From e7c973385e85ff628c5e0e2559626fe926eedaf6 Mon Sep 17 00:00:00 2001
From: Rick van Vonderen <0945444@hr.nl>
Date: Mon, 16 Dec 2019 17:30:20 +0100
Subject: [PATCH] Add event class

---
 inferno/src/inferno/core.h        |  7 ++-
 inferno/src/inferno/event/event.h | 89 +++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 1 deletion(-)
 create mode 100644 inferno/src/inferno/event/event.h

diff --git a/inferno/src/inferno/core.h b/inferno/src/inferno/core.h
index a7ff7ed..f7b1cd2 100644
--- a/inferno/src/inferno/core.h
+++ b/inferno/src/inferno/core.h
@@ -1,7 +1,12 @@
 #ifndef CORE_H
 #define CORE_H
 
-#include <csignal>
+#include <csignal> // raise
+#include <functional> // bind
+
+#define BIT(x) (1 << x)
+
+#define NF_BIND_EVENT(f) std::bind(&f, this, std::placeholders::_1)
 
 // Debugging defines
 #ifndef NDEBUG
diff --git a/inferno/src/inferno/event/event.h b/inferno/src/inferno/event/event.h
new file mode 100644
index 0000000..dbc76d7
--- /dev/null
+++ b/inferno/src/inferno/event/event.h
@@ -0,0 +1,89 @@
+#ifndef EVENT_H
+#define EVENT_H
+
+#include <ostream> // ostream
+
+#include "inferno/core.h"
+
+namespace Inferno {
+
+	enum class EventType {
+		None = 0,
+		WindowClose,
+		WindowResize,
+	};
+
+	enum EventCategory {
+		None = 0,
+		ApplicationEventCategory = BIT(0),
+	};
+
+	class Event {
+		// EventDispatcher is allowed to access Event private/protected members
+		friend class EventDispatcher;
+
+	public:
+		virtual ~Event() {}
+
+		virtual std::string toString() const { return getName(); }
+
+		inline bool inCategory(EventCategory category)
+		{
+			return getCategoryFlags() & category;
+		}
+
+// -----------------------------------------
+
+		// Getter function templates
+		virtual char getCategoryFlags() const = 0;
+		virtual const char* getName() const = 0;
+		virtual EventType getType() const = 0;
+
+	protected:
+		bool handled = false;
+	};
+
+	class EventDispatcher {
+	public:
+		EventDispatcher(Event &e) : m_event(e) {}
+
+		// Easily dispatch all type of Events, call with:
+		// dispatch<T>(std::bind(&F, this, std::placeholders::_1));
+		// T is the type of Event
+		// F is the function to call, signature: bool name(T &e);
+		template<typename T, typename F>
+		bool dispatch(const F &function)
+		{
+			// If <constructed> type is same as member variable type
+			if (T::getTypeStatic() == m_event.getType()) {
+				// Call the function
+				m_event.handled = function(static_cast<T &>(m_event));
+				return true;
+			}
+
+			return false;
+		}
+
+	private:
+		Event &m_event;
+	};
+
+	// Add class type functions macro
+#define EVENT_CLASS_TYPE(type) \
+	virtual const char* getName() const override { return #type; } \
+	virtual EventType getType() const override { return getTypeStatic(); } \
+	static inline EventType getTypeStatic() { return EventType::type; }
+
+	// Add class catergory function macro
+#define EVENT_CLASS_CATEGORY(category) \
+	virtual char getCategoryFlags() const override { return category; }
+
+	// Make Events easily printable
+	inline std::ostream& operator<<(std::ostream &os, const Event &e)
+	{
+		return os << e.toString();
+	}
+
+}
+
+#endif // EVENT_H