#include "win32.hpp"
#include <llarp/win32/windivert.hpp>
#include <llarp/win32/wintun.hpp>
#include <fmt/core.h>

namespace llarp::win32
{
  namespace
  {
    template <typename T>
    std::string
    ip_to_string(T ip)
    {
      return var::visit([](auto&& ip) { return ip.ToString(); }, ip);
    }
  }  // namespace

  void
  VPNPlatform::make_route(std::string ip, std::string gw, std::string cmd)
  {
    llarp::win32::Exec(
        "route.exe", fmt::format("{} {} MASK 255.255.255.255 {} METRIC {}", cmd, ip, gw, m_Metric));
  }

  void
  VPNPlatform::default_route_via_interface(NetworkInterface& vpn, std::string cmd)
  {
    // route hole for loopback bacause god is dead on windows
    llarp::win32::Exec("route.exe", fmt::format("{} 127.0.0.0 MASK 255.0.0.0 0.0.0.0", cmd));
    // set up ipv4 routes
    route_via_interface(vpn, "0.0.0.0", "128.0.0.0", cmd);
    route_via_interface(vpn, "128.0.0.0", "128.0.0.0", cmd);
  }

  void
  VPNPlatform::route_via_interface(
      NetworkInterface& vpn, std::string addr, std::string mask, std::string cmd)
  {
    const auto& info = vpn.Info();
    auto ifaddr = ip_to_string(info[0]);
    // this changes the last 1 to a 0 so that it routes over the interface
    // this is required because windows is idiotic af
    ifaddr.back()--;
    llarp::win32::Exec(
        "route.exe", fmt::format("{} {} MASK {} {} METRIC {}", cmd, addr, mask, ifaddr, m_Metric));
  }

  void
  VPNPlatform::add_route(oxen::quic::Address ip, oxen::quic::Address gateway)
  {
    make_route(ip.to_string(), gateway.to_string(), "ADD");
  }

  void
  VPNPlatform::delete_route(oxen::quic::Address ip, oxen::quic::Address gateway)
  {
    make_route(ip.to_string(), gateway.to_string(), "DELETE");
  }

  void
  VPNPlatform::add_route_via_interface(NetworkInterface& vpn, IPRange range)
  {
    route_via_interface(vpn, range.BaseAddressString(), range.NetmaskString(), "ADD");
  }

  void
  VPNPlatform::delete_route_via_interface(NetworkInterface& vpn, IPRange range)
  {
    route_via_interface(vpn, range.BaseAddressString(), range.NetmaskString(), "DELETE");
  }

  std::vector<oxen::quic::Address>
  VPNPlatform::get_non_interface_gateways(NetworkInterface& vpn)
  {
    std::set<oxen::quic::Address> gateways;

    const auto ifaddr = vpn.Info()[0];
    for (const auto& iface : Net().AllNetworkInterfaces())
    {
      if (not iface.gateway)
        continue;

      bool b = true;

      for (const auto& range : iface.addrs)
      {
        if (not range.Contains(ifaddr))
          b = false;
      }
      if (b)
        gateways.emplace(*iface.gateway);
    }
    return {gateways.begin(), gateways.end()};
  }

  void
  VPNPlatform::add_default_route_via_interface(NetworkInterface& vpn)
  {
    // kill ipv6
    llarp::win32::Exec(
        "WindowsPowerShell\\v1.0\\powershell.exe",
        "-Command (Disable-NetAdapterBinding -Name \"* \" -ComponentID ms_tcpip6)");

    default_route_via_interface(vpn, "ADD");
  }

  void
  VPNPlatform::delete_default_route_via_interface(NetworkInterface& vpn)
  {
    // restore ipv6
    llarp::win32::Exec(
        "WindowsPowerShell\\v1.0\\powershell.exe",
        "-Command (Enable-NetAdapterBinding -Name \"* \" -ComponentID ms_tcpip6)");

    default_route_via_interface(vpn, "DELETE");
  }

  std::shared_ptr<NetworkInterface>
  VPNPlatform::ObtainInterface(InterfaceInfo info, Router* router)
  {
    return wintun::make_interface(std::move(info), router);
  }

  std::shared_ptr<I_Packet_IO>
  VPNPlatform::create_packet_io(
      unsigned int ifindex, const std::optional<SockAddr>& dns_upstream_src)
  {
    // we only want do this on all interfaes with windivert
    if (ifindex)
      throw std::invalid_argument{
          "cannot create packet io on explicitly specified interface, not currently supported on "
          "windows (yet)"};

    uint16_t upstream_src_port = dns_upstream_src ? dns_upstream_src->getPort() : 0;
    std::string udp_filter = upstream_src_port != 0
        ? fmt::format("( udp.DstPort == 53 and udp.SrcPort != {} )", upstream_src_port)
        : "udp.DstPort == 53";

    auto filter = "outbound and ( " + udp_filter + " or tcp.DstPort == 53 )";

    return WinDivert::make_interceptor(filter, [router = _ctx->router] { router->TriggerPump(); });
  }
}  // namespace llarp::win32