[LTR] Implement Gandalf the Grey

Mage.Sets/src/mage/cards/y/YouCannotPass.java

@@ -0,0 +1,98 @@
+package mage.cards.y;
+
+import mage.MageObjectReference;
+import mage.abilities.effects.common.DestroyTargetEffect;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.constants.CardType;
+import mage.constants.WatcherScope;
+import mage.filter.FilterPermanent;
+import mage.filter.common.FilterCreaturePermanent;
+import mage.filter.predicate.Predicate;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.game.permanent.Permanent;
+import mage.target.TargetPermanent;
+import mage.watchers.Watcher;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * @author TheElk801
+ */
+public final class YouCannotPass extends CardImpl {
+
+    private static final FilterPermanent filter
+            = new FilterCreaturePermanent("creature that blocked or was blocked by a legendary creature this turn");
+
+    static {
+        filter.add(YouCannotPassPredicate.instance);
+    }
+
+    public YouCannotPass(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.INSTANT}, "{W}");
+
+        // Destroy target creature that blocked or was blocked by a legendary creature this turn.
+        this.getSpellAbility().addEffect(new DestroyTargetEffect());
+        this.getSpellAbility().addTarget(new TargetPermanent(filter));
+        this.getSpellAbility().addWatcher(new YouCannotPassWatcher());
+    }
+
+    private YouCannotPass(final YouCannotPass card) {
+        super(card);
+    }
+
+    @Override
+    public YouCannotPass copy() {
+        return new YouCannotPass(this);
+    }
+}
+
+enum YouCannotPassPredicate implements Predicate<Permanent> {
+    instance;
+
+    @Override
+    public boolean apply(Permanent input, Game game) {
+        return YouCannotPassWatcher.checkCreature(input, game);
+    }
+}
+
+class YouCannotPassWatcher extends Watcher {
+
+    private final Set<MageObjectReference> set = new HashSet<>();
+
+    YouCannotPassWatcher() {
+        super(WatcherScope.GAME);
+    }
+
+    @Override
+    public void watch(GameEvent event, Game game) {
+        if (event.getType() != GameEvent.EventType.CREATURE_BLOCKED) {
+            return;
+        }
+        Permanent permanent = game.getPermanent(event.getTargetId());
+        if (permanent != null && permanent.isLegendary()) {
+            set.add(new MageObjectReference(event.getSourceId(), game));
+        }
+        permanent = game.getPermanent(event.getSourceId());
+        if (permanent != null && permanent.isLegendary()) {
+            set.add(new MageObjectReference(event.getTargetId(), game));
+        }
+    }
+
+    @Override
+    public void reset() {
+        super.reset();
+        set.clear();
+    }
+
+    static boolean checkCreature(Permanent permanent, Game game) {
+        return game
+                .getState()
+                .getWatcher(YouCannotPassWatcher.class)
+                .set
+                .contains(new MageObjectReference(permanent, game));
+    }
+}

Mage.Sets/src/mage/sets/TheLordOfTheRingsTalesOfMiddleEarth.java

@@ -27,5 +27,6 @@ public final class TheLordOfTheRingsTalesOfMiddleEarth extends ExpansionSet {
         cards.add(new SetCardInfo("Reprieve", 26, Rarity.UNCOMMON, mage.cards.r.Reprieve.class));
         cards.add(new SetCardInfo("Swamp", 276, Rarity.LAND, mage.cards.basiclands.Swamp.class, FULL_ART_BFZ_VARIOUS));
         cards.add(new SetCardInfo("Trailblazer's Boots", 398, Rarity.RARE, mage.cards.t.TrailblazersBoots.class));
+        cards.add(new SetCardInfo("You Cannot Pass!", 38, Rarity.UNCOMMON, mage.cards.y.YouCannotPass.class));
     }
 }