/**
 * Headless `/btw` turn lifecycle shared by the TUI controller and RPC mode:
 * record bookkeeping for a new topic or follow-up, and the ephemeral model turn.
 */
import type { AssistantMessage, ImageContent } from "@oh-my-pi/pi-ai";
import type { AgentSession } from "./agent-session.js";
import { type BtwHistoryRecord, type BtwHistoryTurn } from "./btw-history.js";
export interface BtwTurnStart {
    /** The record with the new turn appended, status `running`. */
    record: BtwHistoryRecord;
    /** Earlier turns of a follow-up's topic, replayed as context. */
    history?: readonly BtwHistoryTurn[];
    /** Provider lineage key; successful follow-ups share one, a failed turn starts a fresh one. */
    conversationKey: string;
}
/** Start a new topic headed by `title` when given, or append a follow-up turn to `previous`. */
export declare function beginBtwTurn(question: string, leafId: string | null, previous?: BtwHistoryRecord, images?: ImageContent[], title?: string): BtwTurnStart;
/** Patch the record's latest turn (the last follow-up, else the record itself). */
export declare function patchLatestBtwTurn(record: BtwHistoryRecord, patch: Partial<BtwHistoryTurn>): BtwHistoryRecord;
/**
 * Run one `/btw` question as an ephemeral turn; earlier turns of its topic are replayed as context.
 * Not `async`: returns the session's own promise so callers settle on the same tick as the turn.
 */
export declare function runBtwTurn(session: Pick<AgentSession, "model" | "runEphemeralTurn">, args: {
    question: string;
    /** Images attached to this question; earlier turns replay their own. */
    images?: ImageContent[];
    history?: readonly BtwHistoryTurn[];
    /** Ask for steering prompts in an `<inject>` block (the `btw.inject` setting). */
    inject?: boolean;
    conversationKey: string;
    onTextDelta: (delta: string) => void;
    signal: AbortSignal;
}): Promise<{
    replyText: string;
    assistantMessage: AssistantMessage;
}>;