AI: Account for transformable cards (e.g. Incubator tokens) when considering defenders (#3232)

* - AI: Account for transformable cards (e.g. Incubator tokens) when looking for possible defenders.

* - Check if the transformed card is actually a creature

* - Some recommended improvements to the logic
- Comment out a block of code which might not be as useful under the current rules and with contemporary cards anymore

* - Style fix

* - Attempt to count the total mana spent on transforming stuff when determining how many extra defenders are available.

* - Check pay costs for Animate as well as for Transform.
- NPE guard for pay costs check.

forge-ai/src/main/java/forge/ai/AiAttackController.java

@@ -17,33 +17,17 @@
  */
 package forge.ai;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.List;
-
-import forge.game.staticability.StaticAbility;
-import forge.game.staticability.StaticAbilityAssignCombatDamageAsUnblocked;
-import org.apache.commons.lang3.tuple.Pair;
-
 import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
-
 import forge.ai.ability.AnimateAi;
 import forge.card.CardTypeView;
 import forge.game.GameEntity;
 import forge.game.ability.AbilityUtils;
 import forge.game.ability.ApiType;
 import forge.game.ability.effects.ProtectEffect;
-import forge.game.card.Card;
+import forge.game.card.*;
-import forge.game.card.CardCollection;
-import forge.game.card.CardCollectionView;
-import forge.game.card.CardLists;
-import forge.game.card.CardPredicates;
-import forge.game.card.CardUtil;
-import forge.game.card.CounterEnumType;
 import forge.game.combat.Combat;
 import forge.game.combat.CombatUtil;
 import forge.game.combat.GlobalAttackRestrictions;
@@ -53,6 +37,8 @@ import forge.game.player.Player;
 import forge.game.player.PlayerCollection;
 import forge.game.spellability.SpellAbility;
 import forge.game.spellability.SpellAbilityPredicates;
+import forge.game.staticability.StaticAbility;
+import forge.game.staticability.StaticAbilityAssignCombatDamageAsUnblocked;
 import forge.game.trigger.Trigger;
 import forge.game.trigger.TriggerType;
 import forge.game.zone.Zone;
@@ -62,6 +48,12 @@ import forge.util.Expressions;
 import forge.util.MyRandom;
 import forge.util.collect.FCollection;
 import forge.util.collect.FCollectionView;
+import org.apache.commons.lang3.tuple.Pair;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
 
 
 /**
@@ -135,6 +127,8 @@ public class AiAttackController {
 
     public static List<Card> getOpponentCreatures(final Player defender) {
         List<Card> defenders = defender.getCreaturesInPlay();
+        int totalMana = ComputerUtilMana.getAvailableManaEstimate(defender, true);
+        int manaReserved = 0; // for paying the cost to transform
         Predicate<Card> canAnimate = new Predicate<Card>() {
             @Override
             public boolean apply(Card c) {
@@ -142,14 +136,33 @@ public class AiAttackController {
             }
         };
         for (Card c : CardLists.filter(defender.getCardsIn(ZoneType.Battlefield), canAnimate)) {
-            if (c.isToken() && c.getCopiedPermanent() == null) {
+            /* TODO: is the commented out code still necessary for anything?
+            if (c.isToken() && c.getCopiedPermanent() == null && !c.canTransform(null)) {
                 continue;
             }
+            */
             for (SpellAbility sa : Iterables.filter(c.getSpellAbilities(), SpellAbilityPredicates.isApi(ApiType.Animate))) {
                 if (ComputerUtilCost.canPayCost(sa, defender, false)
                         && sa.getRestrictions().checkOtherRestrictions(c, sa, defender)) {
                     Card animatedCopy = AnimateAi.becomeAnimated(c, sa);
-                    defenders.add(animatedCopy);
+                    int saCMC = sa.getPayCosts() != null && sa.getPayCosts().hasManaCost() ?
+                            sa.getPayCosts().getTotalMana().getCMC() : 0; // FIXME: imprecise, only works 100% for colorless mana
+                    if (totalMana - manaReserved >= saCMC) {
+                        manaReserved += saCMC;
+                        defenders.add(animatedCopy);
+                    }
+                }
+            }
+            // Transform (e.g. Incubator tokens)
+            for (SpellAbility sa : Iterables.filter(c.getSpellAbilities(), SpellAbilityPredicates.isApi(ApiType.SetState))) {
+                Card transformedCopy = ComputerUtilCombat.canTransform(c);
+                if (transformedCopy.isCreature()) {
+                    int saCMC = sa.getPayCosts() != null && sa.getPayCosts().hasManaCost() ?
+                            sa.getPayCosts().getTotalMana().getCMC() : 0; // FIXME: imprecise, only works 100% for colorless mana
+                    if (totalMana - manaReserved >= saCMC) {
+                        manaReserved += saCMC;
+                        defenders.add(transformedCopy);
+                    }
                 }
             }
         }

forge-ai/src/main/java/forge/ai/ComputerUtilCombat.java

@@ -2307,7 +2307,7 @@ public class ComputerUtilCombat {
      * @param original original creature
      * @return transform creature if possible, original creature otherwise
      */
-    private final static Card canTransform(Card original) {
+    public final static Card canTransform(Card original) {
         if (original.isTransformable() && !original.isInAlternateState()) {
             for (SpellAbility sa : original.getSpellAbilities()) {
                 if (sa.getApi() == ApiType.SetState && ComputerUtilCost.canPayCost(sa, original.getController(), false)) {