1 files changed, 61 insertions, 0 deletions
diff --git a/app/ECS/entity_manager.rb b/app/ECS/entity_manager.rb
new file mode 100644
index 0000000..06f73cd
--- /dev/null
+++ b/app/ECS/entity_manager.rb
@@ -0,0 +1,61 @@
+class ECS
+  class Entity
+    attr_accessor :id
+
+    def initialize(signature = 0)
+      @id = ECS::Entity.generate_new_id
+      self.class.all.push self
+      self.class.signatures.push signature
+      ECS::Components.entity_created(@id)
+    end
+
+    class <<self
+      # All entities that exist
+      def all
+        @all ||= []
+      end
+
+      def id_queue
+        @id_queue ||= []
+      end
+
+      def generate_new_id
+        if id_queue.empty?
+          all.size
+        else
+          id_queue.shift
+        end
+      end
+
+      # What components a given entity uses
+      def signatures
+        @signatures ||= []
+      end
+
+      def destroy_entity(entity_id)
+        if all[entity_id].nil?
+          puts 'Entity can not be destroyed, id out of bounds'
+        elsif entity_id < all.size - 1
+          ECS::Components.constants.each do |constant|
+            unless (signatures[entity_id] & ECS::Components::const_get(constant).id).zero?
+              ECS::Components::const_get(constant).delete(entity_id)
+            end
+          end
+          all[entity_id] = nil
+          signatures[entity_id] = nil
+          id_queue.push entity_id
+        elsif entity_id == all.size - 1
+          ECS::Components.constants.each do |constant|
+            unless (signatures[entity_id] & ECS::Components::const_get(constant).id).zero?
+              ECS::Components::const_get(constant).delete(entity_id)
+            end
+          end
+          all.pop
+          signatures.pop
+        else
+          puts 'Unknown error with destroy_entity, entity not destroyed'
+        end
+      end
+    end
+  end
+end