From 0bd9dd6ee83a956ace9d048f7799a42b37febab7 Mon Sep 17 00:00:00 2001
From: ghostyboyy97 <106448956+ghostyboyy97@users.noreply.github.com>
Date: Sat, 8 Nov 2025 11:21:16 -0500
Subject: [PATCH] fix (contrary): Contrary stat down handling in
 MoveEffectInPlus (#8165)

Co-authored-by: Alex <93446519+AlexOn1ine@users.noreply.github.com>
---
 src/battle_ai_util.c           | 43 ++++++++++++++++++++++++++++++++++
 test/battle/ability/contrary.c | 27 +++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index d866e5b0d0..353705cefc 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -1041,6 +1041,49 @@ static bool32 AI_IsMoveEffectInPlus(u32 battlerAtk, u32 battlerDef, u32 move, s3
         {
             switch (additionalEffect->moveEffect)
             {
+                case MOVE_EFFECT_ATK_MINUS_1:
+                case MOVE_EFFECT_ATK_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_ATK))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_DEF_MINUS_1:
+                case MOVE_EFFECT_DEF_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_ATK))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_SPD_MINUS_1:
+                case MOVE_EFFECT_SPD_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_DEF))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_SP_ATK_MINUS_1:
+                case MOVE_EFFECT_SP_ATK_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_SPATK))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_SP_DEF_MINUS_1:
+                case MOVE_EFFECT_SP_DEF_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_SPDEF))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_EVS_MINUS_1:
+                case MOVE_EFFECT_EVS_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_EVASION))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_ACC_MINUS_1:
+                case MOVE_EFFECT_ACC_MINUS_2:
+                    if (abilityAtk == ABILITY_CONTRARY && BattlerStatCanRise(battlerAtk, abilityAtk, STAT_ACC))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_ATK_DEF_DOWN:
+                    if (abilityAtk == ABILITY_CONTRARY && (BattlerStatCanRise(battlerAtk, abilityAtk, STAT_ATK) || BattlerStatCanRise(battlerAtk, abilityAtk, STAT_DEF)))
+                        return TRUE;
+                    break;
+                case MOVE_EFFECT_DEF_SPDEF_DOWN:
+                    if (abilityAtk == ABILITY_CONTRARY && (BattlerStatCanRise(battlerAtk, abilityAtk, STAT_DEF) || BattlerStatCanRise(battlerAtk, abilityAtk, STAT_SPDEF)))
+                        return TRUE;
+                    break;
                 case MOVE_EFFECT_ATK_PLUS_1:
                 case MOVE_EFFECT_ATK_PLUS_2:
                     if (BattlerStatCanRise(battlerAtk, abilityAtk, STAT_ATK))
diff --git a/test/battle/ability/contrary.c b/test/battle/ability/contrary.c
index c69360a1e1..850ca60734 100644
--- a/test/battle/ability/contrary.c
+++ b/test/battle/ability/contrary.c
@@ -242,4 +242,31 @@ SINGLE_BATTLE_TEST("Sticky Web raises Speed by 1 for Contrary mon on switch-in")
     }
 }
 
+AI_SINGLE_BATTLE_TEST("AI sees Contrary-effected moves correctly in MoveEffectInPlus instead of as a neutral effect")
+{
+    GIVEN{
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_TRY_TO_FAINT | AI_FLAG_CHECK_VIABILITY | AI_FLAG_SMART_SWITCHING | AI_FLAG_SMART_MON_CHOICES | AI_FLAG_OMNISCIENT);
+        PLAYER(SPECIES_HERACROSS){
+            Level(44);
+            HP(1);
+            Speed(5);
+            Nature(NATURE_ADAMANT);
+            Item(ITEM_LOADED_DICE);
+            Moves(MOVE_PIN_MISSILE);
+        }
+        OPPONENT(SPECIES_SERPERIOR){
+            Level(44);
+            Speed(10);
+            Nature(NATURE_TIMID);
+            Ability(ABILITY_CONTRARY);
+            Moves(MOVE_DRAGON_PULSE, MOVE_SPIN_OUT, MOVE_HIDDEN_POWER, MOVE_GLARE);
+        }
+    } WHEN {
+        TURN{
+            MOVE(player, MOVE_PIN_MISSILE);
+            EXPECT_MOVE(opponent, MOVE_SPIN_OUT); // previously all 107, now sees speed can rise w/ Contrary
+        }
+    }
+}
+
 TO_DO_BATTLE_TEST("Contrary does not invert stat changes that have been Baton-passed")