/*
 * Copyright 2008-present MongoDB, Inc.
 *
 * 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.mongodb.connection;

import com.mongodb.ConnectionString;
import com.mongodb.annotations.Immutable;
import com.mongodb.annotations.NotThreadSafe;
import com.mongodb.event.ConnectionPoolListener;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

import static com.mongodb.assertions.Assertions.isTrue;
import static com.mongodb.assertions.Assertions.notNull;
import static java.util.Collections.unmodifiableList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.MINUTES;

All settings that relate to the pool of connections to a MongoDB server.
Since:
3.0/**
 * All settings that relate to the pool of connections to a MongoDB server.
 *
 * @since 3.0
 */
@Immutable
public class ConnectionPoolSettings {
    private final List<ConnectionPoolListener> connectionPoolListeners;
    private final int maxSize;
    private final int minSize;
    private final int maxWaitQueueSize;
    private final long maxWaitTimeMS;
    private final long maxConnectionLifeTimeMS;
    private final long maxConnectionIdleTimeMS;
    private final long maintenanceInitialDelayMS;
    private final long maintenanceFrequencyMS;

    
Gets a Builder for creating a new ConnectionPoolSettings instance.
Returns:
a new Builder for ConnectionPoolSettings./**
     * Gets a Builder for creating a new ConnectionPoolSettings instance.
     *
     * @return a new Builder for ConnectionPoolSettings.
     */
    public static Builder builder() {
        return new Builder();
    }

    
Gets a Builder for creating a new ConnectionPoolSettings instance.
Params:
connectionPoolSettings – the existing connection pool settings to configure the builder with
Returns:
a new Builder for ConnectionPoolSettings
Since:
3.5/**
     * Gets a Builder for creating a new ConnectionPoolSettings instance.
     *
     * @param connectionPoolSettings the existing connection pool settings to configure the builder with
     * @return a new Builder for ConnectionPoolSettings
     * @since 3.5
     */
    public static Builder builder(final ConnectionPoolSettings connectionPoolSettings) {
        return builder().applySettings(connectionPoolSettings);
    }

    
A builder for creating ConnectionPoolSettings.
/**
     * A builder for creating ConnectionPoolSettings.
     */
    @NotThreadSafe
    public static final class Builder {
        private List<ConnectionPoolListener> connectionPoolListeners = new ArrayList<ConnectionPoolListener>();
        private int maxSize = 100;
        private int minSize;
        private int maxWaitQueueSize = 500;
        private long maxWaitTimeMS = 1000 * 60 * 2;
        private long maxConnectionLifeTimeMS;
        private long maxConnectionIdleTimeMS;
        private long maintenanceInitialDelayMS;
        private long maintenanceFrequencyMS = MILLISECONDS.convert(1, MINUTES);

        Builder() {
        }

        
Applies the connectionPoolSettings to the builder
Note: Overwrites all existing settings
Params:
connectionPoolSettings – the connectionPoolSettings
Returns:
this
Since:
3.7/**
         * Applies the connectionPoolSettings to the builder
         *
         * <p>Note: Overwrites all existing settings</p>
         *
         * @param connectionPoolSettings the connectionPoolSettings
         * @return this
         * @since 3.7
         */
        public Builder applySettings(final ConnectionPoolSettings connectionPoolSettings) {
            notNull("connectionPoolSettings", connectionPoolSettings);
            connectionPoolListeners = new ArrayList<ConnectionPoolListener>(connectionPoolSettings.connectionPoolListeners);
            maxSize = connectionPoolSettings.maxSize;
            minSize = connectionPoolSettings.minSize;
            maxWaitQueueSize = connectionPoolSettings.maxWaitQueueSize;
            maxWaitTimeMS = connectionPoolSettings.maxWaitTimeMS;
            maxConnectionLifeTimeMS = connectionPoolSettings.maxConnectionLifeTimeMS;
            maxConnectionIdleTimeMS = connectionPoolSettings.maxConnectionIdleTimeMS;
            maintenanceInitialDelayMS = connectionPoolSettings.maintenanceInitialDelayMS;
            maintenanceFrequencyMS = connectionPoolSettings.maintenanceFrequencyMS;
            return this;
        }

        
The maximum number of connections allowed. Those connections will be kept in the pool when idle. Once the pool is exhausted,
any operation requiring a connection will block waiting for an available connection.
Default is 100.
Params:
maxSize – the maximum number of connections in the pool.
Returns:
this/**
         * <p>The maximum number of connections allowed. Those connections will be kept in the pool when idle. Once the pool is exhausted,
         * any operation requiring a connection will block waiting for an available connection.</p>
         *
         * <p>Default is 100.</p>
         *
         * @param maxSize the maximum number of connections in the pool.
         * @return this
         */
        public Builder maxSize(final int maxSize) {
            this.maxSize = maxSize;
            return this;
        }

        
The minimum number of connections. Those connections will be kept in the pool when idle, and the pool will ensure that it
contains at least this minimum number.
Default is 0.
Params:
minSize – the minimum number of connections to have in the pool at all times.
Returns:
this/**
         * <p>The minimum number of connections. Those connections will be kept in the pool when idle, and the pool will ensure that it
         * contains at least this minimum number.</p>
         *
         * <p>Default is 0.</p>
         *
         * @param minSize the minimum number of connections to have in the pool at all times.
         * @return this
         */
        public Builder minSize(final int minSize) {
            this.minSize = minSize;
            return this;
        }

        
This is the maximum number of waiters for a connection to become available from the pool. All further operations will get an
exception immediately.
Default is 500.
Params:
maxWaitQueueSize – the number of threads that are allowed to be waiting for a connection.
Returns:
this/**
         * <p>This is the maximum number of waiters for a connection to become available from the pool. All further operations will get an
         * exception immediately.</p>
         *
         * <p>Default is 500.</p>
         *
         * @param maxWaitQueueSize the number of threads that are allowed to be waiting for a connection.
         * @return this
         */
        public Builder maxWaitQueueSize(final int maxWaitQueueSize) {
            this.maxWaitQueueSize = maxWaitQueueSize;
            return this;
        }

        
The maximum time that a thread may wait for a connection to become available.
Default is 2 minutes. A value of 0 means that it will not wait.  A negative value means it will wait indefinitely.
Params:
maxWaitTime – the maximum amount of time to wait
timeUnit –    the TimeUnit for this wait period
Returns:
this/**
         * <p>The maximum time that a thread may wait for a connection to become available.</p>
         *
         * <p>Default is 2 minutes. A value of 0 means that it will not wait.  A negative value means it will wait indefinitely.</p>
         *
         * @param maxWaitTime the maximum amount of time to wait
         * @param timeUnit    the TimeUnit for this wait period
         * @return this
         */
        public Builder maxWaitTime(final long maxWaitTime, final TimeUnit timeUnit) {
            this.maxWaitTimeMS = MILLISECONDS.convert(maxWaitTime, timeUnit);
            return this;
        }

        
The maximum time a pooled connection can live for.  A zero value indicates no limit to the life time.  A pooled connection that
has exceeded its life time will be closed and replaced when necessary by a new connection.
Params:
maxConnectionLifeTime – the maximum length of time a connection can live
timeUnit –              the TimeUnit for this time period
Returns:
this/**
         * The maximum time a pooled connection can live for.  A zero value indicates no limit to the life time.  A pooled connection that
         * has exceeded its life time will be closed and replaced when necessary by a new connection.
         *
         * @param maxConnectionLifeTime the maximum length of time a connection can live
         * @param timeUnit              the TimeUnit for this time period
         * @return this
         */
        public Builder maxConnectionLifeTime(final long maxConnectionLifeTime, final TimeUnit timeUnit) {
            this.maxConnectionLifeTimeMS = MILLISECONDS.convert(maxConnectionLifeTime, timeUnit);
            return this;
        }

        
The maximum idle time of a pooled connection.  A zero value indicates no limit to the idle time.  A pooled connection that has
exceeded its idle time will be closed and replaced when necessary by a new connection.
Params:
maxConnectionIdleTime – the maximum time a connection can be unused
timeUnit –              the TimeUnit for this time period
Returns:
this/**
         * The maximum idle time of a pooled connection.  A zero value indicates no limit to the idle time.  A pooled connection that has
         * exceeded its idle time will be closed and replaced when necessary by a new connection.
         *
         * @param maxConnectionIdleTime the maximum time a connection can be unused
         * @param timeUnit              the TimeUnit for this time period
         * @return this
         */
        public Builder maxConnectionIdleTime(final long maxConnectionIdleTime, final TimeUnit timeUnit) {
            this.maxConnectionIdleTimeMS = MILLISECONDS.convert(maxConnectionIdleTime, timeUnit);
            return this;
        }

        
The period of time to wait before running the first maintenance job on the connection pool.
Params:
maintenanceInitialDelay – the time period to wait
timeUnit –                the TimeUnit for this time period
Returns:
this/**
         * The period of time to wait before running the first maintenance job on the connection pool.
         *
         * @param maintenanceInitialDelay the time period to wait
         * @param timeUnit                the TimeUnit for this time period
         * @return this
         */
        public Builder maintenanceInitialDelay(final long maintenanceInitialDelay, final TimeUnit timeUnit) {
            this.maintenanceInitialDelayMS = MILLISECONDS.convert(maintenanceInitialDelay, timeUnit);
            return this;
        }

        
The time period between runs of the maintenance job.
Params:
maintenanceFrequency – the time period between runs of the maintenance job
timeUnit –             the TimeUnit for this time period
Returns:
this/**
         * The time period between runs of the maintenance job.
         *
         * @param maintenanceFrequency the time period between runs of the maintenance job
         * @param timeUnit             the TimeUnit for this time period
         * @return this
         */
        public Builder maintenanceFrequency(final long maintenanceFrequency, final TimeUnit timeUnit) {
            this.maintenanceFrequencyMS = MILLISECONDS.convert(maintenanceFrequency, timeUnit);
            return this;
        }

        
Adds the given connection pool listener.
Params:
connectionPoolListener – the non-null connection pool listener
Returns:
this
Since:
3.5/**
         * Adds the given connection pool listener.
         *
         * @param connectionPoolListener the non-null connection pool listener
         * @return this
         * @since 3.5
         */
        public Builder addConnectionPoolListener(final ConnectionPoolListener connectionPoolListener) {
            connectionPoolListeners.add(notNull("connectionPoolListener", connectionPoolListener));
            return this;
        }

        
Creates a new ConnectionPoolSettings object with the settings initialised on this builder.
Returns:
a new ConnectionPoolSettings object/**
         * Creates a new ConnectionPoolSettings object with the settings initialised on this builder.
         *
         * @return a new ConnectionPoolSettings object
         */
        public ConnectionPoolSettings build() {
            return new ConnectionPoolSettings(this);
        }

        
Takes the settings from the given ConnectionString and applies them to the builder 
Params:
connectionString – the connection string containing details of how to connect to MongoDB
Returns:
this/**
         * Takes the settings from the given {@code ConnectionString} and applies them to the builder
         *
         * @param connectionString the connection string containing details of how to connect to MongoDB
         * @return this
         */
        public Builder applyConnectionString(final ConnectionString connectionString) {
            Integer maxConnectionPoolSize = connectionString.getMaxConnectionPoolSize();
            if (maxConnectionPoolSize != null) {
                maxSize(maxConnectionPoolSize);
            }

            Integer minConnectionPoolSize = connectionString.getMinConnectionPoolSize();
            if (minConnectionPoolSize != null) {
                minSize(minConnectionPoolSize);
            }

            Integer maxWaitTime = connectionString.getMaxWaitTime();
            if (maxWaitTime != null) {
                maxWaitTime(maxWaitTime, MILLISECONDS);
            }

            Integer maxConnectionIdleTime = connectionString.getMaxConnectionIdleTime();
            if (maxConnectionIdleTime != null) {
                maxConnectionIdleTime(maxConnectionIdleTime, MILLISECONDS);
            }

            Integer maxConnectionLifeTime = connectionString.getMaxConnectionLifeTime();
            if (maxConnectionLifeTime != null) {
                maxConnectionLifeTime(maxConnectionLifeTime, MILLISECONDS);
            }

            Integer threadsAllowedToBlockForConnectionMultiplier = connectionString.getThreadsAllowedToBlockForConnectionMultiplier();
            if (threadsAllowedToBlockForConnectionMultiplier != null) {
                maxWaitQueueSize(threadsAllowedToBlockForConnectionMultiplier * maxSize);
            }

            return this;
        }
    }

    
The maximum number of connections allowed. Those connections will be kept in the pool when idle. Once the pool is exhausted, any
operation requiring a connection will block waiting for an available connection.
Default is 100.
Returns:
the maximum number of connections in the pool./**
     * <p>The maximum number of connections allowed. Those connections will be kept in the pool when idle. Once the pool is exhausted, any
     * operation requiring a connection will block waiting for an available connection.</p>
     *
     * <p>Default is 100.</p>
     *
     * @return the maximum number of connections in the pool.
     */
    public int getMaxSize() {
        return maxSize;
    }

    
The minimum number of connections. Those connections will be kept in the pool when idle, and the pool will ensure that it contains
at least this minimum number.
Default is 0.
Returns:
the minimum number of connections to have in the pool at all times./**
     * <p>The minimum number of connections. Those connections will be kept in the pool when idle, and the pool will ensure that it contains
     * at least this minimum number.</p>
     *
     * <p>Default is 0.</p>
     *
     * @return the minimum number of connections to have in the pool at all times.
     */
    public int getMinSize() {
        return minSize;
    }

    
This is the maximum number of operations that may be waiting for a connection to become available from the pool. All further
operations will get an exception immediately.
Default is 500.
Returns:
the number of threads that are allowed to be waiting for a connection./**
     * <p>This is the maximum number of operations that may be waiting for a connection to become available from the pool. All further
     * operations will get an exception immediately.</p>
     *
     * <p>Default is 500.</p>
     *
     * @return the number of threads that are allowed to be waiting for a connection.
     */
    public int getMaxWaitQueueSize() {
        return maxWaitQueueSize;
    }

    
The maximum time that a thread may wait for a connection to become available.
Default is 2 minutes. A value of 0 means that it will not wait.  A negative value means it will wait indefinitely.
Params:
timeUnit – the TimeUnit for this wait period
Returns:
the maximum amount of time to wait in the given TimeUnits/**
     * <p>The maximum time that a thread may wait for a connection to become available.</p>
     *
     * <p>Default is 2 minutes. A value of 0 means that it will not wait.  A negative value means it will wait indefinitely.</p>
     *
     * @param timeUnit the TimeUnit for this wait period
     * @return the maximum amount of time to wait in the given TimeUnits
     */
    public long getMaxWaitTime(final TimeUnit timeUnit) {
        return timeUnit.convert(maxWaitTimeMS, MILLISECONDS);
    }

    
The maximum time a pooled connection can live for.  A zero value indicates no limit to the life time.  A pooled connection that has
exceeded its life time will be closed and replaced when necessary by a new connection.
Params:
timeUnit – the TimeUnit to use for this time period
Returns:
the maximum length of time a connection can live in the given TimeUnits/**
     * The maximum time a pooled connection can live for.  A zero value indicates no limit to the life time.  A pooled connection that has
     * exceeded its life time will be closed and replaced when necessary by a new connection.
     *
     * @param timeUnit the TimeUnit to use for this time period
     * @return the maximum length of time a connection can live in the given TimeUnits
     */
    public long getMaxConnectionLifeTime(final TimeUnit timeUnit) {
        return timeUnit.convert(maxConnectionLifeTimeMS, MILLISECONDS);
    }

    
Returns the maximum idle time of a pooled connection.  A zero value indicates no limit to the idle time.  A pooled connection that
has exceeded its idle time will be closed and replaced when necessary by a new connection.
Params:
timeUnit – the TimeUnit to use for this time period
Returns:
the maximum time a connection can be unused, in the given TimeUnits/**
     * Returns the maximum idle time of a pooled connection.  A zero value indicates no limit to the idle time.  A pooled connection that
     * has exceeded its idle time will be closed and replaced when necessary by a new connection.
     *
     * @param timeUnit the TimeUnit to use for this time period
     * @return the maximum time a connection can be unused, in the given TimeUnits
     */
    public long getMaxConnectionIdleTime(final TimeUnit timeUnit) {
        return timeUnit.convert(maxConnectionIdleTimeMS, MILLISECONDS);
    }

    
Returns the period of time to wait before running the first maintenance job on the connection pool.
Params:
timeUnit – the TimeUnit to use for this time period
Returns:
the time period to wait in the given units/**
     * Returns the period of time to wait before running the first maintenance job on the connection pool.
     *
     * @param timeUnit the TimeUnit to use for this time period
     * @return the time period to wait in the given units
     */
    public long getMaintenanceInitialDelay(final TimeUnit timeUnit) {
        return timeUnit.convert(maintenanceInitialDelayMS, MILLISECONDS);
    }

    
Returns the time period between runs of the maintenance job.
Params:
timeUnit – the TimeUnit to use for this time period
Returns:
the time period between runs of the maintainance job in the given units/**
     * Returns the time period between runs of the maintenance job.
     *
     * @param timeUnit the TimeUnit to use for this time period
     * @return the time period between runs of the maintainance job in the given units
     */
    public long getMaintenanceFrequency(final TimeUnit timeUnit) {
        return timeUnit.convert(maintenanceFrequencyMS, MILLISECONDS);
    }

    
Gets the list of added ConnectionPoolListener. The default is an empty list. 
Returns:
the unmodifiable list of connection pool listeners
Since:
3.5/**
     * Gets the list of added {@code ConnectionPoolListener}. The default is an empty list.
     *
     * @return the unmodifiable list of connection pool listeners
     * @since 3.5
     */
    public List<ConnectionPoolListener> getConnectionPoolListeners() {
        return connectionPoolListeners;
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        ConnectionPoolSettings that = (ConnectionPoolSettings) o;

        if (maxConnectionIdleTimeMS != that.maxConnectionIdleTimeMS) {
            return false;
        }
        if (maxConnectionLifeTimeMS != that.maxConnectionLifeTimeMS) {
            return false;
        }
        if (maxSize != that.maxSize) {
            return false;
        }
        if (minSize != that.minSize) {
            return false;
        }
        if (maintenanceInitialDelayMS != that.maintenanceInitialDelayMS) {
            return false;
        }
        if (maintenanceFrequencyMS != that.maintenanceFrequencyMS) {
            return false;
        }
        if (maxWaitQueueSize != that.maxWaitQueueSize) {
            return false;
        }
        if (maxWaitTimeMS != that.maxWaitTimeMS) {
            return false;
        }
        if (!connectionPoolListeners.equals(that.connectionPoolListeners)) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = maxSize;
        result = 31 * result + minSize;
        result = 31 * result + maxWaitQueueSize;
        result = 31 * result + (int) (maxWaitTimeMS ^ (maxWaitTimeMS >>> 32));
        result = 31 * result + (int) (maxConnectionLifeTimeMS ^ (maxConnectionLifeTimeMS >>> 32));
        result = 31 * result + (int) (maxConnectionIdleTimeMS ^ (maxConnectionIdleTimeMS >>> 32));
        result = 31 * result + (int) (maintenanceInitialDelayMS ^ (maintenanceInitialDelayMS >>> 32));
        result = 31 * result + (int) (maintenanceFrequencyMS ^ (maintenanceFrequencyMS >>> 32));
        result = 31 * result + connectionPoolListeners.hashCode();
        return result;
    }

    @Override
    public String toString() {
        return "ConnectionPoolSettings{"
               + "maxSize=" + maxSize
               + ", minSize=" + minSize
               + ", maxWaitQueueSize=" + maxWaitQueueSize
               + ", maxWaitTimeMS=" + maxWaitTimeMS
               + ", maxConnectionLifeTimeMS=" + maxConnectionLifeTimeMS
               + ", maxConnectionIdleTimeMS=" + maxConnectionIdleTimeMS
               + ", maintenanceInitialDelayMS=" + maintenanceInitialDelayMS
               + ", maintenanceFrequencyMS=" + maintenanceFrequencyMS
               + ", connectionPoolListeners=" + connectionPoolListeners
               + '}';
    }

    ConnectionPoolSettings(final Builder builder) {
        isTrue("maxSize > 0", builder.maxSize > 0);
        isTrue("minSize >= 0", builder.minSize >= 0);
        isTrue("maxWaitQueueSize >= 0", builder.maxWaitQueueSize >= 0);
        isTrue("maintenanceInitialDelayMS >= 0", builder.maintenanceInitialDelayMS >= 0);
        isTrue("maxConnectionLifeTime >= 0", builder.maxConnectionLifeTimeMS >= 0);
        isTrue("maxConnectionIdleTime >= 0", builder.maxConnectionIdleTimeMS >= 0);
        isTrue("sizeMaintenanceFrequency > 0", builder.maintenanceFrequencyMS > 0);
        isTrue("maxSize >= minSize", builder.maxSize >= builder.minSize);

        maxSize = builder.maxSize;
        minSize = builder.minSize;
        maxWaitQueueSize = builder.maxWaitQueueSize;
        maxWaitTimeMS = builder.maxWaitTimeMS;
        maxConnectionLifeTimeMS = builder.maxConnectionLifeTimeMS;
        maxConnectionIdleTimeMS = builder.maxConnectionIdleTimeMS;
        maintenanceInitialDelayMS = builder.maintenanceInitialDelayMS;
        maintenanceFrequencyMS = builder.maintenanceFrequencyMS;
        connectionPoolListeners = unmodifiableList(builder.connectionPoolListeners);
    }
}