/**
 * Copyright (C) 2011  JTalks.org Team
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.jtalks.jcommune.model.validation.validators;

import org.apache.commons.lang.StringUtils;
import org.jtalks.jcommune.model.entity.Poll;
import org.jtalks.jcommune.model.entity.PollItem;
import org.jtalks.jcommune.model.validation.annotations.PollItemsNotEmptyIfTitleFilled;
import org.springframework.util.CollectionUtils;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.util.List;

/**
 * It validates the poll to find cases when poll items are empty,
 * but title of the poll is filled.
 * 
 * @author Anuar_Nurmakanov
 *
 */
public class PollItemsNotEmptyIfTitleFilledValidator 
    implements ConstraintValidator<PollItemsNotEmptyIfTitleFilled, Poll> {
    private String pollItemsFieldName;
    
    /**
     * {@inheritDoc}
     */
    @Override
    public void initialize(PollItemsNotEmptyIfTitleFilled constraintAnnotation) {
        this.pollItemsFieldName = constraintAnnotation.pollItemsFieldName();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isValid(Poll poll, ConstraintValidatorContext context) {
        String pollTitle = poll.getTitle();
        List<PollItem> pollItems = poll.getPollItems();
        boolean isTitleFilled = StringUtils.isNotBlank(pollTitle);
        boolean isItemsFilled = !CollectionUtils.isEmpty(pollItems);
        //
        if (isTitleFilled && !isItemsFilled) {
            addConstraintViolatedErrorMessage(context);
            return false;
        } 
        return true;
    }
    
    /**
     * We must show error for the list of items of validated poll, so
     * we must change the node name in error message to do it.
     * 
     * @param context to add error message for the title fields
     */
    private void addConstraintViolatedErrorMessage(ConstraintValidatorContext context) {
        String message = context.getDefaultConstraintMessageTemplate();
        context.disableDefaultConstraintViolation();
        context.buildConstraintViolationWithTemplate(message)
                .addNode(pollItemsFieldName)
                .addConstraintViolation();
    }
}