status-sharding/src/handlers/queue.ts

Welcome to Status Sharding! This package is designed to provide an efficient and flexible solution for sharding Discord bots, allowing you to scale your bot across multiple processes or workers.

import { ShardingUtils } from '../other/shardingUtils';
import { QueueOptions } from '../types';

/** Item of the queue. */
export interface QueueItem<A = unknown[]> {
    /** Runs the item. */
	run(...args: unknown[]): Promise<unknown>;
    /** Arguments to pass to the item. */
	args: A;
    /** Time when the item was added to the queue. */
	time?: number;
    /** Time to wait until next item. */
	timeout: number;
}

/** Queue class. */
export class Queue {
	/** Whether the queue is paused. */
	private paused: boolean = false;
	/** List of items in the queue. */
	private queue: QueueItem[] = [];

	/** Creates an instance of Queue. */
	constructor(public options: QueueOptions) {}

	/** Starts the queue and run's the item functions. */
	public async start(): Promise<Queue> {
		if (this.options.mode !== 'auto') {
			return new Promise((resolve) => {
				const interval = setInterval(() => {
					if (this.queue.length === 0) {
						clearInterval(interval);
						resolve(this); // Queue successfully finished.
					}
				}, 200);
			});
		}

		const length = this.queue.length;

		for (let i = 0; i < length; i++) {
			if (!this.queue[0]) continue;
			const timeout = this.queue[0].timeout;
			await this.next(); await ShardingUtils.delayFor(timeout);
		}

		return this;
	}

	/** Runs the next item in the queue. */
	public async next(): Promise<unknown> {
		if (this.paused) return;
		const item = this.queue.shift();

		if (!item) return true;
		return item.run(...item.args);
	}

	/** Stops the queue. */
	public stop(): this {
		this.paused = true;
		return this;
	}

	/** Resumes the queue. */
	public resume(): this {
		this.paused = false;
		return this;
	}

	/** Adds an item to the queue. */
	public add(item: QueueItem): this {
		this.queue.push({
			run: item.run,
			args: item.args,
			time: Date.now(),
			timeout: item.timeout ?? this.options.timeout,
		});

		return this;
	}
}