[C21] Implemented Excavation Technique

Mage/src/main/java/mage/abilities/effects/common/CastSourceTriggeredAbility.java

@@ -9,7 +9,6 @@ import mage.game.events.GameEvent;
 import mage.game.stack.Spell;
 
 /**
- *
  * @author Plopman
  */
 public class CastSourceTriggeredAbility extends TriggeredAbilityImpl {
@@ -48,19 +47,19 @@ public class CastSourceTriggeredAbility extends TriggeredAbilityImpl {
 
     @Override
     public boolean checkTrigger(GameEvent event, Game game) {
-        if (event.getSourceId().equals(this.getSourceId())) {
-            MageObject spellObject = game.getObject(sourceId);
-            if ((spellObject instanceof Spell)) {
-                Spell spell = (Spell) spellObject;
-                if (spell.getSpellAbility() != null) {
-                    for (Effect effect : getEffects()) {
-                        effect.setValue(SOURCE_CAST_SPELL_ABILITY, spell.getSpellAbility());
-                    }
-                }
-            }
+        if (!event.getSourceId().equals(this.getSourceId())) {
+            return false;
+        }
+        MageObject spellObject = game.getObject(sourceId);
+        if ((!(spellObject instanceof Spell))) {
             return true;
         }
-        return false;
+        Spell spell = (Spell) spellObject;
+        if (spell.getSpellAbility() != null) {
+            getEffects().setValue(SOURCE_CAST_SPELL_ABILITY, spell.getSpellAbility());
+        }
+        getEffects().setValue("spellCast", spell);
+        return true;
     }
 
     @Override

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

@@ -0,0 +1,70 @@
+package mage.abilities.keyword;
+
+import mage.abilities.Ability;
+import mage.abilities.effects.OneShotEffect;
+import mage.abilities.effects.common.CastSourceTriggeredAbility;
+import mage.constants.Outcome;
+import mage.game.Game;
+import mage.game.stack.Spell;
+import mage.players.Player;
+import mage.target.common.TargetOpponent;
+
+/**
+ * @author TheElk801
+ */
+public class DemonstrateAbility extends CastSourceTriggeredAbility {
+
+    public DemonstrateAbility() {
+        super(new DemonstrateEffect(), true);
+    }
+
+    private DemonstrateAbility(final DemonstrateAbility ability) {
+        super(ability);
+    }
+
+    @Override
+    public DemonstrateAbility copy() {
+        return new DemonstrateAbility(this);
+    }
+
+    @Override
+    public String getRule() {
+        return "Demonstrate <i>(When you cast this spell, you may copy it. If you do, " +
+                "choose an opponent to also copy it. Players may choose new targets for their copies.)</i>";
+    }
+}
+
+class DemonstrateEffect extends OneShotEffect {
+
+    DemonstrateEffect() {
+        super(Outcome.Benefit);
+    }
+
+    private DemonstrateEffect(final DemonstrateEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public DemonstrateEffect copy() {
+        return new DemonstrateEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Player controller = game.getPlayer(source.getControllerId());
+        if (controller == null) {
+            return false;
+        }
+        Spell spell = (Spell) getValue("spellCast");
+        if (spell == null) {
+            return false;
+        }
+        spell.createCopyOnStack(game, source, source.getControllerId(), true);
+        TargetOpponent target = new TargetOpponent(true);
+        controller.choose(outcome, target, source.getSourceId(), game);
+        if (game.getPlayer(target.getFirstTarget()) != null) {
+            spell.createCopyOnStack(game, source, target.getFirstTarget(), true);
+        }
+        return true;
+    }
+}