Fix AI trying to switch when it can't, also ghosts can escape

include/battle_util.h

@@ -81,6 +81,7 @@ u32 IsAbilityOnSide(u32 battlerId, u32 ability);
 u32 IsAbilityOnOpposingSide(u32 battlerId, u32 ability);
 u32 IsAbilityOnField(u32 ability);
 u32 IsAbilityOnFieldExcept(u32 battlerId, u32 ability);
+u32 IsAbilityPreventingEscape(u32 battlerId);
 void BattleScriptExecute(const u8* BS_ptr);
 void BattleScriptPushCursorAndCallback(const u8* BS_ptr);
 u8 ItemBattleEffects(u8 caseID, u8 battlerId, bool8 moveTurn);

include/constants/battle_config.h

@@ -62,6 +62,7 @@
 #define B_ABILITY_WEATHER           GEN_6 // Up to gen5 - weather induced by abilities such as Drought or Drizzle lasted till the battle's end or weather change by a move. From Gen6 onwards, weather caused by abilities lasts the same amount of turns as induced from a move.
 #define B_GALE_WINGS                GEN_6 // Gen7 requires full hp.
 #define B_STANCE_CHANGE_FAIL        GEN_7 // In Gen7, Aegislash's form change does not happen, if the pokemon cannot use a move, because of confusion, paralysis, etc. In gen6, the form change occurs despite not being able to move.
+#define B_GHOSTS_ESCAPE             GEN_6 // From Gen6 onwards, ghosts can escape even when blocked by abilities such as Shadow Tag.
 
 // Other
 #define B_FAST_INTRO                TRUE // If set to TRUE, battle intro texts print at the same time as animation of a pokemon, as opposing to waiting for the animation to end.

src/battle_ai_script_commands.c

@@ -494,41 +494,44 @@ static u8 ChooseMoveOrAction_Singles(void)
         return AI_CHOICE_WATCH;
 
     gActiveBattler = sBattler_AI;
-    // Consider switching if all moves are worthless to use.
+    // If can switch.
-    if (AI_THINKING_STRUCT->aiFlags & (AI_SCRIPT_CHECK_VIABILITY | AI_SCRIPT_CHECK_BAD_MOVE | AI_SCRIPT_TRY_TO_FAINT | AI_SCRIPT_PREFER_BATON_PASS)
+    if (CountUsablePartyMons(sBattler_AI) >= 1
-        && CountUsablePartyMons(sBattler_AI) >= 1
+        && !IsAbilityPreventingEscape(sBattler_AI)
-        && GetTotalBaseStat(gBattleMons[sBattler_AI].species) >= 310 // Mon is not weak.
+        && !(gBattleMons[gActiveBattler].status2 & (STATUS2_WRAPPED | STATUS2_ESCAPE_PREVENTION))
-        && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2
+        && !(gStatuses3[gActiveBattler] & STATUS3_ROOTED)
-        && !(gBattleTypeFlags & BATTLE_TYPE_PALACE))
+        && !(gBattleTypeFlags & (BATTLE_TYPE_ARENA | BATTLE_TYPE_PALACE))
+        && AI_THINKING_STRUCT->aiFlags & (AI_SCRIPT_CHECK_VIABILITY | AI_SCRIPT_CHECK_BAD_MOVE | AI_SCRIPT_TRY_TO_FAINT | AI_SCRIPT_PREFER_BATON_PASS))
     {
-        s32 cap = AI_THINKING_STRUCT->aiFlags & (AI_SCRIPT_CHECK_VIABILITY) ? 95 : 93;
+        // Consider switching if all moves are worthless to use.
-
+        if (GetTotalBaseStat(gBattleMons[sBattler_AI].species) >= 310 // Mon is not weak.
-        for (i = 0; i < MAX_MON_MOVES; i++)
+            && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2)
         {
-            if (AI_THINKING_STRUCT->score[i] > cap)
+            s32 cap = AI_THINKING_STRUCT->aiFlags & (AI_SCRIPT_CHECK_VIABILITY) ? 95 : 93;
-                break;
+            for (i = 0; i < MAX_MON_MOVES; i++)
+            {
+                if (AI_THINKING_STRUCT->score[i] > cap)
+                    break;
+            }
+
+            if (i == MAX_MON_MOVES && GetMostSuitableMonToSwitchInto() != PARTY_SIZE)
+            {
+                AI_THINKING_STRUCT->switchMon = TRUE;
+                return AI_CHOICE_SWITCH;
+            }
         }
 
-        if (i == MAX_MON_MOVES && GetMostSuitableMonToSwitchInto() != PARTY_SIZE)
+        // Consider switching if your mon with truant is bodied by Protect spam.
+        // Or is using a double turn semi invulnerable move(such as Fly) and is faster.
+        if (GetBattlerAbility(sBattler_AI) == ABILITY_TRUANT
+            && IsTruantMonVulnerable(sBattler_AI, gBattlerTarget)
+            && gDisableStructs[sBattler_AI].truantCounter
+            && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2)
         {
-            AI_THINKING_STRUCT->switchMon = TRUE;
+            if (GetMostSuitableMonToSwitchInto() != PARTY_SIZE)
-            return AI_CHOICE_SWITCH;
+            {
-        }
+                AI_THINKING_STRUCT->switchMon = TRUE;
-    }
+                return AI_CHOICE_SWITCH;
-
+            }
-    // Consider switching if your mon with truant is bodied by Protect spam.
-    // Or is using a double turn semi invulnerable move(such as Fly) and is faster.
-    if (GetBattlerAbility(sBattler_AI) == ABILITY_TRUANT
-        && IsTruantMonVulnerable(sBattler_AI, gBattlerTarget)
-        && gDisableStructs[sBattler_AI].truantCounter
-        && AI_THINKING_STRUCT->aiFlags & (AI_SCRIPT_CHECK_VIABILITY)
-        && gBattleMons[sBattler_AI].hp >= gBattleMons[sBattler_AI].maxHP / 2
-        && CountUsablePartyMons(sBattler_AI) >= 1)
-    {
-        if (GetMostSuitableMonToSwitchInto() != PARTY_SIZE)
-        {
-            AI_THINKING_STRUCT->switchMon = TRUE;
-            return AI_CHOICE_SWITCH;
         }
     }
 

src/battle_ai_switch_items.c

@@ -420,44 +420,34 @@ static bool8 FindMonWithFlagsAndSuperEffective(u16 flags, u8 moduloPercent)
 static bool8 ShouldSwitch(void)
 {
     u8 battlerIn1, battlerIn2;
-    u8 *activeBattlerPtr; // Needed to match.
     s32 firstId;
     s32 lastId; // + 1
     struct Pokemon *party;
     s32 i;
     s32 availableToSwitch;
 
-    if (gBattleMons[*(activeBattlerPtr = &gActiveBattler)].status2 & (STATUS2_WRAPPED | STATUS2_ESCAPE_PREVENTION))
+    if (gBattleMons[gActiveBattler].status2 & (STATUS2_WRAPPED | STATUS2_ESCAPE_PREVENTION))
         return FALSE;
     if (gStatuses3[gActiveBattler] & STATUS3_ROOTED)
         return FALSE;
-    if (IsAbilityOnOpposingSide(gActiveBattler, ABILITY_SHADOW_TAG))
+    if (IsAbilityPreventingEscape(gActiveBattler))
         return FALSE;
-    if (IsAbilityOnOpposingSide(gActiveBattler, ABILITY_ARENA_TRAP)) // Misses the flying type and Levitate check.
-        return FALSE;
-    if (IsAbilityOnField(ABILITY_MAGNET_PULL))
-    {
-        if (gBattleMons[gActiveBattler].type1 == TYPE_STEEL)
-            return FALSE;
-        if (gBattleMons[gActiveBattler].type2 == TYPE_STEEL)
-            return FALSE;
-    }
     if (gBattleTypeFlags & BATTLE_TYPE_ARENA)
         return FALSE;
 
     availableToSwitch = 0;
     if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE)
     {
-        battlerIn1 = *activeBattlerPtr;
+        battlerIn1 = gActiveBattler;
-        if (gAbsentBattlerFlags & gBitTable[GetBattlerAtPosition(GetBattlerPosition(*activeBattlerPtr) ^ BIT_FLANK)])
+        if (gAbsentBattlerFlags & gBitTable[GetBattlerAtPosition(GetBattlerPosition(gActiveBattler) ^ BIT_FLANK)])
-            battlerIn2 = *activeBattlerPtr;
+            battlerIn2 = gActiveBattler;
         else
-            battlerIn2 = GetBattlerAtPosition(GetBattlerPosition(*activeBattlerPtr) ^ BIT_FLANK);
+            battlerIn2 = GetBattlerAtPosition(GetBattlerPosition(gActiveBattler) ^ BIT_FLANK);
     }
     else
     {
-        battlerIn1 = *activeBattlerPtr;
+        battlerIn1 = gActiveBattler;
-        battlerIn2 = *activeBattlerPtr;
+        battlerIn2 = gActiveBattler;
     }
 
     GetAIPartyIndexes(gActiveBattler, &firstId, &lastId);

src/battle_main.c

@@ -3652,9 +3652,7 @@ void BattleTurnPassed(void)
 
 u8 IsRunningFromBattleImpossible(void)
 {
-    u8 holdEffect;
+    u32 holdEffect, i;
-    u8 side;
-    s32 i;
 
     if (gBattleMons[gActiveBattler].item == ITEM_ENIGMA_BERRY)
         holdEffect = gEnigmaBerries[gActiveBattler].holdEffect;
@@ -3681,37 +3679,14 @@ u8 IsRunningFromBattleImpossible(void)
     if (gBattleMons[gActiveBattler].ability == ABILITY_RUN_AWAY)
         return 0;
 
-    side = GetBattlerSide(gActiveBattler);
+    if ((i = IsAbilityPreventingEscape(gActiveBattler)))
-
-    for (i = 0; i < gBattlersCount; i++)
-    {
-        if (side != GetBattlerSide(i)
-         && gBattleMons[i].ability == ABILITY_SHADOW_TAG)
-        {
-            gBattleScripting.battler = i;
-            gLastUsedAbility = gBattleMons[i].ability;
-            gBattleCommunication[MULTISTRING_CHOOSER] = 2;
-            return 2;
-        }
-        if (side != GetBattlerSide(i)
-         && gBattleMons[gActiveBattler].ability != ABILITY_LEVITATE
-         && !IS_BATTLER_OF_TYPE(gActiveBattler, TYPE_FLYING)
-         && gBattleMons[i].ability == ABILITY_ARENA_TRAP)
-        {
-            gBattleScripting.battler = i;
-            gLastUsedAbility = gBattleMons[i].ability;
-            gBattleCommunication[MULTISTRING_CHOOSER] = 2;
-            return 2;
-        }
-    }
-    i = IsAbilityOnFieldExcept(gActiveBattler, ABILITY_MAGNET_PULL);
-    if (i != 0 && IS_BATTLER_OF_TYPE(gActiveBattler, TYPE_STEEL))
     {
         gBattleScripting.battler = i - 1;
         gLastUsedAbility = gBattleMons[i - 1].ability;
         gBattleCommunication[MULTISTRING_CHOOSER] = 2;
         return 2;
     }
+
     if ((gBattleMons[gActiveBattler].status2 & (STATUS2_ESCAPE_PREVENTION | STATUS2_WRAPPED))
         || (gStatuses3[gActiveBattler] & STATUS3_ROOTED))
     {
@@ -3895,12 +3870,7 @@ static void HandleTurnActionSelectionState(void)
                     {
                         BtlController_EmitChoosePokemon(0, PARTY_ACTION_CANT_SWITCH, PARTY_SIZE, ABILITY_NONE, gBattleStruct->field_60[gActiveBattler]);
                     }
-                    else if ((i = IsAbilityOnOpposingSide(gActiveBattler, ABILITY_SHADOW_TAG))
+                    else if ((i = IsAbilityPreventingEscape(gActiveBattler)))
-                             || ((i = IsAbilityOnOpposingSide(gActiveBattler, ABILITY_ARENA_TRAP))
-                                 && !IS_BATTLER_OF_TYPE(gActiveBattler, TYPE_FLYING)
-                                 && gBattleMons[gActiveBattler].ability != ABILITY_LEVITATE)
-                             || ((i = IsAbilityOnFieldExcept(gActiveBattler, ABILITY_MAGNET_PULL))
-                                 && IS_BATTLER_OF_TYPE(gActiveBattler, TYPE_STEEL)))
                     {
                         BtlController_EmitChoosePokemon(0, ((i - 1) << 4) | PARTY_ACTION_ABILITY_PREVENTS, PARTY_SIZE, gLastUsedAbility, gBattleStruct->field_60[gActiveBattler]);
                     }

src/battle_util.c

@@ -23,6 +23,7 @@
 #include "field_weather.h"
 #include "constants/abilities.h"
 #include "constants/battle_anim.h"
+#include "constants/battle_config.h"
 #include "constants/battle_move_effects.h"
 #include "constants/battle_script_commands.h"
 #include "constants/battle_string_ids.h"
@@ -3801,6 +3802,23 @@ u32 IsAbilityOnFieldExcept(u32 battlerId, u32 ability)
     return 0;
 }
 
+u32 IsAbilityPreventingEscape(u32 battlerId)
+{
+    u32 id;
+
+    if (B_GHOSTS_ESCAPE >= GEN_6 && IS_BATTLER_OF_TYPE(battlerId, TYPE_GHOST))
+        return 0;
+
+    if ((id = IsAbilityOnOpposingSide(battlerId, ABILITY_SHADOW_TAG)) && gBattleMons[battlerId].ability != ABILITY_SHADOW_TAG)
+        return id;
+    if ((id = IsAbilityOnOpposingSide(battlerId, ABILITY_ARENA_TRAP)) && IsBattlerGrounded(battlerId))
+        return id;
+    if ((id = IsAbilityOnOpposingSide(battlerId, ABILITY_MAGNET_PULL)) && IS_BATTLER_OF_TYPE(battlerId, TYPE_STEEL))
+        return id;
+
+    return 0;
+}
+
 void BattleScriptExecute(const u8 *BS_ptr)
 {
     gBattlescriptCurrInstr = BS_ptr;

src/pokemon.c

@@ -5510,7 +5510,7 @@ void AdjustFriendship(struct Pokemon *mon, u8 event)
         if (friendship > 199)
             friendshipLevel++;
 
-        if ((event != FRIENDSHIP_EVENT_WALKING || !(Random() & 1)) 
+        if ((event != FRIENDSHIP_EVENT_WALKING || !(Random() & 1))
          && (event != FRIENDSHIP_EVENT_LEAGUE_BATTLE || IS_LEAGUE_BATTLE))
         {
             s8 mod = sFriendshipEventModifiers[event][friendshipLevel];