/* Copyright  (C) 2010-2022 The RetroArch team
 *
 * ---------------------------------------------------------------------------------------
 * The following license statement only applies to this file (net_ifinfo.c).
 * ---------------------------------------------------------------------------------------
 *
 * Permission is hereby granted, free of charge,
 * to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <retro_miscellaneous.h>

#if defined(_WIN32) && !defined(_XBOX)
#ifdef _MSC_VER
#pragma comment(lib, "Iphlpapi")
#endif

#include <winsock2.h>
#include <iphlpapi.h>
#include <ws2tcpip.h>
#elif defined (GEKKO) && !defined(WIIU)
#include <network.h>
#else
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>

#ifdef WANT_IFADDRS
#include <compat/ifaddrs.h>
#else
#if !defined HAVE_LIBNX && !defined(_3DS)
#include <ifaddrs.h>
#endif
#endif
#endif

#include <net/net_ifinfo.h>

#if defined(BSD)
#include <netinet/in.h>
#endif

void net_ifinfo_free(net_ifinfo_t *list)
{
   unsigned k;

   if (!list)
      return;

   for (k = 0; k < list->size; k++)
   {
      struct net_ifinfo_entry *ptr =
         (struct net_ifinfo_entry*)&list->entries[k];

      if (*ptr->name)
         free(ptr->name);
      if (*ptr->host)
         free(ptr->host);

      ptr->name = NULL;
      ptr->host = NULL;
   }
   free(list->entries);
}

#if defined(HAVE_LIBNX) || defined(_3DS) || defined(GEKKO)
static void convert_ip(char *dst, size_t size, uint32_t ip, bool inverted)
{
   unsigned char bytes[4];
   bytes[0] = ip & 0xFF;
   bytes[1] = (ip >> 8) & 0xFF;
   bytes[2] = (ip >> 16) & 0xFF;
   bytes[3] = (ip >> 24) & 0xFF;

   if (inverted)
      snprintf(dst, size, "%d.%d.%d.%d", bytes[0], bytes[1], bytes[2], bytes[3]);
   else
      snprintf(dst, size, "%d.%d.%d.%d", bytes[3], bytes[2], bytes[1], bytes[0]);
}
#endif

bool net_ifinfo_new(net_ifinfo_t *list)
{
   unsigned k              = 0;
#if defined(GEKKO)
   char hostname[128];

   memset(list, 0, sizeof(net_ifinfo_t));

   /* loopback */
   list->entries = (struct net_ifinfo_entry*)
         malloc(2 * sizeof(struct net_ifinfo_entry));

   if (!list->entries)
      goto error;

   list->entries[0].name  = strdup("lo");
   list->entries[0].host  = strdup("127.0.0.1");
   list->entries[1].name  = strdup("gekko");
   convert_ip(hostname, sizeof(hostname), net_gethostip(), false);
   list->entries[1].host  = strdup(hostname);
   list->size             = 2;

   return true;

   /*
      actual interface
      can be wlan or eth (with a wiiu adapter)
      so we just use "switch" as a name
   */
#elif defined(HAVE_LIBNX) || defined(_3DS)
   uint32_t id;
#ifdef HAVE_LIBNX
   Result rc;
#endif
   char hostname[128];
   struct net_ifinfo_entry *ptr = NULL;

   memset(list, 0, sizeof(net_ifinfo_t));

   /* loopback */
   convert_ip(hostname, sizeof(hostname), INADDR_LOOPBACK, false);

   ptr = (struct net_ifinfo_entry*)
         realloc(list->entries, (k+1) * sizeof(struct net_ifinfo_entry));

   if (!ptr)
      goto error;

   list->entries          = ptr;

   list->entries[k].name  = strdup("lo");
   list->entries[k].host  = strdup(hostname);
   list->size             = k + 1;

   k++;

   /*
      actual interface
      can be wlan or eth (with a wiiu adapter)
      so we just use "switch" as a name
   */
#if defined(_3DS) || defined (GEKKO)
   convert_ip(hostname, sizeof(hostname), gethostid(), true);
#else
   rc = nifmGetCurrentIpAddress(&id);

   if (!R_SUCCEEDED(rc)) /* not connected to any network */
      return true;

   convert_ip(hostname, sizeof(hostname), id, true);
#endif

   ptr = (struct net_ifinfo_entry*)
         realloc(list->entries, (k+1) * sizeof(struct net_ifinfo_entry));

   if (!ptr)
      goto error;

   list->entries          = ptr;
#if defined(_3DS)
   list->entries[k].name  = strdup("wlan");
#else
   list->entries[k].name  = strdup("switch");
#endif
   list->entries[k].host  = strdup(hostname);
   list->size             = k + 1;

   return true;
#elif defined(_WIN32) && !defined(_XBOX)
   PIP_ADAPTER_ADDRESSES adapter_addresses = NULL, aa = NULL;
   PIP_ADAPTER_UNICAST_ADDRESS ua          = NULL;
#ifdef _WIN32_WINNT_WINXP
   DWORD size                              = 0;
   DWORD rv                                = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, NULL, &size);
   adapter_addresses                       = (PIP_ADAPTER_ADDRESSES)malloc(size);
   rv                                      = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, adapter_addresses, &size);

   memset(list, 0, sizeof(net_ifinfo_t));

   if (rv != ERROR_SUCCESS)
      goto error;
#endif
   for (aa = adapter_addresses; aa != NULL; aa = aa->Next)
   {
      char name[PATH_MAX_LENGTH];
      memset(name, 0, sizeof(name));

      WideCharToMultiByte(CP_UTF8, 0, aa->FriendlyName, wcslen(aa->FriendlyName),
            name, PATH_MAX_LENGTH, NULL, NULL);

      for (ua = aa->FirstUnicastAddress; ua != NULL; ua = ua->Next)
      {
         char host[PATH_MAX_LENGTH];
         struct net_ifinfo_entry *ptr = (struct net_ifinfo_entry*)
            realloc(list->entries, (k+1) * sizeof(struct net_ifinfo_entry));

         if (!ptr)
            goto error;

         list->entries          = ptr;

         memset(host, 0, sizeof(host));

         getnameinfo(ua->Address.lpSockaddr, ua->Address.iSockaddrLength,
               host, sizeof(host), NULL, NI_MAXSERV, NI_NUMERICHOST);

         list->entries[k].name  = strdup(name);
         list->entries[k].host  = strdup(host);
         list->size             = k + 1;

         k++;
      }
   }

   free(adapter_addresses);
#else
   struct ifaddrs *ifa     = NULL;
   struct ifaddrs *ifaddr  = NULL;

   memset(list, 0, sizeof(net_ifinfo_t));

   if (getifaddrs(&ifaddr) == -1)
      goto error;

   if (!list)
      goto error;

   for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next)
   {
      char host[NI_MAXHOST];
      struct net_ifinfo_entry *ptr = NULL;

      if (!ifa->ifa_addr)
         continue;

      if (ifa->ifa_addr->sa_family != AF_INET)
         continue;

      if (getnameinfo(ifa->ifa_addr, sizeof(struct sockaddr_in),
               host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST) != 0)
         goto error;

      ptr = (struct net_ifinfo_entry*)
         realloc(list->entries, (k+1) * sizeof(struct net_ifinfo_entry));

      if (!ptr)
         goto error;

      list->entries          = ptr;

      list->entries[k].name  = strdup(ifa->ifa_name);
      list->entries[k].host  = strdup(host);
      list->size             = k + 1;

      k++;
   }

   freeifaddrs(ifaddr);
#endif
   return true;

error:
#ifdef _WIN32
   if (adapter_addresses)
      free(adapter_addresses);
#elif !defined(HAVE_LIBNX) && !defined(_3DS) && !defined(GEKKO)
   freeifaddrs(ifaddr);
#endif
   net_ifinfo_free(list);

   return false;
}

bool net_ifinfo_best(const char *dst, void *src, bool ipv6)
{
   bool ret = false;

/* TODO/FIXME: Implement for other platforms, if necessary. */
#if defined(_WIN32) && !defined(_XBOX)
   if (!ipv6)
   {
      /* Courtesy of MiniUPnP: https://github.com/miniupnp/miniupnp */
      DWORD index;
      unsigned long udst          = inet_addr(dst);
#ifdef __WINRT__
      struct sockaddr_in addr_dst = {0};
#endif

      if (udst == INADDR_NONE || udst == INADDR_ANY)
         return ret;

      if (!src)
         return ret;

#ifdef __WINRT__
      addr_dst.sin_family      = AF_INET;
      addr_dst.sin_addr.s_addr = udst;
      if (GetBestInterfaceEx((struct sockaddr *) &addr_dst, &index)
         == NO_ERROR)
#else
      if (GetBestInterface(udst, &index) == NO_ERROR)
#endif
      {
         /* Microsoft docs recommend doing it this way. */
         ULONG len                       = 15 * 1024;
         PIP_ADAPTER_ADDRESSES addresses = (PIP_ADAPTER_ADDRESSES)calloc(1, len);

         if (addresses)
         {
            ULONG flags  = GAA_FLAG_SKIP_ANYCAST |
               GAA_FLAG_SKIP_MULTICAST |
               GAA_FLAG_SKIP_DNS_SERVER |
               GAA_FLAG_SKIP_FRIENDLY_NAME;
            ULONG result = GetAdaptersAddresses(AF_INET, flags, NULL,
               addresses, &len);

            if (result == ERROR_BUFFER_OVERFLOW)
            {
               PIP_ADAPTER_ADDRESSES new_addresses = (PIP_ADAPTER_ADDRESSES)realloc(addresses, len);

               if (new_addresses)
               {
                  memset(new_addresses, 0, len);

                  addresses = new_addresses;
                  result    = GetAdaptersAddresses(AF_INET, flags, NULL,
                     addresses, &len);
               }
            }

            if (result == NO_ERROR)
            {
               PIP_ADAPTER_ADDRESSES addr = addresses;

               do
               {
                  if (addr->IfIndex == index)
                  {
                     if (addr->FirstUnicastAddress)
                     {
                        struct sockaddr_in *addr_unicast =
                           (struct sockaddr_in *)
                           addr->FirstUnicastAddress->Address.lpSockaddr;

                        memcpy(src, &addr_unicast->sin_addr,
                           sizeof(addr_unicast->sin_addr));

                        ret = true;
                     }

                     break;
                  }
               } while ((addr = addr->Next));
            }

            free(addresses);
         }
      }
   }
#endif

   return ret;
}