test: Maintain a list of activated players for automated cleanup

[empires-server] / empathy.js

const express = require("express");
const Game = require("./game.js");

const MAX_PROMPT_ITEMS = 20;

/* This time parameter specifies a time period in which a phase will
 * not be considered idle in any circumstance. That is, this should be
 * a reasonable time in which any "active" player should have at least
 * started interacting with the current phase.
 *
 * Specified in seconds
 */
const PHASE_MINIMUM_TIME = 30;

/* This parameter gives the amount of time that the game will wait to
 * see activity from pending players. If this amount of time passes
 * with no activity from any of them, the server will emit an "idle"
 * event which will let clients issue a vote to end the current phase.
 *
 * Specified in seconds
 */
const PHASE_IDLE_TIMEOUT = 30;

class Empathy extends Game {
  constructor(id) {
    super(id);
    this.state = {
      prompts: [],
      active_prompt: null,
      players_answered: [],
      players_answering: new Set(),
      answering_idle: false,
      end_answers: new Set(),
      ambiguities: null,
      players_judged: [],
      players_judging: new Set(),
      judging_idle: false,
      end_judging: new Set(),
      scores: null
    };
    this.answers = [];
    this.answering_idle_timer = 0;
    this.answering_start_time_ms = 0;
    this.judging_idle_timer = 0;
    this.judging_start_time_ms = 0;
    this.next_prompt_id = 1;
    this.equivalencies = {};
  }

  reset() {

    /* Before closing out the current round, we accumulate the score
     * for each player into their runnning total. */
    for (let score of this.state.scores.scores) {
      const player = this.players.find(p => p.name === score.player);
      if (player.score)
        player.score += score.score;
      else
        player.score = score.score;

      /* And broadcast that new score out. */
      this.broadcast_event('player-update', player.info_json());
    }

    /* Now that we're done with the active prompt, we remove it from
     * the list of prompts and also remove any prompts that received
     * no votes. This keeps the list of prompts clean.
     */
    const active_id = this.state.active_prompt.id;
    this.state.prompts =
      this.state.prompts.filter(
        p => p.id !== active_id && p.votes.length > 0
      );

    this.state.active_prompt = null;
    this.state.players_answered = [];
    this.state.players_answering = new Set();
    this.state.answering_idle = false;
    this.state.end_answers = new Set();
    this.state.ambiguities = null;
    this.state.players_judged = [];
    this.state.players_judging = new Set();
    this.state.judging_idle = false;
    this.state.end_judging = new Set();
    this.state.scores = null;

    this.answers = [];
    if (this.answering_idle_timer) {
      clearTimeout(this.answering_idle_timer);
    }
    this.answering_idle_timer = 0;
    this.answering_start_time_ms = 0;
    if (this.judging_idle_timer) {
      clearTimeout(this.judging_idle_timer);
    }
    this.judging_idle_timer = 0;
    this.judging_start_time_ms = 0;
    this.equivalencies = {};

    this.broadcast_event_object('game-state', this.state);
  }

  add_prompt(items, prompt_string) {
    if (items > MAX_PROMPT_ITEMS)
      return {
        valid: false,
        message: `Maximum number of items is ${MAX_PROMPT_ITEMS}`
      };

    const prompt = new Prompt(this.next_prompt_id, items, prompt_string);
    this.next_prompt_id++;

    this.state.prompts.push(prompt);

    this.broadcast_event_object('prompt', prompt);

    return {
      valid: true,
      id: prompt.id
    };
  }

  /* Returns true if vote toggled, false for player or prompt not found */
  toggle_vote(prompt_id, session_id) {
    const player = this.players_by_session[session_id];

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt || ! player)
      return false;

    prompt.toggle_vote(player.name);

    this.broadcast_event_object('prompt', prompt);

    return true;
  }

  /* Returns true on success, false for prompt not found. */
  start(prompt_id) {
    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt)
      return false;

    /* Ignore any start request that comes in while a prompt is
     * already being played. */
    if (this.state.active_prompt)
      return false;

    this.state.active_prompt = prompt;

    this.broadcast_event_object('start', prompt);

    return true;
  }

  receive_answer(prompt_id, session_id, answers) {
    const player = this.players_by_session[session_id];
    if (! player)
      return { valid: false, message: "Player not found" };

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt)
      return { valid: false, message: "Prompt not found" };

    if (prompt !== this.state.active_prompt)
      return { valid: false, message: "Prompt no longer active" };

    /* Save the complete answers for our own use later. */
    this.answers.push({
      player: player,
      answers: answers
    });

    /* Update state (to be sent out to any future clients) */
    this.state.players_answering.delete(player.name);
    this.state.players_answered.push(player.name);

    /* And notify all players that this player has answered. */
    this.broadcast_event_object('player-answered', player.name);

    /* If no players are left in the answering list then we don't need
     * to wait for the answering_idle_timer to fire, because a person
     * who isn't there obviously can't be typing. So we can broadcast
     * the idle event right away. Note that we do this only if the
     * answering phase has been going for a while to avoid the case of
     * the first player being super fast and emptying the
     * players_answering list before anyone else even got in.
     */
    if (this.state.players_answering.size === 0 &&
        ((Date.now() - this.answering_start_time_ms) / 1000) > PHASE_MINIMUM_TIME)
    {
      this.broadcast_event_object('answering-idle', true);
    }

    return { valid: true };
  }

  receive_answering(prompt_id, session_id) {
    const player = this.players_by_session[session_id];
    if (! player)
      return { valid: false, message: "Player not found" };

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt)
      return { valid: false, message: "Prompt not found" };

    if (prompt !== this.state.active_prompt)
      return { valid: false, message: "Prompt no longer active" };

    if (this.answering_idle_timer) {
      clearTimeout(this.answering_idle_timer);
      this.ansering_idle_timer = 0;
    }
    if (! this.state.answering_idle) {
      this.answering_idle_timer = setTimeout(() => {
        this.state.answering_idle = true;
        this.broadcast_event_object('answering-idle', true);
      }, PHASE_IDLE_TIMEOUT * 1000);
    }

    if (this.answering_start_time_ms === 0)
      this.answering_start_time_ms = Date.now();

    /* Notify all players that this player is actively answering. */
    this.state.players_answering.add(player.name);
    this.broadcast_event_object('player-answering', player.name);

    return { valid: true };
  }

  /* Returns true if vote toggled, false for player or prompt not found */
  toggle_end_answers(prompt_id, session_id) {
    const player = this.players_by_session[session_id];

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt || ! player)
      return false;

    if (this.state.end_answers.has(player.name)) {
      this.state.end_answers.delete(player.name);
      this.broadcast_event_object('unvote-end-answers', player.name);
    } else {
      this.state.end_answers.add(player.name);
      this.broadcast_event_object('vote-end-answers', player.name);
    }

    return true;
  }

  perform_judging() {
    const word_map = {};

    for (let a of this.answers) {
      for (let word of a.answers) {
        const key = this.canonize(word);
        word_map[key] = word;
      }
    }

    this.state.ambiguities = Object.values(word_map).sort((a,b) => {
      return a.toLowerCase().localeCompare(b.toLowerCase());
    });

    if (this.judging_start_time_ms === 0) {
      this.judging_start_time_ms = Date.now();
    }

    this.broadcast_event_object('ambiguities', this.state.ambiguities);

    /* Notify all players of every player that is judging. */
    for (let player_name of this.state.players_answered) {
      this.state.players_judging.add(player_name);
      this.broadcast_event_object('player-judging', player_name);
    }
  }

  reset_judging_timeout() {
    if (this.judging_idle_timer) {
      clearTimeout(this.judging_idle_timer);
      this.judging_idle_timer = 0;
    }
    if (! this.state.judging_idle) {
      this.judging_idle_timer = setTimeout(() => {
        this.state.judging_idle = true;
        this.broadcast_event_object('judging-idle', true);
      }, PHASE_IDLE_TIMEOUT * 1000);
    }
  }

  receive_judged(prompt_id, session_id, word_groups) {
    const player = this.players_by_session[session_id];
    if (! player)
      return { valid: false, message: "Player not found" };

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt)
      return { valid: false, message: "Prompt not found" };

    if (prompt !== this.state.active_prompt)
      return { valid: false, message: "Prompt no longer active" };

    this.reset_judging_timeout();

    /* Each player submits some number of groups of answers that
     * should be considered equivalent. The server expands that into
     * the set of pair-wise equivalencies that are expressed. The
     * reason for that is so that the server can determine which
     * pair-wise equivalencies have majority support.
     */
    for (let group of word_groups) {

      for (let i = 0; i < group.length - 1; i++) {
        for (let j = i + 1; j < group.length; j++) {
          let eq = [group[i], group[j]];

          /* Put the two words into a reliable order so that we don't
           * miss a pair of equivalent equivalencies just because they
           * happen to be in the opposite order. */
          if (eq[0].localeCompare(eq[1]) > 0) {
            eq = [group[j], group[i]];
          }

          const key=`${this.canonize(eq[0])}:${this.canonize(eq[1])}`;

          const exist = this.equivalencies[key];
          if (exist) {
            exist.count++;
          } else {
            this.equivalencies[key] = {
              count: 1,
              words: eq
            };
          }

        }
      }
    }

    /* Update state (to be sent out to any future clients) */
    this.state.players_judging.delete(player.name);
    this.state.players_judged.push(player.name);

    /* And notify all players that this player has judged. */
    this.broadcast_event_object('player-judged', player.name);

    /* If no players are left in the judging list then we don't need
     * to wait for the judging_idle_timer to fire, because a person
     * who isn't there obviously can't be judging. So we can broadcast
     * the idle event right away. Note that we do this only if the
     * judging phase has been going for a while to avoid the case of
     * the first player being super fast and emptying the
     * players_judging list before anyone else even got in.
     */
    if (this.state.players_judging.size === 0 &&
        ((Date.now() - this.judging_start_time_ms) / 1000) > PHASE_MINIMUM_TIME)
    {
      this.broadcast_event_object('judging-idle', true);
    }

    return { valid: true };
  }

  receive_judging(prompt_id, session_id) {

    const player = this.players_by_session[session_id];
    if (! player)
      return { valid: false, message: "Player not found" };

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt)
      return { valid: false, message: "Prompt not found" };

    if (prompt !== this.state.active_prompt)
      return { valid: false, message: "Prompt no longer active" };

    this.reset_judging_timeout();

    /* Notify all players that this player is actively judging. */
    this.state.players_judging.add(player.name);
    this.broadcast_event_object('player-judging', player.name);

    return { valid: true };
  }

  /* Returns true if vote toggled, false for player or prompt not found */
  toggle_end_judging(prompt_id, session_id) {
    const player = this.players_by_session[session_id];

    const prompt = this.state.prompts.find(p => p.id === prompt_id);
    if (! prompt || ! player)
      return false;

    if (this.state.end_judging.has(player.name)) {
      this.state.end_judging.delete(player.name);
      this.broadcast_event_object('unvote-end-judging', player.name);
    } else {
      this.state.end_judging.add(player.name);
      this.broadcast_event_object('vote-end-judging', player.name);
    }

    return true;
  }

  canonize(word) {
    return word.trim().toLowerCase();
  }

  compute_scores() {
    const word_submitters = {};

    /* Perform a (non-strict) majority ruling on equivalencies,
     * dropping all that didn't get enough votes. */
    const quorum = Math.floor((this.state.players_judged.length + 1)/2);
    const agreed_equivalencies = Object.values(this.equivalencies).filter(
      eq => eq.count >= quorum);

    /* And with that agreed set of equivalencies, construct the full
     * groups. */
    const word_maps = {};

    for (let e of agreed_equivalencies) {
      const word0_canon = this.canonize(e.words[0]);
      const word1_canon = this.canonize(e.words[1]);
      let group = word_maps[word0_canon];
      if (! group)
        group = word_maps[word1_canon];
      if (! group)
        group = { words: [], players: new Set()};

      if (! word_maps[word0_canon]) {
        word_maps[word0_canon] = group;
        group.words.push(e.words[0]);
      }

      if (! word_maps[word1_canon]) {
        word_maps[word1_canon] = group;
        group.words.push(e.words[1]);
      }
    }

    /* Now go through answers from each player and add the player
     * to the set corresponding to each word group. */
    for (let a of this.answers) {
      for (let word of a.answers) {
        const word_canon = this.canonize(word);
        /* If there's no group yet, this is a singleton word. */
        if (word_maps[word_canon]) {
          word_maps[word_canon].players.add(a.player);
        } else {
          const group = { words: [word], players: new Set() };
          group.players.add(a.player);
          word_maps[word_canon] = group;
        }
      }
    }

    /* Now that we've assigned the players to these word maps, we now
     * want to collapse the groups down to a single array of
     * word_groups.
     *
     * The difference between "word_maps" and "word_groups" is that
     * the former has a property for every word that maps to a group,
     * (so if you iterate over the keys you will see the same group
     * multiple times). In contrast, iterating over"word_groups" will
     * have you visit each group only once. */
    const word_groups = Object.entries(word_maps).filter(
      entry => entry[0] === this.canonize(entry[1].words[0]))
          .map(entry => entry[1]);

    /* Now, go through each word group and assign the scores out to
     * the corresponding players.
     *
     * Note: We do this by going through the word groups, (as opposed
     * to the list of words from the players again), specifically to
     * avoid giving a player points for a wrod group twice (in the
     * case where a player submits two different words that the group
     * ends up judging as equivalent).
     */
    this.players.forEach(p => p.round_score = 0);
    for (let group of word_groups) {
      group.players.forEach(p => p.round_score += group.players.size);
    }

    const scores = this.players.filter(p => p.active).map(p => {
      return {
        player: p.name,
        score: p.round_score
      };
    });

    scores.sort((a,b) => {
      return b.score - a.score;
    });

    /* Put the word groups into a form the client can consume.
     */
    const words_submitted = word_groups.map(
      group => {
        return {
          word: group.words.join('/'),
          players: Array.from(group.players).map(p => p.name)
        };
      }
    );

    words_submitted.sort((a,b) => {
      return b.players.length - a.players.length;
    });

    /* Put this round's scores into the game state object so it will
     * be sent to any new clients that join. */
    this.state.scores = {
      scores: scores,
      words: words_submitted
    };

    /* And broadcast the scores to all connected clients. */
    this.broadcast_event_object('scores', this.state.scores);
  }
}

Empathy.router = express.Router();
const router = Empathy.router;

class Prompt {
  constructor(id, items, prompt) {
    this.id = id;
    this.items = items;
    this.prompt = prompt;
    this.votes = [];
  }

  toggle_vote(player_name) {
    if (this.votes.find(v => v === player_name))
      this.votes = this.votes.filter(v => v !== player_name);
    else
      this.votes.push(player_name);
  }
}

router.post('/prompts', (request, response) => {
  const game = request.game;

  const result = game.add_prompt(request.body.items, request.body.prompt);

  response.json(result);
});

router.post('/vote/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  if (game.toggle_vote(prompt_id, request.session.id))
    response.send('');
  else
    response.sendStatus(404);
});

router.post('/start/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  if (game.start(prompt_id))
    response.send('');
  else
    response.sendStatus(404);
});

router.post('/answer/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  const result = game.receive_answer(prompt_id,
                                     request.session.id,
                                     request.body.answers);
  response.json(result);

  /* If every registered player has answered, then there's no need to
   * wait for anything else. */
  if (game.state.players_answered.length >= game.players.length)
    game.perform_judging();
});

router.post('/answering/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  const result = game.receive_answering(prompt_id,
                                        request.session.id);
  response.json(result);
});

router.post('/end-answers/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  if (game.toggle_end_answers(prompt_id, request.session.id))
    response.send('');
  else
    response.sendStatus(404);

  /* The majority rule here includes all players that have answered as
   * well as all that have started typing. */
  const players_involved = (game.state.players_answered.length +
                            game.state.players_answering.size);

  if (game.state.end_answers.size > players_involved / 2)
    game.perform_judging();
});

router.post('/judged/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  const result = game.receive_judged(prompt_id,
                                     request.session.id,
                                     request.body.word_groups);
  response.json(result);

  /* If every player who answered has also judged, then there's no
   * need to wait for anything else. */
  if (game.state.players_judged.length >= game.state.players_answered.length)
    game.compute_scores();
});

router.post('/judging/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  const result = game.receive_judging(prompt_id,
                                      request.session.id);
  response.json(result);
});

router.post('/end-judging/:prompt_id([0-9]+)', (request, response) => {
  const game = request.game;
  const prompt_id = parseInt(request.params.prompt_id, 10);

  if (game.toggle_end_judging(prompt_id, request.session.id))
    response.send('');
  else
    response.sendStatus(404);

  if (game.state.end_judging.size > (game.state.players_answered.length / 2))
    game.compute_scores();
});

router.post('/reset', (request, response) => {
  const game = request.game;
  game.reset();

  response.send('');
});

Empathy.meta = {
  name: "Empathy",
  identifier: "empathy",
};

exports.Game = Empathy;