Copyright 2010 the original author or authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
/**
 * Copyright 2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.I0Itec.zkclient;

import java.io.File;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Arrays;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.I0Itec.zkclient.exception.ZkException;
import org.I0Itec.zkclient.exception.ZkInterruptedException;
import org.apache.zookeeper.server.NIOServerCnxnFactory;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZkServer {

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

    public static final int DEFAULT_PORT = 2181;
    public static final int DEFAULT_TICK_TIME = 5000;
    public static final int DEFAULT_MIN_SESSION_TIMEOUT = 2 * DEFAULT_TICK_TIME;

    private String _dataDir;
    private String _logDir;

    private IDefaultNameSpace _defaultNameSpace;

    private ZooKeeperServer _zk;
    private NIOServerCnxnFactory _nioFactory;
    private ZkClient _zkClient;
    private int _port;
    private int _tickTime;
    private int _minSessionTimeout;

    public ZkServer(String dataDir, String logDir, IDefaultNameSpace defaultNameSpace) {
        this(dataDir, logDir, defaultNameSpace, DEFAULT_PORT);
    }

    public ZkServer(String dataDir, String logDir, IDefaultNameSpace defaultNameSpace, int port) {
        this(dataDir, logDir, defaultNameSpace, port, DEFAULT_TICK_TIME);
    }

    public ZkServer(String dataDir, String logDir, IDefaultNameSpace defaultNameSpace, int port, int tickTime) {
        this(dataDir, logDir, defaultNameSpace, port, tickTime, DEFAULT_MIN_SESSION_TIMEOUT);
    }

    public ZkServer(String dataDir, String logDir, IDefaultNameSpace defaultNameSpace, int port, int tickTime, int minSessionTimeout) {
        _dataDir = dataDir;
        _logDir = logDir;
        _defaultNameSpace = defaultNameSpace;
        _port = port;
        _tickTime = tickTime;
        _minSessionTimeout = minSessionTimeout;
    }

    public int getPort() {
        return _port;
    }

    @PostConstruct
    public void start() {
        final String[] localHostNames = NetworkUtil.getLocalHostNames();
        String names = "";
        for (int i = 0; i < localHostNames.length; i++) {
            final String name = localHostNames[i];
            names += " " + name;
            if (i + 1 != localHostNames.length) {
                names += ",";
            }
        }
        LOG.info("Starting ZkServer on: [" + names + "] port " + _port + "...");
        try {
            startZooKeeperServer();
            _zkClient = new ZkClient("localhost:" + _port, 10000);
            _defaultNameSpace.createDefaultNameSpace(_zkClient);
        } catch (RuntimeException e) {
            shutdown();
            throw e;
        }
    }

    private void startZooKeeperServer() {
        final String[] localhostHostNames = NetworkUtil.getLocalHostNames();
        final String servers = "localhost:" + _port;
        // check if this server needs to start a _client server.
        int pos = -1;
        LOG.debug("check if hostNames " + servers + " is in list: " + Arrays.asList(localhostHostNames));
        if ((pos = NetworkUtil.hostNamesInList(servers, localhostHostNames)) != -1) {
            // yes this server needs to start a zookeeper server
            final String[] hosts = servers.split(",");
            final String[] hostSplitted = hosts[pos].split(":");
            int port = _port;
            if (hostSplitted.length > 1) {
                port = Integer.parseInt(hostSplitted[1]);
            }
            // check if this machine is already something running..
            if (NetworkUtil.isPortFree(port)) {
                final File dataDir = new File(_dataDir);
                final File dataLogDir = new File(_logDir);
                dataDir.mkdirs();
                dataLogDir.mkdirs();

                if (hosts.length > 1) {
                    // multiple zk servers
                    LOG.info("Start distributed zookeeper server...");
                    throw new IllegalArgumentException("Unable to start distributed zookeeper server");
                }
                // single zk server
                LOG.info("Start single zookeeper server...");
                LOG.info("data dir: " + dataDir.getAbsolutePath());
                LOG.info("data log dir: " + dataLogDir.getAbsolutePath());
                LOG.info("JAAS login file: " + System.getProperty("java.security.auth.login.config", "none"));
                startSingleZkServer(_tickTime, dataDir, dataLogDir, port);
            } else {
                throw new IllegalStateException("Zookeeper port " + port + " was already in use. Running in single machine mode?");
            }
        }
    }

    private void startSingleZkServer(final int tickTime, final File dataDir, final File dataLogDir, final int port) {
        try {
            _zk = new ZooKeeperServer(dataDir, dataLogDir, tickTime);
            _zk.setMinSessionTimeout(_minSessionTimeout);
            _nioFactory = new NIOServerCnxnFactory();
            int maxClientConnections = 0; // 0 means unlimited
            _nioFactory.configure(new InetSocketAddress(port), maxClientConnections);
            _nioFactory.startup(_zk);
        } catch (IOException e) {
            throw new ZkException("Unable to start single ZooKeeper server.", e);
        } catch (InterruptedException e) {
            throw new ZkInterruptedException(e);
        }
    }

    @PreDestroy
    public void shutdown() {
        LOG.info("Shutting down ZkServer...");
        try {
            if(_zkClient != null) {
                _zkClient.close();
            }
        } catch (ZkException e) {
            LOG.warn("Error on closing zkclient: " + e.getClass().getName());
        }
        if (_nioFactory != null) {
            _nioFactory.shutdown();
            try {
                _nioFactory.join();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
            _nioFactory = null;
        }
        if (_zk != null) {
            _zk.shutdown();
            _zk = null;
        }
        LOG.info("Shutting down ZkServer...done");
    }

    public ZkClient getZkClient() {
        return _zkClient;
    }
}