From 103c703208eded2cc4a7347510cc10be24665b3c Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Fri, 14 Aug 2020 14:10:13 +0200
Subject: [PATCH] Add cool new c++ 20 constraint to EventHook.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>
---
 src/Battling/EventHooks/EventHook.hpp | 4 +++-
 src/Battling/Models/Battle.hpp        | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Battling/EventHooks/EventHook.hpp b/src/Battling/EventHooks/EventHook.hpp
index 5edfb6d..66ea46b 100644
--- a/src/Battling/EventHooks/EventHook.hpp
+++ b/src/Battling/EventHooks/EventHook.hpp
@@ -7,6 +7,8 @@
 #include "../../Library/Exceptions/CreatureException.hpp"
 #include "Events/EventData.hpp"
 
+template <class T> concept Event = std::is_base_of<CreatureLib::Battling::EventData, T>::value;
+
 namespace CreatureLib::Battling {
     /// The Event Hook class allows users to write consumers for the battle events, for example to write User Interfaces
     /// for it.
@@ -39,7 +41,7 @@ namespace CreatureLib::Battling {
         size_t GetPosition() const noexcept { return _offset; }
         size_t GetCapacity() const noexcept { return _capacity; }
 
-        template <class T, class... parameters> void Trigger(parameters... args) {
+        template <Event T, class... parameters> void Trigger(parameters... args) {
             if (_listeners.size() == 0)
                 return;
 
diff --git a/src/Battling/Models/Battle.hpp b/src/Battling/Models/Battle.hpp
index e63c9f8..a51d956 100644
--- a/src/Battling/Models/Battle.hpp
+++ b/src/Battling/Models/Battle.hpp
@@ -100,7 +100,7 @@ namespace CreatureLib::Battling {
 
         void DisplayText(const ArbUt::StringView& text);
         void RegisterEventListener(EventHook::EventHookFunc listener) { this->_eventHook.RegisterListener(listener); }
-        template <class T, class... parameters> void TriggerEventListener(parameters... args) {
+        template <Event T, class... parameters> void TriggerEventListener(parameters... args) {
             this->_eventHook.Trigger<T>(args...);
         }
     };