/**
 *    Copyright (C) 2014-2015 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once

#include <string>

#include "mongo/base/disallow_copying.h"
#include "mongo/db/repl/replication_executor.h"
#include "mongo/stdx/functional.h"

namespace mongo {
namespace executor {

    /**
     * Interface to networking used by ReplicationExecutor.
     *
     * TODO(spencer): Change to use a TaskExecutor once that interface is available.
     */
    class NetworkInterface {
        MONGO_DISALLOW_COPYING(NetworkInterface);
    public:

        // A flag to keep replication MessagingPorts open when all other sockets are disconnected.
        static const unsigned int kMessagingPortKeepOpen = 1;

        typedef RemoteCommandResponse Response;
        typedef stdx::function<void (const repl::ResponseStatus&)> RemoteCommandCompletionFn;

        virtual ~NetworkInterface();

        /**
         * Returns diagnostic info.
         */
        virtual std::string getDiagnosticString() = 0;

        /**
         * Starts up the network interface.
         *
         * It is valid to call all methods except shutdown() before this method completes.  That is,
         * implementations may not assume that startup() completes before startCommand() first
         * executes.
         *
         * Called by the owning TaskExecutor inside its run() method.
         */
        virtual void startup() = 0;

        /**
         * Shuts down the network interface. Must be called before this instance gets deleted,
         * if startup() is called.
         *
         * Called by the owning TaskExecutor inside its run() method.
         */
        virtual void shutdown() = 0;

        /**
         * Blocks the current thread (presumably the executor thread) until the network interface
         * knows of work for the executor to perform.
         */
        virtual void waitForWork() = 0;

        /**
         * Similar to waitForWork, but only blocks until "when".
         */
        virtual void waitForWorkUntil(Date_t when) = 0;

        /**
         * Signals to the network interface that there is new work (such as a signaled event) for
         * the executor to process.  Wakes the executor from waitForWork() and friends.
         */
        virtual void signalWorkAvailable() = 0;

        /**
         * Returns the current time.
         */
        virtual Date_t now() = 0;

        /**
         * Starts asynchronous execution of the command described by "request".
         */
        virtual void startCommand(const repl::ReplicationExecutor::CallbackHandle& cbHandle,
                                  const RemoteCommandRequest& request,
                                  const RemoteCommandCompletionFn& onFinish) = 0;

        /**
         * Requests cancelation of the network activity associated with "cbHandle" if it has not yet
         * completed.
         */
        virtual void cancelCommand(const repl::ReplicationExecutor::CallbackHandle& cbHandle) = 0;

    protected:
        NetworkInterface();
    };

} // namespace executor
} // namespace mongo