gwei-alert-bot/src/gasAlertChecker.ts

import { EmbedBuilder, TextChannel } from 'discord.js';

import { DiscordClient } from './discordClient';
import redisClient from './redis';

import { GasAlert } from '../types/gasAlert';
import { GasPrices } from '../types/gasPrices';

const createGasAlertChecker = (client: DiscordClient) => 
  async (gasPrices: GasPrices) => {
    try {
      const gasAlerts: GasAlert[] = await redisClient
        .hVals('gas-alerts')
        .then((values) => values.map(val => JSON.parse(val)));

      gasAlerts.forEach(async (gasAlert) => {
        if (gasPrices.fast <= gasAlert.threshold) {
          const channel = await client.channels.fetch(gasAlert.channelId) as TextChannel;
          const user = await client.users.fetch(gasAlert.userId);

          channel.send({
            embeds: [
              new EmbedBuilder()
                .setTitle('Gas price alert!')
                .setDescription(`<@${gasAlert.userId}>!
Gas prices have fallen below your alert threshold of ${gasAlert.threshold} Gwei:
⚡ ${gasPrices.fast} ⦚⦚🚶 ${gasPrices.average} ⦚⦚ 🐢  ${gasPrices.slow}`)
                .setColor('#FF8C00')
            ],
            target: user
          })

          console.log(`Alerted ${user} under threshold ${gasAlert.threshold}: Removing alert...`)
          await redisClient.hDel('gas-alerts', `${gasAlert.userId}`)
        }
      });
    } catch (error) {
      console.log(`Error checking gas prices:\n`, error);
    }
  };

export { createGasAlertChecker };