/**
 * PDF Processor with Image Fallback Support
 *
 * Handles PDF processing for all providers:
 * - Native PDF support for providers that accept PDF directly (Google AI, Vertex, OpenAI, Anthropic, Bedrock)
 * - PDF → Image conversion for providers that don't support native PDF (Azure, Mistral, Ollama)
 *
 * Page counting, text extraction and page rendering all go through pdf-parse,
 * so the process only ever loads pdf-parse's pdfjs-dist. pdfjs keeps its Node
 * worker in a process-wide global, and a second pdfjs version fails its
 * API-vs-Worker version check against whichever copy loaded first.
 */
import type { FileProcessingResult, PDFProcessorOptions, PDFProviderConfig, PDFImageConversionOptions, PDFImageConversionResult, PDFImagePage } from "../types/index.js";
export declare class PDFProcessor {
    private static readonly PDF_SIGNATURE;
    static process(content: Buffer, options?: PDFProcessorOptions): Promise<FileProcessingResult>;
    /**
     * Check if a provider supports native PDF input
     * @param provider - Provider name
     * @returns true if provider can accept PDF directly, false if requires image conversion
     */
    static supportsNativePDF(provider: string): boolean;
    static getProviderConfig(provider: string): PDFProviderConfig | null;
    /**
     * Best-effort page count for a PDF whose count the caller did not supply
     * (#309). Mirrors what `process()` derives for the `input.pdfFiles` path:
     * the accurate pdfjs count when the document parses, otherwise the header
     * regex estimate. Returns null when neither can determine a count.
     *
     * Exists so the aggregate page-limit guard can enforce against PDFs handed
     * in via `input.content`, where `metadata.pages` is optional and routinely
     * omitted — without it, an absent count silently sums as zero.
     */
    static resolvePageCount(buffer: Buffer): Promise<number | null>;
    private static isValidPDF;
    private static extractBasicMetadata;
    /**
     * Accurate page count via pdf-parse (pdfjs) (#287). The header regex in
     * `extractBasicMetadata` only sees plaintext `/Type /Page` markers and misses
     * compressed/object-stream PDFs (and miscounts when a page dict spans a chunk
     * boundary). This parses the document properly, bounded by a timeout so a
     * pathological PDF can't block; returns null on timeout/failure so the caller
     * falls back to the regex estimate.
     */
    private static getAccuratePageCount;
    /**
     * Font and CMap directories of the pdfjs-dist copy pdf-parse itself loads,
     * so non-embedded standard fonts and CJK text render instead of dropping
     * out. Resolved from pdf-parse's location, never our own, to stay on that
     * single copy. Undefined when resolution fails; rendering still works, with
     * pdfjs falling back to its built-in font substitution.
     */
    private static pdfjsAssetDirs;
    private static resolvePdfjsAssetDirs;
    /**
     * Open a PDF for page-by-page PNG rendering through pdf-parse. Rejects with
     * pdf-parse's PasswordException for encrypted PDFs (#258), which the callers
     * map to typed errors.
     */
    private static openForRendering;
    static estimateTokens(pageCount: number, mode?: "text-only" | "visual"): number;
    /**
     * Estimate the largest page's rendered pixel count from the PDF's MediaBox
     * entries, WITHOUT rendering (#260). Parses `/MediaBox [llx lly urx ury]`
     * (dimensions in points); rendered pixels ≈ (width·scale)·(height·scale).
     * Returns 0 when no plaintext MediaBox is found (e.g. compressed object
     * streams) — the caller then skips downscaling, matching prior behavior.
     *
     * A crafted/malformed MediaBox can have finite but astronomically large
     * width/height; `width * height * scale * scale` can then overflow past
     * `Number.MAX_VALUE` to `Infinity`. Clamp the product to
     * `Number.MAX_SAFE_INTEGER` so it stays finite — a large-but-finite pixel
     * estimate still triggers downscaling, whereas `Infinity` would collapse
     * the computed downscale factor to 0 (see `convertToImages`).
     */
    private static largestPagePixels;
    /**
     * Convert a PDF buffer to an array of base64 PNG images
     *
     * This is used automatically when a provider (like Azure, Mistral, Ollama) doesn't
     * support native PDF input but does support image input. The PDF pages are converted
     * to PNG images and sent as vision content.
     *
     * @param pdfBuffer - PDF file content as Buffer
     * @param options - Conversion options
     * @returns Promise with conversion result including base64 images
     *
     * @example
     * ```typescript
     * // Check if conversion is needed
     * if (!PDFProcessor.supportsNativePDF('azure')) {
     *   const result = await PDFProcessor.convertToImages(pdfBuffer, {
     *     scale: 2,
     *     maxPages: 10
     *   });
     *   // Use images in LLM input instead of PDF
     *   options.input.images = result.images;
     * }
     * ```
     */
    static convertToImages(pdfBuffer: Buffer, options?: PDFImageConversionOptions): Promise<PDFImageConversionResult>;
    /**
     * Shared input validation for the image-conversion paths. Returns the PDF
     * size in MB (needed by the memory-estimate log). Throws on any invalid input
     * with the same messages the batch path has always used.
     */
    private static validateImageConversionInput;
    /**
     * Streaming variant of {@link convertToImages} (#302): yields each page's
     * base64 PNG as soon as it renders instead of buffering the whole document,
     * and reports progress via `options.onProgress`. A page that fails to render
     * is yielded with `error` set (per-page isolation, #294) rather than aborting
     * the stream.
     *
     * NOT a wrapper of/over {@link convertToImages}, despite the similar
     * contract — the two are independent, parallel implementations (each does
     * its own document open, downscale calculation, and page loop)
     * rather than one delegating to the other. Keep behavior changes (page
     * isolation, downscale, password handling) in sync across both by hand.
     */
    static convertToImagesStream(pdfBuffer: Buffer, options?: PDFImageConversionOptions): AsyncGenerator<PDFImagePage, void, void>;
    /**
     * Convert a PDF file path to an array of base64 PNG images
     *
     * @param pdfPath - Path to the PDF file
     * @param options - Conversion options
     * @returns Promise with conversion result
     */
    static convertFromPath(pdfPath: string, options?: PDFImageConversionOptions): Promise<PDFImageConversionResult>;
    /**
     * Check if PDF to image conversion is available
     * Useful for feature detection
     *
     * @returns true if the pdf-parse renderer is available
     */
    static isImageConversionAvailable(): Promise<boolean>;
    /**
     * Get estimated memory usage for converting a PDF
     *
     * @param pdfSizeBytes - Size of PDF file in bytes
     * @param pageCount - Estimated number of pages
     * @param scale - Scale factor
     * @returns Estimated memory usage in MB
     */
    static estimateConversionMemoryUsage(pdfSizeBytes: number, pageCount: number, scale?: number): number;
    /**
     * Get list of providers that require PDF → Image conversion
     */
    static getImageFallbackProviders(): string[];
    /**
     * Get list of providers that support native PDF
     */
    static getNativePDFProviders(): string[];
}
export declare const PDFImageConverter: typeof PDFProcessor;