/*
 * Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
 *
 * 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 com.hazelcast.internal.cluster.impl;

import com.hazelcast.config.Config;
import com.hazelcast.config.InterfacesConfig;
import com.hazelcast.config.JoinConfig;
import com.hazelcast.config.NetworkConfig;
import com.hazelcast.config.TcpIpConfig;
import com.hazelcast.instance.impl.Node;
import com.hazelcast.internal.cluster.impl.SplitBrainJoinMessage.SplitBrainMergeCheckResult;
import com.hazelcast.internal.cluster.impl.operations.JoinMastershipClaimOp;
import com.hazelcast.cluster.Address;
import com.hazelcast.internal.nio.Connection;
import com.hazelcast.spi.impl.operationservice.impl.OperationServiceImpl;
import com.hazelcast.spi.properties.ClusterProperty;
import com.hazelcast.internal.util.AddressUtil;
import com.hazelcast.internal.util.AddressUtil.AddressMatcher;
import com.hazelcast.internal.util.AddressUtil.InvalidAddressException;
import com.hazelcast.internal.util.Clock;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import static com.hazelcast.internal.cluster.impl.ClusterServiceImpl.SERVICE_NAME;
import static com.hazelcast.config.ConfigAccessor.getActiveMemberNetworkConfig;
import static com.hazelcast.instance.EndpointQualifier.MEMBER;
import static com.hazelcast.internal.util.AddressUtil.AddressHolder;
import static com.hazelcast.internal.util.EmptyStatement.ignore;
import static com.hazelcast.internal.util.FutureUtil.RETHROW_EVERYTHING;
import static com.hazelcast.internal.util.FutureUtil.returnWithDeadline;

//FGTODO: 2019/12/2 下午1:51 zmyer
public class TcpIpJoiner extends AbstractJoiner {

    private static final long JOIN_RETRY_WAIT_TIME = 1000L;
    private static final int MASTERSHIP_CLAIM_TIMEOUT = 10;

    private final int maxPortTryCount;
    private volatile boolean claimingMastership;
    private final JoinConfig joinConfig;

    public TcpIpJoiner(Node node) {
        super(node);
        int tryCount = node.getProperties().getInteger(ClusterProperty.TCP_JOIN_PORT_TRY_COUNT);
        if (tryCount <= 0) {
            throw new IllegalArgumentException(String.format("%s should be greater than zero! Current value: %d",
                    ClusterProperty.TCP_JOIN_PORT_TRY_COUNT, tryCount));
        }
        maxPortTryCount = tryCount;
        joinConfig = getActiveMemberNetworkConfig(config).getJoin();
    }

    public boolean isClaimingMastership() {
        return claimingMastership;
    }

    private int getConnTimeoutSeconds() {
        return joinConfig.getTcpIpConfig().getConnectionTimeoutSeconds();
    }

    @Override
    public void doJoin() {
        final Address targetAddress = getTargetAddress();
        if (targetAddress != null) {
            long maxJoinMergeTargetMillis = node.getProperties().getMillis(ClusterProperty.MAX_JOIN_MERGE_TARGET_SECONDS);
            joinViaTargetMember(targetAddress, maxJoinMergeTargetMillis);
            if (!clusterService.isJoined()) {
                joinViaPossibleMembers();
            }
        } else if (joinConfig.getTcpIpConfig().getRequiredMember() != null) {
            Address requiredMember = getRequiredMemberAddress();
            long maxJoinMillis = getMaxJoinMillis();
            joinViaTargetMember(requiredMember, maxJoinMillis);
        } else {
            joinViaPossibleMembers();
        }
    }

    private void joinViaTargetMember(Address targetAddress, long maxJoinMillis) {
        try {
            if (targetAddress == null) {
                throw new IllegalArgumentException("Invalid target address: NULL");
            }
            if (logger.isFineEnabled()) {
                logger.fine("Joining over target member " + targetAddress);
            }
            if (targetAddress.equals(node.getThisAddress()) || isLocalAddress(targetAddress)) {
                clusterJoinManager.setThisMemberAsMaster();
                return;
            }
            long joinStartTime = Clock.currentTimeMillis();
            Connection connection;
            while (shouldRetry() && (Clock.currentTimeMillis() - joinStartTime < maxJoinMillis)) {

                connection = node.getServer().getConnectionManager(MEMBER).getOrConnect(targetAddress);
                if (connection == null) {
                    //noinspection BusyWait
                    Thread.sleep(JOIN_RETRY_WAIT_TIME);
                    continue;
                }
                if (logger.isFineEnabled()) {
                    logger.fine("Sending joinRequest " + targetAddress);
                }
                clusterJoinManager.sendJoinRequest(targetAddress);
                //noinspection BusyWait
                Thread.sleep(JOIN_RETRY_WAIT_TIME);
            }
        } catch (final Exception e) {
            logger.warning(e);
        }
    }

    private void joinViaPossibleMembers() {
        try {
            Collection<Address> possibleAddresses = getPossibleAddressesForInitialJoin();

            long maxJoinMillis = getMaxJoinMillis();
            long startTime = Clock.currentTimeMillis();

            while (shouldRetry() && (Clock.currentTimeMillis() - startTime < maxJoinMillis)) {
                tryJoinAddresses(possibleAddresses);

                if (clusterService.isJoined()) {
                    return;
                }

                if (isAllBlacklisted(possibleAddresses)) {
                    logger.fine(
                            "This node will assume master role since none of the possible members accepted join request.");
                    clusterJoinManager.setThisMemberAsMaster();
                    return;
                }

                if (tryClaimMastership(possibleAddresses)) {
                    return;
                }

                clusterService.setMasterAddressToJoin(null);
            }
        } catch (Throwable t) {
            logger.severe(t);
        }
    }

    private boolean tryClaimMastership(Collection<Address> addresses) {
        boolean consensus = false;
        if (isThisNodeMasterCandidate(addresses)) {
            consensus = claimMastership(addresses);
            if (consensus) {
                if (logger.isFineEnabled()) {
                    Set<Address> votingEndpoints = new HashSet<>(addresses);
                    votingEndpoints.removeAll(blacklistedAddresses.keySet());
                    logger.fine("Setting myself as master after consensus! Voting endpoints: " + votingEndpoints);
                }
                clusterJoinManager.setThisMemberAsMaster();
            } else if (logger.isFineEnabled()) {
                Set<Address> votingEndpoints = new HashSet<>(addresses);
                votingEndpoints.removeAll(blacklistedAddresses.keySet());
                logger.fine("My claim to be master is rejected! Voting endpoints: " + votingEndpoints);
            }
        } else if (logger.isFineEnabled()) {
            logger.fine("Cannot claim myself as master! Will try to connect a possible master...");
        }
        claimingMastership = false;
        return consensus;
    }

    protected Collection<Address> getPossibleAddressesForInitialJoin() {
        return getPossibleAddresses();
    }

    private boolean claimMastership(Collection<Address> possibleAddresses) {
        if (logger.isFineEnabled()) {
            Set<Address> votingEndpoints = new HashSet<>(possibleAddresses);
            votingEndpoints.removeAll(blacklistedAddresses.keySet());
            logger.fine("Claiming myself as master node! Asking to endpoints: " + votingEndpoints);
        }
        claimingMastership = true;
        OperationServiceImpl operationService = node.getNodeEngine().getOperationService();
        Collection<Future<Boolean>> futures = new LinkedList<>();
        for (Address address : possibleAddresses) {
            if (isBlacklisted(address)) {
                continue;
            }

            Future<Boolean> future = operationService
                    .createInvocationBuilder(SERVICE_NAME, new JoinMastershipClaimOp(), address)
                    .setTryCount(1).invoke();
            futures.add(future);
        }

        try {
            Collection<Boolean> responses = returnWithDeadline(futures, MASTERSHIP_CLAIM_TIMEOUT,
                    TimeUnit.SECONDS, RETHROW_EVERYTHING);
            for (Boolean response : responses) {
                if (!response) {
                    return false;
                }
            }
            return true;
        } catch (Exception e) {
            logger.fine(e);
            return false;
        }
    }

    private boolean isThisNodeMasterCandidate(Collection<Address> addresses) {
        int thisHashCode = node.getThisAddress().hashCode();
        for (Address address : addresses) {
            if (isBlacklisted(address)) {
                continue;
            }
            if (node.getServer().getConnectionManager(MEMBER).get(address) != null) {
                if (thisHashCode > address.hashCode()) {
                    return false;
                }
            }
        }
        return true;
    }

    private void tryJoinAddresses(Collection<Address> addresses) throws InterruptedException {
        long connectionTimeoutMillis = TimeUnit.SECONDS.toMillis(getConnTimeoutSeconds());
        long start = Clock.currentTimeMillis();

        while (!clusterService.isJoined() && Clock.currentTimeMillis() - start < connectionTimeoutMillis) {
            Address masterAddress = clusterService.getMasterAddress();
            if (isAllBlacklisted(addresses) && masterAddress == null) {
                return;
            }

            if (masterAddress != null) {
                if (logger.isFineEnabled()) {
                    logger.fine("Sending join request to " + masterAddress);
                }
                clusterJoinManager.sendJoinRequest(masterAddress);
            } else {
                sendMasterQuestion(addresses);
            }

            if (!clusterService.isJoined()) {
                Thread.sleep(JOIN_RETRY_WAIT_TIME);
            }
        }
    }

    private boolean isAllBlacklisted(Collection<Address> possibleAddresses) {
        return blacklistedAddresses.keySet().containsAll(possibleAddresses);
    }

    private void sendMasterQuestion(Collection<Address> addresses) {
        if (logger.isFineEnabled()) {
            logger.fine("NOT sending master question to blacklisted endpoints: " + blacklistedAddresses);
        }
        for (Address address : addresses) {
            if (isBlacklisted(address)) {
                continue;
            }
            if (logger.isFineEnabled()) {
                logger.fine("Sending master question to " + address);
            }
            clusterJoinManager.sendMasterQuestion(address);
        }
    }

    private Address getRequiredMemberAddress() {
        TcpIpConfig tcpIpConfig = joinConfig.getTcpIpConfig();
        String host = tcpIpConfig.getRequiredMember();
        try {
            AddressHolder addressHolder = AddressUtil.getAddressHolder(host, getActiveMemberNetworkConfig(config).getPort());
            if (AddressUtil.isIpAddress(addressHolder.getAddress())) {
                return new Address(addressHolder.getAddress(), addressHolder.getPort());
            }
            InterfacesConfig interfaces = getActiveMemberNetworkConfig(config).getInterfaces();
            if (interfaces.isEnabled()) {
                InetAddress[] inetAddresses = InetAddress.getAllByName(addressHolder.getAddress());
                if (inetAddresses.length > 1) {
                    for (InetAddress inetAddress : inetAddresses) {
                        if (AddressUtil.matchAnyInterface(inetAddress.getHostAddress(), interfaces.getInterfaces())) {
                            return new Address(inetAddress, addressHolder.getPort());
                        }
                    }
                } else if (AddressUtil.matchAnyInterface(inetAddresses[0].getHostAddress(), interfaces.getInterfaces())) {
                    return new Address(addressHolder.getAddress(), addressHolder.getPort());
                }
            } else {
                return new Address(addressHolder.getAddress(), addressHolder.getPort());
            }
        } catch (final Exception e) {
            logger.warning(e);
        }
        return null;
    }

    @SuppressWarnings({"checkstyle:npathcomplexity", "checkstyle:cyclomaticcomplexity"})
    protected Collection<Address> getPossibleAddresses() {
        final Collection<String> possibleMembers = getMembers();
        final Set<Address> possibleAddresses = new HashSet<>();
        final NetworkConfig networkConfig = getActiveMemberNetworkConfig(config);
        for (String possibleMember : possibleMembers) {
            AddressHolder addressHolder = AddressUtil.getAddressHolder(possibleMember);
            try {
                boolean portIsDefined = addressHolder.getPort() != -1 || !networkConfig.isPortAutoIncrement();
                int count = portIsDefined ? 1 : maxPortTryCount;
                int port = addressHolder.getPort() != -1 ? addressHolder.getPort() : networkConfig.getPort();
                AddressMatcher addressMatcher = null;
                try {
                    addressMatcher = AddressUtil.getAddressMatcher(addressHolder.getAddress());
                } catch (InvalidAddressException ignore) {
                    ignore(ignore);
                }
                if (addressMatcher != null) {
                    final Collection<String> matchedAddresses;
                    if (addressMatcher.isIPv4()) {
                        matchedAddresses = AddressUtil.getMatchingIpv4Addresses(addressMatcher);
                    } else {
                        // for IPv6 we are not doing wildcard matching
                        matchedAddresses = Collections.singleton(addressHolder.getAddress());
                    }
                    for (String matchedAddress : matchedAddresses) {
                        addPossibleAddresses(possibleAddresses, null, InetAddress.getByName(matchedAddress), port, count);
                    }
                } else {
                    final String host = addressHolder.getAddress();
                    final InterfacesConfig interfaces = networkConfig.getInterfaces();
                    if (interfaces.isEnabled()) {
                        final InetAddress[] inetAddresses = InetAddress.getAllByName(host);
                        for (InetAddress inetAddress : inetAddresses) {
                            if (AddressUtil.matchAnyInterface(inetAddress.getHostAddress(),
                                    interfaces.getInterfaces())) {
                                addPossibleAddresses(possibleAddresses, host, inetAddress, port, count);
                            }
                        }
                    } else {
                        addPossibleAddresses(possibleAddresses, host, null, port, count);
                    }
                }
            } catch (UnknownHostException e) {
                logger.warning("Cannot resolve hostname '" + addressHolder.getAddress()
                        + "'. Please make sure host is valid and reachable.");
                if (logger.isFineEnabled()) {
                    logger.fine("Error during resolving possible target!", e);
                }
            }
        }

        possibleAddresses.remove(node.getThisAddress());
        return possibleAddresses;
    }

    private void addPossibleAddresses(final Set<Address> possibleAddresses,
                                      final String host, final InetAddress inetAddress,
                                      final int port, final int count) throws UnknownHostException {
        for (int i = 0; i < count; i++) {
            int currentPort = port + i;

            Address address;
            if (host != null && inetAddress != null) {
                address = new Address(host, inetAddress, currentPort);
            } else if (host != null) {
                address = new Address(host, currentPort);
            } else {
                address = new Address(inetAddress, currentPort);
            }
            if (!isLocalAddress(address)) {
                possibleAddresses.add(address);
            }
        }
    }

    private boolean isLocalAddress(final Address address) throws UnknownHostException {
        final Address thisAddress = node.getThisAddress();
        final boolean local = thisAddress.getInetSocketAddress().equals(address.getInetSocketAddress());
        if (logger.isFineEnabled()) {
            logger.fine(address + " is local? " + local);
        }
        return local;
    }

    protected Collection<String> getMembers() {
        return getConfigurationMembers(config);
    }

    public static Collection<String> getConfigurationMembers(Config config) {
        return getConfigurationMembers(getActiveMemberNetworkConfig(config).getJoin().getTcpIpConfig());
    }

    public static Collection<String> getConfigurationMembers(TcpIpConfig tcpIpConfig) {
        final Collection<String> configMembers = tcpIpConfig.getMembers();
        final Set<String> possibleMembers = new HashSet<>();
        for (String member : configMembers) {
            // split members defined in tcp-ip configuration by comma(,) semi-colon(;) space( ).
            String[] members = member.split("[,; ]");
            Collections.addAll(possibleMembers, members);
        }
        return possibleMembers;
    }

    @Override
    public void searchForOtherClusters() {
        final Collection<Address> possibleAddresses;
        try {
            possibleAddresses = getPossibleAddresses();
        } catch (Throwable e) {
            logger.severe(e);
            return;
        }
        possibleAddresses.remove(node.getThisAddress());
        possibleAddresses.removeAll(node.getClusterService().getMemberAddresses());

        if (possibleAddresses.isEmpty()) {
            return;
        }
        SplitBrainJoinMessage request = node.createSplitBrainJoinMessage();
        for (Address address : possibleAddresses) {
            SplitBrainMergeCheckResult result = sendSplitBrainJoinMessageAndCheckResponse(address, request);
            if (result == SplitBrainMergeCheckResult.LOCAL_NODE_SHOULD_MERGE) {
                logger.warning(node.getThisAddress() + " is merging [tcp/ip] to " + address);
                setTargetAddress(address);
                startClusterMerge(address, request.getMemberListVersion());
                return;
            }
        }
    }

    @Override
    public String getType() {
        return "tcp-ip";
    }
}
