Moves ExamineSystem to Shared & adds next step info to construction examine (#1567)

Content.Shared/GameObjects/EntitySystems/ExamineSystemShared.cs

@@ -1,14 +1,26 @@
-using Content.Shared.GameObjects.Components.Mobs;
+using Content.Shared.GameObjects.Components.Mobs;
 using JetBrains.Annotations;
 using Robust.Shared.GameObjects.Systems;
 using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
 
 namespace Content.Shared.GameObjects.EntitySystems
 {
+    public interface IExamine
+    {
+        /// <summary>
+        /// Returns a status examine value for components appended to the end of the description of the entity
+        /// </summary>
+        /// <param name="message">The message to append to which will be displayed.</param>
+        /// <param name="inDetailsRange">Whether the examiner is within the 'Details' range, allowing you to show information logically only availabe when close to the examined entity.</param>
+        void Examine(FormattedMessage message, bool inDetailsRange);
+    }
     public abstract class ExamineSystemShared : EntitySystem
     {
         public const float ExamineRange = 16f;
         public const float ExamineRangeSquared = ExamineRange * ExamineRange;
+        protected const float ExamineDetailsRange = 3f;
 
         [Pure]
         protected static bool CanExamine(IEntity examiner, IEntity examined)
@@ -32,5 +44,44 @@ namespace Content.Shared.GameObjects.EntitySystems
                 .InRangeUnobstructed(examiner.Transform.MapPosition, examined.Transform.MapPosition,
                     ExamineRange, predicate: entity => entity == examiner || entity == examined, ignoreInsideBlocker:true);
         }
+
+        public static FormattedMessage GetExamineText(IEntity entity, IEntity examiner)
+        {
+            var message = new FormattedMessage();
+
+            var doNewline = false;
+
+            //Add an entity description if one is declared
+            if (!string.IsNullOrEmpty(entity.Description))
+            {
+                message.AddText(entity.Description);
+                doNewline = true;
+            }
+
+            message.PushColor(Color.DarkGray);
+
+            var inDetailsRange = Get<SharedInteractionSystem>()
+                .InRangeUnobstructed(examiner.Transform.MapPosition, entity.Transform.MapPosition,
+                    ExamineDetailsRange, predicate: entity0 => entity0 == examiner || entity0 == entity, ignoreInsideBlocker: true);
+
+            //Add component statuses from components that report one
+            foreach (var examineComponent in entity.GetAllComponents<IExamine>())
+            {
+                var subMessage = new FormattedMessage();
+                examineComponent.Examine(subMessage, inDetailsRange);
+                if (subMessage.Tags.Count == 0)
+                    continue;
+
+                if (doNewline)
+                    message.AddText("\n");
+
+                message.AddMessage(subMessage);
+                doNewline = true;
+            }
+
+            message.Pop();
+
+            return message;
+        }
     }
 }