/**
 * Turns the editor buffer into the rows the prompt box draws, and back.
 *
 * The box wraps its own text rather than letting Ink do it. Ink can only wrap a
 * whole `<Text>`, and the caret is drawn as one inverted cell inside that text,
 * so wrapping performed after the caret was placed would leave the caret on a
 * row this module cannot name — and both the visible window, which keeps the
 * frame short, and the up/down keys are counted in drawn rows, not in the
 * buffer's own lines.
 *
 * Widths and grapheme boundaries both come from `shared/utils/grapheme`, which
 * measures with the same package Ink lays its frames out with. Rows are cut
 * between graphemes, so an emoji sequence or a combining sequence is never
 * split and the caret never lands inside one.
 */
export interface PromptLayout {
    /** Drawn rows, top to bottom, each already cut to fit the box. */
    readonly rows: readonly string[];
    /** Buffer offset each row starts at, so a row position maps back to the text. */
    readonly rowStarts: readonly number[];
    /** Index into `rows`; the caret is always on a row that exists. */
    readonly cursorRow: number;
    /** Offset into that row's text, in code units, never past its end. */
    readonly cursorColumn: number;
}
/** Columns the prompt box has left for text once its own chrome is paid for. */
export declare function resolvePromptContentWidth(terminalColumns: number | undefined): number;
export declare function layoutPromptRows(text: string, cursor: number, contentWidth: number): PromptLayout;
/**
 * The buffer offset one row up or down, keeping the display column where the
 * row is wide enough and clamping to its end where it is not. Returns null when
 * the caret is already on the first or last drawn row, which is what hands the
 * key over to the history.
 *
 * The column is read from the caret on every press rather than remembered
 * across presses, so passing through a short row shortens the column instead of
 * springing back — the simpler rule, and the one the buffer alone can state.
 */
export declare function moveCaretByRow(text: string, cursor: number, contentWidth: number, direction: 'up' | 'down'): number | null;
/**
 * The window of rows to draw. It follows the caret and never grows, so the
 * frame Ink erases each tick stays the same height however long the draft is.
 */
export declare function selectVisibleRowRange(rowCount: number, cursorRow: number, maxRows: number): {
    readonly start: number;
    readonly end: number;
};
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