[TMT] Implement Raphael's Technique

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

@@ -0,0 +1,77 @@
+package mage.abilities.keyword;
+
+import mage.MageIdentifier;
+import mage.abilities.SpellAbility;
+import mage.abilities.costs.common.ReturnToHandChosenControlledPermanentCost;
+import mage.abilities.costs.mana.ManaCostsImpl;
+import mage.cards.Card;
+import mage.constants.PhaseStep;
+import mage.constants.SpellAbilityType;
+import mage.constants.TimingRule;
+import mage.constants.Zone;
+import mage.filter.common.FilterControlledPermanent;
+import mage.filter.predicate.permanent.AttackingPredicate;
+import mage.filter.predicate.permanent.UnblockedPredicate;
+import mage.game.Game;
+import mage.target.common.TargetControlledPermanent;
+
+import java.util.Set;
+
+/**
+ * @author TheElk801
+ */
+public class SneakAbility extends SpellAbility {
+
+    public static final String SNEAK_ACTIVATION_VALUE_KEY = "sneakActivation";
+    private static final FilterControlledPermanent filter = new FilterControlledPermanent("unblocked attacker you control");
+
+    static {
+        filter.add(UnblockedPredicate.instance);
+        filter.add(AttackingPredicate.instance);
+    }
+
+    public SneakAbility(Card card, String manaString) {
+        super(card.getSpellAbility());
+        this.newId();
+        this.setCardName(card.getName() + " with Sneak");
+        timing = TimingRule.INSTANT;
+        zone = Zone.HAND;
+        spellAbilityType = SpellAbilityType.BASE_ALTERNATE;
+
+        this.clearManaCosts();
+        this.clearManaCostsToPay();
+        this.addCost(new ManaCostsImpl<>(manaString));
+        this.addCost(new ReturnToHandChosenControlledPermanentCost(new TargetControlledPermanent(filter)));
+
+        this.setRuleAtTheTop(true);
+    }
+
+    protected SneakAbility(final SneakAbility ability) {
+        super(ability);
+    }
+
+    @Override
+    public boolean activate(Game game, Set<MageIdentifier> allowedIdentifiers, boolean noMana) {
+        if (!super.activate(game, allowedIdentifiers, noMana)
+                || game.getStep().getType() != PhaseStep.DECLARE_BLOCKERS) {
+            return false;
+        }
+        this.setCostsTag(SNEAK_ACTIVATION_VALUE_KEY, null);
+        return true;
+    }
+
+    @Override
+    public SneakAbility copy() {
+        return new SneakAbility(this);
+    }
+
+    @Override
+    public String getRule() {
+        StringBuilder sb = new StringBuilder("Sneak ");
+        sb.append(getManaCosts().getText());
+        sb.append(" <i>(You may cast this spell for ");
+        sb.append(getManaCosts().getText());
+        sb.append(" if you also return an unblocked attacker you control to hand during the declare blockers step.)</i>");
+        return sb.toString();
+    }
+}