split into multiple assemblies

Assets/Engine/Runtime/Requirements/Requirement.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using EscapeRoomEngine.Engine.Runtime.Modules;
+using UnityEngine;
+
+namespace EscapeRoomEngine.Engine.Runtime.Requirements
+{
+    public abstract class Requirement<T> : ScriptableObject
+    {
+        protected abstract IEnumerable<T> GenerateCandidates(Module module, Space space);
+
+        public void Restrict(HashSet<T> candidates, Module module, Space space) =>
+            candidates.IntersectWith(GenerateCandidates(module, space));
+
+        public static HashSet<T> Candidates(
+            HashSet<T> initialCandidates,
+            IEnumerable<Requirement<T>> requirements,
+            Module module, Space space)
+        {
+            foreach (var requirement in requirements)
+            {
+                requirement.Restrict(initialCandidates, module, space);
+            }
+
+            return initialCandidates;
+        }
+    }
+}