/*
 * Copyright (c) 2009 INRIA/LRC - Computer Networks Laboratory
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Authors: Jahanzeb Farooq <jahanzeb.farooq@sophia.inria.fr>
 *          Flavio Kobuta <flaviokubota@gmail.com>
 *
 */

#ifndef UPLINK_SCHEDULER_MBQOS_H
#define UPLINK_SCHEDULER_MBQOS_H

#include "bs-uplink-scheduler.h"
#include "service-flow-record.h"
#include "service-flow.h"
#include "ul-job.h"
#include "ul-mac-messages.h"
#include "wimax-phy.h"

#include "ns3/nstime.h"
#include "ns3/object.h"

#include <stdint.h>

namespace ns3
{

class BaseStationNetDevice;
class SSRecord;
class ServiceFlow;
class ServiceFlowRecord;
class UlJob;

/**
 * \ingroup wimax
 * \brief This class implements a Migration-based Quality of Service uplink scheduler(MBQoS).
 *
 * This uplink scheduler uses three queues, the low priority
 * queue, the intermediate queue and the high priority queue.
 * The scheduler serves the requests in strict priority order
 * from the high priority queue to the low priority queue. The
 * low priority queue stores the bandwidth requests of the BE
 * service flow. The intermediate queue holds bandwidth requests
 * sent by rtPS and by nrtPS connections. rtPS and nrtPS requests
 * can migrate to the high priority queue to guarantee that
 * their QoS requirements are met. Besides the requests migrated
 * from the intermediate queue, the high priority queue stores
 * periodic grants and unicast request opportunities that must be
 * scheduled in the following frame. To guarantee the maximum delay
 * requirement, the BS assigns a deadline to each rtPS bandwidth
 * request in the intermediate queue. The minimum bandwidth
 * requirement of both rtPS and nrtPS connections is guaranteed
 * over a window of duration T .
 * Implementation of uplink scheduler:
 * Freitag, J.; da Fonseca, N.L.S., "Uplink Scheduling with Quality of Service in IEEE 802.16
 * Networks," Global Telecommunications Conference, 2007. GLOBECOM '07. IEEE , vol., no.,
 * pp.2503-2508, 26-30 Nov. 2007 URL:
 * http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4411386&isnumber=4410910
 */
class UplinkSchedulerMBQoS : public UplinkScheduler
{
  public:
    UplinkSchedulerMBQoS();
    /**
     * Constructor
     *
     * \param time the time
     */
    UplinkSchedulerMBQoS(Time time);
    ~UplinkSchedulerMBQoS() override;

    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId();

    /**
     * Get uplink allocations
     * \returns std::list<OfdmUlMapIe>
     */
    std::list<OfdmUlMapIe> GetUplinkAllocations() const override;

    /**
     * Determines if channel descriptors sent in the current frame are
     * required to be updated
     * \param updateDcd update DCD if true
     * \param updateUcd update UCD if true
     * \param sendDcd send DCD if true
     * \param sendUcd send UCD if true
     */
    void GetChannelDescriptorsToUpdate(bool& updateDcd,
                                       bool& updateUcd,
                                       bool& sendDcd,
                                       bool& sendUcd) override;
    /**
     * Calculate allocation start time
     * \returns the allocation start time
     */
    uint32_t CalculateAllocationStartTime() override;
    /**
     * Add uplink allocation
     * \param ulMapIe the UL map IE
     * \param allocationSize the allocation size
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     */
    void AddUplinkAllocation(OfdmUlMapIe& ulMapIe,
                             const uint32_t& allocationSize,
                             uint32_t& symbolsToAllocation,
                             uint32_t& availableSymbols) override;

    /**
     * Schedule function
     */
    void Schedule() override;
    /**
     * Service unsolicited grants
     * \param ssRecord the SS record
     * \param schedulingType the scheduling type
     * \param ulMapIe the UL map IE
     * \param modulationType the modulation type
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     */
    void ServiceUnsolicitedGrants(const SSRecord* ssRecord,
                                  enum ServiceFlow::SchedulingType schedulingType,
                                  OfdmUlMapIe& ulMapIe,
                                  const WimaxPhy::ModulationType modulationType,
                                  uint32_t& symbolsToAllocation,
                                  uint32_t& availableSymbols) override;
    /**
     * Service bandwidth requests
     * \param ssRecord the SS record
     * \param schedulingType the scheduling type
     * \param ulMapIe the UL map IE
     * \param modulationType the modulation type
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     */
    void ServiceBandwidthRequests(const SSRecord* ssRecord,
                                  enum ServiceFlow::SchedulingType schedulingType,
                                  OfdmUlMapIe& ulMapIe,
                                  const WimaxPhy::ModulationType modulationType,
                                  uint32_t& symbolsToAllocation,
                                  uint32_t& availableSymbols) override;
    /**
     * Service bandwidth requests
     * \param serviceFlow the service flow
     * \param schedulingType the scheduling type
     * \param ulMapIe the UL map IE
     * \param modulationType the modulation type
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     * \returns true if successful
     */
    bool ServiceBandwidthRequests(ServiceFlow* serviceFlow,
                                  enum ServiceFlow::SchedulingType schedulingType,
                                  OfdmUlMapIe& ulMapIe,
                                  const WimaxPhy::ModulationType modulationType,
                                  uint32_t& symbolsToAllocation,
                                  uint32_t& availableSymbols) override;
    /**
     * Allocate initial ranging interval
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     */
    void AllocateInitialRangingInterval(uint32_t& symbolsToAllocation,
                                        uint32_t& availableSymbols) override;
    /**
     * Setup service flow
     * \param ssRecord the SS record
     * \param serviceFlow the service flow
     */
    void SetupServiceFlow(SSRecord* ssRecord, ServiceFlow* serviceFlow) override;

    /**
     * \param availableSymbols available symbols in the uplink frame
     * \brief Check deadline from jobs. Migrate requests if necessary.
     *
     * This method verifies for each rtPS request whether it should be
     * migrated to the high priority queue or not. The conditions for
     * migration are: request deadline expires in the frame following
     * the next one, and the amount of bandwidth requested is less than
     * or equal to the amount of available bytes in the next uplink frame.
     */
    void CheckDeadline(uint32_t& availableSymbols);

    /**
     * \param availableSymbols available symbols in the uplink frame.
     * \brief Check if Minimum bandwidth is guarantee. Migrate requests if necessary.
     *
     * This method first calculate a priority value for each request
     * in the intermediate queue. Then, sorts the intermediate queue
     * according to the priority values. Finally, while there is available
     * bandwidth, the scheduler migrate the requests to the high priority queue.
     */
    void CheckMinimumBandwidth(uint32_t& availableSymbols);

    /**
     * \brief Reset the current window.
     * According to a configured time, reset the window.
     */
    void UplinkSchedWindowTimer();

    /**
     * \param priority Priority of queue
     * \param job job information
     *
     * \brief Enqueue a job in a priority queue.
     */
    void EnqueueJob(UlJob::JobPriority priority, Ptr<UlJob> job);

    /**
     * \param priority Priority of queue
     * \return Ptr<UlJob>
     *
     * \brief Dequeue a job from a priority queue.
     */
    Ptr<UlJob> DequeueJob(UlJob::JobPriority priority);

    void ProcessBandwidthRequest(const BandwidthRequestHeader& bwRequestHdr) override;

    /**
     * \param serviceFlow Service flow of connection
     * \return Time
     *
     * \brief Calculates deadline of a request.
     */
    Time DetermineDeadline(ServiceFlow* serviceFlow);

    /**
     * This method is called once to initialize window.
     */
    void InitOnce() override;

    /**
     * \param jobs List of jobs
     * \returns the symbols count
     *
     * Sum the amount of symbols of each job of a queue
     */
    uint32_t CountSymbolsQueue(std::list<Ptr<UlJob>> jobs);

    /**
     * \param job job
     * \returns the symbols count
     *
     * Count the amount of symbols of a job.
     */
    uint32_t CountSymbolsJobs(Ptr<UlJob> job);

    /**
     * Set requested bandwidth
     * \param sfr the service flow record
     */
    void OnSetRequestedBandwidth(ServiceFlowRecord* sfr) override;

    /**
     * \param ssRecord Subscriber station record
     * \param schedType Service flow type
     * \param reqType Type of packet
     * \return Ptr<UlJob>
     *
     * Create and fill information of a job.
     */
    Ptr<UlJob> CreateUlJob(SSRecord* ssRecord,
                           enum ServiceFlow::SchedulingType schedType,
                           ReqType reqType);

    /**
     * \param serviceFlow ServiceFlow
     * \return Ptr<UlJob>
     *
     * Get pending size.
     */
    uint32_t GetPendingSize(ServiceFlow* serviceFlow);

    /**
     * Service bandwidth requests bytes.
     * \param serviceFlow the service flow
     * \param schedulingType the scheduling type
     * \param ulMapIe the UL map IE
     * \param modulationType the modulation type
     * \param symbolsToAllocation the symbols to allocation
     * \param availableSymbols the available symbols
     * \param allocationSizeBytes the allocation size in bytes
     * \returns true if successful
     */
    bool ServiceBandwidthRequestsBytes(ServiceFlow* serviceFlow,
                                       enum ServiceFlow::SchedulingType schedulingType,
                                       OfdmUlMapIe& ulMapIe,
                                       const WimaxPhy::ModulationType modulationType,
                                       uint32_t& symbolsToAllocation,
                                       uint32_t& availableSymbols,
                                       uint32_t allocationSizeBytes);

  private:
    std::list<OfdmUlMapIe> m_uplinkAllocations; ///< uplink allocations

    // queues for scheduler
    std::list<Ptr<UlJob>> m_uplinkJobs_high;  ///< uplink jobs high priority
    std::list<Ptr<UlJob>> m_uplinkJobs_inter; ///< uplink jobs intermedite priority
    std::list<Ptr<UlJob>> m_uplinkJobs_low;   ///< uplink jobs low priority

    // interval to reset window
    Time m_windowInterval; ///< windows interval
};

} // namespace ns3

#endif /* UPLINK_SCHEDULER_MBQOS_H */
