From 0530f49fd44c6d29e87f54991ea1d1337b14329c Mon Sep 17 00:00:00 2001
From: Pawkkie <61265402+Pawkkie@users.noreply.github.com>
Date: Thu, 22 May 2025 15:05:02 -0400
Subject: [PATCH] Fix AI boosting stats into mon with Haze (#6894)

---
 src/battle_ai_util.c | 63 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 61 insertions(+), 2 deletions(-)

diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index 6789fa58aa..1079cd7367 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -2192,6 +2192,31 @@ bool32 HasMoveWithEffect(u32 battlerId, enum BattleMoveEffects effect)
     return FALSE;
 }
 
+bool32 HasBattlerSideMoveWithEffect(u32 battler, u32 effect)
+{
+    if (HasMoveWithEffect(battler, effect))
+        return TRUE;
+    if (IsDoubleBattle() && HasMoveWithEffect(BATTLE_OPPOSITE(battler), effect))
+        return TRUE;
+    return FALSE;
+}
+
+// HasSideMoveWithMoveEffect checks if the AI knows a side has a move effect, 
+// while HasBattlerSideUsedMoveWithEffect checks if the side has ever used a move effect.
+// The former acts the same way as the latter if AI_FLAG_OMNISCIENT isn't used.
+bool32 HasBattlerSideUsedMoveWithEffect(u32 battler, u32 effect)
+{
+    u32 i;
+    for (i = 0; i < MAX_MON_MOVES; i++)
+    {
+        if (GetMoveEffect(gBattleHistory->usedMoves[battler][i]) == effect)
+            return TRUE;
+        if (IsDoubleBattle() && GetMoveEffect(gBattleHistory->usedMoves[BATTLE_OPPOSITE(battler)][i]) == effect)
+            return TRUE;
+    }
+    return FALSE;
+}
+
 bool32 HasNonVolatileMoveEffect(u32 battlerId, u32 effect)
 {
     s32 i;
@@ -2237,6 +2262,31 @@ bool32 HasMoveWithAdditionalEffect(u32 battlerId, u32 moveEffect)
     return FALSE;
 }
 
+bool32 HasBattlerSideMoveWithAdditionalEffect(u32 battler, u32 moveEffect)
+{
+    if (HasMoveWithAdditionalEffect(battler, moveEffect))
+        return TRUE;
+    if (IsDoubleBattle() && HasMoveWithAdditionalEffect(BATTLE_OPPOSITE(battler), moveEffect))
+        return TRUE;
+    return FALSE;
+}
+
+// HasBattlerSideMoveWithAdditionalEffect checks if the AI knows a side has a move effect, 
+// while HasBattlerSideUsedMoveWithAdditionalEffect checks if the side has ever used a move effect.
+// The former acts the same way as the latter if AI_FLAG_OMNISCIENT isn't used.
+bool32 HasBattlerSideUsedMoveWithAdditionalEffect(u32 battler, u32 moveEffect)
+{
+    u32 i;
+    for (i = 0; i < MAX_MON_MOVES; i++)
+    {
+        if (MoveHasAdditionalEffect(gBattleHistory->usedMoves[battler][i], moveEffect))
+            return TRUE;
+        if (IsDoubleBattle() && MoveHasAdditionalEffect(gBattleHistory->usedMoves[BATTLE_OPPOSITE(battler)][i], moveEffect))
+            return TRUE;
+    }
+    return FALSE;
+}
+
 bool32 HasMoveWithCriticalHitChance(u32 battlerId)
 {
     s32 i;
@@ -4071,10 +4121,19 @@ static enum AIScore IncreaseStatUpScoreInternal(u32 battlerAtk, u32 battlerDef,
         return NO_INCREASE;
 
     // Don't increase stats if opposing battler has Encore
-    if (HasMoveWithEffect(battlerDef, EFFECT_ENCORE))
+    if (HasBattlerSideMoveWithEffect(battlerDef, EFFECT_ENCORE))
         return NO_INCREASE;
 
-    if (IsDoubleBattle() && HasMoveWithEffect(GetPartnerBattler(battlerDef), EFFECT_ENCORE))
+    // Don't increase stats if opposing battler has used Haze effect
+    if (HasBattlerSideUsedMoveWithEffect(battlerDef, EFFECT_HAZE)
+        || HasBattlerSideUsedMoveWithAdditionalEffect(battlerDef, MOVE_EFFECT_CLEAR_SMOG)
+        || HasBattlerSideUsedMoveWithAdditionalEffect(battlerDef, MOVE_EFFECT_HAZE))
+        return NO_INCREASE;
+
+    // Don't increase if AI is at +1 and opponent has Haze effect
+    if (gBattleMons[battlerAtk].statStages[statId] >= MAX_STAT_STAGE - 5 && (HasBattlerSideMoveWithEffect(battlerDef, EFFECT_HAZE)
+        || HasBattlerSideMoveWithAdditionalEffect(battlerDef, MOVE_EFFECT_CLEAR_SMOG)
+        || HasBattlerSideMoveWithAdditionalEffect(battlerDef, MOVE_EFFECT_HAZE)))
         return NO_INCREASE;
 
     // Predicting switch