import { Component, ComponentOptions, PreStartSettings } from './kalix';
import { Metadata } from './metadata';
/** @public */
export declare namespace View {
    /**
     * Context for a view update event.
     */
    interface UpdateHandlerContext {
        /**
         * The view id.
         */
        viewId: string;
        /**
         * The event subject.
         */
        eventSubject?: string;
        /**
         * The update command name.
         */
        commandName: string;
        /**
         * Metadata for the event.
         */
        metadata: Metadata;
    }
    /**
     * A handler for transforming an incoming event and the previous view state into a new state
     *
     * @typeParam State - the type of the stored state
     * @typeParam Events - the type of all update events, based on the gRPC method input type
     * @param event - The event, this will be of the type of the gRPC event handler input type
     * @param state - The previous view state or 'undefined' if no previous state was stored
     * @param context - The view handler context
     * @returns The state to store in the view or undefined to not update/store state for the event
     */
    type Handler<State extends object = any, Events extends object = any> = Events extends any ? (event: Events, state: State | undefined, context: UpdateHandlerContext) => State | undefined : never;
    /**
     * View update handlers.
     *
     * @remarks
     * The names of the properties must match the names of all the view methods specified in the gRPC
     * descriptor.
     *
     * @typeParam State - the type of the stored state
     * @typeParam Events - the type of all update events, based on the gRPC method input types
     */
    type Handlers<State extends object = any, Events extends object = any> = {
        [methodName: string]: Handler<State, Events>;
    };
    /**
     * Options for a view.
     */
    interface Options extends ComponentOptions {
        /**
         * The id for the view, used for persisting the view.
         *
         * @defaultValue Defaults to the service name
         */
        viewId?: string;
    }
}
/**
 * View.
 *
 * @typeParam State - the type of the stored state
 * @typeParam Events - the type of all update events, based on the gRPC method input types
 *
 * @public
 */
export declare class View<State extends object = any, Events extends object = any, UpdateHandlers extends View.Handlers<State, Events> = View.Handlers<State, Events>> implements Component {
    readonly serviceName: string;
    readonly service: protobuf.Service;
    readonly options: Required<View.Options>;
    readonly clients: undefined;
    /**
     * View update handlers.
     *
     * @remarks
     * The names of the properties must match the names of all the view methods specified in the gRPC
     * descriptor.
     */
    updateHandlers?: UpdateHandlers;
    /**
     * Create a new view.
     *
     * @param desc - A descriptor or list of descriptors to parse, containing the service to serve
     * @param serviceName - The fully qualified name of the service that provides this interface
     * @param options - The options for this view
     */
    constructor(desc: string | string[], serviceName: string, options?: View.Options);
    preStart(settings: PreStartSettings): void;
    lookupType(messageType: string): protobuf.Type;
    /**
     * Set the update handlers of the view.
     *
     * @remarks
     * Only used for updates where event transformation is enabled through
     * `"transform_updates: true"` in the grpc descriptor.
     *
     * @param handlers - The handler callbacks
     * @returns This view
     */
    setUpdateHandlers(handlers: UpdateHandlers): View<State, Events, UpdateHandlers>;
}