Function zimo

src/simulation/zimo.cpp:28–98

namespace Kanachan{

std::any zimo(Kanachan::RoundState &round_state, Kanachan::GameLog &game_log)
{
  auto const [action, zimo_tile] = round_state.onZimo(game_log);

  if (action <= 147u) {
    // Da Pai (打牌)
    // この時点ではロンされる可能性があるため立直は成立しない．
    // また，立直が確定しない限り四家立直も確定しない．
    KANACHAN_ASSERT((zimo_tile < 37u));
    std::uint_fast8_t const tile = action / 4u;
    // 親の配牌14枚のうちどれが第一自摸であるかの区別が存在しないため，
    // 親の第一打牌は常に手出しになる．
    bool const moqi = round_state.getNumLeftTiles() == 69u ? false : ((action - tile * 4u) / 2u == 1u);
    bool const lizhi = ((action - tile * 4u - moqi * 2u) == 1u);
    auto dapai = std::bind(
      &Kanachan::dapai, std::ref(round_state), tile, moqi, lizhi, std::ref(game_log));
    std::function<std::any()> next_step(std::move(dapai));
    return next_step;
  }

  if (action == UINT_FAST16_MAX) {
    // Da Pai after Li Zhi (立直後の打牌)
    KANACHAN_ASSERT((zimo_tile < 37u));
    auto dapai = std::bind(
      &Kanachan::dapai, std::ref(round_state), zimo_tile, /*moqi = */true,
      /*lizhi = */false, std::ref(game_log));
    std::function<std::any()> next_step(std::move(dapai));
    return next_step;
  }

  if (/*148u <= action && */action <= 181u) {
    // An Gang (暗槓)
    // 暗槓は槍槓が成立する可能性があるため，この時点では四槓散了は確定しない．
    KANACHAN_ASSERT((zimo_tile < 37u));
    std::uint_fast8_t const encode = action - 148u;
    auto angang = std::bind(
      &Kanachan::angang, std::ref(round_state), zimo_tile, encode, std::ref(game_log));
    std::function<std::any()> next_step(std::move(angang));
    return next_step;
  }

  if (/*182u <= action && */action <= 218u) {
    // Jia Gang (加槓)
    // 加槓は槍槓が成立する可能性があるため，この時点では四槓散了は確定しない．
    KANACHAN_ASSERT((zimo_tile < 37u));
    std::uint_fast8_t const encode = action - 182u;
    auto jiagang = std::bind(
      &Kanachan::jiagang, std::ref(round_state), zimo_tile, encode, std::ref(game_log));
    std::function<std::any()> next_step(std::move(jiagang));
    return next_step;
  }

  if (action == 219u) {
    // Zi Mo Hu (自摸和)
    KANACHAN_ASSERT((zimo_tile < 37u));
    auto hule = std::bind(&Kanachan::hule, std::ref(round_state), zimo_tile, std::ref(game_log));
    std::function<std::any()> next_step(std::move(hule));
    return next_step;