Implement Read Ahead mechanic (#9407)

* implement Read Ahead mechanic

* [DMU] Implemented The World Spell

* [DMU] Implemented The Elder Dragon War

* added read ahead test

* fix verify failure

* small change to test

* fix read ahead text

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

@@ -0,0 +1,61 @@
+package mage.cards.t;
+
+import mage.abilities.common.SagaAbility;
+import mage.abilities.effects.common.CreateTokenEffect;
+import mage.abilities.effects.common.DamageAllEffect;
+import mage.abilities.effects.common.DamagePlayersEffect;
+import mage.abilities.effects.common.discard.DiscardAndDrawThatManyEffect;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.constants.CardType;
+import mage.constants.SagaChapter;
+import mage.constants.SubType;
+import mage.constants.TargetController;
+import mage.filter.StaticFilters;
+import mage.game.permanent.token.DragonToken;
+
+import java.util.UUID;
+
+/**
+ * @author TheElk801
+ */
+public final class TheElderDragonWar extends CardImpl {
+
+    public TheElderDragonWar(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.ENCHANTMENT}, "{2}{R}{R}");
+
+        this.subtype.add(SubType.SAGA);
+
+        // Read ahead
+        SagaAbility sagaAbility = new SagaAbility(this, SagaChapter.CHAPTER_III, true);
+
+        // I -- The Elder Dragon War deals 2 damage to each creature and each opponent.
+        sagaAbility.addChapterEffect(
+                this, SagaChapter.CHAPTER_I,
+                new DamageAllEffect(2, StaticFilters.FILTER_PERMANENT_CREATURE),
+                new DamagePlayersEffect(2, TargetController.OPPONENT).setText("and each opponent")
+        );
+
+        // II -- Discard any number of cards, then draw that many cards.
+        sagaAbility.addChapterEffect(
+                this, SagaChapter.CHAPTER_II,
+                new DiscardAndDrawThatManyEffect(Integer.MAX_VALUE)
+        );
+
+        // III -- Create a 4/4 red Dragon creature token with flying.
+        sagaAbility.addChapterEffect(
+                this, SagaChapter.CHAPTER_III,
+                new CreateTokenEffect(new DragonToken())
+        );
+        this.addAbility(sagaAbility);
+    }
+
+    private TheElderDragonWar(final TheElderDragonWar card) {
+        super(card);
+    }
+
+    @Override
+    public TheElderDragonWar copy() {
+        return new TheElderDragonWar(this);
+    }
+}

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

@@ -0,0 +1,97 @@
+package mage.cards.t;
+
+import mage.abilities.Ability;
+import mage.abilities.common.SagaAbility;
+import mage.abilities.effects.OneShotEffect;
+import mage.abilities.effects.common.LookLibraryAndPickControllerEffect;
+import mage.abilities.effects.common.LookLibraryControllerEffect;
+import mage.cards.CardImpl;
+import mage.cards.CardSetInfo;
+import mage.cards.CardsImpl;
+import mage.constants.*;
+import mage.filter.FilterCard;
+import mage.filter.common.FilterPermanentCard;
+import mage.filter.predicate.Predicates;
+import mage.game.Game;
+import mage.players.Player;
+import mage.target.common.TargetCardInHand;
+
+import java.util.UUID;
+
+/**
+ * @author TheElk801
+ */
+public final class TheWorldSpell extends CardImpl {
+
+    private static final FilterCard filter = new FilterPermanentCard("non-Saga permanent card");
+
+    static {
+        filter.add(Predicates.not(SubType.SAGA.getPredicate()));
+    }
+
+    public TheWorldSpell(UUID ownerId, CardSetInfo setInfo) {
+        super(ownerId, setInfo, new CardType[]{CardType.ENCHANTMENT}, "{5}{G}{G}");
+
+        this.subtype.add(SubType.SAGA);
+
+        // Read ahead
+        SagaAbility sagaAbility = new SagaAbility(this, SagaChapter.CHAPTER_III, true);
+
+        // I, II -- Look at the top seven cards of your library. You may reveal a non-Saga permanent card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
+        sagaAbility.addChapterEffect(
+                this, SagaChapter.CHAPTER_I, SagaChapter.CHAPTER_II,
+                new LookLibraryAndPickControllerEffect(
+                        7, 1, filter,
+                        LookLibraryControllerEffect.PutCards.HAND,
+                        LookLibraryControllerEffect.PutCards.BOTTOM_RANDOM
+                )
+        );
+
+        // III -- Put up to two non-Saga permanent cards from your hand onto the battlefield.
+        sagaAbility.addChapterEffect(this, SagaChapter.CHAPTER_III, new TheWorldSpellEffect());
+        this.addAbility(sagaAbility);
+    }
+
+    private TheWorldSpell(final TheWorldSpell card) {
+        super(card);
+    }
+
+    @Override
+    public TheWorldSpell copy() {
+        return new TheWorldSpell(this);
+    }
+}
+
+class TheWorldSpellEffect extends OneShotEffect {
+
+    private static final FilterCard filter = new FilterPermanentCard("non-Saga permanent cards");
+
+    static {
+        filter.add(Predicates.not(SubType.SAGA.getPredicate()));
+    }
+
+    TheWorldSpellEffect() {
+        super(Outcome.Benefit);
+        staticText = "put up to two non-Saga permanent cards from your hand onto the battlefield";
+    }
+
+    private TheWorldSpellEffect(final TheWorldSpellEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public TheWorldSpellEffect copy() {
+        return new TheWorldSpellEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Player player = game.getPlayer(source.getControllerId());
+        if (player == null) {
+            return false;
+        }
+        TargetCardInHand target = new TargetCardInHand(0, 2, filter);
+        player.choose(outcome, player.getHand(), target, game);
+        return player.moveCards(new CardsImpl(target.getTargets()), Zone.BATTLEFIELD, source, game);
+    }
+}

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

@@ -189,7 +189,9 @@ public final class DominariaUnited extends ExpansionSet {
         cards.add(new SetCardInfo("Tear Asunder", 183, Rarity.UNCOMMON, mage.cards.t.TearAsunder.class));
         cards.add(new SetCardInfo("Temporal Firestorm", 147, Rarity.RARE, mage.cards.t.TemporalFirestorm.class));
         cards.add(new SetCardInfo("Territorial Maro", 184, Rarity.UNCOMMON, mage.cards.t.TerritorialMaro.class));
+        cards.add(new SetCardInfo("The Elder Dragon War", 121, Rarity.RARE, mage.cards.t.TheElderDragonWar.class));
         cards.add(new SetCardInfo("The Raven Man", 103, Rarity.RARE, mage.cards.t.TheRavenMan.class));
+        cards.add(new SetCardInfo("The World Spell", 189, Rarity.MYTHIC, mage.cards.t.TheWorldSpell.class));
         cards.add(new SetCardInfo("Threats Undetected", 185, Rarity.RARE, mage.cards.t.ThreatsUndetected.class));
         cards.add(new SetCardInfo("Thrill of Possibility", 148, Rarity.COMMON, mage.cards.t.ThrillOfPossibility.class));
         cards.add(new SetCardInfo("Tidepool Turtle", 69, Rarity.COMMON, mage.cards.t.TidepoolTurtle.class));

Mage.Tests/src/test/java/org/mage/test/cards/enchantments/ReadAheadTest.java

@@ -0,0 +1,72 @@
+package org.mage.test.cards.enchantments;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+/**
+ * @author TheElk801
+ */
+public class ReadAheadTest extends CardTestPlayerBase {
+
+    private static final String war = "The Elder Dragon War";
+    private static final String recall = "Ancestral Recall";
+
+    @Test
+    public void testElderDragonWarChapter1() {
+        addCard(Zone.HAND, playerA, war);
+        addCard(Zone.BATTLEFIELD, playerA, "Mountain", 4);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, war);
+        setChoice(playerA, "X=1");
+
+
+        setStopAt(1, PhaseStep.END_TURN);
+        setStrictChooseMode(true);
+        execute();
+
+        assertLife(playerB, 20 - 2);
+        assertPermanentCount(playerA, war, 1);
+        assertGraveyardCount(playerA, war, 0);
+    }
+
+    @Test
+    public void testElderDragonWarChapter2() {
+        addCard(Zone.HAND, playerA, war);
+        addCard(Zone.HAND, playerA, recall);
+        addCard(Zone.BATTLEFIELD, playerA, "Mountain", 4);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, war);
+        setChoice(playerA, "X=2");
+        setChoice(playerA, recall);
+
+        setStopAt(1, PhaseStep.END_TURN);
+        setStrictChooseMode(true);
+        execute();
+
+        assertLife(playerB, 20);
+        assertGraveyardCount(playerA, recall, 1);
+        assertHandCount(playerA, recall, 0);
+        assertPermanentCount(playerA, war, 1);
+        assertGraveyardCount(playerA, war, 0);
+    }
+
+    @Test
+    public void testElderDragonWarChapter3() {
+        addCard(Zone.HAND, playerA, war);
+        addCard(Zone.BATTLEFIELD, playerA, "Mountain", 4);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, war);
+        setChoice(playerA, "X=3");
+
+        setStopAt(1, PhaseStep.END_TURN);
+        setStrictChooseMode(true);
+        execute();
+
+        assertLife(playerB, 20);
+        assertPermanentCount(playerA, "Dragon Token", 1);
+        assertPermanentCount(playerA, war, 0);
+        assertGraveyardCount(playerA, war, 1);
+    }
+}

Mage/src/main/java/mage/abilities/common/SagaAbility.java

@@ -6,8 +6,9 @@ import mage.abilities.TriggeredAbility;
 import mage.abilities.TriggeredAbilityImpl;
 import mage.abilities.effects.Effect;
 import mage.abilities.effects.Effects;
-import mage.abilities.effects.common.counter.AddCountersSourceEffect;
+import mage.abilities.effects.OneShotEffect;
 import mage.cards.Card;
+import mage.constants.Outcome;
 import mage.constants.SagaChapter;
 import mage.constants.Zone;
 import mage.counters.CounterType;
@@ -16,6 +17,7 @@ import mage.game.events.GameEvent;
 import mage.game.permanent.Permanent;
 import mage.game.stack.StackAbility;
 import mage.game.stack.StackObject;
+import mage.players.Player;
 import mage.target.Target;
 import mage.target.Targets;
 import mage.util.CardUtil;
@@ -29,18 +31,24 @@ public class SagaAbility extends SimpleStaticAbility {
 
     private final SagaChapter maxChapter;
     private final boolean showSacText;
+    private final boolean readAhead;
 
     public SagaAbility(Card card) {
         this(card, SagaChapter.CHAPTER_III);
     }
 
     public SagaAbility(Card card, SagaChapter maxChapter) {
-        super(Zone.ALL, new AddCountersSourceEffect(CounterType.LORE.createInstance()));
+        this(card, maxChapter, false);
+    }
+
+    public SagaAbility(Card card, SagaChapter maxChapter, boolean readAhead) {
+        super(Zone.ALL, null);
         this.maxChapter = maxChapter;
         this.showSacText = card.getSecondCardFace() == null;
+        this.readAhead = readAhead;
         this.setRuleVisible(true);
         this.setRuleAtTheTop(true);
-        Ability ability = new EntersBattlefieldAbility(new AddCountersSourceEffect(CounterType.LORE.createInstance()));
+        Ability ability = new EntersBattlefieldAbility(new SagaLoreCountersEffect(readAhead, maxChapter));
         ability.setRuleVisible(false);
         card.addAbility(ability);
     }
@@ -49,6 +57,7 @@ public class SagaAbility extends SimpleStaticAbility {
         super(ability);
         this.maxChapter = ability.maxChapter;
         this.showSacText = ability.showSacText;
+        this.readAhead = ability.readAhead;
     }
 
     public void addChapterEffect(Card card, SagaChapter chapter, Effect... effects) {
@@ -81,7 +90,7 @@ public class SagaAbility extends SimpleStaticAbility {
 
     public void addChapterEffect(Card card, SagaChapter fromChapter, SagaChapter toChapter, Effects effects, Targets targets, boolean optional, Mode... modes) {
         for (int i = fromChapter.getNumber(); i <= toChapter.getNumber(); i++) {
-            ChapterTriggeredAbility ability = new ChapterTriggeredAbility(null, SagaChapter.getChapter(i), toChapter, optional);
+            ChapterTriggeredAbility ability = new ChapterTriggeredAbility(null, SagaChapter.getChapter(i), toChapter, optional, readAhead);
             for (Effect effect : effects) {
                 if (effect != null) {
                     ability.addEffect(effect.copy());
@@ -108,7 +117,10 @@ public class SagaAbility extends SimpleStaticAbility {
 
     @Override
     public String getRule() {
-        return "<i>(As this Saga enters and after your draw step, add a lore counter."
+        return (readAhead
+                ? "Read ahead <i>(Choose a chapter and start with that many lore counters. " +
+                "Add one after your draw step. Skipped chapters don't trigger."
+                : "<i>(As this Saga enters and after your draw step, add a lore counter.")
                 + (showSacText ? " Sacrifice after " + maxChapter.toString() + '.' : "") + ")</i> ";
     }
 
@@ -129,25 +141,71 @@ public class SagaAbility extends SimpleStaticAbility {
     }
 }
 
+class SagaLoreCountersEffect extends OneShotEffect {
+
+    private final boolean readAhead;
+    private final SagaChapter maxChapter;
+
+    SagaLoreCountersEffect(boolean readAhead, SagaChapter maxChapter) {
+        super(Outcome.Benefit);
+        this.readAhead = readAhead;
+        this.maxChapter = maxChapter;
+    }
+
+    private SagaLoreCountersEffect(final SagaLoreCountersEffect effect) {
+        super(effect);
+        this.readAhead = effect.readAhead;
+        this.maxChapter = effect.maxChapter;
+    }
+
+    @Override
+    public SagaLoreCountersEffect copy() {
+        return new SagaLoreCountersEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Permanent permanent = game.getPermanentEntering(source.getSourceId());
+        if (permanent == null) {
+            return false;
+        }
+        if (!readAhead) {
+            return permanent.addCounters(CounterType.LORE.createInstance(), source, game);
+        }
+        Player player = game.getPlayer(source.getControllerId());
+        if (player == null) {
+            return false;
+        }
+        int counters = player.getAmount(
+                1, maxChapter.getNumber(),
+                "Choose the number of lore counters to enter with", game
+        );
+        return permanent.addCounters(CounterType.LORE.createInstance(counters), source, game);
+    }
+}
+
 class ChapterTriggeredAbility extends TriggeredAbilityImpl {
 
     private final SagaChapter chapterFrom, chapterTo;
+    private final boolean readAhead;
 
-    public ChapterTriggeredAbility(Effect effect, SagaChapter chapterFrom, SagaChapter chapterTo, boolean optional) {
+    public ChapterTriggeredAbility(Effect effect, SagaChapter chapterFrom, SagaChapter chapterTo, boolean optional, boolean readAhead) {
         super(Zone.ALL, effect, optional);
         this.chapterFrom = chapterFrom;
         this.chapterTo = chapterTo;
+        this.readAhead = readAhead;
     }
 
     public ChapterTriggeredAbility(final ChapterTriggeredAbility ability) {
         super(ability);
         this.chapterFrom = ability.chapterFrom;
         this.chapterTo = ability.chapterTo;
+        this.readAhead = ability.readAhead;
     }
 
     @Override
     public boolean checkEventType(GameEvent event, Game game) {
-        return event.getType() == GameEvent.EventType.COUNTER_ADDED;
+        return event.getType() == GameEvent.EventType.COUNTERS_ADDED;
     }
 
     @Override
@@ -161,6 +219,9 @@ class ChapterTriggeredAbility extends TriggeredAbilityImpl {
             return false;
         }
         int loreCounters = permanent.getCounters(game).getCount(CounterType.LORE);
+        if (readAhead && permanent.getTurnsOnBattlefield() == 0) {
+            return chapterFrom.getNumber() == loreCounters;
+        }
         return loreCounters - event.getAmount() < chapterFrom.getNumber()
                 && chapterFrom.getNumber() <= loreCounters;
     }