
 */
export default class HttpRangeFetcher {
    chunkSize: number;
    aggregator: AggregatingFetcher;
    chunkCache: LRU<string, Promise<ChunkResponse>>;
    cacheSemantics: CacheSemantics;
    stats: LRU<string, {
        size: number;
        mtime: Date;
    }>;
    constructor({ fetch, size, chunkSize, aggregationTime, minimumTTL, maxFetchSize, maxExtraFetch, }: {
        fetch?: (key: string, start: number, end: number) => Promise<{
            headers: Headers;
            buffer: Uint8Array;
        }>;
        size?: number;
        chunkSize?: number;
        aggregationTime?: number;
        minimumTTL?: number;
        maxFetchSize?: number;
        maxExtraFetch?: number;
    });
    getRange(key: string, position: number, length: number, options?: {}): Promise<{
        headers: {};
        buffer: Uint8Array<ArrayBuffer>;
    } | {
        headers: {
            'content-length': number;
            'content-range': string;
            'x-resource-length': string | undefined;
            append(name: string, value: string): void;
            delete(name: string): void;
            get(name: string): string | null;
            getSetCookie(): string[];
            has(name: string): boolean;
            set(name: string, value: string): void;
            forEach(callbackfn: (value: string, key: string, parent: Headers) => void, thisArg?: any): void;
        };
        buffer: Uint8Array<ArrayBuffer>;
    }>;
    _makeBuffer(chunkResponses: {
        buffer: Uint8Array;
    }[], chunksOffset: number, length: number): Uint8Array<ArrayBuffer>;
    /**
     * Fetches the first few bytes of the remote file (if necessary) and uses
     * the returned headers to populate a `fs`-like stat object.
     *
     * Currently, this attempts to set `size`, `mtime`, and `mtimeMs`, if
     * the information is available from HTTP headers.
     *
     * @param {string} key
     * @returns {Promise} for a stats object
     */
    stat(key: string): Promise<{
        size: number;
        mtime: Date;
    }>;
    _headersToStats(chunkResponse: ChunkResponse): {
        mtimeMs: number;
        mtime: Date;
        size: number;
    };
    _makeHeaders(originalHeaders: Headers, newStart: number, newEnd: number): {
        'content-length': number;
        'content-range': string;
        'x-resource-length': string | undefined;
        append(name: string, value: string): void;
        delete(name: string): void;
        get(name: string): string | null;
        getSetCookie(): string[];
        has(name: string): boolean;
        set(name: string, value: string): void;
        forEach(callbackfn: (value: string, key: string, parent: Headers) => void, thisArg?: any): void;
    };
    _getChunk(key: string, chunkNumber: number, requestOptions?: {
        signal?: AbortSignal;
    }): Promise<ChunkResponse | undefined>;
    _recordStatsIfNecessary(key: string, chunk: ChunkResponse): void;
    _uncacheIfSame(key: string, cachedPromise: Promise<ChunkResponse>): void;
    /**
     * Throw away all cached data, resetting the cache.
     */
    reset(): void;
}