app.js

// @flow
const Discord = require("discord.js");
const MongoClient = require("mongodb").MongoClient;
const _ = require("lodash");
const request = require("request");
const moment = require("moment");

const bot = new Discord.Client();
const { getItemID, calculateUniqueProbability } = require("./utils.js");
const config = require("./config.json");

const ITEM_DATA = require("./itemData.json");

const DB_URI = `mongodb+srv://${config.db_user}:${config.db_password}@${
  config.db_url
}`;
const ROTATIONS_IMAGE_URL = "https://i.redd.it/hdfsf45xwzqy.png";
const OSRS_GE_BASE_URL =
  "http://services.runescape.com/m=itemdb_oldschool/api/catalogue/detail.json?item=";
const HELP_MESSAGE =
  "This bot supports the following commands:\n" +
  "- `!help`: provides an overview of the bots functionality\n" +
  "- `!rotation`: displays the different possible raid rotations\n" +
  "- `!item [itemName]`: displays the drop rate and current price of the specified raids items\n" +
  "- `!drop [points]`: calculates the % chance of receiving a unique drop based on the amount of points accumulated in a raid";
const COMMANDS = {
  HELP: "help",
  ROTATION: "rotation",
  ITEM: "item",
  DROP: "drop"
};

bot.login(config.token);

bot.on("ready", () => {
  console.log("Bot has started successfully!");

  bot.user.setPresence({
    status: "Online",
    game: {
      name: "Old School RuneScape",
      type: "LISTENING"
    }
  });

  updateDBItems();
  setInterval(() => {
    updateDBItems();
  }, config.update_item_interval);
});

bot.on("message", async message => {
  if (message.author.bot || message.content.indexOf(config.prefix) !== 0) {
    return;
  }

  const args = message.content
    .slice(config.prefix.length)
    .trim()
    .split(/ +/g);
  const command = args.shift().toLowerCase();
  const { HELP, ROTATION, DROP, ITEM } = COMMANDS;
  const commandsWithArgs = [DROP, ITEM];

  if (!COMMANDS[command.toUpperCase()]) {
    return;
  }
  if (commandsWithArgs.indexOf(command) !== -1 && _.isEmpty(args)) {
    message.channel.send(
      "ERROR: You must supply an arguement for this command! Use `!help` for an overview of functionality."
    );
    return;
  }

  switch (command) {
    case HELP:
      message.channel.send(HELP_MESSAGE);
      break;
    case ROTATION:
      message.channel.send(ROTATIONS_IMAGE_URL);
      break;
    case DROP:
      message.channel.send(calculateUniqueProbability(args.join(" ")));
      break;
    case ITEM:
      const itemID = getItemID(args.join(" "));
      if (!!itemID) {
        const retVal = await getSingleItem(itemID);
        if (!!retVal) {
          message.channel.send(buildSingleItemTable(retVal));
        } else {
          message.channel.send("ERROR: Item not found!");
        }
      } else {
        message.channel.send("ERROR: Item not found!");
      }
      break;
    default:
      break;
  }
});

// Gets the price of an item from the RuneScape Grand Exchange website (http://services.runescape.com/m=itemdb_oldschool/)
const getExchangePrice = (itemID, callback) => {
  const url = OSRS_GE_BASE_URL + itemID;

  request(
    {
      url: url,
      json: true
    },
    (error, response) => {
      if (error || response.statusCode !== 200) {
        return callback(error || { statusCode: response.statusCode });
      }
      callback(itemID, response);
    }
  );
};

// Updates a single item by id
const updateDBItem = (itemID, response) => {
  const currentPrice = _.get(response, "body.item.current.price");
  if (!currentPrice) {
    console.log("Error retrieving response for item:", itemID);
  }

  MongoClient.connect(DB_URI, (err, client) => {
    if (err) throw err;

    const items = client.db(config.db_name).collection(config.db_collection);
    const itemQuery = { id: itemID };
    const updateQuery = {
      $set: { value: currentPrice }
    };

    items.updateOne(itemQuery, updateQuery, (err, res) => {
      if (err) {
        console.log("Error updating item:", itemID);
        console.log("Error:", err);
      }
      client.close();
    });
  });
};

// Updates all items in the DB
const updateDBItems = () => {
  _.forEach(ITEM_DATA.items, item => {
    getExchangePrice(item.id, updateDBItem);
  });
};

// Retrieves the object for a specific item from the database
async function getSingleItem(itemID) {
  const client = await MongoClient.connect(DB_URI);
  const result = await client
    .db(config.db_name)
    .collection(config.db_collection)
    .find({ id: itemID })
    .toArray();

  return result;
}

// Builds a Discord Rich Embedded Message with the item's information
const buildSingleItemTable = response => {
  if (!response) {
    console.log("null response");
    return null;
  }
  const itemName = _.get(response[0], "itemName", "N/A");
  const value = _.get(response[0], "value", "N/A");
  const probability = _.get(response[0], "probability", "N/A");

  let message = new Discord.RichEmbed();
  message
    .addField("Item", itemName, true)
    .addField("Price", value, true)
    .addField("Drop Rate", probability, true);

  return message;
};