fix(NetworkManagerGUI): prevent potential NRE spam if reference is lo…

…st and tidy up (#1130)

* Add autoconfiguration bool option with tooltip

* System define and Awake function implementation

* Short-circuit to prevent NREs

Somehow NMGUI can lose references for some reason, so short-circuit to prevent log spam.

* update comment

* apply Visual Studio IDE0048 recommendation

"Add parentheses for clarity"

* Regions for tidying up

* Throw warning if trying to Auto Configure but NM field is set

If auto configure is set but NetworkManager field is not null, then don't do anything.

* possible future todo

* Update NetworkManagerGUI.cs

Remove regions as per James request

* fix ups as suggested by James' review

Assets/Mirage/Components/NetworkManagerGUI.cs

@@ -1,18 +1,63 @@
+using System;
 using UnityEngine;
 
 namespace Mirage
 {
     public class NetworkManagerGUI : MonoBehaviour
     {
-        public NetworkManager NetworkManager;
+        [Header("Defaults")]
+        [Tooltip("This is the default string displayed in the client address text box.")]
         public string NetworkAddress = "localhost";
 
-        [Range(0.01f, 10f)]
+        [Header("References")]
+        [Tooltip("If enabled, we'll automatically reference NetworkManager in script's initialization.\nIf you've already set the NetworkManager field, auto configuring will not be performed.")]
+        public bool AutoConfigureNetworkManager = true;
+
+        [Tooltip("The value in this property field (if set) will not be overwritten if Auto Configuration is enabled.")]
+        public NetworkManager NetworkManager;
+
+        [Header("Cosmetics")]
+        [Range(0.01f, 10f), Tooltip("Adjusts scale of the GUI elements. 1x is normal size. 2x might be sane for big screens. <= 0.5x or > 2x is silly.")]
         public float Scale = 1f;
+
+        [Tooltip("Select where you want the NetworkManagerGUI elements to be located on the screen.")]
         public TextAnchor GUIAnchor = TextAnchor.UpperLeft;
 
+        private void Awake()
+        {
+            // Coburn, 2023-02-02: 
+            // If automatic configuration of NetworkManager is enabled, then attempt to grab the
+            // NetworkManager that this script is attached to.
+            if (AutoConfigureNetworkManager)
+            {
+                // Ensure this is null before doing anything. If not, return early.
+                if (NetworkManager != null)
+                {
+                    return;
+                }
+
+                // Attempt to get the NetworkManager component.
+                NetworkManager = GetComponent<NetworkManager>();
+
+                // Is this STILL null? Then we throw in the towel and go home.
+                if (NetworkManager == null)
+                {
+                    throw new InvalidOperationException($"You requested automatic configuration for the NetworkManagerGUI component on '{gameObject.name}'" +
+                        $" but one could not be found. Either disable automatic configuration or ensure this script is on a GameObject with a Mirage NetworkManager.");
+                }
+            }
+        }
+
         private void OnGUI()
         {
+            // Coburn, 2023-02-02: Apparently NMGUI can/may lose reference to NetworkManager for reasons unknown
+            // (maybe due to being in and out of DDOL and scene changes?). To prevent a NRE being spewed every OnGUI
+            // update, short-circuit here to prevent log spam.
+            if (NetworkManager == null)
+            {
+                return;
+            }
+
             GUIUtility.ScaleAroundPivot(Vector2.one * Scale, GetPivotFromAnchor(GUIAnchor));
 
             if (!NetworkManager.Server.Active && !NetworkManager.Client.Active)
@@ -29,6 +74,7 @@ private void StartButtons(Rect position)
         {
             GUILayout.BeginArea(position);
 
+            // Coburn, 2023-02-02, possible TODO: Remove the server buttons for WebGL since it can't be used as server
             if (Application.platform == RuntimePlatform.WebGLPlayer)
             {
                 GUILayout.Box("WebGL cannot host");
@@ -90,6 +136,7 @@ private void StatusLabels(Rect position)
                     }
                 }
             }
+
             if (NetworkManager.Client.IsConnected)
             {
                 GUILayout.Label($"Client: address={NetworkAddress}");
@@ -108,30 +155,26 @@ private void StatusLabels(Rect position)
             GUILayout.EndArea();
         }
 
-        private const int WIDTH = 200;
-        private const int PADDING_X = 10;
-        private const int PADDING_Y = 10;
-
         private static Rect GetRectFromAnchor(TextAnchor anchor, int height)
         {
             switch (anchor)
             {
                 case TextAnchor.UpperLeft:
                     return new Rect(PADDING_X, PADDING_Y, WIDTH, height);
                 case TextAnchor.UpperCenter:
-                    return new Rect(Screen.width / 2 - (WIDTH / 2), PADDING_Y, WIDTH, height);
+                    return new Rect((Screen.width / 2) - (WIDTH / 2), PADDING_Y, WIDTH, height);
                 case TextAnchor.UpperRight:
                     return new Rect(Screen.width - (WIDTH + PADDING_X), PADDING_Y, WIDTH, height);
                 case TextAnchor.MiddleLeft:
-                    return new Rect(PADDING_X, Screen.height / 2 - (height / 2), WIDTH, height);
+                    return new Rect(PADDING_X, (Screen.height / 2) - (height / 2), WIDTH, height);
                 case TextAnchor.MiddleCenter:
-                    return new Rect(Screen.width / 2 - (WIDTH / 2), Screen.height / 2 - (height / 2), WIDTH, height);
+                    return new Rect((Screen.width / 2) - (WIDTH / 2), (Screen.height / 2) - (height / 2), WIDTH, height);
                 case TextAnchor.MiddleRight:
-                    return new Rect(Screen.width - (WIDTH + PADDING_X), Screen.height / 2 - (height / 2), WIDTH, height);
+                    return new Rect(Screen.width - (WIDTH + PADDING_X), (Screen.height / 2) - (height / 2), WIDTH, height);
                 case TextAnchor.LowerLeft:
                     return new Rect(PADDING_X, Screen.height - (height + PADDING_Y), WIDTH, height);
                 case TextAnchor.LowerCenter:
-                    return new Rect(Screen.width / 2 - (WIDTH / 2), Screen.height - (height + PADDING_Y), WIDTH, height);
+                    return new Rect((Screen.width / 2) - (WIDTH / 2), Screen.height - (height + PADDING_Y), WIDTH, height);
                 default: // Lower right
                     return new Rect(Screen.width - (WIDTH + PADDING_X), Screen.height - (height + PADDING_Y), WIDTH, height);
             }
@@ -176,5 +219,9 @@ private void ClickClient()
         {
             NetworkManager.Client.Connect(NetworkAddress);
         }
+
+        private const int WIDTH = 200;
+        private const int PADDING_X = 10;
+        private const int PADDING_Y = 10;
     }
 }