1 files changed, 69 insertions, 0 deletions
diff --git a/lib/felecs/scene_manager.rb b/lib/felecs/scene_manager.rb
new file mode 100644
index 0000000..af61b9c
--- /dev/null
+++ b/lib/felecs/scene_manager.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+module FelECS
+  class Scenes
+    # Allows overwriting the storage of systems, such as for clearing.
+    # This method should generally only need to be used internally and
+    # not by a game developer/
+    # @!visibility private
+    attr_writer :systems
+
+    # How early this Scene should be executed in a list of Scenes
+    attr_accessor :priority
+
+    def priority=(priority)
+      @priority = priority
+      FelECS::Stage.scenes = FelECS::Stage.scenes.sort_by(&:priority)
+      priority
+    end
+
+    # Create a new Scene using the name given
+    # @param name [String] String format must follow requirements of a constant
+    def initialize(name, priority: 0)
+      self.priority = priority
+      FelECS::Scenes.const_set(name, self)
+    end
+
+    # The list of Systems this Scene contains
+    # @return [Array<System>]
+    def systems
+      @systems ||= []
+    end
+
+    # Execute all systems in this Scene, in the order of their priority
+    # @return [Boolean] +true+
+    def call
+      systems.each(&:call)
+      true
+    end
+
+    # Adds any number of Systems to this Scene
+    # @return [Boolean] +true+
+    def add(*systems_to_add)
+      self.systems |= systems_to_add
+      self.systems = systems.sort_by(&:priority)
+      systems_to_add.each do |system|
+        system.scenes |= [self]
+      end
+      true
+    end
+
+    # Removes any number of Systems from this Scene
+    # @return [Boolean] +true+
+    def remove(*systems_to_remove)
+      self.systems -= systems_to_remove
+      true
+    end
+
+    # Removes all Systems from this Scene
+    # @return [Boolean] +true+
+    def clear
+      systems.each do |system|
+        system.scenes.delete self
+      end
+      systems.clear
+      # FelECS::Stage.update_systems_list if FelECS::Stage.scenes.include? self
+      true
+    end
+  end
+end