From 285cee07ef86dff5b6580f84529cbc282042c48b Mon Sep 17 00:00:00 2001
From: Calcitem <calcitem@outlook.com>
Date: Tue, 12 Jan 2021 01:07:29 +0800
Subject: [PATCH] rule50: Judge rule50 and draw (WIP)

---
 src/position.cpp | 2 +-
 src/search.cpp   | 3 +++
 src/thread.cpp   | 4 +++-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/position.cpp b/src/position.cpp
index 7441cf99..b2dbb06a 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -935,7 +935,7 @@ bool Position::check_if_game_is_over()
     }
 
     if (rule.maxStepsLedToDraw > 0 &&
-        rule50_count() > rule.maxStepsLedToDraw) {
+        posKeyHistory.size() > rule.maxStepsLedToDraw) {
         winner = DRAW;
         phase = Phase::gameOver;
         gameOverReason = GameOverReason::drawReasonRule50;
diff --git a/src/search.cpp b/src/search.cpp
index 7f0c822e..59c768e7 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -93,6 +93,9 @@ int Thread::search()
 #endif
 
     if (rootPos->get_phase() == Phase::moving) {
+        if (posKeyHistory.size() > rule.maxStepsLedToDraw) {
+            return 99;
+        }
 #ifdef THREEFOLD_REPETITION
         if (rootPos->has_game_cycle()) {
             return 3;
diff --git a/src/thread.cpp b/src/thread.cpp
index 36a3a7f3..fb26552c 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -143,7 +143,9 @@ void Thread::idle_loop()
             emitCommand();
         } else {
 #endif
-            if (search() == 3) {
+            int ret = search();
+
+            if (ret == 3 || ret == 50) {
                 loggerDebug("Draw\n\n");
                 strCommand = "draw";
                 emitCommand();