/*
 *
 * MariaDB Client for Java
 *
 * Copyright (c) 2012-2014 Monty Program Ab.
 * Copyright (c) 2015-2017 MariaDB Ab.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this library; if not, write to Monty Program Ab info@montyprogram.com.
 *
 * This particular MariaDB Client for Java file is work
 * derived from a Drizzle-JDBC. Drizzle-JDBC file which is covered by subject to
 * the following copyright and notice provisions:
 *
 * Copyright (c) 2009-2011, Marcus Eriksson
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or
 * other materials provided with the distribution.
 *
 * Neither the name of the driver nor the names of its contributors may not be
 * used to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS  AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 */

package org.mariadb.jdbc.internal.failover.impl;

import org.mariadb.jdbc.HostAddress;
import org.mariadb.jdbc.UrlParser;
import org.mariadb.jdbc.internal.failover.AbstractMastersListener;
import org.mariadb.jdbc.internal.failover.HandleErrorResult;
import org.mariadb.jdbc.internal.failover.thread.FailoverLoop;
import org.mariadb.jdbc.internal.failover.tools.SearchFilter;
import org.mariadb.jdbc.internal.logging.Logger;
import org.mariadb.jdbc.internal.logging.LoggerFactory;
import org.mariadb.jdbc.internal.protocol.MasterProtocol;
import org.mariadb.jdbc.internal.protocol.Protocol;
import org.mariadb.jdbc.internal.util.constant.HaMode;
import org.mariadb.jdbc.internal.util.dao.ReconnectDuringTransactionException;
import org.mariadb.jdbc.internal.util.dao.ServerPrepareResult;
import org.mariadb.jdbc.internal.util.pool.GlobalStateInfo;

import java.lang.reflect.Method;
import java.sql.SQLException;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class MastersFailoverListener extends AbstractMastersListener {
    private static final Logger logger = LoggerFactory.getLogger(MastersFailoverListener.class);
    private final HaMode mode;

    /**
     * Initialisation.
     *
     * @param urlParser     url options.
     * @param globalInfo    server global variables information
     */
    public MastersFailoverListener(final UrlParser urlParser, final GlobalStateInfo globalInfo) {
        super(urlParser, globalInfo);
        this.mode = urlParser.getHaMode();
        setMasterHostFail();
    }

    /**
     * Connect to database.
     *
     * @throws SQLException if connection is on error.
     */
    @Override
    public void initializeConnection() throws SQLException {
        super.initializeConnection();
        this.currentProtocol = null;
        //launching initial loop
        reconnectFailedConnection(new SearchFilter(true, false));
        resetMasterFailoverData();
    }

    /**
     * Before executing query, reconnect if connection is closed, and autoReconnect option is set.
     *
     * @throws SQLException if connection has been explicitly closed.
     */
    public void preExecute() throws SQLException {
        lastQueryNanos = System.nanoTime();
        //if connection is closed or failed on slave
        if (this.currentProtocol != null && this.currentProtocol.isClosed()) {
            preAutoReconnect();
        }
    }

    @Override
    public void preClose() {
        if (explicitClosed.compareAndSet(false, true)) {
            proxy.lock.lock();
            try {
                removeListenerFromSchedulers();
                closeConnection(currentProtocol);
            } finally {
                proxy.lock.unlock();
            }
        }
    }

    public long getServerThreadId() {
        return currentProtocol.getServerThreadId();
    }

    @Override
    public void preAbort() {
        if (explicitClosed.compareAndSet(false, true)) {
            proxy.lock.lock();
            try {
                removeListenerFromSchedulers();
                abortConnection(currentProtocol);
            } finally {
                proxy.lock.unlock();
            }
        }
    }

    @Override
    public HandleErrorResult primaryFail(Method method, Object[] args, boolean killCmd) throws Throwable {
        boolean alreadyClosed = !currentProtocol.isConnected();
        boolean inTransaction = currentProtocol != null && currentProtocol.inTransaction();

        if (currentProtocol.isConnected()) currentProtocol.close();

        try {
            reconnectFailedConnection(new SearchFilter(true, false));
            handleFailLoop();

            if (killCmd) return new HandleErrorResult(true, false);

            if (alreadyClosed || !inTransaction && isQueryRelaunchable(method, args)) {
                logger.info("Connection to master lost, new master {} found"
                        + ", query type permit to be re-execute on new server without throwing exception",
                        currentProtocol.getHostAddress());
                return relaunchOperation(method, args);
            }
            return new HandleErrorResult(true);
        } catch (Exception e) {
            //we will throw a Connection exception that will close connection
            if (e.getCause() != null
                    && proxy.hasToHandleFailover((SQLException) e.getCause())
                    && currentProtocol.isConnected()) {
                currentProtocol.close();
            }
            FailoverLoop.removeListener(this);
            return new HandleErrorResult();
        }
    }

    /**
     * Loop to connect failed hosts.
     *
     * @param searchFilter search parameters.
     * @throws SQLException if there is any error during reconnection
     */
    @Override
    public void reconnectFailedConnection(SearchFilter searchFilter) throws SQLException {
        proxy.lock.lock();
        try {
            if (!searchFilter.isInitialConnection()
                    && (isExplicitClosed() || !isMasterHostFail())) {
                return;
            }

            currentConnectionAttempts.incrementAndGet();
            resetOldsBlackListHosts();

            List<HostAddress> loopAddress = new LinkedList<>(urlParser.getHostAddresses());
            if (HaMode.FAILOVER.equals(mode)) {
                //put the list in the following order
                // - random order not connected host
                // - random order blacklist host
                // - random order connected host
                loopAddress.removeAll(getBlacklistKeys());
                Collections.shuffle(loopAddress);
                List<HostAddress> blacklistShuffle = new LinkedList<>(getBlacklistKeys());
                blacklistShuffle.retainAll(urlParser.getHostAddresses());
                Collections.shuffle(blacklistShuffle);
                loopAddress.addAll(blacklistShuffle);
            } else {
                //order in sequence
                loopAddress.removeAll(getBlacklistKeys());
                loopAddress.addAll(getBlacklistKeys());
                loopAddress.retainAll(urlParser.getHostAddresses());
            }

            //put connected at end
            if (currentProtocol != null && !isMasterHostFail()) {
                loopAddress.remove(currentProtocol.getHostAddress());
                //loopAddress.add(currentProtocol.getHostAddress());
            }

            MasterProtocol.loop(this, globalInfo, loopAddress, searchFilter);
            //close loop if all connection are retrieved
            if (!isMasterHostFail()) {
                FailoverLoop.removeListener(this);
            }

            //if no error, reset failover variables
            resetMasterFailoverData();
        } finally {
            proxy.lock.unlock();
        }
    }

    /**
     * Force session to read-only according to options.
     *
     * @param mustBeReadOnly is read-only flag
     * @throws SQLException if a connection error occur
     */
    public void switchReadOnlyConnection(Boolean mustBeReadOnly) throws SQLException {
        if (urlParser.getOptions().assureReadOnly && currentReadOnlyAsked != mustBeReadOnly) {
            proxy.lock.lock();
            try {
                // verify not updated now that hold lock, double check safe due to volatile
                if (currentReadOnlyAsked != mustBeReadOnly) {
                    currentReadOnlyAsked = mustBeReadOnly;
                    setSessionReadOnly(mustBeReadOnly, currentProtocol);
                }
            } finally {
                proxy.lock.unlock();
            }
        }
    }

    /**
     * method called when a new Master connection is found after a fallback.
     *
     * @param protocol the new active connection
     */
    @Override
    public void foundActiveMaster(Protocol protocol) throws SQLException {
        if (isExplicitClosed()) {
            proxy.lock.lock();
            try {
                protocol.close();
            } finally {
                proxy.lock.unlock();
            }
            return;
        }
        syncConnection(this.currentProtocol, protocol);
        proxy.lock.lock();
        try {
            if (currentProtocol != null && !currentProtocol.isClosed()) {
                currentProtocol.close();
            }
            currentProtocol = protocol;
        } finally {
            proxy.lock.unlock();
        }

        resetMasterFailoverData();
        FailoverLoop.removeListener(this);
    }

    /**
     * Try to reconnect connection.
     *
     * @throws SQLException if reconnect a new connection but there was an active transaction.
     */
    public void reconnect() throws SQLException {
        boolean inTransaction = currentProtocol != null && currentProtocol.inTransaction();
        reconnectFailedConnection(new SearchFilter(true, false));
        handleFailLoop();
        if (inTransaction) {
            throw new ReconnectDuringTransactionException("Connection reconnect automatically during an active transaction", 1401, "25S03");
        }
    }

    /**
     * Add listener to FailoverLoop if master connection is not active, so a reconnection will be done.
     * (the reconnection will be done by failover or if append before by the next query/method that will use
     * the failed connection)
     * Remove listener from FailoverLoop is master connection is active.
     */
    public void handleFailLoop() {
        if (isMasterHostFail()) {
            if (!isExplicitClosed()) {
                FailoverLoop.addListener(this);
            }
        } else {
            FailoverLoop.removeListener(this);
        }
    }

    public boolean isMasterConnected() {
        return currentProtocol != null && currentProtocol.isConnected();
    }

    /**
     * Check master status.
     *
     * @param searchFilter search filter
     * @return has some status changed
     */
    public boolean checkMasterStatus(SearchFilter searchFilter) {
        if (currentProtocol != null) {
            pingMasterProtocol(currentProtocol);
        }
        return false;
    }

    public void rePrepareOnSlave(ServerPrepareResult oldServerPrepareResult, boolean mustExecuteOnSlave) {
        //no slave
    }

    /**
     * Reset state of master connection.
     *
     * @throws SQLException if command fail.
     */
    public void reset() throws SQLException {

        if (!isMasterHostFail()) {
            currentProtocol.reset();
        }

    }


}
