/* Copyright 2016, Ableton AG, Berlin. All rights reserved.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  If you would like to incorporate Link into a proprietary software application,
 *  please contact <link-devs@ableton.com>.
 */

#pragma once

#include <ableton/platforms/asio/AsioWrapper.hpp>
#include <ableton/platforms/asio/Util.hpp>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <vector>

namespace ableton
{
namespace platforms
{
namespace posix
{
namespace detail
{

// RAII type to make [get,free]ifaddrs function pairs exception safe
class GetIfAddrs
{
public:
  GetIfAddrs()
  {
    if (getifaddrs(&interfaces)) // returns 0 on success
    {
      interfaces = NULL;
    }
  }
  ~GetIfAddrs()
  {
    if (interfaces)
      freeifaddrs(interfaces);
  }

  // RAII must not copy
  GetIfAddrs(GetIfAddrs&) = delete;
  GetIfAddrs& operator=(GetIfAddrs&) = delete;

  template <typename Function>
  void withIfAddrs(Function f)
  {
    if (interfaces)
      f(*interfaces);
  }

private:
  struct ifaddrs* interfaces = NULL;
};

} // detail


// Posix implementation of ip interface address scanner
struct ScanIpIfAddrs
{
  // Scan active network interfaces and return corresponding addresses
  // for all ip-based interfaces.
  std::vector<::asio::ip::address> operator()()
  {
    std::vector<::asio::ip::address> addrs;

    detail::GetIfAddrs getIfAddrs;
    getIfAddrs.withIfAddrs([&addrs](const struct ifaddrs& interfaces) {
      const struct ifaddrs* interface;
      for (interface = &interfaces; interface; interface = interface->ifa_next)
      {
        auto addr = reinterpret_cast<const struct sockaddr_in*>(interface->ifa_addr);
        if (addr && interface->ifa_flags & IFF_UP)
        {
          if (addr->sin_family == AF_INET)
          {
            auto bytes = reinterpret_cast<const char*>(&addr->sin_addr);
            addrs.emplace_back(asio::makeAddress<::asio::ip::address_v4>(bytes));
          }
          else if (addr->sin_family == AF_INET6)
          {
            auto addr6 = reinterpret_cast<const struct sockaddr_in6*>(addr);
            auto bytes = reinterpret_cast<const char*>(&addr6->sin6_addr);
            addrs.emplace_back(asio::makeAddress<::asio::ip::address_v6>(bytes));
          }
        }
      }
    });
    return addrs;
  }
};

} // namespace posix
} // namespace platforms
} // namespace ableton