reworked/simplified/consolidated effects which exchange life totals, added test (fixes #7668)

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

@@ -0,0 +1,44 @@
+
+package mage.abilities.effects.common;
+
+import mage.abilities.Ability;
+import mage.abilities.Mode;
+import mage.abilities.effects.OneShotEffect;
+import mage.constants.Outcome;
+import mage.game.Game;
+import mage.players.Player;
+
+/**
+ * @author Styxo
+ */
+public class ExchangeLifeControllerTargetEffect extends OneShotEffect {
+
+    public ExchangeLifeControllerTargetEffect() {
+        super(Outcome.Neutral);
+    }
+
+    private ExchangeLifeControllerTargetEffect(final ExchangeLifeControllerTargetEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public ExchangeLifeControllerTargetEffect copy() {
+        return new ExchangeLifeControllerTargetEffect(this);
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Player controller = game.getPlayer(source.getControllerId());
+        Player player = game.getPlayer(source.getFirstTarget());
+        if (controller == null || player == null) {
+            return false;
+        }
+        controller.exchangeLife(player, source, game);
+        return true;
+    }
+
+    @Override
+    public String getText(Mode mode) {
+        return "Exchange life totals with target " + mode.getTargets().get(0).getTargetName();
+    }
+}