import type { QuestionnaireResponse } from 'fhir/r4';
/**
 * A single form update task, representing a `QuestionnaireResponse` that should be processed.
 */
export interface UpdateTask {
    /** The `QuestionnaireResponse` snapshot used to evaluate calculated expressions */
    questionnaireResponse: QuestionnaireResponse;
    /**
     * Optional flag indicating this update is the first update upon pre-population and form build.
     * Useful for distinguishing initialization updates from subsequent user-triggered updates.
     * Defaults to `false`.
     */
    isInitialUpdate?: boolean;
}
/**
 * Zustand store for managing queued, sequential updates to a FHIR form.
 */
export interface FormUpdateQueueStoreType {
    /** Queue of form update tasks (FIFO) */
    queue: UpdateTask[];
    /** Flag indicating if a task is currently being processed */
    isProcessing: boolean;
    /**
     * Adds a new form update task to the end of the queue.
     * Triggers the queue processor if not already running.
     *
     * @param task - The form update task to enqueue
     */
    enqueueFormUpdate: (task: UpdateTask) => void;
    /**
     * Internal processor that handles one task at a time, in order.
     *
     * - Applies the `updateExpressions` function to the `questionnaireResponse`.
     * - Applies the resulting computed updates.
     * - Updates the `QuestionnaireResponse` store in two phases: immediate and async.
     * - Automatically proceeds to the next task in the queue.
     */
    _startProcessing: () => void;
}
/**
 * `formUpdateQueueStore` is a Zustand store that serializes asynchronous form update logic.
 *
 * It ensures that each form update task is processed sequentially, one at a time,
 * to avoid race conditions and inconsistent state during expression evaluation.
 *
 * - `enqueueFormUpdate` adds a new task to the end of the queue.
 * - `_startProcessing` handles processing each task and re-triggers itself as needed.
 */
export declare const formUpdateQueueStore: import("zustand/vanilla").StoreApi<FormUpdateQueueStoreType>;
export declare const useFormUpdateQueueStore: import("zustand/vanilla").StoreApi<FormUpdateQueueStoreType> & {
    use: {
        queue: () => UpdateTask[];
        isProcessing: () => boolean;
        enqueueFormUpdate: () => (task: UpdateTask) => void;
        _startProcessing: () => () => void;
    };
};