/**
 * ThumbnailHttpSource - Buffered HTTP source for thumbnail extraction.
 *
 * Uses a simple sliding buffer to cache data and reduce HTTP requests.
 * Each seek position triggers a larger chunk fetch, and subsequent reads
 * are served from the buffer until a new seek is needed.
 */
import type { SourceAdapter } from "./SourceAdapter";
/**
 * Minimal interface describing a source we can peek into without mutating.
 * HttpSource implements this structurally via peekMetadata() / peekRange().
 */
export interface PeekableSource {
    peekMetadata(offset: number, length: number): Uint8Array | null;
    peekRange(offset: number, length: number): Uint8Array | null;
}
export declare class ThumbnailHttpSource implements SourceAdapter {
    private url;
    private headers;
    private size;
    private position;
    private abortController;
    private rangeUnsupported;
    private buffer;
    private bufferStart;
    private bufferEnd;
    private borrowSource;
    constructor(url: string, headers?: Record<string, string>, borrowSource?: PeekableSource | null);
    setBorrowSource(source: PeekableSource | null): void;
    /**
     * Seed the file size from the main source so getSize() skips its own HEAD /
     * ranged-GET probe. Essential for non-range servers where that probe can't
     * recover a size (Cloudflare strips Content-Length on HEAD and may chunk the
     * 200 GET) — the main source already knows the size, so just reuse it.
     */
    seedSize(size: number): void;
    getSize(): Promise<number>;
    /**
     * Recover total size from a 1-byte ranged GET when HEAD lacks Content-Length.
     * Body is cancelled immediately — we only need the Content-Range header.
     */
    private resolveSizeViaRange;
    /**
     * Check if requested data is in buffer
     */
    private isInBuffer;
    /**
     * Read data - uses buffer cache to minimize HTTP requests
     */
    read(offset: number, length: number): Promise<ArrayBuffer>;
    seek(offset: number): number;
    getPosition(): number;
    /**
     * Clear buffer to free memory when thumbnails aren't being actively generated
     * Call this after thumbnail generation is complete
     */
    clearBuffer(): void;
    close(): void;
    getKey(): string;
    getUrl(): string;
    getBufferedEnd(): number;
    getBufferStart(): number;
}
export declare function createThumbnailHttpSource(url: string, headers?: Record<string, string>): Promise<ThumbnailHttpSource>;
//# sourceMappingURL=ThumbnailHttpSource.d.ts.map