/**
 * 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.
 */

#ifndef _HDFS_LIBHDFS3_RPC_RPCCLIENT_H_
#define _HDFS_LIBHDFS3_RPC_RPCCLIENT_H_

#include "RpcAuth.h"
#include "RpcCall.h"
#include "RpcChannel.h"
#include "RpcChannelKey.h"
#include "RpcConfig.h"
#include "RpcProtocolInfo.h"
#include "RpcServerInfo.h"
#include "SharedPtr.h"
#include "Thread.h"
#include "UnorderedMap.h"

#include <stdint.h>
#include <string>
#include <vector>

#ifdef MOCK
#include "TestRpcChannelStub.h"
#endif

namespace hdfs {
namespace internal {

class RpcClient {
public:
    /**
     * Destroy an RpcClient instance.
     */
    virtual ~RpcClient() {
    }

    /**
     * Get a RPC channel, create a new one if necessary.
     * @param auth Authentication information used to setup RPC connection.
     * @param protocol The RPC protocol used in this call.
     * @param server Remote server information.
     * @param conf RPC connection configuration.
     * @param once If true, the RPC channel will not be reused.
     */
    virtual RpcChannel &getChannel(const RpcAuth &auth,
              const RpcProtocolInfo &protocol,
              const RpcServerInfo &server, const RpcConfig &conf) = 0;

    /**
     * Check the RpcClient is still running.
     * @return true if the RpcClient is still running.
     */
    virtual bool isRunning() = 0;

    virtual std::string getClientId() const = 0;

    virtual int32_t getCallId() = 0;

public:
    static RpcClient &getClient();
    static void createSinglten();

private:
    static once_flag once;
    static shared_ptr<RpcClient> client;
};

class RpcClientImpl: public RpcClient {
public:
    /**
     * Construct a RpcClient.
     */
    RpcClientImpl();

    /**
     * Destroy an RpcClient instance.
     */
    ~RpcClientImpl();

    /**
     * Get a RPC channel, create a new one if necessary.
     * @param auth Authentication information used to setup RPC connection.
     * @param protocol The RPC protocol used in this call.
     * @param server Remote server information.
     * @param conf RPC connection configuration.
     * @param once If true, the RPC channel will not be reused.
     */
    RpcChannel &getChannel(const RpcAuth &auth,
          const RpcProtocolInfo &protocol, const RpcServerInfo &server,
          const RpcConfig &conf);

    /**
     * Close the RPC channel.
     */
    void close();

    /**
     * Check the RpcClient is still running.
     * @return true if the RpcClient is still running.
     */
    bool isRunning();

    std::string getClientId() const {
        return clientId;
    }

    int32_t getCallId() {
        static mutex mutid;
        lock_guard<mutex> lock(mutid);
        ++count;
        count = count < (std::numeric_limits<int32_t>::max)() ? count : 0;
        return count;
    }

private:
    shared_ptr<RpcChannel> createChannelInternal(
        const RpcChannelKey &key);

    void clean();

private:
    atomic<bool> cleaning;
    atomic<bool> running;
    condition_variable cond;
    int64_t count;
    mutex mut;
    std::string clientId;
    thread cleaner;
    unordered_map<RpcChannelKey, shared_ptr<RpcChannel> > allChannels;

#ifdef MOCK
private:
    hdfs::mock::TestRpcChannelStub *stub;
#endif
};

}
}

#endif /* _HDFS_LIBHDFS3_RPC_RPCCLIENT_H_ */