/**
 * Copyright (c) 2009 - 2012 Red Hat, Inc.
 *
 * This software is licensed to you under the GNU General Public License,
 * version 2 (GPLv2). There is NO WARRANTY for this software, express or
 * implied, including the implied warranties of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2
 * along with this software; if not, see
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
 *
 * Red Hat trademarks are not licensed under GPLv2. No permission is
 * granted to use or replicate Red Hat trademarks that are incorporated
 * in this software or its documentation.
 */
package org.candlepin.audit;

import org.candlepin.audit.Event.Target;
import org.candlepin.audit.Event.Type;
import org.candlepin.model.Consumer;
import org.candlepin.model.ConsumerProperty;
import org.candlepin.model.Entitlement;
import org.candlepin.model.Eventful;
import org.candlepin.model.Named;
import org.candlepin.model.Owned;
import org.candlepin.model.Owner;
import org.candlepin.model.Pool;

/**
 * ConsumerEventBuilder Allows us to easily build a consumer modified
 * event one piece at a time.
 *
 */
public class EventBuilder {

    private final EventFactory factory;

    private Event event;

    public EventBuilder(EventFactory factory, Target target, Type type) {
        this.factory = factory;

        event = new Event(type, target, null, factory.principalProvider.get(),
                null, null, null, null, null, null, null);
    }

    private void setEventData(Eventful entity) {
        // Be careful to check for null before setting so we don't overwrite anything useful
        if (entity instanceof Named && ((Named) entity).getName() != null) {
            event.setTargetName(((Named) entity).getName());
        }
        if (entity instanceof Owned) {
            Owner entityOwner = ((Owned) entity).getOwner();
            if (entityOwner != null && entityOwner.getId() != null) {
                event.setOwnerId(entityOwner.getId());
            }
        }
        if (entity instanceof Entitlement) {
            event.setReferenceType(Event.ReferenceType.POOL);
            Pool referencedPool = ((Entitlement) entity).getPool();
            if (referencedPool != null && referencedPool.getId() != null) {
                event.setReferenceId(referencedPool.getId());
            }
        }
        if ((String) entity.getId() != null) {
            event.setEntityId((String) entity.getId());
            if (entity instanceof ConsumerProperty) {
                Consumer owningConsumer = ((ConsumerProperty) entity).getConsumer();
                if (owningConsumer != null && owningConsumer.getId() != null) {
                    event.setConsumerId(owningConsumer.getId());
                }
            }
        }
    }

    public EventBuilder setOldEntity(Eventful old) {
        // Allow null, but don't do anything
        if (old != null) {
            // If the value is non-null and a value is set, we shouldn't allow it to continue
            if (event.getType() == Type.CREATED) {
                throw new IllegalArgumentException("You cannot set the old entity for a creation event");
            }
            setEventData(old);
            event.setOldEntity(factory.entityToJson(old));
        }
        return this;
    }

    public EventBuilder setNewEntity(Eventful updated) {
        if (updated != null) {
            if (event.getType() == Type.DELETED || event.getType() == Type.EXPIRED) {
                throw new IllegalArgumentException("You cannot set the new entity for a deletion event");
            }
            setEventData(updated);
            event.setNewEntity(factory.entityToJson(updated));
        }
        return this;
    }

    public Event buildEvent() {
        return event;
    }
}