/*-
 * ============LICENSE_START=======================================================
 * SDC
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. 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.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.sdc.be.dao.cassandra;

import java.util.List;

import javax.annotation.PreDestroy;

import com.datastax.driver.core.SocketOptions;
import org.apache.commons.lang3.tuple.ImmutablePair;
import org.openecomp.sdc.be.config.ConfigurationManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.policies.ConstantReconnectionPolicy;
import com.datastax.driver.core.policies.DCAwareRoundRobinPolicy;
import com.datastax.driver.core.policies.DefaultRetryPolicy;
import com.datastax.driver.core.policies.LoadBalancingPolicy;
import com.datastax.driver.core.policies.TokenAwarePolicy;
import com.datastax.driver.mapping.Mapper;
import com.datastax.driver.mapping.MappingManager;

import fj.data.Either;

@Component("cassandra-client")
public class CassandraClient {
	private static Logger logger = LoggerFactory.getLogger(CassandraClient.class.getName());

	private Cluster cluster;
	private boolean isConnected;

	public CassandraClient() {
		super();
		isConnected = false;
		List<String> cassandraHosts = null;
		try {
			cassandraHosts = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig()
					.getCassandraHosts();
			Long reconnectTimeout = ConfigurationManager.getConfigurationManager().getConfiguration()
					.getCassandraConfig().getReconnectTimeout();

			logger.debug("creating cluster to hosts:{} with reconnect timeout:{}", cassandraHosts, reconnectTimeout);
			Cluster.Builder clusterBuilder = Cluster.builder()
					.withReconnectionPolicy(new ConstantReconnectionPolicy(reconnectTimeout))
					.withRetryPolicy(DefaultRetryPolicy.INSTANCE);

			cassandraHosts.forEach(host -> clusterBuilder.addContactPoint(host));
			setSocketOptions(clusterBuilder);
			enableAuthentication(clusterBuilder);
			enableSsl(clusterBuilder);
			setLocalDc(clusterBuilder);

			cluster = clusterBuilder.build();
			isConnected = true;
		} catch (Exception e) {
			logger.info("** CassandraClient isn't connected to {}", cassandraHosts);
		}

		logger.info("** CassandraClient created");
	}

	private void setSocketOptions(Cluster.Builder clusterBuilder) {
		SocketOptions socketOptions =new SocketOptions();
		Integer socketConnectTimeout = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig().getSocketConnectTimeout();
		if( socketConnectTimeout!=null ){
			logger.info("SocketConnectTimeout was provided, setting Cassandra client to use SocketConnectTimeout: {} .",socketConnectTimeout);
			socketOptions.setConnectTimeoutMillis(socketConnectTimeout);
		}
		Integer socketReadTimeout = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig().getSocketReadTimeout();
		if( socketReadTimeout != null ){
			logger.info("SocketReadTimeout was provided, setting Cassandra client to use SocketReadTimeout: {} .",socketReadTimeout);
			socketOptions.setReadTimeoutMillis(socketReadTimeout);
		}
		clusterBuilder.withSocketOptions(socketOptions);
	}

	private void setLocalDc(Cluster.Builder clusterBuilder) {
		String localDataCenter = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig()
				.getLocalDataCenter();
		if (localDataCenter != null) {
			logger.info("localDatacenter was provided, setting Cassndra clint to use datacenter: {} as local.",
					localDataCenter);
			LoadBalancingPolicy tokenAwarePolicy = new TokenAwarePolicy(
					DCAwareRoundRobinPolicy.builder().withLocalDc(localDataCenter).build());
			clusterBuilder.withLoadBalancingPolicy(tokenAwarePolicy);
		} else {
			logger.info(
					"localDatacenter was provided,  the driver will use the datacenter of the first contact point that was reached at initialization");
		}
	}

	private void enableSsl(Cluster.Builder clusterBuilder) {
		boolean ssl = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig().isSsl();
		if (ssl) {
			String truststorePath = ConfigurationManager.getConfigurationManager().getConfiguration()
					.getCassandraConfig().getTruststorePath();
			String truststorePassword = ConfigurationManager.getConfigurationManager().getConfiguration()
					.getCassandraConfig().getTruststorePassword();
			if (truststorePath == null || truststorePassword == null) {
				logger.error("ssl is enabled but truststorePath or truststorePassword were not supplied.");
			} else {
				System.setProperty("javax.net.ssl.trustStore", truststorePath);
				System.setProperty("javax.net.ssl.trustStorePassword", truststorePassword);
				clusterBuilder.withSSL();
			}

		}
	}

	private void enableAuthentication(Cluster.Builder clusterBuilder) {
		boolean authenticate = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig()
				.isAuthenticate();
		if (authenticate) {
			String username = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig()
					.getUsername();
			String password = ConfigurationManager.getConfigurationManager().getConfiguration().getCassandraConfig()
					.getPassword();
			if (username == null || password == null) {
				logger.error("authentication is enabled but username or password were not supplied.");
			} else {
				clusterBuilder.withCredentials(username, password);
			}

		}
	}

	/**
	 * 
	 * @param keyspace
	 *            - key space to connect
	 * @return
	 */
	public Either<ImmutablePair<Session, MappingManager>, CassandraOperationStatus> connect(String keyspace) {
		if (cluster != null) {
			try {
				Session session = cluster.connect(keyspace);
				if (session != null) {
					MappingManager manager = new MappingManager(session);
					return Either.left(new ImmutablePair<Session, MappingManager>(session, manager));
				} else {
					return Either.right(CassandraOperationStatus.KEYSPACE_NOT_CONNECTED);
				}
			} catch (Throwable e) {
				logger.debug("Failed to connect to keyspace [{}], error :", keyspace, e);
				return Either.right(CassandraOperationStatus.KEYSPACE_NOT_CONNECTED);
			}
		}
		return Either.right(CassandraOperationStatus.CLUSTER_NOT_CONNECTED);
	}

	public <T> CassandraOperationStatus save(T entity, Class<T> clazz, MappingManager manager) {
		if (!isConnected) {
			return CassandraOperationStatus.CLUSTER_NOT_CONNECTED;
		}
		try {
			Mapper<T> mapper = manager.mapper(clazz);
			mapper.save(entity);
		} catch (Exception e) {
			logger.debug("Failed to save entity [{}], error :", entity, e);
			return CassandraOperationStatus.GENERAL_ERROR;
		}
		return CassandraOperationStatus.OK;
	}

	public <T> Either<T, CassandraOperationStatus> getById(String id, Class<T> clazz, MappingManager manager) {
		if (!isConnected) {
			return Either.right(CassandraOperationStatus.CLUSTER_NOT_CONNECTED);
		}
		try {
			Mapper<T> mapper = manager.mapper(clazz);
			T result = mapper.get(id);
			if (result == null) {
				return Either.right(CassandraOperationStatus.NOT_FOUND);
			}
			return Either.left(result);
		} catch (Exception e) {
			logger.debug("Failed to get by Id [{}], error :", id, e);
			return Either.right(CassandraOperationStatus.GENERAL_ERROR);
		}
	}

	public <T> CassandraOperationStatus delete(String id, Class<T> clazz, MappingManager manager) {
		if (!isConnected) {
			return CassandraOperationStatus.CLUSTER_NOT_CONNECTED;
		}
		try {
			Mapper<T> mapper = manager.mapper(clazz);
			mapper.delete(id);
		} catch (Exception e) {
			logger.debug("Failed to delete by id [{}], error :", id, e);
			return CassandraOperationStatus.GENERAL_ERROR;
		}
		return CassandraOperationStatus.OK;
	}

	public boolean isConnected() {
		return isConnected;
	}

	@PreDestroy
	public void closeClient() {
		if (isConnected) {
			cluster.close();
		}
		logger.info("** CassandraClient cluster closed");
	}
}