noctbot/bot/src/plugins/random_react.ts

import { Message } from "discord.js";
import { getRepository } from "typeorm";
import { RandomMessageReaction } from "@shared/db/entity/RandomMesssageReaction";
import { client } from "src/client";
import { Event, BotEventData, Plugin } from "src/model/plugin";
import { tryDo } from "@shared/common/async_utils";
import { logger } from "src/logging";

const timeout = (ms: number) => new Promise(r => setTimeout(r, ms));

@Plugin
export class RandomReact {
    @Event("message")
    async showHelp({ actionsDone }: BotEventData, msg: Message): Promise<void> {
        if(actionsDone)
            return;

        const repo = getRepository(RandomMessageReaction);

        const reactInfo = await repo.findOne({ where: { userId: msg.author.id } });

        if(!reactInfo)
            return;

        const emote = client.bot.emojis.resolve(reactInfo.reactionEmoteId);

        if(!emote)
            return;

        if(Math.random() < reactInfo.reactProbability) {
            await timeout(Math.random() * reactInfo.maxWaitMs);
            const result = await tryDo(msg.react(emote));
            if (!result.ok) {
                logger.error("Failed to react to user %s#%s (%s): %s", msg.author.username, msg.author.discriminator, msg.author.id, result.error);
            }
        }
    }
}