index.js

const { App } = require('@slack/bolt');
const { connectToDb, Player, Install } = require('./db');
const { getNewRating } = require('./elo');
const { convertMentionToId, shuffle, getMatching } = require('./utils');

// Connect to slack with bolt
const app = new App({
  // token: process.env.SLACK_BOT_TOKEN,
  signingSecret: process.env.SLACK_SIGNING_SECRET,
  clientId: process.env.SLACK_CLIENT_ID,
  clientSecret: process.env.SLACK_CLIENT_SECRET,
  stateSecret: 'matts-state-secret',
  scopes: ['app_mentions:read', 'chat:write', 'users:read'],
  installationStore: {
    storeInstallation: async installation =>
      Install.create({
        _id: installation.team.id,
        installation,
      }),
    fetchInstallation: async installQuery => {
      const install = await Install.findById(installQuery.teamId).exec();
      return install.installation;
    },
  },
});

connectToDb();

app.event('app_mention', async ({ event, client }) => {
  try {
    const words = event.text.split(' ');
    if (words.length < 2) {
      throw new Error('Invalid format. Use `help` for a list of commands.');
    }
    const action = words[1];
    switch (action) {
      case 'register': {
        // Check message format
        if (words.length !== 2) {
          throw new Error('Invalid format. Use `help` for a list of commands.');
        }
        // Get user object from slack
        const user = await client.users.info({ user: event.user });
        await Player.create({
          _id: event.user,
          name: user.user.profile.display_name || user.user.profile.real_name,
          wins: 0,
          losses: 0,
          elo: 1000,
        });
        await client.chat.postMessage({
          text: `Successfully registered <@${event.user}>`,
          channel: event.channel,
        });
        break;
      }
      case 'match': {
        // Check message format
        if (words.length !== 4) {
          throw new Error('Invalid format. Use `help` for a list of commands.');
        }
        // Convert string of form <@userId> to just userId
        const player1Id = convertMentionToId(words[2]);
        const player2Id = convertMentionToId(words[3]);
        // Get players from db
        const player1 = await Player.findById(player1Id).exec();
        const player2 = await Player.findById(player2Id).exec();
        // Compute new ELO for each player
        const player1NewElo = getNewRating(player1.elo, player2.elo, 1);
        const player2NewElo = getNewRating(player2.elo, player1.elo, 0);
        // Update each player and save to db
        player1.elo = player1NewElo;
        player1.wins += 1;
        player2.elo = player2NewElo;
        player2.losses += 1;
        player1.save();
        player2.save();
        // Post message reporting new rankings
        client.chat.postMessage({
          text: `Updated rankings are:\n${player1.name}: ${player1NewElo}\n${player2.name}: ${player2NewElo}`,
          channel: event.channel,
        });
        break;
      }
      case 'leaderboard': {
        // Check message format
        if (words.length !== 2) {
          throw new Error('Invalid format. Use `help` for a list of commands.');
        }
        const players = await Player.find({});
        // Sort players array in descending order by ELO
        players.sort((a, b) => b.elo - a.elo);
        // For each player, append output string to text
        let text = '';
        players.forEach((player, index) => {
          text += `${index + 1}. ${player.name} ${player.elo} record: ${
            player.wins
          }-${player.losses}\n`;
        });
        await client.chat.postMessage({
          text,
          channel: event.channel,
        });
        break;
      }
      case 'matchmake': {
        // Check message format
        if (words.length !== 2) {
          throw new Error('Invalid format. Use `help` for a list of commands.');
        }
        // Get all players from db
        const players2 = await Player.find({});
        // Shuffle players then pairwise match them up
        const shuffledPlayers = shuffle(players2);
        const matchups = getMatching(shuffledPlayers);
        // Send slack message reporting the matchups
        let text2 = 'Here are the matchups for this week:\n';
        matchups.forEach(matchup => {
          if (matchup[1]) {
            text2 += `${matchup[0].name} vs. ${matchup[1].name}\n`;
          } else {
            text2 += `${matchup[0].name} has a bye week`;
          }
        });
        await client.chat.postMessage({
          text: text2,
          channel: event.channel,
        });
        break;
      }
      case 'help':
        await client.chat.postMessage({
          text:
            'All commands are of the form @KingPong `<cmd>`\n\tregister\t\t\tRegisters a new player.\n\tleaderboard\tLists the current standings sorted by ELO rating.\n\tmatch\t\t\t  Reports a match played. The format is `@WinningPlayer @LosingPlayer`. Scores are not necessary.\n\tmatchmake\t Randomly matches all registered players. If an odd number of players, one will have a bye.',
          channel: event.channel,
        });
        break;
      default:
        await client.chat.postMessage({
          text: 'Unrecognized command. Try `help` for a list of commands.',
          channel: event.channel,
        });
    }
  } catch (e) {
    if (e.code && e.code === 11000) {
      await client.chat.postMessage({
        text: 'User already exists!',
        channel: event.channel,
      });
    } else {
      const text = e.message
        ? e.message
        : 'There was an error. Please try again.';
      await client.chat.postMessage({
        text,
        channel: event.channel,
      });
    }
  }
});

(async () => {
  await app.start(process.env.PORT || 3000);
})();