/*
 * 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.controller.netconf.client;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.Sets;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.GlobalEventExecutor;
import org.opendaylight.controller.netconf.api.NetconfMessage;
import org.opendaylight.protocol.framework.NeverReconnectStrategy;
import org.opendaylight.protocol.framework.ReconnectStrategy;
import org.opendaylight.protocol.framework.TimedReconnectStrategy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.net.ssl.SSLContext;
import java.io.Closeable;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;

public class NetconfClient implements Closeable {

    private static final Logger logger = LoggerFactory.getLogger(NetconfClient.class);

    public static final int DEFAULT_CONNECT_TIMEOUT = 5000;
    private final NetconfClientDispatcher dispatch;
    private final String label;
    private final NetconfClientSession clientSession;
    private final NetconfClientSessionListener sessionListener;
    private final long sessionId;
    private final InetSocketAddress address;

    // TODO test reconnecting constructor
    public NetconfClient(String clientLabelForLogging, InetSocketAddress address, int connectionAttempts,
            int attemptMsTimeout) {
        this(clientLabelForLogging, address, getReconnectStrategy(connectionAttempts, attemptMsTimeout), Optional
                .<SSLContext> absent());
    }

    private NetconfClient(String clientLabelForLogging, InetSocketAddress address, ReconnectStrategy strat,
            Optional<SSLContext> maybeSSLContext) {
        this.label = clientLabelForLogging;
        dispatch = new NetconfClientDispatcher(maybeSSLContext);

        sessionListener = new NetconfClientSessionListener();
        Future<NetconfClientSession> clientFuture = dispatch.createClient(address, sessionListener, strat);
        this.address = address;
        clientSession = get(clientFuture);
        this.sessionId = clientSession.getSessionId();
    }

    private NetconfClientSession get(Future<NetconfClientSession> clientFuture) {
        try {
            return clientFuture.get();
        } catch (InterruptedException | CancellationException e) {
            throw new RuntimeException("Netconf client interrupted", e);
        } catch (ExecutionException e) {
            throw new IllegalStateException("Unable to create netconf client", e);
        }
    }

    public NetconfClient(String clientLabelForLogging, InetSocketAddress address, int connectTimeoutMs,
            Optional<SSLContext> maybeSSLContext) {
        this(clientLabelForLogging, address,
                new NeverReconnectStrategy(GlobalEventExecutor.INSTANCE, connectTimeoutMs), maybeSSLContext);
    }

    public NetconfClient(String clientLabelForLogging, InetSocketAddress address, int connectTimeoutMs) {
        this(clientLabelForLogging, address,
                new NeverReconnectStrategy(GlobalEventExecutor.INSTANCE, connectTimeoutMs), Optional
                        .<SSLContext> absent());
    }

    public NetconfClient(String clientLabelForLogging, InetSocketAddress address) {
        this(clientLabelForLogging, address, new NeverReconnectStrategy(GlobalEventExecutor.INSTANCE,
                DEFAULT_CONNECT_TIMEOUT), Optional.<SSLContext> absent());
    }

    public NetconfClient(String clientLabelForLogging, InetSocketAddress address, Optional<SSLContext> maybeSSLContext) {
        this(clientLabelForLogging, address, new NeverReconnectStrategy(GlobalEventExecutor.INSTANCE,
                DEFAULT_CONNECT_TIMEOUT), maybeSSLContext);
    }

    public NetconfMessage sendMessage(NetconfMessage message) {
        return sendMessage(message, 5, 1000);
    }

    public NetconfMessage sendMessage(NetconfMessage message, int attempts, int attemptMsDelay) {
        Preconditions.checkState(clientSession.isUp(), "Session was not up yet");
        clientSession.sendMessage(message);
        try {
            return sessionListener.getLastMessage(attempts, attemptMsDelay);
        } catch (InterruptedException e) {
            throw new RuntimeException(this + " Cannot read message from " + address, e);
        } catch (IllegalStateException e) {
            throw new IllegalStateException(this + " Cannot read message from " + address, e);
        }
    }

    @Override
    public void close() throws IOException {
        clientSession.close();
        dispatch.close();
    }

    private static ReconnectStrategy getReconnectStrategy(int connectionAttempts, int attemptMsTimeout) {
        return new TimedReconnectStrategy(GlobalEventExecutor.INSTANCE, attemptMsTimeout, 1000, 1.0, null,
                Long.valueOf(connectionAttempts), null);
    }

    @Override
    public String toString() {
        final StringBuffer sb = new StringBuffer("NetconfClient{");
        sb.append("label=").append(label);
        sb.append(", sessionId=").append(sessionId);
        sb.append('}');
        return sb.toString();
    }

    public long getSessionId() {
        return sessionId;
    }

    public Set<String> getCapabilities() {
        Preconditions.checkState(clientSession != null, "Client was not initialized successfully");
        return Sets.newHashSet(clientSession.getServerCapabilities());
    }
}