package mage.abilities.effects.common;

import mage.abilities.Ability;
import mage.abilities.SpellAbility;
import mage.abilities.effects.common.cost.CostModificationEffectImpl;
import mage.constants.CostModificationType;
import mage.constants.Duration;
import mage.constants.Outcome;
import mage.filter.common.FilterControlledPermanent;
import mage.game.Game;
import mage.util.CardUtil;

/**
 * 702.40. Affinity
 * 702.40a Affinity is a static ability that functions while the spell with affinity is on the stack.
 * “Affinity for [text]” means “This spell costs you {1} less to cast for each [text] you control.”
 * 702.40b If a spell has multiple instances of affinity, each of them applies.
 */
public class AffinityEffect extends CostModificationEffectImpl {

    private final FilterControlledPermanent filter;

    public AffinityEffect(FilterControlledPermanent affinityFilter) {
        super(Duration.WhileOnStack, Outcome.Benefit, CostModificationType.REDUCE_COST);
        this.filter = affinityFilter;
        staticText = "Affinity for " + filter.getMessage();
    }

    protected AffinityEffect(final AffinityEffect effect) {
        super(effect);
        this.filter = effect.filter.copy();
    }

    @Override
    public boolean apply(Game game, Ability source, Ability abilityToModify) {
        // abilityToModify.getControllerId() works with Sen Triplets and in multiplayer games, see https://github.com/magefree/mage/issues/5931
        int count = game.getBattlefield().getActivePermanents(filter, abilityToModify.getControllerId(), source, game).size();
        CardUtil.reduceCost(abilityToModify, count);
        return true;
    }

    @Override
    public boolean applies(Ability abilityToModify, Ability source, Game game) {
        return abilityToModify instanceof SpellAbility && abilityToModify.getSourceId().equals(source.getSourceId());
    }

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