/*
    * Copyright 2017-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.software.os.mac;
   
   import static com.sun.jna.platform.unix.LibCAPI.HOST_NAME_MAX;
   
   import java.net.InetAddress;
  import java.net.UnknownHostException;
  import java.util.List;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.sun.jna.Native;
  
  import oshi.annotation.concurrent.ThreadSafe;
  import oshi.jna.ByRef.CloseablePointerByReference;
  import oshi.jna.platform.mac.SystemB;
  import oshi.jna.platform.unix.CLibrary;
  import oshi.jna.platform.unix.CLibrary.Addrinfo;
  import oshi.software.common.AbstractNetworkParams;
  import oshi.util.ExecutingCommand;
  import oshi.util.ParseUtil;
  
  /**
   * MacNetworkParams class.
   */
  @ThreadSafe
  final class MacNetworkParams extends AbstractNetworkParams {
  
      private static final Logger LOG = LoggerFactory.getLogger(MacNetworkParams.class);
  
      private static final SystemB SYS = SystemB.INSTANCE;
  
      private static final String IPV6_ROUTE_HEADER = "Internet6:";
  
      private static final String DEFAULT_GATEWAY = "default";
  
      @Override
      public String getDomainName() {
          String hostname = "";
          try {
              hostname = InetAddress.getLocalHost().getHostName();
          } catch (UnknownHostException e) {
              LOG.error("Unknown host exception when getting address of local host: {}", e.getMessage());
              return "";
          }
          try (Addrinfo hint = new Addrinfo(); CloseablePointerByReference ptr = new CloseablePointerByReference()) {
              hint.ai_flags = CLibrary.AI_CANONNAME;
              int res = SYS.getaddrinfo(hostname, null, hint, ptr);
              if (res > 0) {
                  if (LOG.isErrorEnabled()) {
                      LOG.error("Failed getaddrinfo(): {}", SYS.gai_strerror(res));
                  }
                  return "";
              }
              Addrinfo info = new Addrinfo(ptr.getValue()); // NOSONAR
              String canonname = info.ai_canonname.trim();
              SYS.freeaddrinfo(ptr.getValue());
              return canonname;
          }
      }
  
      @Override
      public String getHostName() {
          byte[] hostnameBuffer = new byte[HOST_NAME_MAX + 1];
          if (0 != SYS.gethostname(hostnameBuffer, hostnameBuffer.length)) {
              return super.getHostName();
          }
          return Native.toString(hostnameBuffer);
      }
  
      @Override
      public String getIpv4DefaultGateway() {
          return searchGateway(ExecutingCommand.runNative("route -n get default"));
      }
  
      @Override
      public String getIpv6DefaultGateway() {
          List<String> lines = ExecutingCommand.runNative("netstat -nr");
          boolean v6Table = false;
          for (String line : lines) {
              if (v6Table && line.startsWith(DEFAULT_GATEWAY)) {
                  String[] fields = ParseUtil.whitespaces.split(line);
                  if (fields.length > 2 && fields[2].contains("G")) {
                      return fields[1].split("%")[0];
                  }
              } else if (line.startsWith(IPV6_ROUTE_HEADER)) {
                  v6Table = true;
              }
          }
          return "";
      }
  }