Implemented Bellowing Elk

Mage.Sets/src/mage/cards/b/BellowingElk.java

@@ -0,0 +1,111 @@
+package mage.cards.b;
+
+import mage.MageInt;
+import mage.abilities.Ability;
+import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.condition.Condition;
+import mage.abilities.decorator.ConditionalContinuousEffect;
+import mage.abilities.effects.common.continuous.GainAbilitySourceEffect;
+import mage.abilities.keyword.IndestructibleAbility;
+import mage.abilities.keyword.TrampleAbility;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.constants.*;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.game.events.ZoneChangeEvent;
+import mage.watchers.Watcher;
+
+import java.util.*;
+
+/**
+ * @author TheElk801
+ */
+public final class BellowingElk extends CardImpl {
+
+    public BellowingElk(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.CREATURE}, "{3}{G}");
+
+        this.subtype.add(SubType.ELK);
+        this.power = new MageInt(4);
+        this.toughness = new MageInt(2);
+
+        // As long as you had another creature enter the battlefield under your control this turn, Bellowing Elk has trample and indestructible.
+        Ability ability = new SimpleStaticAbility(new ConditionalContinuousEffect(
+                new GainAbilitySourceEffect(TrampleAbility.getInstance(), Duration.WhileOnBattlefield),
+                BellowingElkCondition.instance, "As long as you had another creature" +
+                " enter the battlefield under your control this turn, {this} has trample"
+        ));
+        ability.addEffect(new ConditionalContinuousEffect(
+                new GainAbilitySourceEffect(IndestructibleAbility.getInstance(), Duration.WhileOnBattlefield),
+                BellowingElkCondition.instance, "and indestructible"
+        ));
+        this.addAbility(ability, new BellowingElkWatcher());
+    }
+
+    private BellowingElk(final BellowingElk card) {
+        super(card);
+    }
+
+    @Override
+    public BellowingElk copy() {
+        return new BellowingElk(this);
+    }
+}
+
+enum BellowingElkCondition implements Condition {
+    instance;
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        BellowingElkWatcher watcher = game.getState().getWatcher(BellowingElkWatcher.class);
+        return watcher != null && watcher.enteredCreatureForPlayer(source.getControllerId(), source.getSourceId());
+    }
+
+    @Override
+    public String toString() {
+        return "you had a creature enter the battlefield under your control this turn";
+    }
+}
+
+class BellowingElkWatcher extends Watcher {
+
+    private final Map<UUID, Set<UUID>> playerMap = new HashMap<>();
+
+    BellowingElkWatcher() {
+        super(WatcherScope.GAME);
+    }
+
+    private BellowingElkWatcher(final BellowingElkWatcher watcher) {
+        super(watcher);
+        this.playerMap.putAll(watcher.playerMap);
+    }
+
+    @Override
+    public void watch(GameEvent event, Game game) {
+        if (event.getType() == GameEvent.EventType.ZONE_CHANGE) {
+            ZoneChangeEvent zEvent = (ZoneChangeEvent) event;
+            if (zEvent.getToZone() == Zone.BATTLEFIELD
+                    && zEvent.getTarget().isCreature()) {
+                playerMap.putIfAbsent(zEvent.getTarget().getControllerId(), new HashSet<>());
+                playerMap.get(zEvent.getTarget().getControllerId()).add(zEvent.getTargetId());
+            }
+        }
+    }
+
+    @Override
+    public void reset() {
+        playerMap.clear();
+    }
+
+    boolean enteredCreatureForPlayer(UUID playerId, UUID creatureId) {
+        Set<UUID> s = playerMap.getOrDefault(playerId, null);
+        return s != null && s.stream().anyMatch((UUID id) -> (id != creatureId));
+    }
+
+    @Override
+    public BellowingElkWatcher copy() {
+        return new BellowingElkWatcher(this);
+    }
+}
+// I'm not THAT loud...

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

@@ -40,6 +40,7 @@ public final class ModernHorizons extends ExpansionSet {
         cards.add(new SetCardInfo("Barren Moor", 236, Rarity.UNCOMMON, mage.cards.b.BarrenMoor.class));
         cards.add(new SetCardInfo("Battle Screech", 4, Rarity.UNCOMMON, mage.cards.b.BattleScreech.class));
         cards.add(new SetCardInfo("Bazaar Trademage", 41, Rarity.RARE, mage.cards.b.BazaarTrademage.class));
+        cards.add(new SetCardInfo("Bellowing Elk", 157, Rarity.COMMON, mage.cards.b.BellowingElk.class));
         cards.add(new SetCardInfo("Birthing Boughs", 221, Rarity.UNCOMMON, mage.cards.b.BirthingBoughs.class));
         cards.add(new SetCardInfo("Bladeback Sliver", 119, Rarity.COMMON, mage.cards.b.BladebackSliver.class));
         cards.add(new SetCardInfo("Cabal Therapist", 80, Rarity.RARE, mage.cards.c.CabalTherapist.class));