/**
 * SherpaONNXBridge - V2 canonical ONNX backend bridge.
 *
 * STT/TTS/VAD inference flows entirely through the RACommons proto-byte
 * C ABI (`_rac_stt_component_*_proto`, `_rac_tts_component_*_proto`,
 * `_rac_vad_component_*_proto`) exported by this bridge's dedicated
 * `racommons-onnx-sherpa.wasm` artifact.
 *
 * Responsibilities:
 *  1. Always load this package's own `racommons-onnx-sherpa.{js,wasm}`
 *     artifact as an independent Emscripten module. The bridge does not
 *     piggy-back on any other package's WASM module — the ONNX and
 *     Sherpa backend registration entry points
 *     (`_rac_backend_onnx_register` / `_rac_backend_sherpa_register`) are
 *     only exported by this artifact, so each ONNX bridge instance owns
 *     its own dedicated module.
 *  2. Install the shared browser `PlatformAdapter`, call `rac_init()`, and
 *     claim the speech/embedding/RAG capabilities on the per-capability
 *     registry so the core proto-byte adapters can resolve this module.
 *  3. Call `_rac_backend_onnx_register()` and
 *     `_rac_backend_sherpa_register()` to register the ONNX runtime and
 *     Sherpa speech vtables with the C++ plugin registry. After this, all
 *     proto-byte STT/TTS/VAD calls in core route through the registered
 *     backend.
 *
 * Backend availability requirement:
 *   The `racommons-onnx-sherpa.wasm` artifact MUST be built with ONNX
 *   Runtime WASM and Sherpa-ONNX WASM static archives linked, so
 *   `_rac_backend_onnx_register` and `_rac_backend_sherpa_register` are
 *   exported. Without both, `register()` reports a typed
 *   `BackendNotAvailable` error and STT/TTS/VAD calls stay unavailable.
 */
export interface SherpaONNXBridgeLoadOptions {
    /**
     * Override URL to the `racommons-onnx-sherpa.js` glue file. When omitted,
     * the bridge resolves it via `import.meta.url` so bundlers (Vite/webpack)
     * can rewrite the asset path correctly.
     */
    wasmUrl?: string;
}
/**
 * Singleton orchestrator for the ONNX backend. The TS surface is a thin
 * shell — all real STT/TTS/VAD work happens in C++ via the proto-byte
 * adapters in `@runanywhere/web` core.
 */
export declare class SherpaONNXBridge {
    private static _instance;
    private _module;
    private _onnxBackendRegistered;
    private _sherpaBackendRegistered;
    private _loaded;
    private _loading;
    /**
     * Shared browser adapter retained for the entire lifetime of this WASM
     * module. RACommons stores its struct pointer during `rac_init`, so the
     * callback table and allocation must remain alive until after
     * `_rac_shutdown` completes.
     */
    private _platformAdapter;
    /**
     * `true` when this bridge has loaded the dedicated
     * `racommons-onnx-sherpa` WASM and called `_rac_init` on it (i.e.
     * `_doLoad` ran to completion). When ownership is held, `unregister()`
     * mirrors LlamaCppBridge teardown and calls `_rac_shutdown` plus
     * cleans up the shared platform adapter before dropping the module from the
     * capability registry.
     */
    private _bridgeOwnedInit;
    /** Override URL to `racommons-onnx-sherpa.js`. Set before `register()`. */
    wasmUrl: string | null;
    static get shared(): SherpaONNXBridge;
    get isLoaded(): boolean;
    get isBackendRegistered(): boolean;
    /** Acquire/load the commons module and register the ONNX backend vtable. */
    ensureLoaded(options?: SherpaONNXBridgeLoadOptions): Promise<void>;
    /**
     * Unregister the ONNX/Sherpa backend vtables. Idempotent.
     *
     * Mirrors LlamaCppBridge teardown: drops the module from the
     * capability registry (releasing only the slots it owned —
     * STT/TTS/VAD/voice-agent), leaving siblings (commons, llamacpp) intact.
     * If this bridge held the module install, calls `_rac_shutdown` to
     * unwind C++ state too.
     */
    unregister(): void;
    /** Release backend registrations, native state, and JS callbacks in order. */
    private _teardown;
    private _doLoad;
    /**
     * Build the ordered list of candidate URLs from which to import the
     * `racommons-onnx-sherpa.js` Emscripten glue. The dedicated ONNX/Sherpa
     * artifact lives in this package's own `wasm/` folder, so we do not
     * need to probe sibling-package paths.
     */
    private _collectCommonsModuleCandidates;
    private _loadCommonsModule;
    /** Call `rac_init()` with the shared browser platform adapter. */
    private _initCommons;
    private _isRegistrationSuccess;
    /**
     * Invoke an exported C function via `ccall`, awaiting a Promise when the
     * module was built with ASYNCIFY/JSPI.
     */
    private _callMaybeAsync;
}
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