[FIN] Implement Cloud, Planet's Champion

Mage/src/main/java/mage/abilities/effects/common/cost/ReduceCostEquipTargetSourceEffect.java

@@ -0,0 +1,65 @@
+package mage.abilities.effects.common.cost;
+
+import mage.abilities.Ability;
+import mage.abilities.keyword.EquipAbility;
+import mage.constants.CostModificationType;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.game.Game;
+import mage.target.Target;
+import mage.util.CardUtil;
+
+import java.util.Collection;
+
+/**
+ * @author TheElk801
+ */
+public class ReduceCostEquipTargetSourceEffect extends CostModificationEffectImpl {
+
+    private final int amount;
+
+    public ReduceCostEquipTargetSourceEffect(int amount) {
+        super(Duration.Custom, Outcome.Benefit, CostModificationType.REDUCE_COST);
+        this.amount = amount;
+        staticText = "equip abilities you activate that target {this} cost {" + amount + "} less to activate";
+    }
+
+    private ReduceCostEquipTargetSourceEffect(final ReduceCostEquipTargetSourceEffect effect) {
+        super(effect);
+        this.amount = effect.amount;
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source, Ability abilityToModify) {
+        CardUtil.reduceCost(abilityToModify, amount);
+        return true;
+    }
+
+    @Override
+    public boolean applies(Ability abilityToModify, Ability source, Game game) {
+        if (!(abilityToModify instanceof EquipAbility)
+                || !abilityToModify.isControlledBy(source.getControllerId())) {
+            return false;
+        }
+        if (game != null && game.inCheckPlayableState()) {
+            return !abilityToModify
+                    .getTargets()
+                    .isEmpty()
+                    && abilityToModify
+                    .getTargets()
+                    .get(0)
+                    .canTarget(source.getSourceId(), abilityToModify, game);
+        }
+        return abilityToModify
+                .getTargets()
+                .stream()
+                .map(Target::getTargets)
+                .flatMap(Collection::stream)
+                .anyMatch(source.getSourceId()::equals);
+    }
+
+    @Override
+    public ReduceCostEquipTargetSourceEffect copy() {
+        return new ReduceCostEquipTargetSourceEffect(this);
+    }
+}