From 87ff267f800fc72a0859a529070a9aa0dab3c037 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maximilian=20Ke=C3=9Fler?= <git@maximilian-kessler.de>
Date: Sun, 6 Aug 2023 17:34:07 +0200
Subject: [PATCH] fix clue count when playing 5s on 8 clues

---
 game_state.h   |  2 +-
 game_state.hpp | 16 +++++++++-------
 main.cpp       |  2 +-
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/game_state.h b/game_state.h
index 424e09b..15c31e9 100644
--- a/game_state.h
+++ b/game_state.h
@@ -162,7 +162,7 @@ public:
     void normalize_draw_and_positions();
 
     void revert_clue();
-    void revert_play(const BacktrackAction &action);
+    void revert_play(const BacktrackAction &action, bool was_on_8_clues);
     void revert_discard(const BacktrackAction &action);
 
     uint8_t draw(uint8_t index);
diff --git a/game_state.hpp b/game_state.hpp
index 1b05326..1f52c37 100644
--- a/game_state.hpp
+++ b/game_state.hpp
@@ -128,7 +128,7 @@ namespace Hanabi {
 
         BacktrackAction ret{_hands[_turn][index], index, 0};
 
-        if (card.rank == 0) {
+        if (card.rank == 0 and _num_clues < max_num_clues) {
             // update clues if we played the last card of a stack
             _num_clues++;
         }
@@ -301,9 +301,10 @@ namespace Hanabi {
     }
 
     template<std::size_t num_suits, player_t num_players, std::size_t hand_size>
-    void HanabiState<num_suits, num_players, hand_size>::revert_play(const BacktrackAction& action) {
+    void HanabiState<num_suits, num_players, hand_size>::revert_play(const BacktrackAction& action, bool was_on_8_clues) {
+        ASSERT(!was_on_8_clues or _num_clues == 8);
         decr_turn();
-        if (action.discarded.rank == 0) {
+        if (action.discarded.rank == 0 and not was_on_8_clues) {
             _num_clues--;
         }
         revert_draw(action.index, action.discarded);
@@ -353,19 +354,20 @@ namespace Hanabi {
         for(std::uint8_t index = 0; index < hand_size; index++) {
             if(is_playable(hand[index])) {
                 if (_draw_pile.empty()) {
-                    auto copy = *this;
+                    bool on_8_clues = _num_clues == 8;
                     BacktrackAction action = play(index);
                     const double probability_for_this_play = backtrack(depth + 1);
-                    revert_play(action);
+                    revert_play(action, on_8_clues);
                     UPDATE_PROBABILITY(probability_for_this_play);
                 } else {
                     double sum_of_probabilities = 0;
                     uint8_t sum_of_mults = 0;
                     for (size_t i = 0; i < _draw_pile.size(); i++) {
+                        bool on_8_clues = _num_clues == 8;
                         BacktrackAction action = play(index);
                         sum_of_probabilities += backtrack(depth + 1) * action.multiplicity;
                         sum_of_mults += action.multiplicity;
-                        revert_play(action);
+                        revert_play(action, on_8_clues);
                         ASSERT(sum_of_mults <= _weighted_draw_pile_size);
                     }
                     ASSERT(sum_of_mults == _weighted_draw_pile_size);
@@ -376,7 +378,7 @@ namespace Hanabi {
         }
 
         // Check for discards now
-        if(_pace > 0) {
+        if(_pace > 0 and _num_clues < max_num_clues) {
             for(std::uint8_t index = 0; index < hand_size; index++) {
                 if (is_trash(hand[index])) {
                     double sum_of_probabilities = 0;
diff --git a/main.cpp b/main.cpp
index d350a12..fd143ca 100644
--- a/main.cpp
+++ b/main.cpp
@@ -30,7 +30,7 @@ void test_game() {
 
   auto a = state.play(4);
   std::cout << state;
-  state.revert_play(a);
+  state.revert_play(a, false);
 
   std::cout << state << std::endl;
   std::cout << state2 << std::endl;