From 2f5a83e171f567fb27f5ead1dbc7d5b7e0916efc Mon Sep 17 00:00:00 2001
From: "Jamin W. Collins" <jamin.collins@gmail.com>
Date: Fri, 30 Mar 2018 08:37:17 -0600
Subject: [PATCH] Show external IP when hosting, if possible

Fixes: core-developers/forge#396

Signed-off-by: Jamin W. Collins <jamin.collins@gmail.com>
---
 .../main/java/forge/net/NetConnectUtil.java   | 22 ++++++++++---
 .../java/forge/net/server/FServerManager.java | 33 +++++++++++++++----
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/forge-gui/src/main/java/forge/net/NetConnectUtil.java b/forge-gui/src/main/java/forge/net/NetConnectUtil.java
index cf1e624a423..3e3cdf8e28b 100644
--- a/forge-gui/src/main/java/forge/net/NetConnectUtil.java
+++ b/forge-gui/src/main/java/forge/net/NetConnectUtil.java
@@ -106,10 +106,24 @@ public class NetConnectUtil {
     }
 
     public static void copyHostedServerUrl() {
-        String hostname = FServerManager.getInstance().getLocalAddress();
-        String url = hostname + ":" + ForgeProfileProperties.getServerPort();
-        GuiBase.getInterface().copyToClipboard(url);
-        SOptionPane.showMessageDialog("Share the following URL with anyone who wishes to join your server. It has been copied to your clipboard for convenience.\n\n" + url, "Server URL", SOptionPane.INFORMATION_ICON);
+        String internalAddress = FServerManager.getInstance().getLocalAddress();
+        String externalAddress = FServerManager.getInstance().getExternalAddress();
+        String internalUrl = internalAddress + ":" + ForgeProfileProperties.getServerPort();
+        String externalUrl = null;
+        if (externalAddress != null) {
+            externalUrl = externalAddress + ":" + ForgeProfileProperties.getServerPort();
+            GuiBase.getInterface().copyToClipboard(externalUrl);
+        } else {
+            GuiBase.getInterface().copyToClipboard(internalAddress);
+        }
+
+        String message = "Share the following URL with anyone who wishes to join your server. It has been copied to your clipboard for convenience.\n\n";
+        if (externalUrl != null) {
+            message += externalUrl + "\n\nFor internal games, use the following URL: " + internalUrl;
+        } else {
+            message = "Forge was unable to determine your external IP!\n\n" + message + internalUrl;
+        }
+        SOptionPane.showMessageDialog(message, "Server URL", SOptionPane.INFORMATION_ICON);
     }
 
     public static ChatMessage join(final String url, final IOnlineLobby onlineLobby, final IOnlineChatInterface chatInterface) {
diff --git a/forge-gui/src/main/java/forge/net/server/FServerManager.java b/forge-gui/src/main/java/forge/net/server/FServerManager.java
index c5af180361c..fad16bfb982 100644
--- a/forge-gui/src/main/java/forge/net/server/FServerManager.java
+++ b/forge-gui/src/main/java/forge/net/server/FServerManager.java
@@ -30,13 +30,10 @@ import io.netty.handler.codec.serialization.ObjectEncoder;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;
 
-import java.net.DatagramSocket;
-import java.net.Inet4Address;
-import java.net.Inet6Address;
-import java.net.InetAddress;
-import java.net.NetworkInterface;
-import java.net.SocketException;
-import java.net.UnknownHostException;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.*;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
@@ -253,6 +250,28 @@ public final class FServerManager {
         }
     }
 
+    public static String getExternalAddress() {
+        BufferedReader in = null;
+        try {
+            URL whatismyip = new URL("http://checkip.amazonaws.com");
+            in = new BufferedReader(new InputStreamReader(
+                    whatismyip.openStream()));
+            String ip = in.readLine();
+            return ip;
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            if (in != null) {
+                try {
+                    in.close();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+        return null;
+    }
+
     private void mapNatPort(final int port) {
         final String localAddress = getLocalAddress();
         final PortMapping portMapping = new PortMapping(port, localAddress, PortMapping.Protocol.TCP, "Forge");