import { type Key } from './keys.js';
import type { Tty } from './tty.js';
export declare class CancelledError extends Error {
    readonly name = "CancelledError";
}
/**
 * One question, as a state machine over keypresses.
 *
 * Rendering is a pure function of the state and returns lines rather than writing
 * them, and `press` is the only way the state moves. Nothing here touches a
 * terminal, so every prompt is exercised in-process by feeding it keys and reading
 * the frame back; `PromptRunner` is the half that owns the real one.
 */
export declare abstract class Prompt<T> {
    #private;
    /** The interactive frame, one entry per line, within `width` and `height`. */
    abstract frame(width: number, height: number): readonly string[];
    /** The single line left in the scrollback once the question is answered. */
    abstract summary(width: number): string;
    protected abstract handle(key: Key): void;
    press(key: Key): void;
    protected finish(answer: T): void;
    get done(): boolean;
    get cancelled(): boolean;
    /** The answer. Reading it before `done`, or after a cancel, is a bug here. */
    get answer(): T;
}
/**
 * Drives one prompt at a time against a real terminal.
 *
 * Repainting is "up N lines, erase to the bottom, write the frame" rather than an
 * alternate screen: the answered prompts stay in the scrollback above, which is
 * what makes the summary line a record of what was chosen rather than something
 * that vanishes on exit.
 *
 * Every line is clipped to the terminal's width and the frame to its height, so a
 * wrapped line can never make the cursor arithmetic wrong.
 */
export declare class PromptRunner {
    #private;
    constructor(tty: Tty);
    ask<T>(prompt: Prompt<T>): Promise<T>;
}