import type { SlackAdapter } from './slack.js';
import type { OutputStream, MutableRegion, OpenOutputStreamOpts } from '../output-stream.js';
import type { MessageRef, RichBlock, ActionElement, Destination } from '../types.js';
/**
 * Test-only: override retry delays to skip real wall-clock waits.
 * Pass [] for no retries, [0,0,0,0] to keep 4-attempt retry semantics with no wait.
 * Production code must never call this.
 */
export declare function _testSetRetryDelays(delays: readonly number[]): void;
/** Test-only: restore production retry delays. */
export declare function _testResetRetryDelays(): void;
export declare class SlackOutputStream implements OutputStream {
    private adapter;
    private destination;
    private threadId;
    private onMessagePosted;
    private maxChunk;
    private durable;
    /** Readable label for log messages, extracted from the Destination kind. */
    private get _logChannel();
    private parentRef;
    private currentRef;
    private currentContent;
    private mutableTail;
    private allRefs;
    private queue;
    private lastError;
    /** Generation counter for MutableRegion staleness tracking.
     *  Incremented every time openMutable is called or a seal event occurs. */
    private _regionGeneration;
    constructor(adapter: SlackAdapter, destination: Destination, opts?: OpenOutputStreamOpts);
    emitText(text: string): void;
    openMutable(text: string): MutableRegion;
    postInteractive(text: string, opts?: {
        richBlocks?: RichBlock[];
        actions?: ActionElement[];
    }): Promise<MessageRef | null>;
    flush(): Promise<void>;
    getRefs(): MessageRef[];
    getParentRef(): MessageRef | null;
    /** Called by SlackMutableRegion.update(). No-op if the generation is stale. */
    _regionUpdate(generation: number, text: string): void;
    /** Return a no-op region for empty text. */
    private _noopRegion;
    private _processAppend;
    private _processOpenMutable;
    private _processEditMutableTail;
    /** Combined display = currentContent [+ SEP + mutableTail]. */
    private _renderWithTail;
    /** Synchronously move mutableTail into currentContent. */
    private _sealMutableTailNow;
    private _postNew;
    private _postOne;
    private _updateCurrent;
}