AI: move check for isUseless from AttachAi to SpellAbilityAi

update SetStateAi to use new canPlay()
add check for useless Legendary in SetStateAi (try to replace Legendary if current one is useless)
add extra check for Legendary KI creatures, more counters are better.

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

@@ -239,4 +239,19 @@ public abstract class SpellAbilityAi {
         System.err.println("Warning: default (ie. inherited from base class) implementation of chooseSingleEntity is used for " + this.getClass().getName() + ". Consider declaring an overloaded method");
         return Iterables.getFirst(options, null);
     }
+
+
+    protected static boolean isUselessCreature(Player ai, Card c) {
+        if (c == null) {
+            return true;
+        }
+
+        if (c.hasKeyword("CARDNAME can't attack or block.")
+                || (c.hasKeyword("CARDNAME doesn't untap during your untap step.") && c.isTapped())
+                || (c.getOwner() == ai && ai.getOpponents().contains(c.getController()))) {
+            return true;
+        }
+
+        return false;
+    }
 }

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

@@ -1412,20 +1412,6 @@ public class AttachAi extends SpellAbilityAi {
         return true;
     }
 
-    private static boolean isUselessCreature(Player ai, Card c) {
-        if (c == null) {
-            return true;
-        }
-
-        if (c.hasKeyword("CARDNAME can't attack or block.")
-                || (c.hasKeyword("CARDNAME doesn't untap during your untap step.") && c.isTapped())
-                || (c.getOwner() == ai && ai.getOpponents().contains(c.getController()))) {
-            return true;
-        }
-
-        return false;
-    }
-    
     @Override
     public boolean confirmAction(Player player, SpellAbility sa, PlayerActionConfirmMode mode, String message) {
         return true;

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

@@ -43,6 +43,15 @@ public class LegendaryRuleAi extends SpellAbilityAi {
                 }
             }
             return best;
+        } else if (firstOption.getCounters(CounterType.KI) > 0) {
+        	// Extra Rule for KI counter
+        	Card best = firstOption;
+            for (Card c : options) {
+                if (c.getCounters(CounterType.KI) > best.getCounters(CounterType.KI)) {
+                    best = c;
+                }
+            }
+            return best;
         }
 
         return firstOption;

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

@@ -5,28 +5,51 @@ import forge.ai.SpellAbilityAi;
 import forge.game.GlobalRuleChange;
 import forge.game.card.Card;
 import forge.game.card.CardState;
+import forge.game.card.CounterType;
 import forge.game.player.Player;
 import forge.game.spellability.SpellAbility;
+import forge.game.zone.ZoneType;
 
 public class SetStateAi extends SpellAbilityAi {
     @Override
-    protected boolean canPlayAI(Player aiPlayer, SpellAbility sa) {
-        // Prevent transform into legendary creature if copy already exists
+    protected boolean checkApiLogic(final Player aiPlayer, final SpellAbility sa) {
         final Card source = sa.getHostCard();
-        
+
+        if (!source.hasAlternateState()) {
+            System.err.println("Warning: SetState without ALTERNATE on " + source.getName() + ".");
+            return false;
+        }
+
+        // Prevent transform into legendary creature if copy already exists
         // Check first if Legend Rule does still apply
         if (!aiPlayer.getGame().getStaticEffects().getGlobalRuleChange(GlobalRuleChange.noLegendRule)) {
 
-        	// check if the other side is legendary and if such Card already is in Play
+            // check if the other side is legendary and if such Card already is in Play
             final CardState other = source.getAlternateState();
+
             if (other != null && other.getType().isLegendary() && aiPlayer.isCardInPlay(other.getName())) {
-            	return false;
+                if (!other.getType().isCreature()) {
+                    return false;
+                }
+
+                final Card othercard = aiPlayer.getCardsIn(ZoneType.Battlefield, other.getName()).getFirst();
+                
+                // for legendary KI counter creatures
+                if (othercard.getCounters(CounterType.KI) >= source.getCounters(CounterType.KI)) {
+                	// if the other legendary is useless try to replace it
+                    if (!isUselessCreature(aiPlayer, othercard)) {                    	
+                        return false;
+                    }
+                }
             }
         }
         
         if (sa.getTargetRestrictions() == null && "Transform".equals(sa.getParam("Mode"))) {
             return !source.hasKeyword("CARDNAME can't transform");
         }
+        if ("Flip".equals(sa.getParam("Mode"))) {
+        	return true;
+        }
         return false;
     }
 
@@ -36,13 +59,4 @@ public class SetStateAi extends SpellAbilityAi {
         // states more powerful
         return !sa.getHostCard().isInAlternateState();
     }
-
-
-    /* (non-Javadoc)
-    * @see forge.card.abilityfactory.SpellAiLogic#doTriggerAINoCost(forge.game.player.Player, java.util.Map, forge.card.spellability.SpellAbility, boolean)
-    */
-    @Override
-    protected boolean doTriggerAINoCost(Player aiPlayer, SpellAbility sa, boolean mandatory) {
-        return true;
-    }
 }