/**
 * @module PicoEmitter  
 * This module contains the PicoEmitter class, which is an even tinier event emitter powered by [nanoevents](https://www.npmjs.com/package/nanoevents) - [see the documentation for more info](https://github.com/Sv443-Network/UserUtils/blob/main/docs.md#picoemitter)  
 * Contrary to `PicoEmitter`, it's purely meant for bootstrapping event-emitting classes in OOP and doesn't have much in the way of helper methods, just pure internal emitting and public subscribing.  
 */
import { type DefaultEvents, type Emitter, type EventsMap, type Unsubscribe } from "nanoevents";
import type { Prettify } from "./types.ts";
export type PicoEmitterOptions = {
    /**
     * When provided, the emitter will remember the last arguments of each listed event.  
     * Any listener attached via `on()` or `once()` after the event has already fired will  
     * be immediately called / resolved with the cached arguments (catch-up behaviour).  
     * Only works for emissions that go through the public `emit()` or the protected `emitEvent()` method.  
     */
    catchUpEvents?: PropertyKey[];
};
type PicoEmitterOnMultiTriggerOptions<TEvtMap extends EventsMap, TKey extends keyof TEvtMap = keyof TEvtMap> = {
    /** Calls the callback when one of the given events is emitted. Either one of or both of `oneOf` and `allOf` need to be set. If both are set, they behave like an "AND" condition. */
    oneOf?: TKey[];
    /** Calls the callback when all of the given events are emitted. Either one of or both of `oneOf` and `allOf` need to be set. If both are set, they behave like an "AND" condition. */
    allOf?: TKey[];
};
/** Options for the {@linkcode PicoEmitter.onMulti()} method */
export type PicoEmitterOnMultiOptions<TEvtMap extends EventsMap, TKey extends keyof TEvtMap = keyof TEvtMap> = Prettify<{
    /** If true, the callback will be called only once for the first event (or set of events) that match the criteria */
    once?: boolean;
    /** If provided, can be used to cancel the subscription if the signal is aborted */
    signal?: AbortSignal;
    /** The callback to call when the event with the given name is emitted */
    callback: (event: TKey, ...args: Parameters<TEvtMap[TKey]>) => void;
} & PicoEmitterOnMultiTriggerOptions<TEvtMap, TKey> & (Pick<Required<PicoEmitterOnMultiTriggerOptions<TEvtMap, TKey>>, "oneOf"> | Pick<Required<PicoEmitterOnMultiTriggerOptions<TEvtMap, TKey>>, "allOf">)>;
/**
 * Abstract class that can be extended to bootstrap a class with a lightweight event emitter, with some protected helper methods and a strongly typed event map.  
 * For a more feature-rich emitter that can also be used in a non-OOP context, see `NanoEmitter` which extends from this class.  
 *  
 * ⚠️ Prefer using `this.emitEvent()` over `this.events.emit()` — it updates the catch-up memory for any events listed in `catchUpEvents`.  
 */
export declare abstract class PicoEmitter<TEvtMap extends EventsMap = DefaultEvents> {
    /**
     * The nanoevents emitter instance used internally.  
     * ⚠️ You should use the protected method `emitEvent()` instead of emitting directly through this, as it updates the catch-up memory for any events listed in `catchUpEvents`. Only use `this.events.emit()` if you're not using `catchUpEvents` or are doing manual memory management.  
     */
    protected readonly events: Emitter<TEvtMap>;
    protected eventUnsubscribes: Unsubscribe[];
    protected emitterOptions: PicoEmitterOptions;
    /** Stores the latest arguments for each emitted event that's listed in `catchUpEvents`. */
    protected catchUpMemory: Map<PropertyKey, unknown[]>;
    /**
     * ⚠️ You cannot instantiate `PicoEmitter` directly, it's only meant for extending in your own classes. If you want a standalone emitter, use `NanoEmitter` instead.  
     */
    constructor(options?: Partial<PicoEmitterOptions>);
    /**
     * Emits an event on this instance.  
     * You should use this over `this.events.emit()` in subclasses as it updates the catch-up memory for any event listed in `catchUpEvents`, so that listeners attached after emitting can still receive the latest value.  
     */
    protected emitEvent<TKey extends keyof TEvtMap>(event: TKey, ...args: Parameters<TEvtMap[TKey]>): void;
    /**
     * Subscribes to an event and calls the callback when it's emitted.  
     * If the event has already been emitted and is listed in `catchUpEvents`, the callback will be called immediately with the latest emitted arguments (catch-up behaviour).  
     * @param event The event to subscribe to. Use `as "_"` in case your event names aren't thoroughly typed (like when using a template literal, e.g. \`event-${val}\` as "_")  
     * @returns Returns a function that can be called to unsubscribe the event listener  
     * @example ```ts  
     * const emitter = new PicoEmitter<{  
     *   foo: (bar: string) => void;  
     * }>({  
     *   publicEmit: true,  
     * });  
     *  
     * let i = 0;  
     * const unsub = emitter.on("foo", (bar) => {  
     *   // unsubscribe after 10 events:  
     *   if(++i === 10) unsub();  
     *   console.log(bar);  
     * });  
     *  
     * emitter.emit("foo", "bar");  
     * ```  
     */
    on<TKey extends keyof TEvtMap>(event: TKey | "_", cb: TEvtMap[TKey]): () => void;
    /**
     * Subscribes to an event and calls the callback or resolves the Promise only once when it's emitted.  
     * If the event has already been emitted and is listed in `catchUpEvents`, the callback will be called immediately with the latest emitted arguments (catch-up behaviour).  
     * @param event The event to subscribe to. Use `as "_"` in case your event names aren't thoroughly typed (like when using a template literal, e.g. \`event-${val}\` as "_")  
     * @param cb The callback to call when the event is emitted - if provided or not, the returned Promise will resolve with the event arguments  
     * @returns Returns a Promise that resolves with the event arguments when the event is emitted  
     * @example ```ts  
     * const emitter = new PicoEmitter<{  
     *   foo: (bar: string) => void;  
     * }>();  
     *  
     * // Promise syntax:  
     * const [bar] = await emitter.once("foo");  
     * console.log(bar);  
     *  
     * // Callback syntax:  
     * emitter.once("foo", (bar) => console.log(bar));  
     * ```  
     */
    once<TKey extends keyof TEvtMap>(event: TKey | "_", cb?: TEvtMap[TKey]): Promise<Parameters<TEvtMap[TKey]>>;
    /**
     * Allows subscribing to multiple events and calling the callback only when one of, all of, or a subset of the events are emitted, either continuously or only once.  
     * If any of the events have already been emitted and are listed in `catchUpEvents`, the callback will be called immediately if the criteria are met, with the latest emitted arguments (catch-up behaviour).  
     * @param options An object or array of objects with the following properties:  
     * `callback` (required) is the function that will be called when the conditions are met.  
     *  
     * Set `once` to true to call the callback only once for the first event (or set of events) that match the criteria, then stop listening.  
     * If `signal` is provided, the subscription will be canceled when the given signal is aborted.  
     *  
     * If `oneOf` is used, the callback will be called when any of the matching events are emitted.  
     * If `allOf` is used, the callback will be called after all of the matching events are emitted at least once, then any time any of them are emitted.  
     * If both `oneOf` and `allOf` are used together, the callback will be called when any of the `oneOf` events are emitted AND all of the `allOf` events have been emitted at least once.  
     * At least one of `oneOf` or `allOf` must be provided.  
     *  
     * @returns Returns a function that can be called to unsubscribe all listeners created by this call. Alternatively, pass an `AbortSignal` to all options objects to achieve the same effect or for finer control.  
     */
    onMulti<TEvt extends keyof TEvtMap>(options: PicoEmitterOnMultiOptions<TEvtMap> | Array<PicoEmitterOnMultiOptions<TEvtMap>>): Unsubscribe;
    /** Unsubscribes all event listeners from this instance. Also clears the event catch-up memory. */
    protected unsubscribeAll(): void;
}
export {};