/*
 * Copyright (c) 2013-2014 - Adjacent Link LLC, Bridgewater, New Jersey
 * Copyright (c) 2010 - DRS CenGen, LLC, Columbia, Maryland
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 * * Neither the name of DRS CenGen, LLC nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef EMANEFLOWCONTROLMANAGER_HEADER_
#define EMANEFLOWCONTROLMANAGER_HEADER_

#include "emane/downstreamtransport.h"
#include "emane/controls/flowcontrolcontrolmessage.h"

namespace EMANE
{
  /**
   * @class FlowControlManager
   *
   * @brief Flow Control Manager (token producer) side.
   */
  class FlowControlManager
  { 
  public:
    /**
     * Creates an instance
     *
     * @param transport reference to the DownstremTransport
     */
    FlowControlManager(EMANE::DownstreamTransport & transport);
    
    /**
     * Destroys an instance
     */
    ~FlowControlManager();

    /**
     * Starts flow control processing
     *
     * @param u16TotalTokensAvailable initial number of flow control tokens available
     */
    void start(std::uint16_t u16TotalTokensAvailable);

    /**
     * Stops flow control processing
     */
    void stop();

    /**
     * Removes a flow control token
     *
     * @return Total number of tokens available and a flag indicating success
     */
    std::pair<std::uint16_t,bool> removeToken();

    /**
     * Add one or more flow control token(s)
     *
     * @param u16Tokens number of tokens
     *
     * @return Total number of tokens available and a flag indicating success
     */
    std::pair<std::uint16_t,bool> addToken(std::uint16_t u16Tokens = 1);

    /**
     * Handles a flow control update message
     *
     * @param pMsg Flow control message
     */
    void processFlowControlMessage(const Controls::FlowControlControlMessage * pMsg);
    
  private:
    class Implementation;
    std::unique_ptr<Implementation> pImpl_;

    FlowControlManager(const FlowControlManager &) = delete;

    FlowControlManager & 
    operator=(const FlowControlManager &) = delete;
  };
}

#endif // EMANEUTILSFLOWCONTROLMANAGER_HEADER_
