- Refactored AI logic for cards like Goblin Dark-Dwellers and Snapcaster Mage.

- Rewired AI logic for Goblin Dark-Dwellers to work with the new card implementation.

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

@@ -2636,4 +2636,34 @@ public class ComputerUtil {
 
         return false;
     }
+    
+    public static boolean targetPlayableSpellCard(final Player ai, CardCollection options, final SpellAbility sa, final boolean withoutPayingManaCost) {
+            // determine and target a card with a SA that the AI can afford and will play
+        AiController aic = ((PlayerControllerAi) ai.getController()).getAi();
+        Card targetSpellCard = null;
+        for (Card c : options) {
+            for (SpellAbility ab : c.getSpellAbilities()) {
+                if (ab.getApi() == null) {
+                    // only API-based SAs are supported, other things may lead to a NPE (e.g. Ancestral Vision Suspend SA)
+                    continue;
+                }
+                SpellAbility abTest = withoutPayingManaCost ? ab.copyWithNoManaCost() : ab.copy();
+                // at this point, we're assuming that card will be castable from whichever zone it's in by the AI player.
+                abTest.setActivatingPlayer(ai);
+                abTest.getRestrictions().setZone(c.getZone().getZoneType());
+                final boolean play = AiPlayDecision.WillPlay == aic.canPlaySa(abTest);
+                final boolean pay = ComputerUtilCost.canPayCost(abTest, ai);
+                if (play && pay) {
+                    targetSpellCard = c;
+                    break;
+                }
+            }
+        }
+        if (targetSpellCard == null) {
+            return false;
+        } else {
+            sa.getTargets().add(targetSpellCard);
+        }
+        return true;
+    }
 }

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

@@ -3,10 +3,12 @@ package forge.ai.ability;
 import java.util.List;
 
 import com.google.common.base.Predicate;
+import forge.ai.AiController;
 
 import forge.ai.AiPlayDecision;
 import forge.ai.ComputerUtil;
 import forge.ai.ComputerUtilCard;
+import forge.ai.ComputerUtilCost;
 import forge.ai.PlayerControllerAi;
 import forge.ai.SpellAbilityAi;
 import forge.game.Game;
@@ -68,7 +70,34 @@ public class PlayAi extends SpellAbilityAi {
      */
     @Override
     protected boolean doTriggerAINoCost(final Player ai, final SpellAbility sa, final boolean mandatory) {
+        final Card source = sa.getHostCard();
+        final Game game = ai.getGame();
+        
+        // general logic (no AILogic specified)
         if (sa.usesTargeting()) {
+            if (!sa.hasParam("AILogic")) {
+                return false;
+            }
+            
+            CardCollection cards = null;
+            final TargetRestrictions tgt = sa.getTargetRestrictions();
+            if (tgt != null) {
+                ZoneType zone = tgt.getZone().get(0);
+                cards = CardLists.getValidCards(game.getCardsIn(zone), tgt.getValidTgts(), ai, source, sa);
+                if (cards.isEmpty()) {
+                    return false;
+                }
+            } else if (!sa.hasParam("Valid")) {
+                cards = AbilityUtils.getDefinedCards(sa.getHostCard(), sa.getParam("Defined"), sa);
+                if (cards.isEmpty()) {
+                    return false;
+                }
+            }
+
+            if ("PlayWithNoManaCost".equals(sa.getParam("AILogic"))) {
+                return ComputerUtil.targetPlayableSpellCard(ai, cards, sa, true);                
+            }
+            
             return false;
         }
 

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

@@ -478,11 +478,7 @@ public class PumpAi extends PumpAiBase {
         }
         
         if ("Snapcaster".equals(sa.getParam("AILogic"))) {
-            if (!doTargetSpellToPlayLogic(ai, list, sa, false)) {
-                return false;
-            }
-        } else if ("PlaySpellForFree".equals(sa.getParam("AILogic"))) {
-            if (!doTargetSpellToPlayLogic(ai, list, sa, true)) {
+            if (!ComputerUtil.targetPlayableSpellCard(ai, list, sa, false)) {
                 return false;
             }
         }
@@ -520,36 +516,6 @@ public class PumpAi extends PumpAiBase {
         return true;
     } // pumpTgtAI()
 
-    private boolean doTargetSpellToPlayLogic(final Player ai, CardCollection options, final SpellAbility sa, final boolean withoutPayingManaCost) {
-        // determine and target a card with a SA that the AI can afford and will play
-        AiController aic = ((PlayerControllerAi) ai.getController()).getAi();
-        Card targetSpellCard = null;
-        for (Card c : options) {
-            for (SpellAbility ab : c.getSpellAbilities()) {
-                if (ab.getApi() == null) {
-                    // only API-based SAs are supported, other things may lead to a NPE (e.g. Ancestral Vision Suspend SA)
-                    continue;
-                }
-                SpellAbility abTest = withoutPayingManaCost ? ab.copyWithNoManaCost() : ab.copy();
-                // at this point, we're assuming that card will be castable from whichever zone it's in by the AI player.
-                abTest.setActivatingPlayer(ai);
-                abTest.getRestrictions().setZone(c.getZone().getZoneType());
-                final boolean play = AiPlayDecision.WillPlay == aic.canPlaySa(abTest);
-                final boolean pay = ComputerUtilCost.canPayCost(abTest, ai);
-                if (play && pay) {
-                    targetSpellCard = c;
-                    break;
-                }
-            }
-        }
-        if (targetSpellCard == null) {
-            return false;
-        } else {
-            sa.getTargets().add(targetSpellCard);
-        }
-        return true;
-    }
-
     private boolean pumpMandatoryTarget(final Player ai, final SpellAbility sa) {
         final Game game = ai.getGame();
         final TargetRestrictions tgt = sa.getTargetRestrictions();

forge-gui/res/cardsfolder/g/goblin_dark_dwellers.txt

@@ -4,6 +4,6 @@ Types:Creature Goblin
 PT:4/4
 K:Menace
 T:Mode$ ChangesZone | Origin$ Any | Destination$ Battlefield | ValidCard$ Card.Self | Execute$ TrigPlay | TriggerDescription$ When CARDNAME enters the battlefield, you may cast target instant or sorcery card with converted mana cost 3 or less from your graveyard without paying its mana cost. If that card would be put into your graveyard this turn, exile it instead.
-SVar:TrigPlay:DB$ Play | TgtZone$ Graveyard | ValidTgts$ Instant.YouCtrl+cmcLE3,Sorcery.YouCtrl+cmcLE3 | TgtPrompt$ Choose target instant or sorcery card with converted mana cost 3 or less from your graveyard | WithoutManaCost$ True | Optional$ True | ReplaceGraveyard$ Exile
+SVar:TrigPlay:DB$ Play | TgtZone$ Graveyard | ValidTgts$ Instant.YouCtrl+cmcLE3,Sorcery.YouCtrl+cmcLE3 | TgtPrompt$ Choose target instant or sorcery card with converted mana cost 3 or less from your graveyard | WithoutManaCost$ True | Optional$ True | ReplaceGraveyard$ Exile | AILogic$ PlayWithNoManaCost
 SVar:Picture:http://www.wizards.com/global/images/magic/general/goblin_dark_dwellers.jpg
 Oracle:Menace\nWhen Goblin Dark-Dwellers enters the battlefield, you may cast target instant or sorcery card with converted mana cost 3 or less from your graveyard without paying its mana cost. If that card would be put into your graveyard this turn, exile it instead.