/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.brooklyn.entity.nosql.mongodb;

import java.net.UnknownHostException;
import java.util.List;
import java.util.Map;

import org.apache.brooklyn.core.location.access.BrooklynAccessUtils;
import org.bson.types.ObjectId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Throwables;
import com.google.common.net.HostAndPort;
import com.mongodb.BasicDBObject;
import com.mongodb.CommandResult;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.ReadPreference;

public class MongoDBTestHelper {

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

    private static final String TEST_DB = "brooklyn_test";
    private static final String TEST_COLLECTION = "test_collection";
    private static final String ADMIN_DB = "admin";

    /**
     * Inserts a new object with { key: value } at given server.
     * @return The new document's id
     */
    public static String insert(AbstractMongoDBServer entity, String key, Object value) {
        LOG.info("Inserting {}:{} at {}", new Object[]{key, value, entity});
        MongoClient mongoClient = clientForServer(entity);
        try {
            DB db = mongoClient.getDB(TEST_DB);
            DBCollection testCollection = db.getCollection(TEST_COLLECTION);
            BasicDBObject doc = new BasicDBObject(key, value);
            testCollection.insert(doc);
            ObjectId id = (ObjectId) doc.get("_id");
            return id.toString();
        } finally {
            mongoClient.close();
        }
    }

    /** @return The {@link DBObject} representing the object with the given id */
    public static DBObject getById(AbstractMongoDBServer entity, String id) {
        LOG.info("Getting {} from {}", new Object[]{id, entity});
        MongoClient mongoClient = clientForServer(entity);
        // Secondary preferred means the driver will let us read from secondaries too.
        mongoClient.setReadPreference(ReadPreference.secondaryPreferred());
        try {
            DB db = mongoClient.getDB(TEST_DB);
            DBCollection testCollection = db.getCollection(TEST_COLLECTION);
            return testCollection.findOne(new BasicDBObject("_id", new ObjectId(id)));
        } finally {
            mongoClient.close();
        }
    }
    
    public static List<String> getDatabaseNames(AbstractMongoDBServer entity) {
        LOG.info("Getting database names from {}", entity);
        MongoClient mongoClient = clientForServer(entity);
        try {
            return mongoClient.getDatabaseNames();
        } finally {
            mongoClient.close();
        }
    }
    
    public static boolean isConfigServer(AbstractMongoDBServer entity) {
        LOG.info("Checking if {} is a config server", entity);
        MongoClient mongoClient = clientForServer(entity);
        try {
            DB db = mongoClient.getDB(ADMIN_DB);
            CommandResult commandResult = db.command("getCmdLineOpts");
            Map<?, ?> parsedArgs = (Map<?, ?>)commandResult.get("parsed");
            if (parsedArgs == null) return false;
            Boolean configServer = (Boolean)parsedArgs.get("configsvr");
            if (configServer != null) {
                // v2.5 format
                return Boolean.TRUE.equals(configServer);
            } else {
                // v2.6 format
                String role = (String) ((Map)parsedArgs.get("sharding")).get("clusterRole");
                return "configsvr".equals(role);
            }
        } finally {
            mongoClient.close();
        }
    }

    private static MongoClient clientForServer(AbstractMongoDBServer server) {
        try {
            HostAndPort hap = BrooklynAccessUtils.getBrooklynAccessibleAddress(server, server.getAttribute(MongoDBServer.PORT));
            return new MongoClient(hap.getHostText(), hap.getPort());
        } catch (Exception e) {
            // Fail whatever test called this method.
            throw Throwables.propagate(e);
        }
    }
}