import type { EngineInternals } from './internals.ts';
/**
 * Discriminator for `replayWorkflowFeed` / `snapshotWorkflowFeedTail`
 * / `subscribeWorkflowFeedCommits`. Mirrored by `EventSelector` in
 * `src/server/workflow-event-feed.ts` so the core engine takes no
 * dependency on the server package.
 */
export type WorkflowFeedSelector = 'events' | 'tokens';
/**
 * Hard-coded stream key for the `tokens` selector. Every transport that
 * exposes the token feed — `engine.getStreamChunks(id, 'tokens')` and the REST
 * SSE / WebSocket stream-chunk routes layered on it — keys its stored chunks
 * under this single value, so a resumption cursor issued by one transport
 * round-trips through another.
 */
export declare const TOKENS_STREAM_KEY = "tokens";
/** Record `kind` for every token stream chunk emitted by the feed. */
export declare const STREAM_CHUNK_KIND = "stream:chunk";
/**
 * Record `kind` emitted when a subscriber resumes from a cursor below the
 * event-log compaction watermark. The `[cursor, watermark.sequence)` records
 * were truncated, so the feed reports an explicit boundary marker (rather than
 * silently skipping) before continuing from the surviving records. `sequence`
 * is the watermark sequence (the first surviving record).
 */
export declare const COMPACTION_BOUNDARY_KIND = "workflow:compaction-boundary";
/**
 * A committed workflow-feed record surfaced to subscribers of
 * `subscribeWorkflowFeedCommits()`. Fires after the storage commit resolves, so
 * replay and live delivery share the same committed sequence authority. The
 * same shape covers both selectors — consumers filter on `selector` before
 * interpreting `payload`.
 *
 *   - `events` selector: `kind` is the durable log entry type
 *     (e.g. `'workflow:checkpoint'`). `sequence` / `timestamp` come
 *     from the `WorkflowLogEntry` written inside the batch.
 *   - `tokens` selector: `kind` is always `'stream:chunk'`.
 *     `sequence` is the chunk index; `timestamp` is wall-clock at
 *     write time.
 */
export type WorkflowFeedRecord = {
    readonly workflowId: string;
    readonly selector: WorkflowFeedSelector;
    readonly kind: string;
    readonly sequence: number;
    readonly timestamp: number;
    readonly payload: unknown;
};
export type WorkflowFeedRecordValue = WorkflowFeedRecord;
/**
 * Listener signature for `subscribeWorkflowFeedCommits()`. Returning
 * `void | Promise<void>` is explicit: an async listener's rejected
 * promise is caught by the notifier and discarded, exactly like a
 * sync throw. This is the only correct shape for a notifier called
 * from a hot path — an escaped unhandled rejection would surface as
 * a test-runner or Node process-level crash.
 */
export type WorkflowFeedListener = (record: WorkflowFeedRecord) => void | Promise<void>;
/**
 * Iterate over the workflow's post-commit records for a given selector.
 */
export declare function replayWorkflowFeed(internals: EngineInternals, workflowId: string, selector: WorkflowFeedSelector, afterSequence: number): AsyncIterable<WorkflowFeedRecord>;
/**
 * Snapshot the current tail sequence for the selector.
 */
export declare function snapshotWorkflowFeedTail(internals: EngineInternals, workflowId: string, selector: WorkflowFeedSelector): Promise<number>;
/**
 * Subscribe to post-commit workflow-feed notifications.
 */
export declare function subscribeWorkflowFeedCommits(internals: EngineInternals, workflowId: string, selector: WorkflowFeedSelector, listener: WorkflowFeedListener): () => void;
/**
 * Replay committed workflow event-log entries after a durable sequence cursor.
 */
export declare function replayWorkflowEventLog(internals: EngineInternals, workflowId: string, afterSequence: number): AsyncIterable<WorkflowFeedRecord>;
/**
 * Replay committed token stream chunks after a durable sequence cursor.
 */
export declare function replayWorkflowTokens(internals: EngineInternals, workflowId: string, afterSequence: number): AsyncIterable<WorkflowFeedRecord>;
/**
 * Dispatch a committed record to every listener registered for
 * `(workflowId, selector)`.
 */
export declare function notifyWorkflowFeedCommit(internals: EngineInternals, workflowId: string, selector: WorkflowFeedSelector, record: WorkflowFeedRecord): void;