Fix polling overwriting manually entered IP addresses

app/src/main/java/com/limelight/computers/ComputerManagerService.java

@@ -588,8 +588,11 @@ public class ComputerManagerService extends Service {
             }
         }
 
-        // Save the old MAC address
+        // Save some details about the old state of the PC that we may wish
+        // to restore later.
         String savedMacAddress = details.macAddress;
+        String savedLocalAddress = details.localAddress;
+        String savedRemoteAddress = details.remoteAddress;
 
         // If we got here, it's reachable
         details.update(initialReachTuple.computer);
@@ -600,6 +603,25 @@ public class ComputerManagerService extends Service {
             details.macAddress = savedMacAddress;
         }
 
+        // We never want to lose IP addresses by polling server info. If we get a poll back
+        // where localAddress == remoteAddress but savedLocalAddress != savedRemoteAddress,
+        // then we've lost an address in the polling and we should restore the one that's missing.
+        if (details.localAddress.equals(details.remoteAddress) &&
+                !savedLocalAddress.equals(savedRemoteAddress)) {
+            if (details.localAddress.equals(savedLocalAddress)) {
+                // Local addresses are identical, so put the old remote address back
+                details.remoteAddress = savedRemoteAddress;
+            }
+            else if (details.remoteAddress.equals(savedRemoteAddress)) {
+                // Remote addresses are identical, so put the old local address back
+                details.localAddress = savedLocalAddress;
+            }
+            else {
+                // Neither IP address match. Let's restore the remote address to be safe.
+                details.remoteAddress = savedRemoteAddress;
+            }
+        }
+
         return true;
     }