/*
 * Copyright (c) 2013 Cisco Systems, 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.protocol.bgp.rib.mock;

import com.google.common.collect.Lists;
import com.google.common.eventbus.EventBus;

import io.netty.buffer.Unpooled;

import java.io.Closeable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import javax.annotation.concurrent.GuardedBy;
import javax.annotation.concurrent.ThreadSafe;

import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
import org.opendaylight.protocol.bgp.parser.BGPError;
import org.opendaylight.protocol.bgp.parser.BGPParsingException;
import org.opendaylight.protocol.bgp.parser.spi.MessageRegistry;
import org.opendaylight.protocol.bgp.rib.spi.BGPSessionListener;
import org.opendaylight.protocol.util.ByteArray;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.Notification;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Mock BGP session. It provides a way how to route a set of messages to BGPSessionListener.
 */
@ThreadSafe
public final class BGPMock implements Closeable {

    private static final Logger LOG = LoggerFactory.getLogger(BGPMock.class);

    static final Notification CONNECTION_LOST_MAGIC_MSG = new NotifyBuilder().setErrorCode(BGPError.CEASE.getCode()).build();

    @GuardedBy("this")
    private final List<byte[]> allPreviousByteMessages;
    private final List<Notification> allPreviousBGPMessages;
    private final EventBus eventBus;

    @GuardedBy("this")
    private final List<EventBusRegistration> openRegistrations = Lists.newLinkedList();

    public BGPMock(final EventBus eventBus, final MessageRegistry registry, final List<byte[]> bgpMessages) {
        this.allPreviousByteMessages = Lists.newLinkedList(bgpMessages);
        this.eventBus = eventBus;
        this.allPreviousBGPMessages = this.parsePrevious(registry, this.allPreviousByteMessages);
    }

    private List<Notification> parsePrevious(final MessageRegistry registry, final List<byte[]> msgs) {
        final List<Notification> messages = Lists.newArrayList();
        try {
            for (final byte[] b : msgs) {

                final byte[] body = ByteArray.cutBytes(b, 1);

                messages.add(registry.parseMessage(Unpooled.copiedBuffer(body)));
            }
        } catch (final BGPDocumentedException | BGPParsingException e) {
            LOG.warn("Failed to parse message {}", e.getMessage(), e);
        }
        return messages;
    }

    public synchronized void insertConnectionLostEvent() {
        this.insertMessage(CONNECTION_LOST_MAGIC_MSG);
    }

    public synchronized void insertMessages(final List<Notification> messages) {
        for (final Notification message : messages) {
            this.insertMessage(message);
        }
    }

    @GuardedBy("this")
    private void insertMessage(final Notification message) {
        this.allPreviousBGPMessages.add(message);
        this.eventBus.post(message);
    }

    @Override
    public synchronized void close() {
        // unregister all EventBusRegistration instances
        for (final EventBusRegistration registration : this.openRegistrations) {
            registration.close();
        }
        this.openRegistrations.clear();
    }

    public boolean isMessageListSame(final List<byte[]> newMessages) {
        if (this.allPreviousBGPMessages.size() != newMessages.size()) {
            return false;
        }
        final Iterator<byte[]> i1 = this.allPreviousByteMessages.iterator();
        final Iterator<byte[]> i2 = this.allPreviousByteMessages.iterator();
        for (int i = 0; i < this.allPreviousBGPMessages.size(); i++) {
            if (!Arrays.equals(i1.next(), i2.next())) {
                return false;
            }
        }
        return true;
    }

    public EventBus getEventBus() {
        return this.eventBus;
    }

    public ListenerRegistration<BGPSessionListener> registerUpdateListener(final BGPSessionListener listener) {
        return EventBusRegistration.createAndRegister(this.eventBus, listener, this.allPreviousBGPMessages);
    }
}