import type { InferenceSession } from "onnxruntime-common";
/**
 * The image processing engine to use for preprocessing.
 *
 * - `"opencv"` – Uses OpenCV.js (`ImageProcessor` / `Contours` from `ppu-ocv`).
 *   More accurate region detection; recommended for production use. **(default)**
 * - `"canvas-native"` – Uses pure HTML Canvas operations (`CanvasProcessor` from `ppu-ocv/canvas`).
 *   No OpenCV dependency; suitable for lightweight or browser-extension environments.
 */
export type ProcessingEngine = "opencv" | "canvas-native";
/**
 * Paths to the OCR model and dictionary files.
 *
 * **Preset models** (import from `"ppu-paddle-ocr"`):
 *
 * - **PP-OCRv6**: `V6_SMALL_MODEL` (default), `V6_MEDIUM_MODEL`, `V6_TINY_MODEL`
 * - **PP-OCRv5**: `V5_EN_MOBILE_MODEL`, `V5_EN_MOBILE_INT8_MODEL`, `V5_EN_SERVER_MODEL`, `V5_MOBILE_MODEL`, `V5_SERVER_MODEL`
 * - **PP-OCRv5 Languages**: `V5_ARABIC_MOBILE_MODEL`, `V5_CYRILLIC_MOBILE_MODEL`, `V5_DEVANAGARI_MOBILE_MODEL`, `V5_GREEK_MOBILE_MODEL`, `V5_ESLAV_MOBILE_MODEL`, `V5_KOREAN_MOBILE_MODEL`, `V5_LATIN_MOBILE_MODEL`, `V5_TAMIL_MOBILE_MODEL`, `V5_TELUGU_MOBILE_MODEL`, `V5_THAI_MOBILE_MODEL`
 * - **PP-OCRv4**: `V4_EN_MOBILE_MODEL`, `V4_MOBILE_MODEL`, `V4_SERVER_MODEL`, `V4_SERVER_DOC_MODEL`
 * - **PP-OCRv3**: `V3_MOBILE_MODEL`, `V3_JAPANESE_MOBILE_MODEL`
 *
 * Or provide granular custom paths for `detection`, `recognition`, `charactersDictionary`.
 *
 * @example
 * ```ts
 * import { PaddleOcrService, V6_SMALL_MODEL } from "ppu-paddle-ocr";
 * const service = new PaddleOcrService({ model: V6_SMALL_MODEL });
 * ```
 */
export type ModelPathOptions = {
    /**
     * Onnx file buffer or path for the text detection model.
     * Required if not using the library's built‑in default model.
     */
    detection?: ArrayBuffer | string;
    /**
     * Onnx file buffer or path for the text recognition model.
     * Required if not using the library's built‑in default model.
     */
    recognition?: ArrayBuffer | string;
    /**
     * Onnx file buffer or path for the character dictionary.
     * Required if not using the library's built‑in default dictionary (en_dict.txt).
     */
    charactersDictionary?: ArrayBuffer | string;
};
/**
 * Controls verbose output and image dumps for debugging OCR.
 */
export type DebuggingOptions = {
    /**
     * Enable detailed logging of each processing step.
     * @default false
     */
    verbose?: boolean;
    /**
     * Save intermediate image data to disk for inspection.
     * @default false
     */
    debug?: boolean;
    /**
     * Directory where debug images will be written.
     * Relative to the current working directory.
     * @default "out"
     */
    debugFolder?: string;
};
/**
 * Parameters for the text detection preprocessing and filtering stage.
 */
export type DetectionOptions = {
    /**
     * Per-channel mean values used to normalize input pixels [R, G, B].
     * @default [0.485, 0.456, 0.406]
     */
    mean?: [number, number, number];
    /**
     * Per-channel standard deviation values used to normalize input pixels [R, G, B].
     * @default [0.229, 0.224, 0.225]
     */
    stdDeviation?: [number, number, number];
    /**
     * Maximum dimension (longest side) for input images, in pixels.
     * Images above this size will be scaled down, maintaining aspect ratio.
     * @default 640
     */
    maxSideLength?: number;
    /**
     * Padding applied to each detected box vertical as a fraction of its height
     * @default 0.4
     */
    paddingVertical?: number;
    /**
     * Padding applied to each detected box vertical as a fraction of its height
     * @default 0.6
     */
    paddingHorizontal?: number;
    /**
     * Remove detected boxes with area below this threshold, in pixels.
     * @default 50
     */
    minimumAreaThreshold?: number;
};
/**
 * Strategy for recognizing text in detected regions.
 *
 * - `"per-box"` – Each detected box is recognized individually (most accurate, n inferences).
 * - `"per-line"` – Boxes on the same line are merged and recognized together (fewer inferences, good accuracy).
 * - `"cross-line"` – Crops are packed into uniform-width batches across lines to minimize inference count.
 *
 * @default "per-line"
 */
export type RecognitionStrategy = "per-box" | "per-line" | "cross-line";
/**
 * Parameters for the text recognition preprocessing stage.
 */
export type RecognitionOptions = {
    /**
     * Fixed height for input images, in pixels.
     * Models will resize width proportionally.
     * @default 48
     */
    imageHeight?: number;
    /**
     * Recognition strategy for processing detected text regions.
     * - `"per-box"` – Each box recognized individually (most accurate, n inferences)
     * - `"per-line"` – Same-line boxes merged per line (fewer inferences, good accuracy)
     * - `"cross-line"` – Crops packed into uniform-width batches across lines (fewest inferences)
     * @default "per-line"
     */
    strategy?: RecognitionStrategy;
    /**
     * Width multiplier for the cross-line strategy's bin-packing target.
     * The batch target width is computed as `maxLineWidth × factor`.
     * Larger values pack more lines per batch (fewer inferences, potentially
     * lower accuracy); smaller values keep lines isolated (more inferences).
     *
     * Only used when `strategy` is `"cross-line"`.
     * @default 1.0
     */
    crossLineWidthFactor?: number;
    /**
     * A list of loaded character dictionary (string) for
     * recognition result decoding.
     */
    charactersDictionary: string[];
};
/**
 * Options for individual recognize() calls.
 */
export type RecognizeOptions = {
    /**
     * Return flattened results instead of grouped by lines.
     * @default false
     */
    flatten?: boolean;
    /**
     * Override the recognition strategy for this call.
     * If omitted, the strategy from the service options is used.
     */
    strategy?: RecognitionStrategy;
    /**
     * Custom character dictionary for this specific call.
     * If provided, caching will be disabled for this call.
     */
    dictionary?: string | ArrayBuffer;
    /**
     * Disable caching for this specific call.
     * @default false
     */
    noCache?: boolean;
};
/**
 * Options for `batchRecognize()` / `batchRecognizeStream()`.
 *
 * Extends {@link RecognizeOptions} (applied to every image) with controls for
 * concurrency, error handling, progress, and cancellation.
 */
export type BatchRecognizeOptions = RecognizeOptions & {
    /**
     * Maximum number of images processed concurrently.
     *
     * `"auto"` (default) picks `1` when an accelerator execution provider
     * (e.g. CUDA, WebGPU) is configured — a shared inference session serializes
     * device work anyway and parallel runs would stack VRAM — and a small CPU
     * default otherwise, to overlap JS preprocessing with native inference.
     * @default "auto"
     */
    concurrency?: number | "auto";
    /**
     * When `true`, a failing image does not abort the batch: its slot is filled
     * with a `{ status: "rejected", reason }` entry. When `false` (default), the
     * first failure rejects the whole call, matching `recognize()`.
     * @default false
     */
    settle?: boolean;
    /**
     * Cancels the batch. Pending images are not scheduled and the call rejects
     * with an `AbortError`. In-flight inferences are allowed to finish but their
     * results are discarded.
     */
    signal?: AbortSignal;
    /**
     * Invoked after each image settles with the running completed count and the
     * total (when the input length is known up front, e.g. an array).
     */
    onProgress?: (done: number, total: number | undefined) => void;
};
/**
 * Controls the image processing backend.
 */
export type ProcessingOptions = {
    /**
     * The image processing engine used for detection preprocessing and
     * recognition resizing.
     *
     * - `"opencv"` – Uses OpenCV.js via `ppu-ocv` (more accurate, **default**).
     * - `"canvas-native"` – Pure canvas operations via `ppu-ocv/canvas` (no OpenCV dependency).
     *
     * @default "opencv"
     */
    engine?: ProcessingEngine;
};
/**
 * Full configuration for the PaddleOCR service.
 * Combines model file paths with detection, recognition, and debugging parameters.
 */
export type PaddleOptions = {
    /**
     * File paths to the required OCR model components.
     */
    model?: ModelPathOptions;
    /**
     * Controls parameters for text detection.
     */
    detection?: DetectionOptions;
    /**
     * Controls parameters for text recognition.
     */
    recognition?: RecognitionOptions;
    /**
     * Controls logging and image dump behavior for debugging.
     */
    debugging?: DebuggingOptions;
    /**
     * ONNX Runtime session configuration options.
     */
    session?: SessionOptions;
    /**
     * Controls the image processing backend.
     */
    processing?: ProcessingOptions;
};
/**
 * ONNX Runtime session configuration options.
 *
 * Extends the native `InferenceSession.SessionOptions` from ONNX Runtime
 * so that any valid provider configuration (e.g. WebAssembly, CUDA, CoreML)
 * is accepted without type mismatch.
 */
export type SessionOptions = InferenceSession.SessionOptions & {
    /**
     * Execution providers to use for inference (e.g., 'cpu', 'cuda', 'wasm').
     * Accepts provider name strings or provider-specific configuration objects.
     * @default ['cpu']
     */
    executionProviders?: InferenceSession.SessionOptions["executionProviders"];
};
/**
 * Simple rectangle representation.
 */
export type Box = {
    /** X-coordinate of the top-left corner. */
    x: number;
    /** Y-coordinate of the top-left corner. */
    y: number;
    /** Width of the box in pixels. */
    width: number;
    /** Height of the box in pixels. */
    height: number;
};