From 34ee3f0a6eaa5e401d28348e5855be2d64778081 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 19 Aug 2022 09:49:14 +0300
Subject: [PATCH] Support ecs behavior forbidden components that prevent
 applying it to a certain species

---
 libs/util/include/psemek/util/ecs.hpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/libs/util/include/psemek/util/ecs.hpp b/libs/util/include/psemek/util/ecs.hpp
index ce65fbd3..617b536a 100644
--- a/libs/util/include/psemek/util/ecs.hpp
+++ b/libs/util/include/psemek/util/ecs.hpp
@@ -89,6 +89,8 @@ namespace psemek::util
 			template <typename Behavior, typename ... Args>
 			void apply(Behavior & behavior, Args const & ... args)
 			{
+				if (!check_forbidden(behavior, 0))
+					return;
 				apply_impl(behavior, static_cast<typename Behavior::component_types *>(nullptr), std::make_index_sequence<std::tuple_size_v<typename Behavior::component_types>>{}, args...);
 			}
 
@@ -103,6 +105,24 @@ namespace psemek::util
 			std::string name_;
 			species_handle id_;
 
+			template <typename Behavior>
+			bool check_forbidden(Behavior &, typename Behavior::forbidden_component_types * helper)
+			{
+				return check_forbidden_impl(helper);
+			}
+
+			template <typename Behavior>
+			bool check_forbidden(Behavior &, ...)
+			{
+				return true;
+			}
+
+			template <typename ... Components>
+			bool check_forbidden_impl(std::tuple<Components...> *)
+			{
+				return (!get_species_component<Components>() && ...);
+			}
+
 			template <typename Behavior, typename ... Components, std::size_t ... Is, typename ... Args>
 			void apply_impl(Behavior & behavior, std::tuple<Components...> *, std::index_sequence<Is...>, Args const & ... args)
 			{
@@ -395,6 +415,12 @@ namespace psemek::util
 			friend auto operator <=> (entity_handle const &, entity_handle const &) = default;
 		};
 
+		template <typename ... Components>
+		struct without
+		{
+			using forbidden_component_types = std::tuple<Components...>;
+		};
+
 		template <typename ... Components>
 		struct behavior
 		{