import { type ReactNode } from "react";
type RestoreDisclosureAnchor = (() => void) | null;
export type UserMessageDisclosureLabels = {
    /** Collapsed disclosure action. Defaults to "Show more". */
    showMore?: string | undefined;
    /** Expanded disclosure action. Defaults to "Show less". */
    showLess?: string | undefined;
};
export type UserMessageDisclosureContextValue = {
    labels?: UserMessageDisclosureLabels | undefined;
    expandedByMessageId: Map<string, boolean>;
    beginChange: (messageBody: HTMLElement, disclosureControl: HTMLElement) => RestoreDisclosureAnchor;
};
export declare function UserMessageDisclosureProvider({ value, children, }: {
    value: UserMessageDisclosureContextValue;
    children: ReactNode;
}): import("react").JSX.Element;
/**
 * Deterministic first-paint fallback for runtimes without layout measurement.
 * Real browsers replace this estimate with the rendered-height decision in the
 * first layout effect. The complete text always remains mounted either way.
 */
export declare function userMessageLikelyNeedsDisclosure(text: string): boolean;
export type UserMessageBodyProps = {
    /** Durable timeline item id. Expansion memory is keyed by this value. */
    messageId: string;
    /** Complete source text. Used only for the deterministic measurement fallback. */
    text: string;
    children: ReactNode;
    className?: string | undefined;
    /** Per-field overrides for timeline labels, then the English defaults. */
    disclosureLabels?: UserMessageDisclosureLabels | undefined;
};
/**
 * Lossless disclosure boundary for already-sent user-message text.
 *
 * The full rendered subtree always remains in the DOM. A real browser decides
 * whether disclosure is needed from rendered height (including Markdown
 * structure and wrapping); the source-text heuristic is only a deterministic
 * fallback for SSR/test environments without layout. Timeline-owned context
 * remembers expansion per durable message id and preserves the reader's scroll
 * anchor when height changes.
 */
export declare function UserMessageBody({ messageId, text, children, className, disclosureLabels, }: UserMessageBodyProps): import("react").JSX.Element;
export {};