feat(helpers): events collector

packages/helpers/src/Collector.ts

@@ -0,0 +1,79 @@
+import { MakeRequired, Options } from '@biscuitland/common';
+import { type Session, Handler } from '@biscuitland/core';
+import { GatewayEvents } from '@biscuitland/ws';
+import { EventEmitter } from 'node:events';
+
+interface CollectorOptions<E extends keyof GatewayEvents> {
+  event: `${E}`;
+  filter?: (...args: Parameters<Handler[E]>) => unknown;
+  max?: number;
+  time?: number;
+  idle?: number;
+}
+
+export const DEFAULT_OPTIONS = {
+  filter: () => true,
+  max: -1
+};
+
+export enum CollectorStatus {
+  Idle = 0,
+  Started = 1,
+  Ended = 2
+}
+
+export class EventCollector<E extends keyof GatewayEvents> extends EventEmitter {
+  collected = new Set<Parameters<Handler[E]>[0]>();
+  status: CollectorStatus = CollectorStatus.Idle;
+  options: MakeRequired<CollectorOptions<E>, 'filter' | 'max'>;
+  private timeout: NodeJS.Timeout | null = null;
+
+  constructor(readonly session: Session, rawOptions: CollectorOptions<E>) {
+    super();
+    this.options = Options(DEFAULT_OPTIONS, rawOptions);
+  }
+
+  start() {
+    this.session.setMaxListeners(this.session.getMaxListeners() + 1);
+    this.session.on(this.options.event, (...args: unknown[]) => this.collect(...(args as Parameters<Handler[E]>)));
+    this.timeout = setTimeout(() => this.stop('time'), this.options.idle ?? this.options.time);
+  }
+
+  private collect(...args: Parameters<Handler[E]>) {
+    if (this.options.filter?.(...args)) {
+      this.collected.add(args[0]);
+      this.emit('collect', ...args);
+    }
+
+    if (this.options.idle) {
+      if (this.timeout) clearTimeout(this.timeout);
+      this.timeout = setTimeout(() => this.stop('time'), this.options.idle);
+    }
+
+    if (this.collected.size >= this.options.max!) this.stop('max');
+  }
+
+  stop(reason = 'User stopped') {
+    if (this.status === CollectorStatus.Ended) return;
+
+    if (this.timeout) clearTimeout(this.timeout);
+
+    this.session.removeListener(this.options.event, (...args: unknown[]) => this.collect(...(args as Parameters<Handler[E]>)));
+    this.session.setMaxListeners(this.session.getMaxListeners() - 1);
+
+    this.status = CollectorStatus.Ended;
+    this.emit('end', reason, this.collected);
+  }
+
+  on(event: 'collect', listener: (...args: Parameters<Handler[E]>) => unknown): this;
+  on(event: 'end', listener: (reason: string | null | undefined, collected: Set<Parameters<Handler[E]>[0]>) => void): this;
+  on(event: string, listener: unknown): this {
+    return super.on(event, listener as () => unknown);
+  }
+
+  once(event: 'collect', listener: (...args: Parameters<Handler[E]>) => unknown): this;
+  once(event: 'end', listener: (reason: string | null | undefined, collected: Set<Parameters<Handler[E]>[0]>) => void): this;
+  once(event: string, listener: unknown): this {
+    return super.once(event, listener as () => unknown);
+  }
+}