Commander: improved lands compatibility with cost modification and restriction effects;

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

@@ -0,0 +1,57 @@
+package mage.abilities.effects.common.cost;
+
+import mage.abilities.Ability;
+import mage.abilities.common.CastCommanderAbility;
+import mage.abilities.common.PlayLandAsCommanderAbility;
+import mage.abilities.costs.mana.GenericManaCost;
+import mage.constants.CostModificationType;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.game.Game;
+import mage.watchers.common.CommanderPlaysCountWatcher;
+
+import java.util.UUID;
+
+/**
+ * @author Plopman
+ */
+    /*
+    903.8. A player may cast a commander they own from the command zone. A commander cast from the
+    command zone costs an additional {2} for each previous time the player casting it has cast it from
+    the command zone that game. This additional cost is informally known as the “commander tax.”
+     */
+public class CommanderCostModification extends CostModificationEffectImpl {
+
+    private final UUID commanderId;
+
+    public CommanderCostModification(UUID commanderId) {
+        super(Duration.Custom, Outcome.Neutral, CostModificationType.INCREASE_COST);
+        this.commanderId = commanderId;
+    }
+
+    public CommanderCostModification(final CommanderCostModification effect) {
+        super(effect);
+        this.commanderId = effect.commanderId;
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source, Ability abilityToModify) {
+        CommanderPlaysCountWatcher watcher = game.getState().getWatcher(CommanderPlaysCountWatcher.class);
+        int castCount = watcher.getPlaysCount(commanderId);
+        if (castCount > 0) {
+            abilityToModify.getManaCostsToPay().add(new GenericManaCost(2 * castCount));
+        }
+        return true;
+    }
+
+    @Override
+    public boolean applies(Ability abilityToModify, Ability source, Game game) {
+        return commanderId.equals(abilityToModify.getSourceId())
+                && (abilityToModify instanceof CastCommanderAbility || abilityToModify instanceof PlayLandAsCommanderAbility);
+    }
+
+    @Override
+    public CommanderCostModification copy() {
+        return new CommanderCostModification(this);
+    }
+}