import type { CommitReceipt, MeteringDirective, MeteringUsage } from './Session.js';
import { type CommitTransport, SessionConsumer } from './SessionConsumer.js';
/**
 * Raw Server-Sent Event.
 */
export interface SseEvent {
    readonly data: string;
    readonly event?: string | undefined;
    readonly id?: string | undefined;
    readonly retry?: number | undefined;
}
/**
 * Parsed metered SSE event.
 */
export type MeteredSseEvent<Message = string> = {
    readonly data: Message;
    readonly type: 'message';
} | {
    readonly directive: MeteringDirective;
    readonly type: 'metering';
} | {
    readonly receipt: unknown;
    readonly type: 'receipt';
} | {
    readonly type: 'done';
} | {
    readonly type: 'usage';
    readonly usage: MeteringUsage;
};
/**
 * Incremental SSE decoder for HTTP streaming responses.
 */
export declare class SseDecoder {
    #private;
    /**
     * Pushes a text or byte chunk and returns all complete SSE events.
     */
    pushChunk(chunk: Uint8Array | string): SseEvent[];
    /**
     * Flushes the decoder and parses any trailing event.
     */
    finish(): SseEvent[];
    private drainCompleteEvents;
}
/**
 * Parses one raw SSE block into an event.
 */
export declare function parseSseEventBlock(block: string): SseEvent | null;
/**
 * Parses one raw SSE event into the metered event model used by session streams.
 */
export declare function parseMeteredSseEvent<Message = string>(event: SseEvent, parseMessage?: (data: string) => Message): MeteredSseEvent<Message>;
/**
 * Tracks metering state for an HTTP/SSE response and commits final usage on `ack()`.
 */
export declare class MeteredSseSession<Transport extends CommitTransport = CommitTransport> {
    #private;
    constructor(consumer: SessionConsumer<Transport>);
    /** Whether a terminal stream marker has been observed. */
    get isDone(): boolean;
    /** Last server-issued metering directive. */
    get directive(): MeteringDirective | undefined;
    /** Final usage reported by the stream. */
    get usage(): MeteringUsage | undefined;
    /**
     * Accepts one SSE event and updates local metering state.
     */
    acceptEvent<Message = string>(event: SseEvent, parseMessage?: (data: string) => Message): MeteredSseEvent<Message>;
    /**
     * Commits the final usage amount, falling back to the reserved directive amount.
     */
    ack(): Promise<CommitReceipt>;
}
/**
 * Decodes a `ReadableStream` of SSE bytes into metered events.
 */
export declare function decodeMeteredSseStream<Message = string>(stream: ReadableStream<Uint8Array>, parseMessage?: (data: string) => Message): AsyncGenerator<MeteredSseEvent<Message>>;
//# sourceMappingURL=HttpStream.d.ts.map