[FIN] Implement The Wind Crystal

Mage/src/main/java/mage/abilities/effects/common/replacement/GainDoubleLifeReplacementEffect.java

@@ -0,0 +1,45 @@
+package mage.abilities.effects.common.replacement;
+
+import mage.abilities.Ability;
+import mage.abilities.effects.ReplacementEffectImpl;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.util.CardUtil;
+
+/**
+ * @author TheElk801
+ */
+public class GainDoubleLifeReplacementEffect extends ReplacementEffectImpl {
+
+    public GainDoubleLifeReplacementEffect() {
+        super(Duration.WhileOnBattlefield, Outcome.Benefit);
+        staticText = "if you would gain life, you gain twice that much life instead";
+    }
+
+    private GainDoubleLifeReplacementEffect(final GainDoubleLifeReplacementEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public GainDoubleLifeReplacementEffect copy() {
+        return new GainDoubleLifeReplacementEffect(this);
+    }
+
+    @Override
+    public boolean replaceEvent(GameEvent event, Ability source, Game game) {
+        event.setAmount(CardUtil.overflowMultiply(event.getAmount(), 2));
+        return false;
+    }
+
+    @Override
+    public boolean checksEventType(GameEvent event, Game game) {
+        return event.getType() == GameEvent.EventType.GAIN_LIFE;
+    }
+
+    @Override
+    public boolean applies(GameEvent event, Ability source, Game game) {
+        return source.isControlledBy(event.getPlayerId());
+    }
+}