Add AI for Zero to Hero Palafin (#6791)

src/battle_ai_switch_items.c

@@ -769,6 +769,11 @@ static bool32 ShouldSwitchIfAbilityBenefit(u32 battler)
                 break;
 
             return FALSE;
+        
+        case ABILITY_ZERO_TO_HERO:
+            // Want to activate Palafin-Zero at all costs
+            if (gBattleMons[battler].species == SPECIES_PALAFIN_ZERO)
+                break;
 
         default:
             return FALSE;

src/battle_ai_util.c

@@ -2907,6 +2907,12 @@ enum AIPivot ShouldPivot(u32 battlerAtk, u32 battlerDef, u32 defAbility, u32 mov
 
     battlerToSwitch = gBattleStruct->AI_monToSwitchIntoId[battlerAtk];
 
+    // Palafin always wants to activate Zero to Hero
+    if (gBattleMons[battlerAtk].species == SPECIES_PALAFIN_ZERO
+        && gBattleMons[battlerAtk].ability == ABILITY_ZERO_TO_HERO
+        && CountUsablePartyMons(battlerAtk) != 0)
+        return SHOULD_PIVOT;
+
     if (PartyBattlerShouldAvoidHazards(battlerAtk, battlerToSwitch))
         return DONT_PIVOT;
 

test/battle/ai/ai_switching.c

@@ -1153,3 +1153,27 @@ AI_SINGLE_BATTLE_TEST("AI_FLAG_SMART_SWITCHING: AI will switch out if all moves
         TURN { EXPECT_SWITCH(opponent, 1); MOVE(player, MOVE_ROOST); }
     }
 }
+
+AI_SINGLE_BATTLE_TEST("Switch AI: AI will switch out if Palafin-Zero isn't transformed yet")
+{
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT);
+        PLAYER(SPECIES_FINIZEN);
+        OPPONENT(SPECIES_PALAFIN_ZERO);
+        OPPONENT(SPECIES_FINIZEN);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); EXPECT_SWITCH(opponent, 1); }
+    }
+}
+
+AI_SINGLE_BATTLE_TEST("Switch AI: AI will use pivot move to activate Palafin's Zero to Hero rather than hard switching")
+{
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT);
+        PLAYER(SPECIES_FINIZEN);
+        OPPONENT(SPECIES_PALAFIN_ZERO) { Moves(MOVE_FLIP_TURN); }
+        OPPONENT(SPECIES_FINIZEN);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); EXPECT_MOVE(opponent, MOVE_FLIP_TURN); EXPECT_SEND_OUT(opponent, 1); }
+    }
+}