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 *  Copyright 2011 BetaSteward_at_googlemail.com. All rights reserved.
 *
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 *        conditions and the following disclaimer.
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 *        of conditions and the following disclaimer in the documentation and/or other materials
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package mage.abilities.effects.common.combat;

import java.util.UUID;
import mage.abilities.Ability;
import mage.abilities.effects.RequirementEffect;
import mage.constants.Duration;
import mage.game.Game;
import mage.game.permanent.Permanent;

/**
 * http://tappedout.net/mtg-questions/must-be-blocked-if-able-effect-makes-other-attacking-creatures-essentially-unblockable/
 *
 * When you Declare Blockers, you choose an arrangement for your blockers, then
 * check to see if there are any restrictions or requirements.
 *
 * If any restrictions are violated, the block is illegal. (For example, trying
 * to block with Sightless Ghoul) If any requirements are violated, the least
 * possible number of requirements must be violated, otherwise the block is
 * illegal. (For example, your opponent control two creatures that he has cast
 * Deadly Allure on, but you control only one creature. Blocking either one will
 * violate a requirement, "This creature must be blocked this turn if able", but
 * it will also violate the least possible number of requirements, thus it is
 * legal.) If the block is illegal, the game state backs up and you declare
 * blockers again. (Note that while you can, in some cases, circumvent
 * requirements such as "This creature must be blocked" or "This creature must
 * block any attacking creature" you can never circumvent restrictions: "This
 * creature can't block" or "Only one creature may block this turn.") Because
 * you declare ALL your blockers at once, THEN check for
 * restrictions/requirements, you may block Deadly Allure'd creatures with only
 * one creature, if you choose. This still works with Lure: This card sets up a
 * requirement that ALL creatures must block it if able. Any block that violates
 * more than the minimum number of requirements is still illegal.
 *
 * @author LevelX2
 */
public class MustBeBlockedByAtLeastOneSourceEffect extends RequirementEffect {

    public MustBeBlockedByAtLeastOneSourceEffect() {
        this(Duration.EndOfTurn);
    }

    public MustBeBlockedByAtLeastOneSourceEffect(Duration duration) {
        super(duration);
        staticText = "{this} must be blocked " + (duration == Duration.EndOfTurn ? "this turn " : "") + "if able";
    }

    public MustBeBlockedByAtLeastOneSourceEffect(final MustBeBlockedByAtLeastOneSourceEffect effect) {
        super(effect);
    }

    @Override
    public boolean applies(Permanent permanent, Ability source, Game game) {
        return permanent.canBlock(source.getSourceId(), game);
    }

    @Override
    public boolean mustAttack(Game game) {
        return false;
    }

    @Override
    public boolean mustBlock(Game game) {
        return false;
    }

    @Override
    public UUID mustBlockAttackerIfElseUnblocked(Ability source, Game game) {
        return source.getSourceId();
    }

    @Override
    public MustBeBlockedByAtLeastOneSourceEffect copy() {
        return new MustBeBlockedByAtLeastOneSourceEffect(this);
    }

}