import type { Logger } from '@kubun/logger';
import { type UnsubscribeFunction } from '@sozai/event';
/**
 * Map of event names to their data types.
 * Uses `Record<string, unknown>` so any namespaced string key is valid.
 */
type EventMap = Record<string, unknown>;
/**
 * Transaction-aware event bus built on top of `@sozai/event`.
 *
 * Events emitted outside a transaction fire immediately.
 * Events emitted inside a transaction are buffered until commit,
 * and discarded on rollback.
 */
export declare class EngineEventBus<TEvents extends EventMap = EventMap> {
    #private;
    constructor(options?: {
        logger?: Logger;
    });
    /**
     * Subscribe to a namespaced event.
     * Returns an unsubscribe function.
     */
    on<TName extends keyof TEvents & string>(name: TName, listener: (data: TEvents[TName]) => void | Promise<void>): UnsubscribeFunction;
    /**
     * Emit an event immediately (not inside any transaction).
     */
    emit<TName extends keyof TEvents & string>(name: TName, data: TEvents[TName]): Promise<void>;
    /**
     * Begin a new transaction context for event buffering.
     * Events emitted via `emitBuffered` with this transaction ID
     * will be held until `commit` or `rollback` is called.
     */
    beginTransaction(transactionID: string): void;
    /**
     * Emit an event inside a transaction. The event is buffered
     * and will only be delivered to listeners upon commit.
     */
    emitBuffered<TName extends keyof TEvents & string>(transactionID: string, name: TName, data: TEvents[TName]): void;
    /**
     * Commit a transaction: release all buffered events to listeners
     * in the order they were emitted.
     *
     * Listener errors do not prevent remaining buffered events from firing.
     * Since `@sozai/event` uses `Promise.allSettled` internally, all listeners
     * for a given event run even if some throw. Errors from individual event
     * emissions are caught so the full buffer is always drained.
     */
    commit(transactionID: string): Promise<void>;
    /**
     * Rollback a transaction: discard all buffered events.
     */
    rollback(transactionID: string): void;
}
export {};