Add combat target reacquire telemetry

src/game/char.cpp

@@ -161,6 +161,16 @@ void CHARACTER::Initialize()
 	m_iFishingPatternTightSequence = 0;
 	m_dwMiningWindowStart = 0;
 	m_iMiningWindowCount = 0;
+	m_dwCombatPatternWindowStart = 0;
+	m_dwLastCombatPatternTime = 0;
+	m_dwLastCombatPatternVictimVID = 0;
+	m_lLastCombatPatternVictimX = 0;
+	m_lLastCombatPatternVictimY = 0;
+	m_iCombatPatternSampleCount = 0;
+	m_iCombatPatternMinIntervalMs = 0;
+	m_iCombatPatternMaxIntervalMs = 0;
+	m_iCombatPatternMinStep = 0;
+	m_iCombatPatternMaxStep = 0;
 	
 	m_iLastPMPulse = 0;
 	m_iPMCounter = 0;

src/game/char.h

@@ -2073,6 +2073,16 @@ class CHARACTER : public CEntity, public CFSM, public CHorseRider
 		int					m_iFishingPatternTightSequence;
 		DWORD				m_dwMiningWindowStart;
 		int					m_iMiningWindowCount;
+		DWORD				m_dwCombatPatternWindowStart;
+		DWORD				m_dwLastCombatPatternTime;
+		DWORD				m_dwLastCombatPatternVictimVID;
+		long				m_lLastCombatPatternVictimX;
+		long				m_lLastCombatPatternVictimY;
+		int					m_iCombatPatternSampleCount;
+		int					m_iCombatPatternMinIntervalMs;
+		int					m_iCombatPatternMaxIntervalMs;
+		int					m_iCombatPatternMinStep;
+		int					m_iCombatPatternMaxStep;
 		void ClearPMCounter(void)       { m_iPMCounter = 0;      } 
 		void IncreasePMCounter(void)    { m_iPMCounter++;        }
 		void SetLastPMPulse(void);

src/game/char_battle.cpp

@@ -41,6 +41,119 @@
 #include <random>
 #include <algorithm>
 
+namespace
+{
+	constexpr DWORD kCombatPatternWindowMs = 10 * 60 * 1000;
+	constexpr int kCombatPatternMinSamples = 10;
+	constexpr int kCombatPatternMaxIntervalMs = 8000;
+	constexpr int kCombatPatternMaxIntervalSpreadMs = 280;
+	constexpr int kCombatPatternMaxStepSpread = 480;
+	constexpr int kCombatPatternMinRouteStep = 250;
+
+	void ResetCombatPatternWindow(LPCHARACTER ch, LPCHARACTER victim, DWORD now)
+	{
+		if (!ch)
+			return;
+
+		ch->m_dwCombatPatternWindowStart = now;
+		ch->m_dwLastCombatPatternTime = now;
+		ch->m_dwLastCombatPatternVictimVID = victim ? victim->GetVID() : 0;
+		ch->m_lLastCombatPatternVictimX = victim ? victim->GetX() : 0;
+		ch->m_lLastCombatPatternVictimY = victim ? victim->GetY() : 0;
+		ch->m_iCombatPatternSampleCount = 0;
+		ch->m_iCombatPatternMinIntervalMs = 0;
+		ch->m_iCombatPatternMaxIntervalMs = 0;
+		ch->m_iCombatPatternMinStep = 0;
+		ch->m_iCombatPatternMaxStep = 0;
+	}
+
+	void ObserveCombatTargetPattern(LPCHARACTER ch, LPCHARACTER victim, DWORD now)
+	{
+		if (!ch || !victim || !ch->IsPC())
+			return;
+
+		if (!victim->IsMonster() && !victim->IsStone())
+			return;
+
+		if (0 == ch->m_dwCombatPatternWindowStart || now - ch->m_dwCombatPatternWindowStart >= kCombatPatternWindowMs)
+		{
+			ResetCombatPatternWindow(ch, victim, now);
+			return;
+		}
+
+		if (0 == ch->m_dwLastCombatPatternVictimVID)
+		{
+			ResetCombatPatternWindow(ch, victim, now);
+			return;
+		}
+
+		if (ch->m_dwLastCombatPatternVictimVID == victim->GetVID())
+		{
+			ch->m_dwLastCombatPatternTime = now;
+			ch->m_lLastCombatPatternVictimX = victim->GetX();
+			ch->m_lLastCombatPatternVictimY = victim->GetY();
+			return;
+		}
+
+		const int iIntervalMs = static_cast<int>(now - ch->m_dwLastCombatPatternTime);
+		const int iStep = DISTANCE_APPROX(victim->GetX() - ch->m_lLastCombatPatternVictimX,
+						      victim->GetY() - ch->m_lLastCombatPatternVictimY);
+
+		ch->m_dwLastCombatPatternTime = now;
+		ch->m_dwLastCombatPatternVictimVID = victim->GetVID();
+		ch->m_lLastCombatPatternVictimX = victim->GetX();
+		ch->m_lLastCombatPatternVictimY = victim->GetY();
+
+		if (iIntervalMs <= 0 || iIntervalMs > kCombatPatternMaxIntervalMs)
+		{
+			ResetCombatPatternWindow(ch, victim, now);
+			return;
+		}
+
+		if (0 == ch->m_iCombatPatternSampleCount)
+		{
+			ch->m_iCombatPatternSampleCount = 1;
+			ch->m_iCombatPatternMinIntervalMs = iIntervalMs;
+			ch->m_iCombatPatternMaxIntervalMs = iIntervalMs;
+			ch->m_iCombatPatternMinStep = iStep;
+			ch->m_iCombatPatternMaxStep = iStep;
+			return;
+		}
+
+		++ch->m_iCombatPatternSampleCount;
+		ch->m_iCombatPatternMinIntervalMs = MIN(ch->m_iCombatPatternMinIntervalMs, iIntervalMs);
+		ch->m_iCombatPatternMaxIntervalMs = MAX(ch->m_iCombatPatternMaxIntervalMs, iIntervalMs);
+		ch->m_iCombatPatternMinStep = MIN(ch->m_iCombatPatternMinStep, iStep);
+		ch->m_iCombatPatternMaxStep = MAX(ch->m_iCombatPatternMaxStep, iStep);
+
+		if (ch->m_iCombatPatternSampleCount < kCombatPatternMinSamples)
+			return;
+
+		const int iIntervalSpread = ch->m_iCombatPatternMaxIntervalMs - ch->m_iCombatPatternMinIntervalMs;
+		const int iStepSpread = ch->m_iCombatPatternMaxStep - ch->m_iCombatPatternMinStep;
+		if (iIntervalSpread > kCombatPatternMaxIntervalSpreadMs ||
+		    iStepSpread > kCombatPatternMaxStepSpread ||
+		    ch->m_iCombatPatternMaxStep < kCombatPatternMinRouteStep)
+			return;
+
+		char szDetail[160];
+		snprintf(szDetail,
+			 sizeof(szDetail),
+			 "samples=%d interval=%d..%d step=%d..%d target=%u",
+			 ch->m_iCombatPatternSampleCount,
+			 ch->m_iCombatPatternMinIntervalMs,
+			 ch->m_iCombatPatternMaxIntervalMs,
+			 ch->m_iCombatPatternMinStep,
+			 ch->m_iCombatPatternMaxStep,
+			 victim->GetVID());
+		ch->RecordAntiCheatViolation("TARGET_REACQUIRE_PATTERN",
+						 iIntervalSpread <= 140 && iStepSpread <= 280 ? 2 : 1,
+						 szDetail);
+
+		ResetCombatPatternWindow(ch, victim, now);
+	}
+}
+
 DWORD AdjustExpByLevel(const LPCHARACTER ch, const DWORD exp)
 {
 	if (PLAYER_EXP_TABLE_MAX < ch->GetLevel())
@@ -271,6 +384,9 @@ bool CHARACTER::Attack(LPCHARACTER pkVictim, BYTE bType)
 	//	sys_log(0, "%s Attack %s type %u ret %d", GetName(), pkVictim->GetName(), bType, iRet);
 	if (iRet == BATTLE_DAMAGE || iRet == BATTLE_DEAD)
 	{
+		if (IsPC() && 0 == bType)
+			ObserveCombatTargetPattern(this, pkVictim, dwCurrentTime);
+
 		OnMove(true);
 		pkVictim->OnMove();