- Basic Mutate AI support, first pass.

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

@@ -105,6 +105,7 @@ public enum SpellApiToAi {
             .put(ApiType.MultiplyCounter, CountersMultiplyAi.class)
             .put(ApiType.MustAttack, MustAttackAi.class)
             .put(ApiType.MustBlock, MustBlockAi.class)
+            .put(ApiType.Mutate, MutateAi.class)
             .put(ApiType.NameCard, ChooseCardNameAi.class)
             .put(ApiType.NoteCounters, AlwaysPlayAi.class)
             .put(ApiType.PeekAndReveal, PeekAndRevealAi.class)

forge-ai/src/main/java/forge/ai/ability/MutateAi.java

@@ -0,0 +1,62 @@
+package forge.ai.ability;
+
+import com.google.common.base.Predicates;
+import forge.ai.ComputerUtilCard;
+import forge.ai.SpellAbilityAi;
+import forge.game.card.Card;
+import forge.game.card.CardCollectionView;
+import forge.game.card.CardLists;
+import forge.game.card.CardPredicates;
+import forge.game.keyword.Keyword;
+import forge.game.player.Player;
+import forge.game.player.PlayerActionConfirmMode;
+import forge.game.spellability.SpellAbility;
+
+import java.util.Map;
+
+public class MutateAi extends SpellAbilityAi {
+    @Override
+    protected boolean canPlayAI(Player aiPlayer, SpellAbility sa) {
+        CardCollectionView mutateTgts = CardLists.filter(CardLists.getTargetableCards(aiPlayer.getCreaturesInPlay(), sa),
+                Predicates.not(CardPredicates.isType("Human")));
+
+        // Filter out some abilities that are useless
+        // TODO: add other stuff useless for Mutate here
+        mutateTgts = CardLists.filter(mutateTgts, Predicates.not(Predicates.or(
+                CardPredicates.hasKeyword(Keyword.DEFENDER),
+                CardPredicates.hasKeyword("CARDNAME can't attack."),
+                CardPredicates.hasKeyword("CARDNAME can't block.")
+        )));
+
+        if (mutateTgts.isEmpty()) {
+            return false;
+        }
+
+        // Choose the best target
+        // TODO: maybe, instead of the standard evaluator, this could inspect the abilities and decide
+        // which are better in context, but that's a bit complicated for the time being (not sure if necessary?).
+        Card mutateTgt = ComputerUtilCard.getBestCreatureAI(mutateTgts);
+        sa.getTargets().add(mutateTgt);
+
+        return true;
+    }
+
+    @Override
+    protected Card chooseSingleCard(Player ai, SpellAbility sa, Iterable<Card> options, boolean isOptional, Player targetedPlayer, Map<String, Object> params) {
+        // Decide which card goes on top here. Pretty rudimentary, feel free to improve.
+        Card choice = null;
+
+        for (Card c : options) {
+            if (choice == null || c.getBasePower() > choice.getBasePower() || c.getBaseToughness() > choice.getBaseToughness()) {
+                choice = c;
+            }
+        }
+
+        return choice;
+    }
+
+    @Override
+    public boolean confirmAction(Player player, SpellAbility sa, PlayerActionConfirmMode mode, String message) {
+        return true;
+    }
+}