/*
 * 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.binding;

import com.mongodb.ReadConcern;
import com.mongodb.ReadPreference;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.connection.AsyncConnection;
import com.mongodb.connection.Cluster;
import com.mongodb.connection.Server;
import com.mongodb.connection.ServerDescription;
import com.mongodb.internal.binding.AbstractReferenceCounted;
import com.mongodb.internal.binding.AsyncClusterAwareReadWriteBinding;
import com.mongodb.internal.connection.ReadConcernAwareNoOpSessionContext;
import com.mongodb.selector.ReadPreferenceServerSelector;
import com.mongodb.selector.ServerSelector;
import com.mongodb.selector.WritableServerSelector;
import com.mongodb.session.SessionContext;

import static com.mongodb.assertions.Assertions.notNull;

A simple ReadWriteBinding implementation that supplies write connection sources bound to a possibly different primary each time, and a
read connection source bound to a possible different server each time.
Since:
3.0/**
 * A simple ReadWriteBinding implementation that supplies write connection sources bound to a possibly different primary each time, and a
 * read connection source bound to a possible different server each time.
 *
 * @since 3.0
 */
@Deprecated
public class AsyncClusterBinding extends AbstractReferenceCounted implements AsyncClusterAwareReadWriteBinding {
    private final Cluster cluster;
    private final ReadPreference readPreference;
    private final ReadConcern readConcern;

    
Creates an instance.
Params:
cluster –        a non-null Cluster which will be used to select a server to bind to
readPreference – a non-null ReadPreference for read operations
Deprecated:
Prefer AsyncClusterBinding(Cluster, ReadPreference, ReadConcern)/**
     * Creates an instance.
     *
     * @param cluster        a non-null Cluster which will be used to select a server to bind to
     * @param readPreference a non-null ReadPreference for read operations
     * @deprecated Prefer {@link #AsyncClusterBinding(Cluster, ReadPreference, ReadConcern)}
     */
    @Deprecated
    public AsyncClusterBinding(final Cluster cluster, final ReadPreference readPreference) {
        this(cluster, readPreference, ReadConcern.DEFAULT);
    }

    
Creates an instance.
Params:
cluster –        a non-null Cluster which will be used to select a server to bind to
readPreference – a non-null ReadPreference for read operations
readConcern –    a non-null read concern
Since:
3.8/**
     * Creates an instance.
     *
     * @param cluster        a non-null Cluster which will be used to select a server to bind to
     * @param readPreference a non-null ReadPreference for read operations
     * @param readConcern    a non-null read concern
     * @since 3.8
     */
    public AsyncClusterBinding(final Cluster cluster, final ReadPreference readPreference, final ReadConcern readConcern) {
        this.cluster = notNull("cluster", cluster);
        this.readPreference = notNull("readPreference", readPreference);
        this.readConcern = (notNull("readConcern", readConcern));
    }

    @Override
    public AsyncReadWriteBinding retain() {
        super.retain();
        return this;
    }

    @Override
    public Cluster getCluster() {
        return cluster;
    }

    @Override
    public ReadPreference getReadPreference() {
        return readPreference;
    }

    @Override
    public SessionContext getSessionContext() {
        return new ReadConcernAwareNoOpSessionContext(readConcern);
    }

    @Override
    public void getReadConnectionSource(final SingleResultCallback<AsyncConnectionSource> callback) {
        getAsyncClusterBindingConnectionSource(new ReadPreferenceServerSelector(readPreference), callback);
    }

    @Override
    public void getWriteConnectionSource(final SingleResultCallback<AsyncConnectionSource> callback) {
        getAsyncClusterBindingConnectionSource(new WritableServerSelector(), callback);
    }

    private void getAsyncClusterBindingConnectionSource(final ServerSelector serverSelector,
                                                        final SingleResultCallback<AsyncConnectionSource> callback) {
        cluster.selectServerAsync(serverSelector, new SingleResultCallback<Server>() {
            @Override
            public void onResult(final Server result, final Throwable t) {
                if (t != null) {
                    callback.onResult(null, t);
                } else {
                    callback.onResult(new AsyncClusterBindingConnectionSource(result), null);
                }
            }
        });
    }

    private final class AsyncClusterBindingConnectionSource extends AbstractReferenceCounted implements AsyncConnectionSource {
        private final Server server;

        private AsyncClusterBindingConnectionSource(final Server server) {
            this.server = server;
            AsyncClusterBinding.this.retain();
        }

        @Override
        public ServerDescription getServerDescription() {
            return server.getDescription();
        }

        @Override
        public SessionContext getSessionContext() {
            return new ReadConcernAwareNoOpSessionContext(readConcern);
        }

        @Override
        public void getConnection(final SingleResultCallback<AsyncConnection> callback) {
            server.getConnectionAsync(callback);
        }

        public AsyncConnectionSource retain() {
            super.retain();
            AsyncClusterBinding.this.retain();
            return this;
        }

        @Override
        public void release() {
            super.release();
            AsyncClusterBinding.this.release();
        }
    }
}