server/www/game.js

function Game(modules) {
  var sets = {
    river : cardSet('river'),
    hand : cardSet('hand'),
  };
  var selected = null;

  modules.messaging.addEventListener(["NewGame"], function(o) {
    o.game.river.forEach(function(cardName) {
      var card = new RiverCard(cardName);
      sets.river.card[card.value] = card;
      sets.river.dom.appendChild(card.dom);
    });
    o.game.players[modules.session.getKey()].hand.forEach(function(cardName) {
      var card = new HandCard(cardName);
      sets.hand.card[card.value] = card;
      sets.hand.dom.appendChild(card.dom);
    });
  });

  function cardSet(id) {
    return {
      card: {},
      dom: document.getElementById(id)
    };
  }

  function matchingInRiver(card) {
    return modules.fun.mapFilter(
      modules.fun.of(sets.river.card),
      modules.fun.isSet
    )(modules.hanafuda.sameMonth(card));
  }

  function Card(name) {
    this.value = modules.hanafuda.Card[name];
    this.name = name;
    this.dom = document.createElement('li');
    this.dom.className = "card";
    this.dom.textContent = name;
    this.dom.addEventListener('click', this.onClick());
  }

  Card.prototype.onClick = function() {return function() {};};

  function RiverCard() {
    Card.apply(this, arguments);
    this.candidate = false;
  }

  RiverCard.prototype.onClick = function() {
    var card = this;
    return function() {
      if(card.candidate) {
        modules.messaging.send({
          tag: "Play",
          move: {capture: [sets.hand.card[selected].name, card.name]}
        });
      }
    };
  };

  RiverCard.prototype.setCandidate = function(yes) {
    this.candidate = yes;
    this.dom.classList.toggle("candidate", yes);
  }

  function HandCard() {
    Card.apply(this, arguments);
  }

  HandCard.prototype.onClick = function() {
    var card = this;
    return function() {
      if(selected != undefined) {
        sets.hand.card[selected].setSelected(false);
      } else {
        card.play();
      }
    };
  };

  HandCard.prototype.setSelected = function(yes) {
    selected = yes ? this.value : null;
    this.dom.classList.toggle('selected', yes);
    matchingInRiver(this.value).forEach(function(card) {card.setCandidate(yes);});
  }

  HandCard.prototype.play = function() {
    var matching = matchingInRiver(this.value);
    if(matching.length > 1) {
      this.setSelected(true);
    } else {
      modules.messaging.send({tag: "Play", move: {play: this.name}})
    }
  }

}