From b084dcd8d3e8ae1653de2a4d52420e2c181d8697 Mon Sep 17 00:00:00 2001
From: Pawkkie <61265402+Pawkkie@users.noreply.github.com>
Date: Sun, 14 Jul 2024 16:00:51 -0400
Subject: [PATCH] Fix Upper Hand being used blindly (#4973)

---
 src/battle_ai_main.c                 |  2 +-
 test/battle/move_effect/upper_hand.c | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/battle_ai_main.c b/src/battle_ai_main.c
index b890493c3aaa..d9055162341b 100644
--- a/src/battle_ai_main.c
+++ b/src/battle_ai_main.c
@@ -2644,7 +2644,7 @@ static s32 AI_CheckBadMove(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
                 ADJUST_SCORE(-10);
             break;
         case EFFECT_UPPER_HAND:
-            if (predictedMove == MOVE_NONE || IS_MOVE_STATUS(predictedMove) || AI_WhoStrikesFirst(battlerAtk, battlerDef, move) == AI_IS_SLOWER || GetMovePriority(battlerDef, move) < 1 || GetMovePriority(battlerDef, move) > 3) // Opponent going first or not using priority move
+            if (predictedMove == MOVE_NONE || IS_MOVE_STATUS(predictedMove) || AI_WhoStrikesFirst(battlerAtk, battlerDef, move) == AI_IS_SLOWER || GetMovePriority(battlerDef, predictedMove) < 1 || GetMovePriority(battlerDef, predictedMove) > 3) // Opponent going first or not using priority move
                 ADJUST_SCORE(-10);
             break;
         case EFFECT_PLACEHOLDER:
diff --git a/test/battle/move_effect/upper_hand.c b/test/battle/move_effect/upper_hand.c
index 04f2b8522565..6a041182fe5f 100644
--- a/test/battle/move_effect/upper_hand.c
+++ b/test/battle/move_effect/upper_hand.c
@@ -116,3 +116,19 @@ SINGLE_BATTLE_TEST("Upper Hand is boosted by Sheer Force")
         HP_BAR(player);
     }
 }
+
+AI_SINGLE_BATTLE_TEST("AI won't use Upper Hand unless it has seen a priority move")
+{
+    u16 move;
+    PARAMETRIZE { move = MOVE_TACKLE; }
+    PARAMETRIZE { move = MOVE_QUICK_ATTACK; }
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT);
+        ASSUME(gMovesInfo[MOVE_QUICK_ATTACK].priority == 1);
+        PLAYER(SPECIES_WOBBUFFET) {Moves(move); }
+        OPPONENT(SPECIES_WOBBUFFET) { Moves(MOVE_UPPER_HAND, MOVE_KARATE_CHOP); }
+    } WHEN {
+        TURN { MOVE(player, move); EXPECT_MOVE(opponent, MOVE_KARATE_CHOP); }
+        TURN { MOVE(player, move); EXPECT_MOVE(opponent, move == MOVE_QUICK_ATTACK ? MOVE_UPPER_HAND : MOVE_KARATE_CHOP); }
+    }
+}