Endgame-Analyzer/game_state.h

#ifndef DYNAMIC_PROGRAM_GAME_STATE_H
#define DYNAMIC_PROGRAM_GAME_STATE_H

#include <array>
#include <cstdint>
#include <algorithm>
#include <cstddef>
#include <bitset>
#include <limits>
#include <optional>
#include <boost/container/static_vector.hpp>
#include <list>
#include <ostream>


namespace Hanabi {

using rank_t = std::uint8_t;
using suit_t = std::uint8_t;
using clue_t = std::uint8_t;
using player_t = std::int8_t;

using state_t = std::uint32_t;

/**
 * We will generally assume that stacks are played from n to 0
 * Playing a 0 will yield a clue
 * Therefore, for the default hanabi, we will play 4,3,2,1,0 in that order
 * on each stack. A stack with no cards played implicitly has value 5 on it
 * This is just easier to implement, since then the remaining number of cards
 * to be played is always the current number of the stack
 */
constexpr rank_t starting_card_rank = 5;
constexpr suit_t max_suit_index = 5;
constexpr size_t max_card_duplicity = 3;
constexpr player_t draw_pile = -1;
constexpr player_t trash_or_play_stack = -2;
constexpr clue_t max_num_clues = 8;

constexpr std::array<std::string, 6> suit_initials{"r", "y", "g", "b", "p", "t"};

struct Card {
  suit_t suit;
  rank_t rank;
  uint8_t copy;

  Card &operator++();
  Card successor() const;
  const Card operator++(int);

  auto operator<=>(const Card &) const = default;
};

std::ostream &operator<<(std::ostream &os, const Card &card) {
  os << suit_initials[card.suit] << 5 - card.rank;
  return os;
}

constexpr Card r0 = {0, 0, 0};
constexpr Card r1 = {0, 1, 0};
constexpr Card r2 = {0, 2, 0};
constexpr Card r3 = {0, 3, 0};
constexpr Card r4 = {0, 4, 0};
constexpr Card y0 = {1, 0, 0};
constexpr Card y1 = {1, 1, 0};
constexpr Card y2 = {1, 2, 0};
constexpr Card y3 = {1, 3, 0};
constexpr Card y4 = {1, 4, 0};

/**
 * To store:
 * - Draw pile size
 * - Distribution of cards
 *      - Which cards exist?
 * - Number of clues
 */

template <std::size_t num_suits> using Stacks = std::array<rank_t, num_suits>;

template <std::size_t num_suits>
std::ostream &operator<<(std::ostream &os, const Stacks<num_suits> &stacks);

struct CardMultiplicity {
  Card card;
  std::uint8_t multiplicity;

  auto operator<=>(const CardMultiplicity &) const = default;
};

template <std::size_t num_suits, typename T, bool respect_card_duplicity>
struct CardArrayMember {
};

template <std::size_t num_suits, typename T>
struct CardArrayMember<num_suits, T, true> {
    auto operator<=>(const CardArrayMember &) const = default;
    std::array<std::array<std::array<T , max_card_duplicity>, starting_card_rank>, num_suits> array {};
};

template <std::size_t num_suits, typename T>
struct CardArrayMember<num_suits, T, false> {
    auto operator<=>(const CardArrayMember &) const = default;
    std::array<std::array<T, starting_card_rank>, num_suits> array {};
};

template <std::size_t num_suits, typename T, bool respect_card_duplicity = true> struct CardArray {

    using value_type = T;

    CardArray() = default;
    explicit CardArray(value_type default_val);

    const value_type &operator[](const Card &card) const;

    value_type &operator[](const Card &card);

    auto operator<=>(const CardArray &) const = default;

private:
    CardArrayMember<num_suits, T, respect_card_duplicity> _vals;
};

enum class ActionType {
    play = 0,
    discard = 1,
    clue = 2,
    color_clue = 2,
    rank_clue = 3,
    end_game = 4,
    vote_terminate = 10,
};

struct BacktrackAction {
  ActionType type{};
  // The card that was discarded or played
  Card discarded{};
  // Index of card in hand that was discarded or played
  std::uint8_t index{};
  // Multiplicity of new draw (needed for probability calculations)
  std::uint8_t multiplicity{};
};

template <std::size_t num_suits, player_t num_players, std::size_t hand_size>
class HanabiState {
public:
    HanabiState() = default;
    explicit HanabiState(const std::vector<Card>& deck);

    double backtrack(size_t depth);

    BacktrackAction clue();

    /**
     * Plays a card from current hand, drawing top card of draw pile and rotating draw pile
     * @param index of card in hand to be played
     */
    BacktrackAction play(std::uint8_t index);

    BacktrackAction discard(std::uint8_t index);

    std::uint8_t find_card_in_hand(const Card& card) const;

    void normalize_draw_and_positions();

    void revert(const BacktrackAction &action);

    uint8_t draw(uint8_t index);

    void revert_draw(std::uint8_t index, Card discarded_card);

    void incr_turn();

    void decr_turn();

    bool is_trash(const Card& card) const;
    bool is_playable(const Card& card) const;

    player_t _turn{};
    clue_t _num_clues{};
    std::uint8_t _weighted_draw_pile_size{};
    Stacks<num_suits> _stacks{};
    std::array<std::array<Card, hand_size>, num_players> _hands{};
    CardArray<num_suits, player_t> _card_positions{};
    std::list<CardMultiplicity> _draw_pile{};
    std::uint8_t endgame_turns_left;

    static constexpr uint8_t no_endgame = std::numeric_limits<uint8_t>::max();

    // further statistics that we might want to keep track of
    uint8_t _pace{};
    uint8_t _score{};

    auto operator<=>(const HanabiState &) const = default;
};

template <std::size_t num_suits, player_t num_players, std::size_t hand_size>
std::ostream & operator<<(std::ostream &os, HanabiState<num_suits, num_players, hand_size> hanabi_state);

template class HanabiState<5, 3, 4>;

}

#include "game_state.hpp"

#endif // DYNAMIC_PROGRAM_GAME_STATE_H