Affinity (currently broken)

Mage/src/mage/abilities/effects/common/AffinityEffect.java

@@ -0,0 +1,52 @@
+package mage.abilities.effects.common;
+
+import mage.Constants;
+import mage.Mana;
+import mage.abilities.Ability;
+import mage.abilities.SpellAbility;
+import mage.abilities.effects.CostModificationEffectImpl;
+import mage.filter.common.FilterControlledPermanent;
+import mage.game.Game;
+
+public class AffinityEffect extends CostModificationEffectImpl<AffinityEffect> {
+    private FilterControlledPermanent filter;
+
+    public AffinityEffect(FilterControlledPermanent affinityFilter) {
+        super(Constants.Duration.Custom, Constants.Outcome.Benefit);
+        this.filter = affinityFilter;
+        staticText = "Affinity for " + filter.getMessage();
+    }
+
+    public AffinityEffect(final AffinityEffect effect) {
+        super(effect);
+        this.filter = effect.filter.copy();
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source, Ability abilityToModify) {
+        SpellAbility spellAbility = (SpellAbility)abilityToModify;
+        Mana mana = spellAbility.getManaCostsToPay().getMana();
+        if (mana.getColorless() > 0) {
+            int count = game.getBattlefield().count(filter, source.getControllerId(), game);
+            int newCount = mana.getColorless() - count;
+            if (newCount < 0) newCount = 0;
+            mana.setColorless(newCount);
+            spellAbility.getManaCostsToPay().load(mana.toString());
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean applies(Ability abilityToModify, Ability source, Game game) {
+        if (abilityToModify instanceof SpellAbility && abilityToModify.getSourceId().equals(source.getSourceId())) {
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public AffinityEffect copy() {
+        return new AffinityEffect(this);
+    }
+}