void step()

in simple_game/simple_hanabi.h [327:406]
59 lines of code
12 McCabe index (conditional complexity)

  void step(int action) override {
    if (allCards_.empty()) {
      // Initialize the game.
      for (int suit = 0; suit < (int)options_.cards.size(); ++suit) {
        for (int rank = 0; rank < (int)options_.cards[suit].size(); ++rank) {
          for (int k = 0; k < options_.cards[suit][rank]; ++k) {
            allCards_.emplace_back(suit, rank);
          }
        }
      }

      std::mt19937 rng(options_.seeds[action]);

      // Shuffle the card.
      std::shuffle(allCards_.begin(), allCards_.end(), rng);
      cardIdx_ = 0;

      // Deal the card.
      hands_.resize(options_.numPlayer);
      for (int i = 0; i < options_.numPlayer; ++i) {
        hands_[i].resize(options_.numHold);
        for (int j = 0; j < options_.numHold; ++j) {
          hands_[i][j] = allCards_[cardIdx_++];
        }
      }
      cardUsed_ = 0;
      currPlayer_ = 1;
      hints_ = options_.initHints;
      lives_ = options_.initLives;

      currTops_ = std::vector<int>(options_.cards.size(), -1);
      return;
    }

    assert(currPlayer_ >= 1 && currPlayer_ <= options_.numPlayer);
    Action a = parser_.decode(action);

    // During the game play.
    std::string pubAct = "p" + std::to_string(currPlayer_) + "_";
    if (a.type == HINT) {
      assert(hints_ > 0);
      // Hints.
      auto hintCard = hands_[a.hintPlayer - 1][a.cardIdx];
      // Note that the public information is the index not the card itself (the
      // player being hinted doesn't know the card).
      pubAct += a.info() + "(" + hintCard.hintStr(a.hintType) + ")";
      publicActions_.push_back(pubAct);
      hints_--;
      _nextPlayer();
      return;
    }

    auto& card = hands_[currPlayer_ - 1][a.cardIdx];
    assert(card.valid());

    // The card is revealed after the action. so we need to put them to pubAct.
    pubAct += a.info() + "(" + card.info(false) + ")";
    publicActions_.push_back(pubAct);

    if (a.type == PLAY) {
      if (card.rank == currTops_[card.suit] + 1) {
        currTops_[card.suit]++;
      } else {
        lives_--;
      }
    } else {
      // Discard card.
      hints_++;
    }

    cardUsed_++;
    // Take another card from the pool
    if (cardIdx_ < (int)allCards_.size()) {
      card = allCards_[cardIdx_++];
    } else {
      // Missing card.
      card.setInvalid();
    }
    _nextPlayer();
  }