/*
 * Copyright (c) 2017 Universita' degli Studi di Napoli Federico II
 *
 * 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
 *
 * Author: Stefano Avallone <stefano.avallone@.unina.it>
 */

#include "ns3/net-device-queue-interface.h"

#include "ns3/abort.h"
#include "ns3/queue-item.h"
#include "ns3/queue-limits.h"
#include "ns3/simulator.h"
#include "ns3/uinteger.h"

namespace ns3
{

NS_LOG_COMPONENT_DEFINE("NetDeviceQueueInterface");

TypeId
NetDeviceQueue::GetTypeId()
{
    static TypeId tid = TypeId("ns3::NetDeviceQueue")
                            .SetParent<Object>()
                            .SetGroupName("Network")
                            .AddConstructor<NetDeviceQueue>();
    return tid;
}

NetDeviceQueue::NetDeviceQueue()
    : m_stoppedByDevice(false),
      m_stoppedByQueueLimits(false),
      NS_LOG_TEMPLATE_DEFINE("NetDeviceQueueInterface")
{
    NS_LOG_FUNCTION(this);
}

NetDeviceQueue::~NetDeviceQueue()
{
    NS_LOG_FUNCTION(this);

    m_queueLimits = nullptr;
    m_wakeCallback.Nullify();
    m_device = nullptr;
}

bool
NetDeviceQueue::IsStopped() const
{
    NS_LOG_FUNCTION(this);
    return m_stoppedByDevice || m_stoppedByQueueLimits;
}

void
NetDeviceQueue::Start()
{
    NS_LOG_FUNCTION(this);
    m_stoppedByDevice = false;
}

void
NetDeviceQueue::Stop()
{
    NS_LOG_FUNCTION(this);
    m_stoppedByDevice = true;
}

void
NetDeviceQueue::Wake()
{
    NS_LOG_FUNCTION(this);

    bool wasStoppedByDevice = m_stoppedByDevice;
    m_stoppedByDevice = false;

    // Request the queue disc to dequeue a packet
    if (wasStoppedByDevice && !m_wakeCallback.IsNull())
    {
        Simulator::ScheduleNow(&NetDeviceQueue::m_wakeCallback, this);
    }
}

void
NetDeviceQueue::NotifyAggregatedObject(Ptr<NetDeviceQueueInterface> ndqi)
{
    NS_LOG_FUNCTION(this << ndqi);

    m_device = ndqi->GetObject<NetDevice>();
    NS_ABORT_MSG_IF(!m_device, "No NetDevice object was aggregated to the NetDeviceQueueInterface");
}

void
NetDeviceQueue::SetWakeCallback(WakeCallback cb)
{
    m_wakeCallback = cb;
}

void
NetDeviceQueue::NotifyQueuedBytes(uint32_t bytes)
{
    NS_LOG_FUNCTION(this << bytes);
    if (!m_queueLimits)
    {
        return;
    }
    m_queueLimits->Queued(bytes);
    if (m_queueLimits->Available() >= 0)
    {
        return;
    }
    m_stoppedByQueueLimits = true;
}

void
NetDeviceQueue::NotifyTransmittedBytes(uint32_t bytes)
{
    NS_LOG_FUNCTION(this << bytes);
    if ((!m_queueLimits) || (!bytes))
    {
        return;
    }
    m_queueLimits->Completed(bytes);
    if (m_queueLimits->Available() < 0)
    {
        return;
    }
    bool wasStoppedByQueueLimits = m_stoppedByQueueLimits;
    m_stoppedByQueueLimits = false;
    // Request the queue disc to dequeue a packet
    if (wasStoppedByQueueLimits && !m_wakeCallback.IsNull())
    {
        Simulator::ScheduleNow(&NetDeviceQueue::m_wakeCallback, this);
    }
}

void
NetDeviceQueue::ResetQueueLimits()
{
    NS_LOG_FUNCTION(this);
    if (!m_queueLimits)
    {
        return;
    }
    m_queueLimits->Reset();
}

void
NetDeviceQueue::SetQueueLimits(Ptr<QueueLimits> ql)
{
    NS_LOG_FUNCTION(this << ql);
    m_queueLimits = ql;
}

Ptr<QueueLimits>
NetDeviceQueue::GetQueueLimits()
{
    NS_LOG_FUNCTION(this);
    return m_queueLimits;
}

NS_OBJECT_ENSURE_REGISTERED(NetDeviceQueueInterface);

TypeId
NetDeviceQueueInterface::GetTypeId()
{
    static TypeId tid =
        TypeId("ns3::NetDeviceQueueInterface")
            .SetParent<Object>()
            .SetGroupName("Network")
            .AddConstructor<NetDeviceQueueInterface>()
            .AddAttribute("TxQueuesType",
                          "The type of transmission queues to be used",
                          TypeId::ATTR_CONSTRUCT,
                          TypeIdValue(NetDeviceQueue::GetTypeId()),
                          MakeTypeIdAccessor(&NetDeviceQueueInterface::SetTxQueuesType),
                          MakeTypeIdChecker())
            .AddAttribute("NTxQueues",
                          "The number of device transmission queues",
                          TypeId::ATTR_GET | TypeId::ATTR_CONSTRUCT,
                          UintegerValue(1),
                          MakeUintegerAccessor(&NetDeviceQueueInterface::SetNTxQueues,
                                               &NetDeviceQueueInterface::GetNTxQueues),
                          MakeUintegerChecker<uint16_t>(1, 65535));
    return tid;
}

NetDeviceQueueInterface::NetDeviceQueueInterface()
{
    NS_LOG_FUNCTION(this);

    // the default select queue callback returns 0
    m_selectQueueCallback = [](Ptr<QueueItem> item) { return 0; };
}

NetDeviceQueueInterface::~NetDeviceQueueInterface()
{
    NS_LOG_FUNCTION(this);
}

Ptr<NetDeviceQueue>
NetDeviceQueueInterface::GetTxQueue(std::size_t i) const
{
    NS_ASSERT(i < m_txQueuesVector.size());
    return m_txQueuesVector[i];
}

std::size_t
NetDeviceQueueInterface::GetNTxQueues() const
{
    return m_txQueuesVector.size();
}

void
NetDeviceQueueInterface::DoDispose()
{
    NS_LOG_FUNCTION(this);

    m_txQueuesVector.clear();
    Object::DoDispose();
}

void
NetDeviceQueueInterface::NotifyNewAggregate()
{
    NS_LOG_FUNCTION(this);

    // Notify the NetDeviceQueue objects that an object was aggregated
    for (auto& tx : m_txQueuesVector)
    {
        tx->NotifyAggregatedObject(this);
    }
    Object::NotifyNewAggregate();
}

void
NetDeviceQueueInterface::SetTxQueuesType(TypeId type)
{
    NS_LOG_FUNCTION(this << type);

    NS_ABORT_MSG_IF(!m_txQueuesVector.empty(),
                    "Cannot call SetTxQueuesType after creating device queues");

    m_txQueues = ObjectFactory();
    m_txQueues.SetTypeId(type);
}

void
NetDeviceQueueInterface::SetNTxQueues(std::size_t numTxQueues)
{
    NS_LOG_FUNCTION(this << numTxQueues);
    NS_ASSERT(numTxQueues > 0);

    NS_ABORT_MSG_IF(!m_txQueuesVector.empty(),
                    "Cannot call SetNTxQueues after creating device queues");

    // create the netdevice queues
    for (std::size_t i = 0; i < numTxQueues; i++)
    {
        m_txQueuesVector.push_back(m_txQueues.Create()->GetObject<NetDeviceQueue>());
    }
}

void
NetDeviceQueueInterface::SetSelectQueueCallback(SelectQueueCallback cb)
{
    m_selectQueueCallback = cb;
}

NetDeviceQueueInterface::SelectQueueCallback
NetDeviceQueueInterface::GetSelectQueueCallback() const
{
    return m_selectQueueCallback;
}

} // namespace ns3