import { Unsubscribable, Observable } from 'rxjs';
/**
 * @alpha
 * internal interface
 */
export interface BusEvent {
    readonly type: string;
    readonly payload?: any;
    origin?: EventBus;
}
/**
 * @alpha
 * Base event type
 */
export declare abstract class BusEventBase implements BusEvent {
    readonly type: string;
    readonly payload?: any;
    readonly origin?: EventBus;
    /** @internal */
    tags?: Set<string>;
    constructor();
    /**
     * @internal
     * Tag event for finer-grained filtering in subscribers
     */
    setTags(tags: string[]): this;
}
/**
 * @alpha
 * Base event type with payload
 */
export declare abstract class BusEventWithPayload<T> extends BusEventBase {
    readonly payload: T;
    constructor(payload: T);
}
export interface BusEventType<T extends BusEvent> {
    type: string;
    new (...args: any[]): T;
}
/**
 * @alpha
 * Event callback/handler type
 */
export interface BusEventHandler<T extends BusEvent> {
    (event: T): void;
}
/**
 * @alpha
 * Main minimal interface
 */
export interface EventFilterOptions {
    onlyLocal: boolean;
}
/**
 * @alpha
 * Main minimal interface
 */
export interface EventBus {
    /**
     * Publish single event
     */
    publish<T extends BusEvent>(event: T): void;
    /**
     * Get observable of events
     */
    getStream<T extends BusEvent>(eventType: BusEventType<T>): Observable<T>;
    /**
     * Subscribe to an event stream
     *
     * This function is a wrapper around the `getStream(...)` function
     */
    subscribe<T extends BusEvent>(eventType: BusEventType<T>, handler: BusEventHandler<T>): Unsubscribable;
    /**
     * Remove all event subscriptions
     */
    removeAllListeners(): void;
    /**
     * Returns a new bus scoped that knows where it exists in a heiarchy
     *
     * @internal -- This is included for internal use only should not be used directly
     */
    newScopedBus(key: string, filter: EventFilterOptions): EventBus;
}
/**
 * @public
 * @deprecated event type
 */
export interface AppEvent<T> {
    readonly name: string;
    payload?: T;
}
/** @public */
export interface LegacyEmitter {
    /**
     * @deprecated use $emit
     */
    emit<T>(event: AppEvent<T> | string, payload?: T): void;
    /**
     * @deprecated use $on
     */
    on<T>(event: AppEvent<T> | string, handler: LegacyEventHandler<T>): void;
    /**
     * @deprecated use $on
     */
    off<T>(event: AppEvent<T> | string, handler: LegacyEventHandler<T>): void;
}
/** @public */
export interface LegacyEventHandler<T> {
    (payload?: T): void;
    wrapper?: (event: BusEvent) => void;
}
/** @alpha */
export interface EventBusExtended extends EventBus, LegacyEmitter {
}