Implemented Fiendish Duo

Mage.Sets/src/mage/cards/f/FiendishDuo.java

@@ -0,0 +1,88 @@
+package mage.cards.f;
+
+import mage.MageInt;
+import mage.abilities.Ability;
+import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.effects.ReplacementEffectImpl;
+import mage.abilities.keyword.FirstStrikeAbility;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.constants.CardType;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.constants.SubType;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.players.Player;
+import mage.util.CardUtil;
+
+import java.util.UUID;
+
+/**
+ * @author TheElk801
+ */
+public final class FiendishDuo extends CardImpl {
+
+    public FiendishDuo(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.CREATURE}, "{4}{R}{R}");
+
+        this.subtype.add(SubType.DEVIL);
+        this.power = new MageInt(5);
+        this.toughness = new MageInt(5);
+
+        // First strike
+        this.addAbility(FirstStrikeAbility.getInstance());
+
+        // If a source would deal damage to an opponent, it deals double that damage that player instead.
+        this.addAbility(new SimpleStaticAbility(new FiendishDuoEffect()));
+    }
+
+    private FiendishDuo(final FiendishDuo card) {
+        super(card);
+    }
+
+    @Override
+    public FiendishDuo copy() {
+        return new FiendishDuo(this);
+    }
+}
+
+class FiendishDuoEffect extends ReplacementEffectImpl {
+
+    FiendishDuoEffect() {
+        super(Duration.WhileOnBattlefield, Outcome.Damage);
+        staticText = "If a source would deal damage to an opponent, " +
+                "it deals double that damage to that player instead";
+    }
+
+    private FiendishDuoEffect(final FiendishDuoEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public FiendishDuoEffect copy() {
+        return new FiendishDuoEffect(this);
+    }
+
+    @Override
+    public boolean checksEventType(GameEvent event, Game game) {
+        return event.getType() == GameEvent.EventType.DAMAGE_PLAYER;
+    }
+
+    @Override
+    public boolean applies(GameEvent event, Ability source, Game game) {
+        Player player = game.getPlayer(source.getControllerId());
+        return player != null && player.hasOpponent(event.getTargetId(), game);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        return true;
+    }
+
+    @Override
+    public boolean replaceEvent(GameEvent event, Ability source, Game game) {
+        event.setAmount(CardUtil.addWithOverflowCheck(event.getAmount(), event.getAmount()));
+        return false;
+    }
+}

Mage.Sets/src/mage/sets/GameNight2019.java

@@ -20,6 +20,7 @@ public final class GameNight2019 extends ExpansionSet {
         this.hasBasicLands = false; // TODO: change when spoiled
 
         cards.add(new SetCardInfo("Earthshaker Giant", 5, Rarity.MYTHIC, mage.cards.e.EarthshakerGiant.class));
+        cards.add(new SetCardInfo("Fiendish Duo", 4, Rarity.MYTHIC, mage.cards.f.FiendishDuo.class));
         cards.add(new SetCardInfo("Highcliff Felidar", 1, Rarity.MYTHIC, mage.cards.h.HighcliffFelidar.class));
         cards.add(new SetCardInfo("Sphinx of Enlightenment", 2, Rarity.MYTHIC, mage.cards.s.SphinxOfEnlightenment.class));
     }