/*
 * Copyright (c) 2013, 2015 Red Hat, Inc. and others. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.ovsdb.openstack.netvirt;

import org.opendaylight.ovsdb.openstack.netvirt.api.EventDispatcher;
import org.opendaylight.ovsdb.openstack.netvirt.api.Status;
import org.opendaylight.ovsdb.openstack.netvirt.api.StatusCode;

import com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.HttpURLConnection;

/**
 * OpenStack related events originate from multiple north callbacks as well as south.
 * This interface provides a layer of abstraction between the event dispatcher and the
 * handlers.
 */
public abstract class AbstractHandler {
    private static final Logger LOG = LoggerFactory.getLogger(AbstractHandler.class);

    // The implementation for each of these services is resolved by the OSGi Service Manager
    protected volatile EventDispatcher eventDispatcher;

    /**
     * Convert failure status returned by the  manager into
     * neutron API service errors.
     *
     * @param status  manager status
     * @return  An error to be returned to neutron API service.
     */
    protected static int getException(Status status) {
        assert !status.isSuccess();

        StatusCode code = status.getCode();
        LOG.debug(" Exception code - {}, description - {}",
                code, status.getDescription());

        switch(code) {
            case BADREQUEST:
                return HttpURLConnection.HTTP_BAD_REQUEST;
            case CONFLICT:
                return HttpURLConnection.HTTP_CONFLICT;
            case NOTACCEPTABLE:
                return HttpURLConnection.HTTP_NOT_ACCEPTABLE;
            case NOTFOUND:
                return HttpURLConnection.HTTP_NOT_FOUND;
            default:
                return HttpURLConnection.HTTP_INTERNAL_ERROR;
        }
    }

    /**
     * Enqueue the event.
     *
     * @param abstractEvent the {@link org.opendaylight.ovsdb.openstack.netvirt.AbstractEvent} event to be handled.
     * @see org.opendaylight.ovsdb.openstack.netvirt.api.EventDispatcher
     */
    protected void enqueueEvent(AbstractEvent abstractEvent) {
        LOG.info("enqueueEvent: evenDispatcher: {} - {}", eventDispatcher, abstractEvent);
        Preconditions.checkNotNull(eventDispatcher);
        eventDispatcher.enqueueEvent(abstractEvent);
    }

    /**
     * Process the event.
     *
     * @param abstractEvent the {@link org.opendaylight.ovsdb.openstack.netvirt.AbstractEvent} event to be handled.
     * @see org.opendaylight.ovsdb.openstack.netvirt.api.EventDispatcher
     */
    public abstract void processEvent(AbstractEvent abstractEvent);

}