/**
 * OpenAI-chat delta assembly, done once and correctly (WS5.1).
 *
 * Fed the {@link SseEvent}s of an OpenAI Chat Completions stream, this rebuilds
 * a single turn: content and reasoning text, tool calls (fragmented arguments
 * merged by `index`, falling back to `id`, with id/index-less fragments
 * appended to the last open call), the finish reason, and the top-level `usage`
 * and opaque top-level extensions. It replaces several ad-hoc assemblers that
 * dropped parallel tool calls, mis-attributed argument fragments, or silently
 * swallowed malformed JSON.
 */
import type { Reasoning, ToolCall, Usage } from "@velum-labs/routekit-contracts/protocol-ir";
import { type ResponsesReasoningState } from "../adapters/openai-chat-wire.js";
import { type SseEvent } from "./parse.js";
export type AssembledTurn = {
    content: string;
    reasoning: string;
    reasoningDetails: Reasoning[];
    responsesReasoning?: ResponsesReasoningState;
    toolCalls: ToolCall[];
    finishReason?: string;
    usage?: Usage;
    extensions: Readonly<Record<string, unknown>>;
};
export declare class ChatStreamAssembler {
    #private;
    /**
     * Merge one event. Empty `data` (keepalive) is ignored; the `[DONE]` sentinel
     * marks stream end (it does not, on its own, clear truncation). Malformed JSON
     * surfaces as {@link SseParseError} rather than being swallowed.
     */
    push(event: SseEvent): void;
    /**
     * Merge an already-parsed chunk. Lets buffered-scan callers that decode + JSON
     * parse an event once (for both assembly and, say, provider-cost extraction)
     * reuse this assembler without a second parse.
     */
    pushParsed(json: unknown): void;
    result(): AssembledTurn;
    /** True until a `finish_reason` is seen; a `[DONE]` without one stays truncated. */
    get truncated(): boolean;
}