//
//
// Copyright 2020 gRPC authors.
//
// 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
//
//     http://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 "test/core/test_util/resolve_localhost_ip46.h"

#include <grpc/support/sync.h>

#include <memory>
#include <vector>

#include "absl/log/check.h"
#include "absl/status/statusor.h"
#include "absl/strings/str_cat.h"
#include "src/core/lib/iomgr/resolve_address.h"
#include "src/core/lib/iomgr/resolved_address.h"
#include "src/core/lib/iomgr/sockaddr.h"

namespace grpc_core {
namespace {

bool localhost_to_ipv4 = false;
bool localhost_to_ipv6 = false;
gpr_once g_resolve_localhost_ipv46 = GPR_ONCE_INIT;

void InitResolveLocalhost() {
  absl::StatusOr<std::vector<grpc_resolved_address>> addresses_or =
      GetDNSResolver()->LookupHostnameBlocking("localhost", "https");
  CHECK_OK(addresses_or);
  for (const auto& addr : *addresses_or) {
    const grpc_sockaddr* sock_addr =
        reinterpret_cast<const grpc_sockaddr*>(&addr);
    if (sock_addr->sa_family == GRPC_AF_INET) {
      localhost_to_ipv4 = true;
    } else if (sock_addr->sa_family == GRPC_AF_INET6) {
      localhost_to_ipv6 = true;
    }
  }
}
}  // namespace

void LocalhostResolves(bool* ipv4, bool* ipv6) {
  gpr_once_init(&g_resolve_localhost_ipv46, InitResolveLocalhost);
  *ipv4 = localhost_to_ipv4;
  *ipv6 = localhost_to_ipv6;
}

bool RunningWithIPv6Only() {
  bool localhost_resolves_to_ipv4 = false;
  bool localhost_resolves_to_ipv6 = false;
  LocalhostResolves(&localhost_resolves_to_ipv4, &localhost_resolves_to_ipv6);
  return !localhost_resolves_to_ipv4 && localhost_resolves_to_ipv6;
}

absl::string_view LocalIp() {
  return RunningWithIPv6Only() ? "[::1]" : "127.0.0.1";
}

std::string LocalIpAndPort(int port) {
  return absl::StrCat(LocalIp(), ":", port);
}

std::string LocalIpUri(int port) {
  return absl::StrCat(
      RunningWithIPv6Only() ? "ipv6:%5b::1%5d:" : "ipv4:127.0.0.1:", port);
}

}  // namespace grpc_core
