Switch AI can see weather abilities of switchin candidates during damage calcs (#7373)

include/battle_ai_util.h

@@ -102,6 +102,7 @@ s32 AI_DecideKnownAbilityForTurn(u32 battlerId);
 enum ItemHoldEffect AI_DecideHoldEffectForTurn(u32 battlerId);
 bool32 DoesBattlerIgnoreAbilityChecks(u32 battlerAtk, u32 atkAbility, u32 move);
 u32 AI_GetWeather(void);
+u32 AI_GetSwitchinWeather(struct BattlePokemon battleMon);
 enum WeatherState IsWeatherActive(u32 flags);
 bool32 CanAIFaintTarget(u32 battlerAtk, u32 battlerDef, u32 numHits);
 bool32 CanIndexMoveFaintTarget(u32 battlerAtk, u32 battlerDef, u32 index, enum DamageCalcContext calcContext);

src/battle_ai_util.c

@@ -1638,6 +1638,33 @@ u32 AI_GetWeather(void)
     return gBattleWeather;
 }
 
+u32 AI_GetSwitchinWeather(struct BattlePokemon battleMon)
+{
+    u32 ability = battleMon.ability;
+    // Forced weather behaviour
+    if (!AI_WeatherHasEffect())
+        return B_WEATHER_NONE;
+    if (ability == ABILITY_CLOUD_NINE || ability == ABILITY_AIR_LOCK)
+        return B_WEATHER_NONE;
+    if (gBattleWeather & B_WEATHER_PRIMAL_ANY)
+        return gBattleWeather;
+        
+    // Switchin will introduce new weather
+    switch(ability)
+    {
+    case ABILITY_DRIZZLE:
+        return B_WEATHER_RAIN_NORMAL;
+    case ABILITY_DROUGHT:
+        return B_WEATHER_SUN_NORMAL;
+    case ABILITY_SAND_STREAM:
+        return B_WEATHER_SANDSTORM;
+    case ABILITY_SNOW_WARNING:
+        return B_SNOW_WARNING >= GEN_9 ? B_WEATHER_SNOW : B_WEATHER_HAIL;
+    default:
+        return gBattleWeather;
+    }    
+}
+
 enum WeatherState IsWeatherActive(u32 flags)
 {
     enum WeatherState state = WEATHER_INACTIVE;
@@ -4057,7 +4084,7 @@ s32 AI_CalcPartyMonDamage(u32 move, u32 battlerAtk, u32 battlerDef, struct Battl
         gAiThinkingStruct->saved[battlerAtk].saved = FALSE;
     }
 
-    dmg = AI_CalcDamage(move, battlerAtk, battlerDef, &effectiveness, NO_GIMMICK, NO_GIMMICK, AI_GetWeather());
+    dmg = AI_CalcDamage(move, battlerAtk, battlerDef, &effectiveness, NO_GIMMICK, NO_GIMMICK, AI_GetSwitchinWeather(switchinCandidate));
     // restores original gBattleMon struct
     FreeRestoreBattleMons(savedBattleMons);
 

test/battle/ai/ai_switching.c

@@ -1267,3 +1267,22 @@ AI_SINGLE_BATTLE_TEST("AI_FLAG_SMART_SWITCHING: AI considers 0 hits to KO as los
         TURN { MOVE(player, MOVE_TACKLE); EXPECT_SEND_OUT(opponent, 2); }
     }
 }
+
+AI_SINGLE_BATTLE_TEST("AI_SMART_MON_CHOICES: AI sees its own weather setting ability when considering switchin candidates")
+{
+    u32 ability = ABILITY_NONE;
+    PARAMETRIZE { ability = ABILITY_WATER_ABSORB; }
+    PARAMETRIZE { ability = ABILITY_DRIZZLE; }
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT | AI_FLAG_SMART_MON_CHOICES | AI_FLAG_OMNISCIENT);
+        PLAYER(SPECIES_ZIGZAGOON) { Speed(2); Moves(MOVE_SCRATCH); }
+        OPPONENT(SPECIES_ZIGZAGOON) { Speed(1); Level(1); Moves(MOVE_SCRATCH); }
+        OPPONENT(SPECIES_POLITOED) { Speed(5); Ability(ability); Moves(MOVE_BUBBLE_BEAM); }
+        OPPONENT(SPECIES_CONKELDURR) { Speed(1); Ability(ABILITY_GUTS); Moves(MOVE_SUPERPOWER); }
+    } WHEN {
+        if (ability == ABILITY_DRIZZLE)
+            TURN { MOVE(player, MOVE_SCRATCH); EXPECT_MOVE(opponent, MOVE_SCRATCH); EXPECT_SEND_OUT(opponent, 1); }
+        else
+            TURN { MOVE(player, MOVE_SCRATCH); EXPECT_MOVE(opponent, MOVE_SCRATCH); EXPECT_SEND_OUT(opponent, 2); }
+    }
+}