[PIP] Implement Sentinel Sarah Lyons; The Prydwen, Steel Flagship; add common watcher + condition (#12250)

* [PIP] Implement Sentinel Sarah Lyons

* Create common watcher and condition for artifacts entering

* [PIP] Implement The Prydwen, Steel Flagship

* Use common classes in Akal Pakal, First Among Equals; string correction

* Add warning about watcher to ArtifactEnteredUnderYourControlCondition

* Add tests

* Move test file

* Test with opponent casting artifact during your turn

* Use checkPT(), don't call execute() multiple times

* Check final assertion at upkeep instead of untap step

Mage.Sets/src/mage/cards/a/AkalPakalFirstAmongEquals.java

@@ -3,19 +3,14 @@ package mage.cards.a;
 import mage.MageInt;
 import mage.abilities.Ability;
 import mage.abilities.common.BeginningOfEndStepTriggeredAbility;
-import mage.abilities.condition.Condition;
+import mage.abilities.condition.common.ArtifactEnteredUnderYourControlCondition;
 import mage.abilities.effects.common.LookLibraryAndPickControllerEffect;
 import mage.abilities.hint.ConditionHint;
 import mage.cards.CardImpl;
 import mage.cards.CardSetInfo;
 import mage.constants.*;
-import mage.game.Game;
-import mage.game.events.GameEvent;
-import mage.game.permanent.Permanent;
-import mage.watchers.Watcher;
+import mage.watchers.common.ArtifactEnteredControllerWatcher;
 
-import java.util.HashSet;
-import java.util.Set;
 import java.util.UUID;
 
 /**
@@ -36,11 +31,11 @@ public final class AkalPakalFirstAmongEquals extends CardImpl {
         Ability ability = new BeginningOfEndStepTriggeredAbility(
                 new LookLibraryAndPickControllerEffect(2, 1, PutCards.HAND, PutCards.GRAVEYARD),
                 TargetController.EACH_PLAYER,
-                AkalPakalCondition.instance,
+                ArtifactEnteredUnderYourControlCondition.instance,
                 false
         );
-        ability.addHint(new ConditionHint(AkalPakalCondition.instance));
-        this.addAbility(ability, new AkalPakalWatcher());
+        ability.addHint(new ConditionHint(ArtifactEnteredUnderYourControlCondition.instance));
+        this.addAbility(ability, new ArtifactEnteredControllerWatcher());
     }
 
     private AkalPakalFirstAmongEquals(final AkalPakalFirstAmongEquals card) {
@@ -52,50 +47,3 @@ public final class AkalPakalFirstAmongEquals extends CardImpl {
         return new AkalPakalFirstAmongEquals(this);
     }
 }
-
-enum AkalPakalCondition implements Condition {
-    instance;
-
-    @Override
-    public boolean apply(Game game, Ability source) {
-        return AkalPakalWatcher.checkPlayer(source.getControllerId(), game);
-    }
-
-    @Override
-    public String toString() {
-        return "an artifact entered the battlefield under your control this turn";
-    }
-}
-
-class AkalPakalWatcher extends Watcher {
-
-    // Set of the players that had an artifact enter this turn.
-    private final Set<UUID> playerSet = new HashSet<>();
-
-    AkalPakalWatcher() {
-        super(WatcherScope.GAME);
-    }
-
-    @Override
-    public void watch(GameEvent event, Game game) {
-        if (event.getType() != GameEvent.EventType.ENTERS_THE_BATTLEFIELD) {
-            return;
-        }
-        Permanent permanent = game.getPermanent(event.getTargetId());
-        if (permanent != null && permanent.isArtifact(game)) {
-            playerSet.add(event.getPlayerId());
-        }
-    }
-
-    @Override
-    public void reset() {
-        super.reset();
-        playerSet.clear();
-    }
-
-    static boolean checkPlayer(UUID playerId, Game game) {
-        AkalPakalWatcher watcher = game.getState().getWatcher(AkalPakalWatcher.class);
-        return watcher != null && watcher.playerSet.contains(playerId);
-    }
-
-}

Mage.Sets/src/mage/cards/s/SentinelSarahLyons.java

@@ -0,0 +1,66 @@
+package mage.cards.s;
+
+import java.util.UUID;
+
+import mage.MageInt;
+import mage.abilities.Ability;
+import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.condition.common.ArtifactEnteredUnderYourControlCondition;
+import mage.abilities.decorator.ConditionalContinuousEffect;
+import mage.abilities.dynamicvalue.common.ArtifactYouControlCount;
+import mage.abilities.effects.common.DamageTargetEffect;
+import mage.abilities.effects.common.continuous.BoostControlledEffect;
+import mage.abilities.hint.ConditionHint;
+import mage.abilities.hint.common.ArtifactYouControlHint;
+import mage.abilities.keyword.BattalionAbility;
+import mage.constants.*;
+import mage.abilities.keyword.HasteAbility;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.target.TargetPlayer;
+import mage.watchers.common.ArtifactEnteredControllerWatcher;
+
+/**
+ * @author Cguy7777
+ */
+public final class SentinelSarahLyons extends CardImpl {
+
+    public SentinelSarahLyons(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.CREATURE}, "{3}{R}{W}");
+
+        this.supertype.add(SuperType.LEGENDARY);
+        this.subtype.add(SubType.HUMAN);
+        this.subtype.add(SubType.KNIGHT);
+        this.power = new MageInt(4);
+        this.toughness = new MageInt(4);
+
+        // Haste
+        this.addAbility(HasteAbility.getInstance());
+
+        // As long as an artifact entered the battlefield under your control this turn, creatures you control get +2/+2.
+        this.addAbility(new SimpleStaticAbility(new ConditionalContinuousEffect(
+                        new BoostControlledEffect(2, 2, Duration.WhileOnBattlefield),
+                        ArtifactEnteredUnderYourControlCondition.instance,
+                        "as long as an artifact entered the battlefield under your control this turn, " +
+                                "creatures you control get +2/+2"))
+                        .addHint(new ConditionHint(ArtifactEnteredUnderYourControlCondition.instance)),
+                new ArtifactEnteredControllerWatcher());
+
+        // Battalion -- Whenever Sentinel Sarah Lyons and at least two other creatures attack,
+        // Sentinel Sarah Lyons deals damage equal to the number of artifacts you control to target player.
+        Ability ability = new BattalionAbility(new DamageTargetEffect(ArtifactYouControlCount.instance)
+                .setText("{this} deals damage equal to the number of artifacts you control to target player"));
+        ability.addTarget(new TargetPlayer());
+        ability.addHint(ArtifactYouControlHint.instance);
+        this.addAbility(ability);
+    }
+
+    private SentinelSarahLyons(final SentinelSarahLyons card) {
+        super(card);
+    }
+
+    @Override
+    public SentinelSarahLyons copy() {
+        return new SentinelSarahLyons(this);
+    }
+}

Mage.Sets/src/mage/cards/s/ShipwreckSentry.java

@@ -1,26 +1,19 @@
 package mage.cards.s;
 
 import mage.MageInt;
-import mage.abilities.Ability;
 import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.condition.common.ArtifactEnteredUnderYourControlCondition;
 import mage.abilities.decorator.ConditionalAsThoughEffect;
 import mage.abilities.effects.common.combat.CanAttackAsThoughItDidntHaveDefenderSourceEffect;
 import mage.abilities.hint.ConditionHint;
-import mage.abilities.hint.Hint;
 import mage.abilities.keyword.DefenderAbility;
 import mage.cards.CardImpl;
 import mage.cards.CardSetInfo;
 import mage.constants.CardType;
 import mage.constants.Duration;
 import mage.constants.SubType;
-import mage.constants.WatcherScope;
-import mage.game.Game;
-import mage.game.events.EntersTheBattlefieldEvent;
-import mage.game.events.GameEvent;
-import mage.watchers.Watcher;
+import mage.watchers.common.ArtifactEnteredControllerWatcher;
 
-import java.util.HashSet;
-import java.util.Set;
 import java.util.UUID;
 
 /**
@@ -28,11 +21,6 @@ import java.util.UUID;
  */
 public final class ShipwreckSentry extends CardImpl {
 
-    private static final Hint hint = new ConditionHint(
-            ShipwreckSentryWatcher::checkPlayer,
-            "An artifact entered under your control this turn"
-    );
-
     public ShipwreckSentry(UUID ownerId, CardSetInfo setInfo) {
         super(ownerId, setInfo, new CardType[]{CardType.CREATURE}, "{1}{U}");
 
@@ -47,9 +35,11 @@ public final class ShipwreckSentry extends CardImpl {
         // As long as an artifact entered the battlefield under your control this turn, Shipwreck Sentry can attack as though it didn't have defender.
         this.addAbility(new SimpleStaticAbility(new ConditionalAsThoughEffect(
                 new CanAttackAsThoughItDidntHaveDefenderSourceEffect(Duration.WhileOnBattlefield),
-                ShipwreckSentryWatcher::checkPlayer
+                ArtifactEnteredUnderYourControlCondition.instance
         ).setText("as long as an artifact entered the battlefield under your control this turn, " +
-                "{this} can attack as though it didn't have defender")).addHint(hint), new ShipwreckSentryWatcher());
+                        "{this} can attack as though it didn't have defender"))
+                        .addHint(new ConditionHint(ArtifactEnteredUnderYourControlCondition.instance)),
+                new ArtifactEnteredControllerWatcher());
     }
 
     private ShipwreckSentry(final ShipwreckSentry card) {
@@ -61,37 +51,3 @@ public final class ShipwreckSentry extends CardImpl {
         return new ShipwreckSentry(this);
     }
 }
-
-class ShipwreckSentryWatcher extends Watcher {
-
-    private final Set<UUID> playerSet = new HashSet<>();
-
-    ShipwreckSentryWatcher() {
-        super(WatcherScope.GAME);
-    }
-
-    @Override
-    public void watch(GameEvent event, Game game) {
-        if (event.getType() != GameEvent.EventType.ENTERS_THE_BATTLEFIELD) {
-            return;
-        }
-        EntersTheBattlefieldEvent eEvent = (EntersTheBattlefieldEvent) event;
-        if (eEvent.getTarget() != null && eEvent.getTarget().isArtifact(game)) {
-            playerSet.add(eEvent.getTarget().getControllerId());
-        }
-    }
-
-    @Override
-    public void reset() {
-        super.reset();
-        playerSet.clear();
-    }
-
-    static boolean checkPlayer(Game game, Ability source) {
-        return game
-                .getState()
-                .getWatcher(ShipwreckSentryWatcher.class)
-                .playerSet
-                .contains(source.getControllerId());
-    }
-}

Mage.Sets/src/mage/cards/t/ThePrydwenSteelFlagship.java

@@ -0,0 +1,65 @@
+package mage.cards.t;
+
+import java.util.UUID;
+
+import mage.MageInt;
+import mage.abilities.common.EntersBattlefieldControlledTriggeredAbility;
+import mage.abilities.effects.common.CreateTokenEffect;
+import mage.constants.SubType;
+import mage.constants.SuperType;
+import mage.abilities.keyword.FlyingAbility;
+import mage.abilities.keyword.CrewAbility;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.constants.CardType;
+import mage.filter.common.FilterArtifactPermanent;
+import mage.filter.predicate.mageobject.AnotherPredicate;
+import mage.filter.predicate.permanent.TokenPredicate;
+import mage.game.permanent.token.ThePrydwenSteelFlagshipHumanKnightToken;
+import mage.watchers.common.ArtifactEnteredControllerWatcher;
+
+/**
+ * @author Cguy7777
+ */
+public final class ThePrydwenSteelFlagship extends CardImpl {
+
+    private static final FilterArtifactPermanent filter = new FilterArtifactPermanent("another nontoken artifact");
+
+    static {
+        filter.add(AnotherPredicate.instance);
+        filter.add(TokenPredicate.FALSE);
+    }
+
+    public ThePrydwenSteelFlagship(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.ARTIFACT}, "{4}{W}{W}");
+
+        this.supertype.add(SuperType.LEGENDARY);
+        this.subtype.add(SubType.VEHICLE);
+        this.power = new MageInt(6);
+        this.toughness = new MageInt(6);
+
+        // Flying
+        this.addAbility(FlyingAbility.getInstance());
+
+        // Whenever another nontoken artifact enters the battlefield under your control,
+        // create a 2/2 white Human Knight creature token with
+        // "This creature gets +2/+2 as long as an artifact entered the battlefield under your control this turn."
+        this.addAbility(
+                new EntersBattlefieldControlledTriggeredAbility(
+                        new CreateTokenEffect(new ThePrydwenSteelFlagshipHumanKnightToken()), filter),
+                new ArtifactEnteredControllerWatcher());
+
+        // Crew 2
+        this.addAbility(new CrewAbility(2));
+
+    }
+
+    private ThePrydwenSteelFlagship(final ThePrydwenSteelFlagship card) {
+        super(card);
+    }
+
+    @Override
+    public ThePrydwenSteelFlagship copy() {
+        return new ThePrydwenSteelFlagship(this);
+    }
+}

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

@@ -289,6 +289,10 @@ public final class Fallout extends ExpansionSet {
         cards.add(new SetCardInfo("Screeching Scorchbeast", 49, Rarity.RARE, mage.cards.s.ScreechingScorchbeast.class));
         cards.add(new SetCardInfo("Secure the Wastes", 171, Rarity.RARE, mage.cards.s.SecureTheWastes.class));
         cards.add(new SetCardInfo("Securitron Squadron", 23, Rarity.RARE, mage.cards.s.SecuritronSquadron.class));
+        cards.add(new SetCardInfo("Sentinel Sarah Lyons", 118, Rarity.RARE, mage.cards.s.SentinelSarahLyons.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("Sentinel Sarah Lyons", 428, Rarity.RARE, mage.cards.s.SentinelSarahLyons.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("Sentinel Sarah Lyons", 646, Rarity.RARE, mage.cards.s.SentinelSarahLyons.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("Sentinel Sarah Lyons", 956, Rarity.RARE, mage.cards.s.SentinelSarahLyons.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("Sentry Bot", 24, Rarity.RARE, mage.cards.s.SentryBot.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("Sentry Bot", 371, Rarity.RARE, mage.cards.s.SentryBot.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("Sentry Bot", 552, Rarity.RARE, mage.cards.s.SentryBot.class, NON_FULL_USE_VARIOUS));
@@ -361,6 +365,10 @@ public final class Fallout extends ExpansionSet {
         cards.add(new SetCardInfo("The Nipton Lottery", 423, Rarity.RARE, mage.cards.t.TheNiptonLottery.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("The Nipton Lottery", 641, Rarity.RARE, mage.cards.t.TheNiptonLottery.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("The Nipton Lottery", 951, Rarity.RARE, mage.cards.t.TheNiptonLottery.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("The Prydwen, Steel Flagship", 22, Rarity.RARE, mage.cards.t.ThePrydwenSteelFlagship.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("The Prydwen, Steel Flagship", 370, Rarity.RARE, mage.cards.t.ThePrydwenSteelFlagship.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("The Prydwen, Steel Flagship", 550, Rarity.RARE, mage.cards.t.ThePrydwenSteelFlagship.class, NON_FULL_USE_VARIOUS));
+        cards.add(new SetCardInfo("The Prydwen, Steel Flagship", 898, Rarity.RARE, mage.cards.t.ThePrydwenSteelFlagship.class, NON_FULL_USE_VARIOUS));
         cards.add(new SetCardInfo("The Wise Mothman", 4, Rarity.MYTHIC, mage.cards.t.TheWiseMothman.class));
         cards.add(new SetCardInfo("Thirst for Knowledge", 180, Rarity.UNCOMMON, mage.cards.t.ThirstForKnowledge.class));
         cards.add(new SetCardInfo("Thought Vessel", 251, Rarity.COMMON, mage.cards.t.ThoughtVessel.class));

Mage.Tests/src/test/java/org/mage/test/cards/single/pip/SentinelSarahLyonsTest.java

@@ -0,0 +1,86 @@
+package org.mage.test.cards.single.pip;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+public class SentinelSarahLyonsTest extends CardTestPlayerBase {
+
+    /*
+     * Sentinel Sarah Lyons {3}{R}{W}
+     * Legendary Creature - Human Knight (4/4)
+     * Haste
+     * As long as an artifact entered the battlefield under your control this turn, creatures you control get +2/+2.
+     * Battalion - Whenever Sentinel Sarah Lyons and at least two other creatures attack,
+     * Sentinel Sarah Lyons deals damage equal to the number of artifacts you control to target player.
+     */
+
+    @Test
+    public void test_ArtifactEntersUnderYourControlBeforeAndAfter() {
+        addCard(Zone.BATTLEFIELD, playerA, "Sentinel Sarah Lyons", 1);
+        addCard(Zone.HAND, playerA, "Darksteel Relic", 1); // Artifact w/ Indestructible
+
+        // Before casting an artifact (4/4)
+        checkPT("1: before casting Relic", 1, PhaseStep.UPKEEP, playerA, "Sentinel Sarah Lyons", 4, 4);
+
+        // Casting the artifact (should become a 6/6 until end of turn)
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Darksteel Relic");
+        checkPT("1: after casting Relic", 1, PhaseStep.END_TURN, playerA, "Sentinel Sarah Lyons", 6, 6);
+
+        // Turn after casting the artifact (should return to 4/4)
+        setStrictChooseMode(true);
+        setStopAt(2, PhaseStep.UPKEEP);
+        execute();
+
+        assertPowerToughness(playerA, "Sentinel Sarah Lyons", 4, 4);
+    }
+
+    @Test
+    public void test_ArtifactEntersUnderOpponentsControl() {
+        addCard(Zone.BATTLEFIELD, playerA, "Sentinel Sarah Lyons", 1);
+
+        addCard(Zone.HAND, playerB, "Darksteel Relic", 1);
+        // Artifact w/ "You may cast spells as though they had flash."
+        addCard(Zone.BATTLEFIELD, playerB, "Vedalken Orrery", 1);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerB, "Darksteel Relic");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertPowerToughness(playerA, "Sentinel Sarah Lyons", 4, 4);
+    }
+
+    @Test
+    public void test_NonartifactEntersUnderYourControl() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 2);
+        addCard(Zone.BATTLEFIELD, playerA, "Sentinel Sarah Lyons", 1);
+        addCard(Zone.HAND, playerA, "Grizzly Bears", 1);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Grizzly Bears");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertPowerToughness(playerA, "Sentinel Sarah Lyons", 4, 4);
+    }
+
+    @Test
+    public void test_ArtifactEntersBeforeSarahLyons() {
+        addCard(Zone.BATTLEFIELD, playerA, "Plateau", 5);
+        addCard(Zone.HAND, playerA, "Sentinel Sarah Lyons", 1);
+        addCard(Zone.HAND, playerA, "Darksteel Relic", 1);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Darksteel Relic", true);
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Sentinel Sarah Lyons");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertPowerToughness(playerA, "Sentinel Sarah Lyons", 6, 6);
+    }
+}

Mage/src/main/java/mage/abilities/condition/common/ArtifactEnteredUnderYourControlCondition.java

@@ -0,0 +1,25 @@
+package mage.abilities.condition.common;
+
+import mage.abilities.Ability;
+import mage.abilities.condition.Condition;
+import mage.game.Game;
+import mage.watchers.common.ArtifactEnteredControllerWatcher;
+
+/**
+ * /!\ You need to add ArtifactEnteredControllerWatcher to any card using this condition
+ *
+ * @author Cguy7777
+ */
+public enum ArtifactEnteredUnderYourControlCondition implements Condition {
+    instance;
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        return ArtifactEnteredControllerWatcher.enteredArtifactForPlayer(source.getControllerId(), game);
+    }
+
+    @Override
+    public String toString() {
+        return "an artifact entered the battlefield under your control this turn";
+    }
+}

Mage/src/main/java/mage/game/permanent/token/ThePrydwenSteelFlagshipHumanKnightToken.java

@@ -0,0 +1,45 @@
+package mage.game.permanent.token;
+
+import mage.MageInt;
+import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.condition.common.ArtifactEnteredUnderYourControlCondition;
+import mage.abilities.decorator.ConditionalContinuousEffect;
+import mage.abilities.effects.common.continuous.BoostSourceEffect;
+import mage.abilities.hint.ConditionHint;
+import mage.constants.CardType;
+import mage.constants.Duration;
+import mage.constants.SubType;
+
+/**
+ * @author Cguy7777
+ */
+public class ThePrydwenSteelFlagshipHumanKnightToken extends TokenImpl {
+
+    /**
+     * /!\ You need to add ArtifactEnteredControllerWatcher to any card using this token
+     */
+    public ThePrydwenSteelFlagshipHumanKnightToken() {
+        super("Human Knight Token", "2/2 white Human Knight creature token with \"This creature " +
+                "gets +2/+2 as long as an artifact entered the battlefield under your control this turn.\"");
+        cardType.add(CardType.CREATURE);
+        color.setWhite(true);
+        subtype.add(SubType.HUMAN, SubType.KNIGHT);
+        power = new MageInt(2);
+        toughness = new MageInt(2);
+
+        this.addAbility(new SimpleStaticAbility(new ConditionalContinuousEffect(
+                new BoostSourceEffect(2, 2, Duration.WhileOnBattlefield),
+                ArtifactEnteredUnderYourControlCondition.instance,
+                "This creature gets +2/+2 as long as an artifact entered the battlefield under your control this turn"))
+                .addHint(new ConditionHint(ArtifactEnteredUnderYourControlCondition.instance)));
+    }
+
+    private ThePrydwenSteelFlagshipHumanKnightToken(final ThePrydwenSteelFlagshipHumanKnightToken token) {
+        super(token);
+    }
+
+    @Override
+    public ThePrydwenSteelFlagshipHumanKnightToken copy() {
+        return new ThePrydwenSteelFlagshipHumanKnightToken(this);
+    }
+}

Mage/src/main/java/mage/watchers/common/ArtifactEnteredControllerWatcher.java

@@ -0,0 +1,49 @@
+package mage.watchers.common;
+
+import mage.constants.WatcherScope;
+import mage.game.Game;
+import mage.game.events.EntersTheBattlefieldEvent;
+import mage.game.events.GameEvent;
+import mage.watchers.Watcher;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * @author Cguy7777
+ */
+public class ArtifactEnteredControllerWatcher extends Watcher {
+
+    private final Set<UUID> players = new HashSet<>();
+
+    public ArtifactEnteredControllerWatcher() {
+        super(WatcherScope.GAME);
+    }
+
+    @Override
+    public void watch(GameEvent event, Game game) {
+        if (event.getType() != GameEvent.EventType.ENTERS_THE_BATTLEFIELD) {
+            return;
+        }
+
+        EntersTheBattlefieldEvent eEvent = (EntersTheBattlefieldEvent) event;
+        if (eEvent.getTarget() != null && eEvent.getTarget().isArtifact(game)) {
+            players.add(eEvent.getTarget().getControllerId());
+        }
+    }
+
+    @Override
+    public void reset() {
+        super.reset();
+        players.clear();
+    }
+
+    public static boolean enteredArtifactForPlayer(UUID playerId, Game game) {
+        return game
+                .getState()
+                .getWatcher(ArtifactEnteredControllerWatcher.class)
+                .players
+                .contains(playerId);
+    }
+}