// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <cstring>
#include <exception>
#include <string>

// #include <cstddef>
#include "absl/strings/str_format.h"
#include "internal/platform/implementation/wifi.h"
#include "internal/platform/implementation/wifi_utils.h"
#include "internal/platform/implementation/windows/utils.h"
#include "internal/platform/implementation/windows/wifi.h"
#include "internal/platform/logging.h"

namespace nearby {
namespace windows {

namespace {
constexpr int kMacAddrLen = 6;
constexpr int kDefaultApFreq = -1;
constexpr int kUseEthernet = -2;
}  // namespace

WifiMedium::WifiMedium() { InitCapability(); }

PWLAN_INTERFACE_INFO_LIST EnumInterface(PHANDLE client_handle) {
  DWORD client_version = 2;
  DWORD negotiated_version = 0;
  DWORD result = 0;

  /* variables used for WlanEnumInterfaces */
  PWLAN_INTERFACE_INFO_LIST p_intf_list = nullptr;

  result = WlanOpenHandle(client_version, nullptr, &negotiated_version,
                          client_handle);
  if (result != ERROR_SUCCESS) {
    LOG(INFO) << "WlanOpenHandle failed with error: " << result;
    return p_intf_list;
  }

  result = WlanEnumInterfaces(*client_handle, nullptr, &p_intf_list);
  if (result != ERROR_SUCCESS) {
    LOG(INFO) << "WlanEnumInterfaces failed with error: " << result;
  }
  return p_intf_list;
}

bool WifiMedium::IsInterfaceValid() const { return wifi_interface_valid_; }

void WifiMedium::InitCapability() {
  HANDLE client_handle = nullptr;

  /* variables used for WlanEnumInterfaces */
  PWLAN_INTERFACE_INFO_LIST p_intf_list = nullptr;
  PWLAN_INTERFACE_INFO p_intf_info = nullptr;
  PWLAN_INTERFACE_CAPABILITY p_intf_capability = nullptr;

  wifi_capability_.supports_5_ghz = false;
  wifi_capability_.supports_6_ghz = false;
  wifi_interface_valid_ = false;

  p_intf_list = EnumInterface(&client_handle);
  if (!client_handle) {
    LOG(INFO)
        << "Client Handle is null, wifi maybe not supported on this device.";
    return;
  }
  if (!p_intf_list) {
    WlanCloseHandle(client_handle, nullptr);
    return;
  }
  wifi_interface_valid_ = true;

  for (int i = 0; i < (int)p_intf_list->dwNumberOfItems; i++) {
    p_intf_info = (WLAN_INTERFACE_INFO*)&p_intf_list->InterfaceInfo[i];
    if (WlanGetInterfaceCapability(client_handle, &p_intf_info->InterfaceGuid,
                                   nullptr,
                                   &p_intf_capability) != ERROR_SUCCESS) {
      LOG(INFO) << "Get Capability failed";
      WlanFreeMemory(p_intf_list);
      p_intf_list = nullptr;
      WlanCloseHandle(client_handle, nullptr);
      return;
    }

    for (int j = 0; j < p_intf_capability->dwNumberOfSupportedPhys; j++) {
      if (p_intf_capability->dot11PhyTypes[j] == dot11_phy_type_ofdm)
        wifi_capability_.supports_5_ghz = true;
    }
  }

  WlanFreeMemory(p_intf_capability);
  p_intf_capability = nullptr;
  WlanFreeMemory(p_intf_list);
  p_intf_list = nullptr;
  WlanCloseHandle(client_handle, nullptr);
}

// TODO(b/259414512): the return type should be optional.
api::WifiInformation& WifiMedium::GetInformation() {
  HANDLE client_handle = nullptr;
  PWLAN_AVAILABLE_NETWORK_LIST pWLAN_AVAILABLE_NETWORK_LIST = nullptr;
  DWORD result = 0;
  DWORD connect_info_size = sizeof(WLAN_CONNECTION_ATTRIBUTES);
  WLAN_OPCODE_VALUE_TYPE op_code_value_type = wlan_opcode_value_type_invalid;

  /* variables used for WlanEnumInterfaces */
  PWLAN_INTERFACE_INFO_LIST p_intf_list = nullptr;
  PWLAN_INTERFACE_INFO p_intf_info = nullptr;
  PWLAN_CONNECTION_ATTRIBUTES p_connect_info = nullptr;
  ULONG* channel = nullptr;

  wifi_information_.is_connected = false;
  wifi_information_.ap_frequency = kDefaultApFreq;
  wifi_information_.ssid.clear();
  wifi_information_.bssid.clear();
  wifi_information_.ip_address_dot_decimal.clear();
  wifi_information_.ip_address_4_bytes.clear();

  p_intf_list = EnumInterface(&client_handle);
  if (!client_handle) {
    LOG(INFO) << "Client Handle is nullptr";
    FillupEthernetParams();
    return wifi_information_;
  }
  if (!p_intf_list) {
    LOG(INFO) << "WlanEnumInterfaces failed with error: ";
    WlanCloseHandle(client_handle, nullptr);
    FillupEthernetParams();
    return wifi_information_;
  }

  for (int i = 0; i < (int)p_intf_list->dwNumberOfItems; i++) {
    p_intf_info = (WLAN_INTERFACE_INFO*)&p_intf_list->InterfaceInfo[i];
    if (p_intf_info->isState == wlan_interface_state_connected) {
      LOG(INFO) << "Found connected WiFi interface No: " << i;
      wifi_information_.is_connected = true;

      DWORD channel_size;
      result = WlanQueryInterface(client_handle, &p_intf_info->InterfaceGuid,
                                  wlan_intf_opcode_channel_number, nullptr,
                                  &channel_size, (PVOID*)&channel,
                                  &op_code_value_type);
      if (result != ERROR_SUCCESS) {
        LOG(INFO) << "WlanQueryInterface channel error = " << result;
        WlanFreeMemory(p_intf_list);
        p_intf_list = nullptr;
        WlanCloseHandle(client_handle, nullptr);
        FillupEthernetParams();
        return wifi_information_;
      }
      wifi_information_.ap_frequency = WifiUtils::ConvertChannelToFrequencyMhz(
          *channel, api::WifiBandType::kUnknown);
      LOG(INFO) << "Channel: " << (channel == nullptr ? 0 : *channel)
                << "; ap_frequency: " << wifi_information_.ap_frequency;
      WlanFreeMemory(channel);
      channel = nullptr;

      result = WlanQueryInterface(client_handle, &p_intf_info->InterfaceGuid,
                                  wlan_intf_opcode_current_connection, nullptr,
                                  &connect_info_size, (PVOID*)&p_connect_info,
                                  &op_code_value_type);
      if (result != ERROR_SUCCESS) {
        LOG(INFO) << "WlanQueryInterface current AP error = " << result;
        WlanFreeMemory(p_intf_list);
        p_intf_list = nullptr;
        WlanCloseHandle(client_handle, nullptr);
        FillupEthernetParams();
        return wifi_information_;
      }

      wifi_information_.ssid.resize(
          p_connect_info->wlanAssociationAttributes.dot11Ssid.uSSIDLength);
      std::memcpy(
          wifi_information_.ssid.data(),
          reinterpret_cast<const char*>(
              p_connect_info->wlanAssociationAttributes.dot11Ssid.ucSSID),
          wifi_information_.ssid.size());
      LOG(INFO) << "wifi ssid is: " << wifi_information_.ssid
                << "; length is:" << wifi_information_.ssid.length();

      char str_tmp[kMacAddrLen];
      strncpy(str_tmp,
              reinterpret_cast<const char*>(
                  p_connect_info->wlanAssociationAttributes.dot11Bssid),
              kMacAddrLen);
      wifi_information_.bssid = absl::StrFormat(
          "%02llx:%02llx:%02llx:%02llx:%02llx:%02llx", str_tmp[0], str_tmp[1],
          str_tmp[2], str_tmp[3], str_tmp[4], str_tmp[5]);
      LOG(INFO) << "wifi bssid is: " << wifi_information_.bssid;
    }
  }

  WlanFreeMemory(p_connect_info);
  p_connect_info = nullptr;
  WlanFreeMemory(p_intf_list);
  p_intf_list = nullptr;
  WlanCloseHandle(client_handle, nullptr);

  if (wifi_information_.is_connected) {
    wifi_information_.ip_address_dot_decimal = InternalGetWifiIpAddress();
    wifi_information_.ip_address_4_bytes = ipaddr_dotdecimal_to_4bytes_string(
        wifi_information_.ip_address_dot_decimal);
  } else {
    FillupEthernetParams();
  }

  return wifi_information_;
}

std::string WifiMedium::GetIpAddress() {
  GetInformation();
  return wifi_information_.ip_address_dot_decimal;
}

std::string WifiMedium::InternalGetWifiIpAddress() {
  try {
    auto host_names = NetworkInformation::GetHostNames();
    for (auto host_name : host_names) {
      if (host_name.IPInformation() != nullptr &&
          host_name.IPInformation().NetworkAdapter() != nullptr &&
          host_name.Type() == HostNameType::Ipv4) {
        std::string ipv4_s = winrt::to_string(host_name.ToString());
        LOG(INFO) << "Found IP: " << ipv4_s;

        auto profile = host_name.IPInformation()
                           .NetworkAdapter()
                           .GetConnectedProfileAsync()
                           .get();
        if (profile != nullptr && profile.IsWlanConnectionProfile()) {
          auto profile_details = profile.WlanConnectionProfileDetails();
          if (profile_details != nullptr &&
              wifi_information_.ssid ==
                  winrt::to_string(profile_details.GetConnectedSsid())) {
            LOG(INFO)
                << "SSID of this IP matches with this WiFi interface's SSID:"
                << wifi_information_.ssid << ", return this IP: " << ipv4_s;
            return ipv4_s;
          }
        }
      }
    }
    return {};
  } catch (std::exception exception) {
    LOG(ERROR) << __func__ << ": Exception: " << exception.what();
    return {};
  } catch (const winrt::hresult_error& error) {
    LOG(ERROR) << __func__ << ": WinRT exception: " << error.code() << ": "
               << winrt::to_string(error.message());
    return {};
  } catch (...) {
    LOG(ERROR) << __func__ << ": Unknown exeption.";
    return {};
  }
}

std::string WifiMedium::InternalGetEthernetIpAddress() {
  try {
    auto host_names = NetworkInformation::GetHostNames();
    for (auto host_name : host_names) {
      if (host_name.IPInformation() != nullptr &&
          host_name.IPInformation().NetworkAdapter() != nullptr &&
          host_name.Type() == HostNameType::Ipv4) {
        std::string ipv4_s = winrt::to_string(host_name.ToString());
        if (host_name.IPInformation().NetworkAdapter().IanaInterfaceType() ==
            Constants::kInterfaceTypeEthernet) {
          LOG(INFO) << "Found IP: " << ipv4_s;
          return ipv4_s;
        }
      }
    }
    return {};
  } catch (std::exception exception) {
    LOG(ERROR) << __func__ << ": Exception: " << exception.what();
    return {};
  } catch (const winrt::hresult_error& error) {
    LOG(ERROR) << __func__ << ": WinRT exception: " << error.code() << ": "
               << winrt::to_string(error.message());
    return {};
  } catch (...) {
    LOG(ERROR) << __func__ << ": Unknown exeption.";
    return {};
  }
}

void WifiMedium::FillupEthernetParams() {
  wifi_information_.ip_address_dot_decimal = InternalGetEthernetIpAddress();
  if (wifi_information_.ip_address_dot_decimal.empty()) {
    LOG(INFO) << "No Etherent IP Addr found.";
    return;
  }
  wifi_information_.ip_address_4_bytes = ipaddr_dotdecimal_to_4bytes_string(
      wifi_information_.ip_address_dot_decimal);
  wifi_information_.ap_frequency = kUseEthernet;
}

}  // namespace windows
}  // namespace nearby