/*
 * Copyright (c) 2016 Sébastien Deronne
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Sébastien Deronne <sebastien.deronne@gmail.com>
 */

#include "ns3/boolean.h"
#include "ns3/command-line.h"
#include "ns3/config.h"
#include "ns3/internet-stack-helper.h"
#include "ns3/ipv4-address-helper.h"
#include "ns3/log.h"
#include "ns3/mobility-helper.h"
#include "ns3/packet-sink-helper.h"
#include "ns3/ssid.h"
#include "ns3/string.h"
#include "ns3/udp-client-server-helper.h"
#include "ns3/udp-server.h"
#include "ns3/uinteger.h"
#include "ns3/wifi-mac.h"
#include "ns3/wifi-net-device.h"
#include "ns3/yans-wifi-channel.h"
#include "ns3/yans-wifi-helper.h"

// This is an example that illustrates how 802.11n aggregation is configured.
// It defines 4 independent Wi-Fi networks (working on different channels).
// Each network contains one access point and one station. Each station
// continuously transmits data packets to its respective AP.
//
// Network topology (numbers in parentheses are channel numbers):
//
//  Network A (36)   Network B (40)   Network C (44)   Network D (48)
//   *      *          *      *         *      *          *      *
//   |      |          |      |         |      |          |      |
//  AP A   STA A      AP B   STA B     AP C   STA C      AP D   STA D
//
// The aggregation parameters are configured differently on the 4 stations:
// - station A uses default aggregation parameter values (A-MSDU disabled, A-MPDU enabled with
// maximum size of 65 kB);
// - station B doesn't use aggregation (both A-MPDU and A-MSDU are disabled);
// - station C enables A-MSDU (with maximum size of 8 kB) but disables A-MPDU;
// - station D uses two-level aggregation (A-MPDU with maximum size of 32 kB and A-MSDU with maximum
// size of 4 kB).
//
// Packets in this simulation belong to BestEffort Access Class (AC_BE).
//
// The user can select the distance between the stations and the APs and can enable/disable the
// RTS/CTS mechanism. Example: ./ns3 run "wifi-aggregation --distance=10 --enableRts=0
// --simulationTime=20s"
//
// The output prints the throughput measured for the 4 cases/networks described above. When default
// aggregation parameters are enabled, the maximum A-MPDU size is 65 kB and the throughput is
// maximal. When aggregation is disabled, the throughput is about the half of the physical bitrate.
// When only A-MSDU is enabled, the throughput is increased but is not maximal, since the maximum
// A-MSDU size is limited to 7935 bytes (whereas the maximum A-MPDU size is limited to 65535 bytes).
// When A-MSDU and A-MPDU are both enabled (= two-level aggregation), the throughput is slightly
// smaller than the first scenario since we set a smaller maximum A-MPDU size.
//
// When the distance is increased, the frame error rate gets higher, and the output shows how it
// affects the throughput for the 4 networks. Even through A-MSDU has less overheads than A-MPDU,
// A-MSDU is less robust against transmission errors than A-MPDU. When the distance is augmented,
// the throughput for the third scenario is more affected than the throughput obtained in other
// networks.

using namespace ns3;

NS_LOG_COMPONENT_DEFINE("SimpleMpduAggregation");

int
main(int argc, char* argv[])
{
    uint32_t payloadSize{1472}; // bytes
    Time simulationTime{"10s"};
    meter_u distance{5};
    bool enableRts{false};
    bool enablePcap{false};
    bool verifyResults{false}; // used for regression

    CommandLine cmd(__FILE__);
    cmd.AddValue("payloadSize", "Payload size in bytes", payloadSize);
    cmd.AddValue("enableRts", "Enable or disable RTS/CTS", enableRts);
    cmd.AddValue("simulationTime", "Simulation time", simulationTime);
    cmd.AddValue("distance",
                 "Distance in meters between the station and the access point",
                 distance);
    cmd.AddValue("enablePcap", "Enable/disable pcap file generation", enablePcap);
    cmd.AddValue("verifyResults",
                 "Enable/disable results verification at the end of the simulation",
                 verifyResults);
    cmd.Parse(argc, argv);

    Config::SetDefault("ns3::WifiRemoteStationManager::RtsCtsThreshold",
                       enableRts ? StringValue("0") : StringValue("999999"));

    NodeContainer wifiStaNodes;
    wifiStaNodes.Create(4);
    NodeContainer wifiApNodes;
    wifiApNodes.Create(4);

    YansWifiChannelHelper channel = YansWifiChannelHelper::Default();
    YansWifiPhyHelper phy;
    phy.SetPcapDataLinkType(WifiPhyHelper::DLT_IEEE802_11_RADIO);
    phy.SetChannel(channel.Create());

    WifiHelper wifi;
    wifi.SetStandard(WIFI_STANDARD_80211n);
    wifi.SetRemoteStationManager("ns3::ConstantRateWifiManager",
                                 "DataMode",
                                 StringValue("HtMcs7"),
                                 "ControlMode",
                                 StringValue("HtMcs0"));
    WifiMacHelper mac;

    NetDeviceContainer staDeviceA;
    NetDeviceContainer staDeviceB;
    NetDeviceContainer staDeviceC;
    NetDeviceContainer staDeviceD;
    NetDeviceContainer apDeviceA;
    NetDeviceContainer apDeviceB;
    NetDeviceContainer apDeviceC;
    NetDeviceContainer apDeviceD;
    Ssid ssid;

    // Network A
    ssid = Ssid("network-A");
    phy.Set("ChannelSettings", StringValue("{36, 0, BAND_5GHZ, 0}"));
    mac.SetType("ns3::StaWifiMac", "Ssid", SsidValue(ssid));
    staDeviceA = wifi.Install(phy, mac, wifiStaNodes.Get(0));

    mac.SetType("ns3::ApWifiMac",
                "Ssid",
                SsidValue(ssid),
                "EnableBeaconJitter",
                BooleanValue(false));
    apDeviceA = wifi.Install(phy, mac, wifiApNodes.Get(0));

    // Network B
    ssid = Ssid("network-B");
    phy.Set("ChannelSettings", StringValue("{40, 0, BAND_5GHZ, 0}"));
    mac.SetType("ns3::StaWifiMac", "Ssid", SsidValue(ssid));

    staDeviceB = wifi.Install(phy, mac, wifiStaNodes.Get(1));

    // Disable A-MPDU
    Ptr<NetDevice> dev = wifiStaNodes.Get(1)->GetDevice(0);
    Ptr<WifiNetDevice> wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(0));

    mac.SetType("ns3::ApWifiMac",
                "Ssid",
                SsidValue(ssid),
                "EnableBeaconJitter",
                BooleanValue(false));
    apDeviceB = wifi.Install(phy, mac, wifiApNodes.Get(1));

    // Disable A-MPDU
    dev = wifiApNodes.Get(1)->GetDevice(0);
    wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(0));

    // Network C
    ssid = Ssid("network-C");
    phy.Set("ChannelSettings", StringValue("{44, 0, BAND_5GHZ, 0}"));
    mac.SetType("ns3::StaWifiMac", "Ssid", SsidValue(ssid));

    staDeviceC = wifi.Install(phy, mac, wifiStaNodes.Get(2));

    // Disable A-MPDU and enable A-MSDU with the highest maximum size allowed by the standard (7935
    // bytes)
    dev = wifiStaNodes.Get(2)->GetDevice(0);
    wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(0));
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmsduSize", UintegerValue(7935));

    mac.SetType("ns3::ApWifiMac",
                "Ssid",
                SsidValue(ssid),
                "EnableBeaconJitter",
                BooleanValue(false));
    apDeviceC = wifi.Install(phy, mac, wifiApNodes.Get(2));

    // Disable A-MPDU and enable A-MSDU with the highest maximum size allowed by the standard (7935
    // bytes)
    dev = wifiApNodes.Get(2)->GetDevice(0);
    wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(0));
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmsduSize", UintegerValue(7935));

    // Network D
    ssid = Ssid("network-D");
    phy.Set("ChannelSettings", StringValue("{48, 0, BAND_5GHZ, 0}"));
    mac.SetType("ns3::StaWifiMac", "Ssid", SsidValue(ssid));

    staDeviceD = wifi.Install(phy, mac, wifiStaNodes.Get(3));

    // Enable A-MPDU with a smaller size than the default one and
    // enable A-MSDU with the smallest maximum size allowed by the standard (3839 bytes)
    dev = wifiStaNodes.Get(3)->GetDevice(0);
    wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(32768));
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmsduSize", UintegerValue(3839));

    mac.SetType("ns3::ApWifiMac",
                "Ssid",
                SsidValue(ssid),
                "EnableBeaconJitter",
                BooleanValue(false));
    apDeviceD = wifi.Install(phy, mac, wifiApNodes.Get(3));

    // Enable A-MPDU with a smaller size than the default one and
    // enable A-MSDU with the smallest maximum size allowed by the standard (3839 bytes)
    dev = wifiApNodes.Get(3)->GetDevice(0);
    wifi_dev = DynamicCast<WifiNetDevice>(dev);
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmpduSize", UintegerValue(32768));
    wifi_dev->GetMac()->SetAttribute("BE_MaxAmsduSize", UintegerValue(3839));

    // Setting mobility model
    MobilityHelper mobility;
    Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator>();
    mobility.SetMobilityModel("ns3::ConstantPositionMobilityModel");

    // Set position for APs
    positionAlloc->Add(Vector(0.0, 0.0, 0.0));
    positionAlloc->Add(Vector(10.0, 0.0, 0.0));
    positionAlloc->Add(Vector(20.0, 0.0, 0.0));
    positionAlloc->Add(Vector(30.0, 0.0, 0.0));
    // Set position for STAs
    positionAlloc->Add(Vector(distance, 0.0, 0.0));
    positionAlloc->Add(Vector(10 + distance, 0.0, 0.0));
    positionAlloc->Add(Vector(20 + distance, 0.0, 0.0));
    positionAlloc->Add(Vector(30 + distance, 0.0, 0.0));

    mobility.SetPositionAllocator(positionAlloc);
    mobility.Install(wifiApNodes);
    mobility.Install(wifiStaNodes);

    // Internet stack
    InternetStackHelper stack;
    stack.Install(wifiApNodes);
    stack.Install(wifiStaNodes);

    Ipv4AddressHelper address;
    address.SetBase("192.168.1.0", "255.255.255.0");
    Ipv4InterfaceContainer StaInterfaceA;
    StaInterfaceA = address.Assign(staDeviceA);
    Ipv4InterfaceContainer ApInterfaceA;
    ApInterfaceA = address.Assign(apDeviceA);

    address.SetBase("192.168.2.0", "255.255.255.0");
    Ipv4InterfaceContainer StaInterfaceB;
    StaInterfaceB = address.Assign(staDeviceB);
    Ipv4InterfaceContainer ApInterfaceB;
    ApInterfaceB = address.Assign(apDeviceB);

    address.SetBase("192.168.3.0", "255.255.255.0");
    Ipv4InterfaceContainer StaInterfaceC;
    StaInterfaceC = address.Assign(staDeviceC);
    Ipv4InterfaceContainer ApInterfaceC;
    ApInterfaceC = address.Assign(apDeviceC);

    address.SetBase("192.168.4.0", "255.255.255.0");
    Ipv4InterfaceContainer StaInterfaceD;
    StaInterfaceD = address.Assign(staDeviceD);
    Ipv4InterfaceContainer ApInterfaceD;
    ApInterfaceD = address.Assign(apDeviceD);

    // Setting applications
    uint16_t port = 9;
    UdpServerHelper serverA(port);
    ApplicationContainer serverAppA = serverA.Install(wifiStaNodes.Get(0));
    serverAppA.Start(Seconds(0));
    serverAppA.Stop(simulationTime + Seconds(1));

    UdpClientHelper clientA(StaInterfaceA.GetAddress(0), port);
    clientA.SetAttribute("MaxPackets", UintegerValue(4294967295U));
    clientA.SetAttribute("Interval", TimeValue(Time("0.0001"))); // packets/s
    clientA.SetAttribute("PacketSize", UintegerValue(payloadSize));

    ApplicationContainer clientAppA = clientA.Install(wifiApNodes.Get(0));
    clientAppA.Start(Seconds(1));
    clientAppA.Stop(simulationTime + Seconds(1));

    UdpServerHelper serverB(port);
    ApplicationContainer serverAppB = serverB.Install(wifiStaNodes.Get(1));
    serverAppB.Start(Seconds(0));
    serverAppB.Stop(simulationTime + Seconds(1));

    UdpClientHelper clientB(StaInterfaceB.GetAddress(0), port);
    clientB.SetAttribute("MaxPackets", UintegerValue(4294967295U));
    clientB.SetAttribute("Interval", TimeValue(Time("0.0001"))); // packets/s
    clientB.SetAttribute("PacketSize", UintegerValue(payloadSize));

    ApplicationContainer clientAppB = clientB.Install(wifiApNodes.Get(1));
    clientAppB.Start(Seconds(1));
    clientAppB.Stop(simulationTime + Seconds(1));

    UdpServerHelper serverC(port);
    ApplicationContainer serverAppC = serverC.Install(wifiStaNodes.Get(2));
    serverAppC.Start(Seconds(0));
    serverAppC.Stop(simulationTime + Seconds(1));

    UdpClientHelper clientC(StaInterfaceC.GetAddress(0), port);
    clientC.SetAttribute("MaxPackets", UintegerValue(4294967295U));
    clientC.SetAttribute("Interval", TimeValue(Time("0.0001"))); // packets/s
    clientC.SetAttribute("PacketSize", UintegerValue(payloadSize));

    ApplicationContainer clientAppC = clientC.Install(wifiApNodes.Get(2));
    clientAppC.Start(Seconds(1));
    clientAppC.Stop(simulationTime + Seconds(1));

    UdpServerHelper serverD(port);
    ApplicationContainer serverAppD = serverD.Install(wifiStaNodes.Get(3));
    serverAppD.Start(Seconds(0));
    serverAppD.Stop(simulationTime + Seconds(1));

    UdpClientHelper clientD(StaInterfaceD.GetAddress(0), port);
    clientD.SetAttribute("MaxPackets", UintegerValue(4294967295U));
    clientD.SetAttribute("Interval", TimeValue(Time("0.0001"))); // packets/s
    clientD.SetAttribute("PacketSize", UintegerValue(payloadSize));

    ApplicationContainer clientAppD = clientD.Install(wifiApNodes.Get(3));
    clientAppD.Start(Seconds(1));
    clientAppD.Stop(simulationTime + Seconds(1));

    if (enablePcap)
    {
        phy.EnablePcap("AP_A", apDeviceA.Get(0));
        phy.EnablePcap("STA_A", staDeviceA.Get(0));
        phy.EnablePcap("AP_B", apDeviceB.Get(0));
        phy.EnablePcap("STA_B", staDeviceB.Get(0));
        phy.EnablePcap("AP_C", apDeviceC.Get(0));
        phy.EnablePcap("STA_C", staDeviceC.Get(0));
        phy.EnablePcap("AP_D", apDeviceD.Get(0));
        phy.EnablePcap("STA_D", staDeviceD.Get(0));
    }

    Simulator::Stop(simulationTime + Seconds(1));
    Simulator::Run();

    // Show results
    double totalPacketsThroughA = DynamicCast<UdpServer>(serverAppA.Get(0))->GetReceived();
    double totalPacketsThroughB = DynamicCast<UdpServer>(serverAppB.Get(0))->GetReceived();
    double totalPacketsThroughC = DynamicCast<UdpServer>(serverAppC.Get(0))->GetReceived();
    double totalPacketsThroughD = DynamicCast<UdpServer>(serverAppD.Get(0))->GetReceived();

    Simulator::Destroy();

    auto throughput = totalPacketsThroughA * payloadSize * 8 / simulationTime.GetMicroSeconds();
    std::cout << "Throughput with default configuration (A-MPDU aggregation enabled, 65kB): "
              << throughput << " Mbit/s" << '\n';
    if (verifyResults && (throughput < 59.0 || throughput > 60.0))
    {
        NS_LOG_ERROR("Obtained throughput " << throughput << " is not in the expected boundaries!");
        exit(1);
    }

    throughput = totalPacketsThroughB * payloadSize * 8 / simulationTime.GetMicroSeconds();
    std::cout << "Throughput with aggregation disabled: " << throughput << " Mbit/s" << '\n';
    if (verifyResults && (throughput < 30 || throughput > 31))
    {
        NS_LOG_ERROR("Obtained throughput " << throughput << " is not in the expected boundaries!");
        exit(1);
    }

    throughput = totalPacketsThroughC * payloadSize * 8 / simulationTime.GetMicroSeconds();
    std::cout << "Throughput with A-MPDU disabled and A-MSDU enabled (8kB): " << throughput
              << " Mbit/s" << '\n';
    if (verifyResults && (throughput < 51 || throughput > 52))
    {
        NS_LOG_ERROR("Obtained throughput " << throughput << " is not in the expected boundaries!");
        exit(1);
    }

    throughput = totalPacketsThroughD * payloadSize * 8 / simulationTime.GetMicroSeconds();
    std::cout << "Throughput with A-MPDU enabled (32kB) and A-MSDU enabled (4kB): " << throughput
              << " Mbit/s" << '\n';
    if (verifyResults && (throughput < 58 || throughput > 59))
    {
        NS_LOG_ERROR("Obtained throughput " << throughput << " is not in the expected boundaries!");
        exit(1);
    }

    return 0;
}