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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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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;


/**
 * !! This effect does only support one target.
 *
 *
 * 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 MustBeBlockedByAtLeastOneTargetEffect extends RequirementEffect {

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

    public MustBeBlockedByAtLeastOneTargetEffect(Duration duration) {
        super(duration);
        staticText = "Target creature must be blocked this turn if able";
    }

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

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

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

}