/*
 * SPDX-License-Identifier: GPL-2.0-only
 */

#include "mpi-test-fixtures.h"

#include "ns3/applications-module.h"
#include "ns3/core-module.h"
#include "ns3/csma-module.h"
#include "ns3/internet-module.h"
#include "ns3/mobility-module.h"
#include "ns3/mpi-module.h"
#include "ns3/network-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/ssid.h"
#include "ns3/yans-wifi-helper.h"

#include <iomanip>

/**
 * @file
 * @ingroup mpi
 *
 * Distributed version of third.cc from the tutorial.
 *
 *  Default Network Topology
 *
 * (same as third.cc from tutorial)
 * Distributed simulation, split across the p2p link
 *                          |
 *                 Rank 0   |   Rank 1
 * -------------------------|----------------------------
 *   Wifi 10.1.3.0
 *                 AP
 *  *    *    *    *
 *  |    |    |    |    10.1.1.0
 * n5   n6   n7   n0 -------------- n1   n2   n3   n4
 *                   point-to-point  |    |    |    |
 *                                   ================
 *                                    LAN 10.1.2.0
 */

using namespace ns3;

NS_LOG_COMPONENT_DEFINE("ThirdExampleDistributed");

int
main(int argc, char* argv[])
{
    bool verbose = false;
    uint32_t nCsma = 3;
    uint32_t nWifi = 3;
    bool tracing = false;
    bool nullmsg = false;
    bool testing = false;

    CommandLine cmd(__FILE__);
    cmd.AddValue("nCsma", "Number of \"extra\" CSMA nodes/devices", nCsma);
    cmd.AddValue("nWifi", "Number of wifi STA devices", nWifi);
    cmd.AddValue("verbose", "Tell echo applications to log if true", verbose);
    cmd.AddValue("tracing", "Enable pcap tracing", tracing);
    cmd.AddValue("nullmsg", "Enable the use of null-message synchronization", nullmsg);
    cmd.AddValue("test", "Enable regression test output", testing);

    cmd.Parse(argc, argv);

    // The underlying restriction of 18 is due to the grid position
    // allocator's configuration; the grid layout will exceed the
    // bounding box if more than 18 nodes are provided.
    if (nWifi > 18)
    {
        std::cout << "nWifi should be 18 or less; otherwise grid layout exceeds the bounding box"
                  << std::endl;
        return 1;
    }

    if (verbose)
    {
        LogComponentEnable("UdpEchoClientApplication",
                           (LogLevel)(LOG_LEVEL_INFO | LOG_PREFIX_NODE | LOG_PREFIX_TIME));
        LogComponentEnable("UdpEchoServerApplication",
                           (LogLevel)(LOG_LEVEL_INFO | LOG_PREFIX_NODE | LOG_PREFIX_TIME));
    }

    // Sequential fallback values
    uint32_t systemId = 0;
    uint32_t systemCount = 1;

    // Distributed simulation setup; by default use granted time window algorithm.
    if (nullmsg)
    {
        GlobalValue::Bind("SimulatorImplementationType",
                          StringValue("ns3::NullMessageSimulatorImpl"));
    }
    else
    {
        GlobalValue::Bind("SimulatorImplementationType",
                          StringValue("ns3::DistributedSimulatorImpl"));
    }

    MpiInterface::Enable(&argc, &argv);

    SinkTracer::Init();

    systemId = MpiInterface::GetSystemId();
    systemCount = MpiInterface::GetSize();

    // Check for valid distributed parameters.
    // Must have 2 and only 2 Logical Processors (LPs)
    if (systemCount != 2)
    {
        std::cout << "This simulation requires 2 and only 2 logical processors." << std::endl;
        return 1;
    }

    // System id of Wifi side
    uint32_t systemWifi = 0;

    // System id of CSMA side
    uint32_t systemCsma = systemCount - 1;

    NodeContainer p2pNodes;
    // Create each end of the P2P link on a separate system (rank)
    Ptr<Node> p2pNode1 = CreateObject<Node>(systemWifi);
    Ptr<Node> p2pNode2 = CreateObject<Node>(systemCsma);
    p2pNodes.Add(p2pNode1);
    p2pNodes.Add(p2pNode2);

    PointToPointHelper pointToPoint;
    pointToPoint.SetDeviceAttribute("DataRate", StringValue("5Mbps"));
    pointToPoint.SetChannelAttribute("Delay", StringValue("2ms"));

    NetDeviceContainer p2pDevices;
    p2pDevices = pointToPoint.Install(p2pNodes);

    NodeContainer csmaNodes;
    csmaNodes.Add(p2pNodes.Get(1));
    // Create the csma nodes on one system (rank)
    csmaNodes.Create(nCsma, systemCsma);

    CsmaHelper csma;
    csma.SetChannelAttribute("DataRate", StringValue("100Mbps"));
    csma.SetChannelAttribute("Delay", TimeValue(NanoSeconds(6560)));

    NetDeviceContainer csmaDevices;
    csmaDevices = csma.Install(csmaNodes);

    NodeContainer wifiStaNodes;
    // Create the wifi nodes on the other system (rank)
    wifiStaNodes.Create(nWifi, systemWifi);
    NodeContainer wifiApNode = p2pNodes.Get(0);

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

    WifiMacHelper mac;
    Ssid ssid = Ssid("ns-3-ssid");

    WifiHelper wifi;

    NetDeviceContainer staDevices;
    mac.SetType("ns3::StaWifiMac", "Ssid", SsidValue(ssid), "ActiveProbing", BooleanValue(false));
    staDevices = wifi.Install(phy, mac, wifiStaNodes);

    NetDeviceContainer apDevices;
    mac.SetType("ns3::ApWifiMac", "Ssid", SsidValue(ssid));
    apDevices = wifi.Install(phy, mac, wifiApNode);

    MobilityHelper mobility;

    mobility.SetPositionAllocator("ns3::GridPositionAllocator",
                                  "MinX",
                                  DoubleValue(0.0),
                                  "MinY",
                                  DoubleValue(0.0),
                                  "DeltaX",
                                  DoubleValue(5.0),
                                  "DeltaY",
                                  DoubleValue(10.0),
                                  "GridWidth",
                                  UintegerValue(3),
                                  "LayoutType",
                                  StringValue("RowFirst"));

    mobility.SetMobilityModel("ns3::RandomWalk2dMobilityModel",
                              "Bounds",
                              RectangleValue(Rectangle(-50, 50, -50, 50)));
    mobility.Install(wifiStaNodes);

    mobility.SetMobilityModel("ns3::ConstantPositionMobilityModel");
    mobility.Install(wifiApNode);

    InternetStackHelper stack;
    stack.Install(csmaNodes);
    stack.Install(wifiApNode);
    stack.Install(wifiStaNodes);

    Ipv4AddressHelper address;

    address.SetBase("10.1.1.0", "255.255.255.0");
    Ipv4InterfaceContainer p2pInterfaces;
    p2pInterfaces = address.Assign(p2pDevices);

    address.SetBase("10.1.2.0", "255.255.255.0");
    Ipv4InterfaceContainer csmaInterfaces;
    csmaInterfaces = address.Assign(csmaDevices);

    address.SetBase("10.1.3.0", "255.255.255.0");
    address.Assign(staDevices);
    address.Assign(apDevices);

    // If this rank is systemCsma,
    // it should contain the server application,
    // since it is on one of the csma nodes
    if (systemId == systemCsma)
    {
        UdpEchoServerHelper echoServer(9);

        ApplicationContainer serverApps = echoServer.Install(csmaNodes.Get(nCsma));
        serverApps.Start(Seconds(1));
        serverApps.Stop(Seconds(10));

        if (testing)
        {
            serverApps.Get(0)->TraceConnectWithoutContext("RxWithAddresses",
                                                          MakeCallback(&SinkTracer::SinkTrace));
        }
    }

    // If this rank is systemWifi
    // it should contain the client application,
    // since it is on one of the wifi nodes
    if (systemId == systemWifi)
    {
        UdpEchoClientHelper echoClient(csmaInterfaces.GetAddress(nCsma), 9);
        echoClient.SetAttribute("MaxPackets", UintegerValue(1));
        echoClient.SetAttribute("Interval", TimeValue(Seconds(1)));
        echoClient.SetAttribute("PacketSize", UintegerValue(1024));

        ApplicationContainer clientApps = echoClient.Install(wifiStaNodes.Get(nWifi - 1));
        clientApps.Start(Seconds(2));
        clientApps.Stop(Seconds(10));

        if (testing)
        {
            clientApps.Get(0)->TraceConnectWithoutContext("RxWithAddresses",
                                                          MakeCallback(&SinkTracer::SinkTrace));
        }
    }

    Ipv4GlobalRoutingHelper::PopulateRoutingTables();

    Simulator::Stop(Seconds(10));

    if (tracing)
    {
        // Depending on the system Id (rank), the pcap information
        // traced will be different.  For example, the ethernet pcap
        // will be empty for rank0, since these nodes are placed on
        // on rank 1.  All ethernet traffic will take place on rank 1.
        // Similar differences are seen in the p2p and wireless pcaps.
        if (systemId == systemCsma)
        {
            pointToPoint.EnablePcapAll("third-distributed-csma");
            phy.EnablePcap("third-distributed-csma", apDevices.Get(0));
            csma.EnablePcap("third-distributed-csma", csmaDevices.Get(0), true);
        }
        else // systemWifi
        {
            pointToPoint.EnablePcapAll("third-distributed-wifi");
            phy.EnablePcap("third-distributed-wifi", apDevices.Get(0));
            csma.EnablePcap("third-distributed-wifi", csmaDevices.Get(0), true);
        }
    }

    Simulator::Run();
    Simulator::Destroy();

    if (testing)
    {
        SinkTracer::Verify(2);
    }

    // Exit the MPI execution environment
    MpiInterface::Disable();

    return 0;
}
