[SNC] Implemented shield counter mechanic (#8830)

* [SNC] Implemented shield counter mechanic

* Rework shield counter to be a global replacement effect

* Add unit test for shield counter

Co-authored-by: Evan Kranzler <theelk801@gmail.com>

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

@@ -12,7 +12,7 @@ import java.util.List;
  */
 public final class StreetsOfNewCapenna extends ExpansionSet {
 
-    private static final List<String> unfinished = Arrays.asList("Caldaia Strongarm", "Disciplined Duelist", "Elspeth Resplendent", "Falco Spara, Pactweaver", "Jaxis, the Troublemaker", "Mayhem Patrol", "Night Clubber", "Plasma Jockey", "Workshop Warchief", "Ziatora's Envoy");
+  private static final List<String> unfinished = Arrays.asList("Elspeth Resplendent", "Falco Spara, Pactweaver", "Jaxis, the Troublemaker");
 
     private static final StreetsOfNewCapenna instance = new StreetsOfNewCapenna();
 

Mage.Tests/src/test/java/org/mage/test/cards/replacement/ShieldCounterTest.java

@@ -0,0 +1,68 @@
+package org.mage.test.cards.replacement;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import mage.counters.CounterType;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+/**
+ *
+ * @author weirddan455
+ */
+public class ShieldCounterTest extends CardTestPlayerBase {
+
+    @Test
+    public void testNoncombatDamage() {
+        addCard(Zone.BATTLEFIELD, playerA, "Mountain", 2);
+        addCard(Zone.BATTLEFIELD, playerA, "Disciplined Duelist");
+        addCard(Zone.HAND, playerA, "Lightning Bolt", 2);
+        setStrictChooseMode(true);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Lightning Bolt");
+        addTarget(playerA, "Disciplined Duelist");
+
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertAllCommandsUsed();
+        assertPermanentCount(playerA, "Disciplined Duelist", 1);
+        assertCounterCount("Disciplined Duelist", CounterType.SHIELD, 0);
+    }
+
+    @Test
+    public void testCombatDamage() {
+        addCard(Zone.BATTLEFIELD, playerA, "Disciplined Duelist");
+        addCard(Zone.BATTLEFIELD, playerB, "Hill Giant");
+        setStrictChooseMode(true);
+
+        attack(1, playerA, "Disciplined Duelist");
+        block(1, playerB, "Hill Giant", "Disciplined Duelist");
+
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertAllCommandsUsed();
+        assertPermanentCount(playerA, "Disciplined Duelist", 1);
+        assertCounterCount("Disciplined Duelist", CounterType.SHIELD, 0);
+        assertGraveyardCount(playerB, "Hill Giant", 1);
+    }
+
+    @Test
+    public void testDestroyEffect() {
+        addCard(Zone.BATTLEFIELD, playerA, "Disciplined Duelist");
+        addCard(Zone.BATTLEFIELD, playerA, "Swamp", 3);
+        addCard(Zone.HAND, playerA, "Murder");
+        setStrictChooseMode(true);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Murder");
+        addTarget(playerA, "Disciplined Duelist");
+
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertAllCommandsUsed();
+        assertPermanentCount(playerA, "Disciplined Duelist", 1);
+        assertCounterCount("Disciplined Duelist", CounterType.SHIELD, 0);
+    }
+}

Mage/src/main/java/mage/abilities/effects/keyword/ShieldCounterEffect.java

@@ -0,0 +1,61 @@
+package mage.abilities.effects.keyword;
+
+import mage.abilities.Ability;
+import mage.abilities.effects.ReplacementEffectImpl;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.counters.CounterType;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.game.permanent.Permanent;
+
+/**
+ *
+ * @author weirddan455
+ */
+public class ShieldCounterEffect extends ReplacementEffectImpl {
+
+    public ShieldCounterEffect() {
+        super(Duration.Custom, Outcome.PreventDamage);
+        this.staticText = "If it would be dealt damage or destroyed, remove a shield counter from it instead";
+    }
+
+    private ShieldCounterEffect(final ShieldCounterEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public ShieldCounterEffect copy() {
+        return new ShieldCounterEffect(this);
+    }
+
+    @Override
+    public boolean replaceEvent(GameEvent event, Ability source, Game game) {
+        Permanent permanent = game.getPermanent(event.getTargetId());
+        if (permanent != null && permanent.getCounters(game).getCount(CounterType.SHIELD) > 0) {
+            permanent.removeCounters(CounterType.SHIELD.getName(), 1, source, game);
+            if (!game.isSimulation()) {
+                game.informPlayers("Removed a shield counter from " + permanent.getLogName());
+            }
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean checksEventType(GameEvent event, Game game) {
+        switch (event.getType()) {
+            case DAMAGE_PERMANENT:
+            case DESTROY_PERMANENT:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public boolean applies(GameEvent event, Ability source, Game game) {
+        Permanent permanent = game.getPermanent(event.getTargetId());
+        return permanent != null && permanent.getCounters(game).getCount(CounterType.SHIELD) > 0;
+    }
+}

Mage/src/main/java/mage/game/GameImpl.java

@@ -14,6 +14,7 @@ import mage.abilities.effects.Effect;
 import mage.abilities.effects.PreventionEffectData;
 import mage.abilities.effects.common.CopyEffect;
 import mage.abilities.effects.common.InfoEffect;
+import mage.abilities.effects.keyword.ShieldCounterEffect;
 import mage.abilities.keyword.*;
 import mage.abilities.mana.DelayedTriggeredManaAbility;
 import mage.abilities.mana.TriggeredManaAbility;
@@ -1130,6 +1131,9 @@ public abstract class GameImpl implements Game {
             return;
         }
 
+        // Apply shield counter mechanic from SNC
+        state.addAbility(new SimpleStaticAbility(Zone.ALL, new ShieldCounterEffect()), null);
+
         // Handle companions
         Map<Player, Card> playerCompanionMap = new HashMap<>();
         for (Player player : state.getPlayers().values()) {