Implement Impending mechanic (#12865)

* implement Impending mechanic

* add initial test

* add more tests

* small fix

Mage.Sets/src/mage/cards/o/OverlordOfTheBalemurk.java

@@ -36,7 +36,7 @@ public final class OverlordOfTheBalemurk extends CardImpl {
         this.toughness = new MageInt(5);
 
         // Impending 5--{1}{B}
-        this.addAbility(new ImpendingAbility("{1}{B}", 5));
+        this.addAbility(new ImpendingAbility(5, "{1}{B}"));
 
         // Whenever Overlord of the Balemurk enters or attacks, mill four cards, then you may return a non-Avatar creature card or a planeswalker card from your graveyard to your hand.
         Ability ability = new EntersBattlefieldOrAttacksSourceTriggeredAbility(new MillCardsControllerEffect(4));

Mage.Sets/src/mage/cards/o/OverlordOfTheBoilerbilges.java

@@ -27,7 +27,7 @@ public final class OverlordOfTheBoilerbilges extends CardImpl {
         this.toughness = new MageInt(5);
 
         // Impending 4--{2}{R}{R}
-        this.addAbility(new ImpendingAbility("{2}{R}{R}"));
+        this.addAbility(new ImpendingAbility(4, "{2}{R}{R}"));
 
         // Whenever Overlord of the Boilerbilges enters or attacks, it deals 4 damage to any target.
         Ability ability = new EntersBattlefieldOrAttacksSourceTriggeredAbility(new DamageTargetEffect(4));

Mage.Sets/src/mage/cards/o/OverlordOfTheFloodpits.java

@@ -26,7 +26,7 @@ public final class OverlordOfTheFloodpits extends CardImpl {
         this.toughness = new MageInt(3);
 
         // Impending 4--{1}{U}{U}
-        this.addAbility(new ImpendingAbility("{1}{U}{U}"));
+        this.addAbility(new ImpendingAbility(4, "{1}{U}{U}"));
 
         // Flying
         this.addAbility(FlyingAbility.getInstance());

Mage.Sets/src/mage/cards/o/OverlordOfTheHauntwoods.java

@@ -26,7 +26,7 @@ public final class OverlordOfTheHauntwoods extends CardImpl {
         this.toughness = new MageInt(5);
 
         // Impending 4--{1}{G}{G}
-        this.addAbility(new ImpendingAbility("{1}{G}{G}"));
+        this.addAbility(new ImpendingAbility(4, "{1}{G}{G}"));
 
         // Whenever Overlord of the Hauntwoods enters or attacks, create a tapped colorless land token named Everywhere that is every basic land type.
         this.addAbility(new EntersBattlefieldOrAttacksSourceTriggeredAbility(

Mage.Sets/src/mage/cards/o/OverlordOfTheMistmoors.java

@@ -26,7 +26,7 @@ public final class OverlordOfTheMistmoors extends CardImpl {
         this.toughness = new MageInt(6);
 
         // Impending 4--{2}{W}{W}
-        this.addAbility(new ImpendingAbility("{2}{W}{W}"));
+        this.addAbility(new ImpendingAbility(4, "{2}{W}{W}"));
 
         // Whenever Overlord of the Mistmoors enters or attacks, create two 2/1 white Insect creature tokens with flying.
         this.addAbility(new EntersBattlefieldOrAttacksSourceTriggeredAbility(new CreateTokenEffect(new InsectWhiteToken(), 2)));

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

@@ -224,7 +224,5 @@ public final class DuskmournHouseOfHorror extends ExpansionSet {
         cards.add(new SetCardInfo("Winter, Misanthropic Guide", 240, Rarity.RARE, mage.cards.w.WinterMisanthropicGuide.class));
         cards.add(new SetCardInfo("Withering Torment", 124, Rarity.UNCOMMON, mage.cards.w.WitheringTorment.class));
         cards.add(new SetCardInfo("Zimone, All-Questioning", 241, Rarity.RARE, mage.cards.z.ZimoneAllQuestioning.class));
-
-        cards.removeIf(setCardInfo -> setCardInfo.getName().startsWith("Overlord"));
     }
 }

Mage.Tests/src/test/java/org/mage/test/cards/abilities/keywords/ImpendingTest.java

@@ -0,0 +1,226 @@
+package org.mage.test.cards.abilities.keywords;
+
+import mage.abilities.keyword.ImpendingAbility;
+import mage.constants.CardType;
+import mage.constants.PhaseStep;
+import mage.constants.SubType;
+import mage.constants.Zone;
+import mage.counters.CounterType;
+import mage.game.permanent.Permanent;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+/**
+ * @author TheElk801
+ */
+public class ImpendingTest extends CardTestPlayerBase {
+
+    private static final String hauntwoods = "Overlord of the Hauntwoods";
+
+    public void assertHasImpending(String name, boolean hasAbility) {
+        Permanent permanent = getPermanent(name);
+        Assert.assertEquals(
+                "Should" + (hasAbility ? "" : "n't") + " have Impending ability",
+                hasAbility, permanent.getAbilities(currentGame).containsClass(ImpendingAbility.class)
+        );
+    }
+
+    @Test
+    public void testCastRegular() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 5);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with no");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, true);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    @Test
+    public void testCastImpending() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, false);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 4);
+        assertHasImpending(hauntwoods, true);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    @Test
+    public void testImpendingRemoveCounter() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        setStrictChooseMode(true);
+        setStopAt(2, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, false);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 4 - 1);
+        assertHasImpending(hauntwoods, true);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    @Test
+    public void testCastImpendingRemoveAllCounters() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        setStrictChooseMode(true);
+        setStopAt(8, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, false);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    private static final String hexmage = "Vampire Hexmage";
+
+    @Test
+    public void testCastImpendingHexmage() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.BATTLEFIELD, playerA, hexmage);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        activateAbility(1, PhaseStep.BEGIN_COMBAT, playerA, "Sacrifice", hauntwoods);
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, true);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    @Test
+    public void testCastImpendingHexmageNextTurn() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.BATTLEFIELD, playerA, hexmage);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        activateAbility(1, PhaseStep.BEGIN_COMBAT, playerA, "Sacrifice", hauntwoods);
+
+        setStrictChooseMode(true);
+        setStopAt(2, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, false);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    private static final String solemnity = "Solemnity";
+
+    @Test
+    public void testCastImpendingSolemnity() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.BATTLEFIELD, playerA, solemnity);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, true);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+
+    @Test
+    public void testCastImpendingSolemnityNextTurn() {
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.BATTLEFIELD, playerA, solemnity);
+        addCard(Zone.HAND, playerA, hauntwoods);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, hauntwoods);
+        setChoice(playerA, "Cast with Impending");
+
+        setStrictChooseMode(true);
+        setStopAt(2, PhaseStep.POSTCOMBAT_MAIN);
+        execute();
+
+        assertPermanentCount(playerA, hauntwoods, 1);
+        assertType(hauntwoods, CardType.ENCHANTMENT, true);
+        assertType(hauntwoods, CardType.CREATURE, true);
+        assertSubtype(hauntwoods, SubType.AVATAR);
+        assertSubtype(hauntwoods, SubType.HORROR);
+        assertCounterCount(playerA, hauntwoods, CounterType.TIME, 0);
+        assertPowerToughness(playerA, hauntwoods, 6, 5);
+        assertHasImpending(hauntwoods, false);
+
+        assertPermanentCount(playerA, "Everywhere", 1);
+    }
+}

Mage/src/main/java/mage/abilities/costs/AlternativeSourceCostsImpl.java

@@ -30,11 +30,15 @@ public abstract class AlternativeSourceCostsImpl extends StaticAbility implement
     }
 
     protected AlternativeSourceCostsImpl(String name, String reminderText, Cost cost) {
+        this(name, reminderText, cost, name);
+    }
+
+    protected AlternativeSourceCostsImpl(String name, String reminderText, Cost cost, String activationKey) {
         super(Zone.ALL, null);
         this.name = name;
         this.reminderText = reminderText;
         this.alternativeCost = new AlternativeCostImpl<>(name, reminderText, cost);
-        this.activationKey = getActivationKey(name);
+        this.activationKey = getActivationKey(activationKey);
     }
 
     protected AlternativeSourceCostsImpl(final AlternativeSourceCostsImpl ability) {

Mage/src/main/java/mage/abilities/keyword/ImpendingAbility.java

@@ -1,12 +1,33 @@
 package mage.abilities.keyword;
 
 import mage.abilities.Ability;
+import mage.abilities.common.BeginningOfEndStepTriggeredAbility;
+import mage.abilities.common.EntersBattlefieldAbility;
+import mage.abilities.common.SimpleStaticAbility;
+import mage.abilities.condition.Condition;
+import mage.abilities.condition.common.SourceHasCounterCondition;
 import mage.abilities.costs.AlternativeSourceCostsImpl;
+import mage.abilities.costs.mana.ManaCostsImpl;
+import mage.abilities.decorator.ConditionalOneShotEffect;
+import mage.abilities.effects.ContinuousEffectImpl;
+import mage.abilities.effects.common.AddContinuousEffectToGame;
+import mage.abilities.effects.common.counter.AddCountersSourceEffect;
+import mage.abilities.effects.common.counter.RemoveCounterSourceEffect;
+import mage.constants.*;
+import mage.counters.CounterType;
 import mage.game.Game;
+import mage.game.permanent.Permanent;
 import mage.util.CardUtil;
 
+import java.util.stream.Collectors;
+
 /**
- * TODO: Implement this
+ * "Impending N–[cost]" is a keyword that represents multiple abilities.
+ * The official rules are as follows:
+ * (a) You may choose to pay [cost] rather than pay this spell's mana cost.
+ * (b) If you chose to pay this spell's impending cost, it enters the battlefield with N time counters on it.
+ * (c) As long as this permanent has a time counter on it, if it was cast for its impending cost, it's not a creature.
+ * (d) At the beginning of your end step, if this permanent was cast for its impending cost, remove a time counter from it. Then if it has no time counters on it, it loses impending.
  *
  * @author TheElk801
  */
@@ -16,14 +37,24 @@ public class ImpendingAbility extends AlternativeSourceCostsImpl {
     private static final String IMPENDING_REMINDER = "If you cast this spell for its impending cost, " +
             "it enters with %s time counters and isn't a creature until the last is removed. " +
             "At the beginning of your end step, remove a time counter from it.";
+    private static final Condition counterCondition = new SourceHasCounterCondition(CounterType.TIME, 0, 0);
 
-    public ImpendingAbility(String manaString) {
+    public ImpendingAbility(int amount, String manaString) {
-        this(manaString, 4);
+        super(IMPENDING_KEYWORD + ' ' + amount, String.format(IMPENDING_REMINDER, CardUtil.numberToText(amount)), new ManaCostsImpl<>(manaString), IMPENDING_KEYWORD);
-    }
-
-    public ImpendingAbility(String manaString, int amount) {
-        super(IMPENDING_KEYWORD + ' ' + amount, String.format(IMPENDING_REMINDER, CardUtil.numberToText(amount)), manaString);
         this.setRuleAtTheTop(true);
+        this.addSubAbility(new EntersBattlefieldAbility(new ConditionalOneShotEffect(
+                new AddCountersSourceEffect(CounterType.TIME.createInstance(amount)), ImpendingCondition.instance, ""
+        ), "").setRuleVisible(false));
+        this.addSubAbility(new SimpleStaticAbility(new ImpendingAbilityTypeEffect()).setRuleVisible(false));
+        Ability ability = new BeginningOfEndStepTriggeredAbility(
+                new RemoveCounterSourceEffect(CounterType.TIME.createInstance()),
+                TargetController.YOU, ImpendingCondition.instance, false
+        );
+        ability.addEffect(new ConditionalOneShotEffect(
+                new AddContinuousEffectToGame(new ImpendingAbilityRemoveEffect()),
+                counterCondition, "Then if it has no time counters on it, it loses impending"
+        ));
+        this.addSubAbility(ability.setRuleVisible(false));
     }
 
     private ImpendingAbility(final ImpendingAbility ability) {
@@ -35,12 +66,81 @@ public class ImpendingAbility extends AlternativeSourceCostsImpl {
         return new ImpendingAbility(this);
     }
 
-    @Override
-    public boolean isAvailable(Ability source, Game game) {
-        return true;
-    }
-
     public static String getActivationKey() {
         return getActivationKey(IMPENDING_KEYWORD);
     }
 }
+
+enum ImpendingCondition implements Condition {
+    instance;
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        return CardUtil.checkSourceCostsTagExists(game, source, ImpendingAbility.getActivationKey());
+    }
+}
+
+class ImpendingAbilityTypeEffect extends ContinuousEffectImpl {
+
+    ImpendingAbilityTypeEffect() {
+        super(Duration.WhileOnBattlefield, Layer.TypeChangingEffects_4, SubLayer.NA, Outcome.Detriment);
+        staticText = "As long as this permanent has a time counter on it, if it was cast for its impending cost, it's not a creature.";
+    }
+
+    private ImpendingAbilityTypeEffect(final ImpendingAbilityTypeEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public ImpendingAbilityTypeEffect copy() {
+        return new ImpendingAbilityTypeEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        if (!ImpendingCondition.instance.apply(game, source)) {
+            return false;
+        }
+        Permanent permanent = source.getSourcePermanentIfItStillExists(game);
+        if (permanent.getCounters(game).getCount(CounterType.TIME) < 1) {
+            return false;
+        }
+        permanent.removeCardType(game, CardType.CREATURE);
+        permanent.removeAllCreatureTypes(game);
+        return true;
+    }
+}
+
+class ImpendingAbilityRemoveEffect extends ContinuousEffectImpl {
+
+    ImpendingAbilityRemoveEffect() {
+        super(Duration.Custom, Layer.AbilityAddingRemovingEffects_6, SubLayer.NA, Outcome.LoseAbility);
+    }
+
+    private ImpendingAbilityRemoveEffect(final ImpendingAbilityRemoveEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public ImpendingAbilityRemoveEffect copy() {
+        return new ImpendingAbilityRemoveEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Permanent permanent = source.getSourcePermanentIfItStillExists(game);
+        if (permanent == null) {
+            discard();
+            return false;
+        }
+        permanent.removeAbilities(
+                permanent
+                        .getAbilities(game)
+                        .stream()
+                        .filter(ImpendingAbility.class::isInstance)
+                        .collect(Collectors.toList()),
+                source.getSourceId(), game
+        );
+        return true;
+    }
+}