module relations and module staging

Assets/Engine/Runtime/Space.cs

@@ -15,10 +15,30 @@ namespace EscapeRoomEngine.Engine.Runtime
         /// The room relative (<i>RR</i>) dimensions of this space.
         /// </summary>
         internal readonly Dimensions rrDimensions;
-        internal List<Module> Modules { get; } = new(2);
         internal readonly Room room;
         
+        /// <summary>
+        /// A list of all modules.
+        /// </summary>
+        internal List<Module> Modules { get; } = new(2);
+        /// <summary>
+        /// A list of all staged and added modules.
+        /// </summary>
+        internal List<Module> AllModules
+        {
+            get
+            {
+                var modules = new List<Module>(Modules);
+                if (_stagedModules.Count > 0)
+                {
+                    modules.AddRange(_stagedModules);
+                }
+                return modules;
+            }
+        }
+        
         private GameObject _spaceObject, _spaceTiles;
+        private List<Module> _stagedModules = new();
 
         internal Space(Room room, Passage entrance)
         {
@@ -31,24 +51,41 @@ namespace EscapeRoomEngine.Engine.Runtime
             // connect the space to its passage
             entrance.ConnectTo(new DoorModule(this,
                 ((DoorModuleDescription)entrance.fromOut.description).connectedDoorDescription));
-            AddModule(entrance.toIn);
-        }
-
-        internal void AddModule(Module module)
-        {
-            Modules.Add(module);
+            Modules.Add(entrance.toIn);
         }
 
         internal bool AddModuleWithRequirements(Module module)
         {
-            var requirementsFulfilled =
-                PreconditionRequirement.CheckPreconditions(module, this) &&
-                PlacementRequirement.TryPlacing(module, this) &&
-                OrientationRequirement.TryOrienting(module, this);
-
+            var requirementsFulfilled = module.CheckRequirements();
             if (requirementsFulfilled)
             {
-                AddModule(module);
+                // add all previously staged modules first ...
+                for (var i = _stagedModules.Count - 1; i >= 0; i--)
+                {
+                    Modules.Add(_stagedModules[i]);
+                }
+                
+                // ... and then add the module itself
+                Modules.Add(module);
+            }
+            
+            // always clear the staged modules. if a module isn't added, its corresponding staged modules should be discarded
+            _stagedModules = new List<Module>();
+
+            return requirementsFulfilled;
+        }
+
+        /// <summary>
+        /// Stage a module if its requirements are currently met. It will be added as soon as the next module is added by <see cref="AddModuleWithRequirements"/>.
+        /// </summary>
+        /// <param name="module">The module to stage</param>
+        /// <returns>Whether the requirements were met and the module was staged</returns>
+        internal bool StageModuleWithRequirements(Module module)
+        {
+            var requirementsFulfilled = module.CheckRequirements();
+            if (requirementsFulfilled)
+            {
+                _stagedModules.Add(module);
             }
 
             return requirementsFulfilled;