Improved Guaranteed Flinch logic (fake out et al) (#7501)

include/battle_ai_util.h

@@ -197,7 +197,8 @@ bool32 IsHealingMove(u32 move);
 bool32 HasHealingEffect(u32 battler);
 bool32 IsTrappingMove(u32 move);
 bool32 HasTrappingMoveEffect(u32 battler);
-bool32 ShouldFakeOut(u32 battlerAtk, u32 battlerDef, u32 move);
+bool32 IsFlinchGuaranteed(u32 battlerAtk, u32 battlerDef, u32 move);
+bool32 HasChoiceEffect(u32 battler);
 bool32 HasThawingMove(u32 battler);
 bool32 IsStatRaisingEffect(enum BattleMoveEffects effect);
 bool32 IsStatLoweringEffect(enum BattleMoveEffects effect);

src/battle_ai_main.c

@@ -1138,6 +1138,12 @@ static s32 AI_CheckBadMove(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
     if (DoesBattlerIgnoreAbilityChecks(battlerAtk, abilityAtk, move))
         abilityDef = ABILITY_NONE;
 
+    // If a pokemon can be guaranteed flinched, don't target the pokemon that can't be flinched.
+    if (hasTwoOpponents 
+     && !IsFlinchGuaranteed(battlerAtk, battlerDef, move) && IsFlinchGuaranteed(battlerAtk, BATTLE_PARTNER(battlerDef), move)
+     && aiData->effectiveness[battlerAtk][BATTLE_PARTNER(battlerDef)][gAiThinkingStruct->movesetIndex] != UQ_4_12(0.0))
+        ADJUST_SCORE(-5);
+
     // check non-user target
     if (!(moveTarget & MOVE_TARGET_USER))
     {
@@ -1999,6 +2005,8 @@ static s32 AI_CheckBadMove(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
         case EFFECT_FIRST_TURN_ONLY:
             if (!gDisableStructs[battlerAtk].isFirstTurn)
                 ADJUST_SCORE(-10);
+            if (HasChoiceEffect(battlerAtk))
+                ADJUST_SCORE(-5);
             break;
         case EFFECT_STOCKPILE:
             if (gDisableStructs[battlerAtk].stockpileCounter >= 3)
@@ -3946,6 +3954,10 @@ static u32 AI_CalcMoveEffectScore(u32 battlerAtk, u32 battlerDef, u32 move)
             ADJUST_SCORE(-20); // Force switch if all your attacking moves are physical and you have Natural Cure.
     }
 
+    // check guaranteed flinch, a la Fake Out
+    if (IsFlinchGuaranteed(battlerAtk, battlerDef, move))
+        ADJUST_SCORE(BEST_EFFECT);
+
     // Non-volatile statuses
     switch(GetMoveNonVolatileStatus(move))
     {
@@ -4551,9 +4563,7 @@ static u32 AI_CalcMoveEffectScore(u32 battlerAtk, u32 battlerDef, u32 move)
         ADJUST_SCORE(IncreaseStatUpScore(battlerAtk, battlerDef, STAT_CHANGE_DEF));
         break;
     case EFFECT_FIRST_TURN_ONLY:
-        if (ShouldFakeOut(battlerAtk, battlerDef, move) && MoveHasAdditionalEffectWithChance(move, MOVE_EFFECT_FLINCH, 100))
-            ADJUST_SCORE(GOOD_EFFECT);
-        else if (gDisableStructs[battlerAtk].isFirstTurn && GetBestDmgMoveFromBattler(battlerAtk, battlerDef, AI_ATTACKING) == move)
+        if (gDisableStructs[battlerAtk].isFirstTurn && GetBestDmgMoveFromBattler(battlerAtk, battlerDef, AI_ATTACKING) == move)
             ADJUST_SCORE(BEST_EFFECT);
         break;
     case EFFECT_STOCKPILE:

src/battle_ai_util.c

@@ -3502,18 +3502,57 @@ bool32 ShouldTrap(u32 battlerAtk, u32 battlerDef, u32 move)
     return FALSE;
 }
 
-bool32 ShouldFakeOut(u32 battlerAtk, u32 battlerDef, u32 move)
+bool32 IsFlinchGuaranteed(u32 battlerAtk, u32 battlerDef, u32 move)
 {
-    if ((!gDisableStructs[battlerAtk].isFirstTurn && MoveHasAdditionalEffectWithChance(move, MOVE_EFFECT_FLINCH, 100))
-    || gAiLogicData->abilities[battlerAtk] == ABILITY_GORILLA_TACTICS
-    || gAiLogicData->holdEffects[battlerAtk] == HOLD_EFFECT_CHOICE_BAND
-    || gAiLogicData->holdEffects[battlerDef] == HOLD_EFFECT_COVERT_CLOAK
-    || DoesSubstituteBlockMove(battlerAtk, battlerDef, move)
-    || (!IsMoldBreakerTypeAbility(battlerAtk, gAiLogicData->abilities[battlerAtk])
-    && (gAiLogicData->abilities[battlerDef] == ABILITY_SHIELD_DUST || gAiLogicData->abilities[battlerDef] == ABILITY_INNER_FOCUS)))
+    if (!MoveHasAdditionalEffect(move, MOVE_EFFECT_FLINCH))
         return FALSE;
 
-    return TRUE;
+    if (AI_IsSlower(battlerAtk, battlerDef, move, GetIncomingMove(battlerAtk, battlerDef, gAiLogicData), CONSIDER_PRIORITY))
+        return FALSE;
+
+    u32 i;
+    u32 additionalEffectCount = GetMoveAdditionalEffectCount(move);
+    // check move additional effects that are likely to happen
+    for (i = 0; i < additionalEffectCount; i++)
+    {
+        const struct AdditionalEffect *additionalEffect = GetMoveAdditionalEffectById(move, i);
+        // Only consider effects with a guaranteed chance to happen
+        if (!MoveEffectIsGuaranteed(battlerAtk, gAiLogicData->abilities[battlerAtk], additionalEffect))
+            continue;
+
+        if (additionalEffect->moveEffect == MOVE_EFFECT_FLINCH)
+        {
+            if (gAiLogicData->holdEffects[battlerDef] == HOLD_EFFECT_COVERT_CLOAK
+            || DoesSubstituteBlockMove(battlerAtk, battlerDef, move)
+            || (!IsMoldBreakerTypeAbility(battlerAtk, gAiLogicData->abilities[battlerAtk])
+            && (gAiLogicData->abilities[battlerDef] == ABILITY_SHIELD_DUST || gAiLogicData->abilities[battlerDef] == ABILITY_INNER_FOCUS)))
+                return FALSE;
+            else
+                return TRUE;
+        }
+    }
+    return FALSE;
+}
+
+bool32 HasChoiceEffect(u32 battler)
+{
+    u32 ability = gAiLogicData->abilities[battler];
+    if (ability == ABILITY_GORILLA_TACTICS)
+        return TRUE;
+
+    if (ability == ABILITY_KLUTZ)
+        return FALSE;
+    
+    enum ItemHoldEffect holdEffect = gAiLogicData->holdEffects[battler];
+    switch (holdEffect)
+    {
+    case HOLD_EFFECT_CHOICE_BAND:
+    case HOLD_EFFECT_CHOICE_SCARF:
+    case HOLD_EFFECT_CHOICE_SPECS:
+        return TRUE;
+    default:
+        return FALSE;
+    }
 }
 
 static u32 FindMoveUsedXTurnsAgo(u32 battlerId, u32 x)

test/battle/ai/ai_doubles.c

@@ -648,3 +648,16 @@ AI_DOUBLE_BATTLE_TEST("AI uses Power Split to improve its stats")
     }
 }
 
+AI_DOUBLE_BATTLE_TEST("AI prefers to Fake Out the opponent vulnerable to flinching.")
+{
+
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_TRY_TO_FAINT | AI_FLAG_CHECK_VIABILITY | AI_FLAG_DOUBLE_BATTLE | AI_FLAG_OMNISCIENT);
+        PLAYER(SPECIES_ZUBAT) { Ability(ABILITY_INNER_FOCUS); }
+        PLAYER(SPECIES_BRAIXEN) { Ability(ABILITY_BLAZE); }
+        OPPONENT(SPECIES_WOBBUFFET) { Moves(MOVE_FAKE_OUT, MOVE_BRANCH_POKE, MOVE_ROCK_SMASH); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { EXPECT_MOVE(opponentLeft, MOVE_FAKE_OUT, target:playerRight); }
+    }
+}