// Distributed under the MIT License (MIT) (see accompanying LICENSE file)

#pragma once

#include <Containers/Map.h>
#include <Delegates/Delegate.h>


struct FImGuiDelegatesContainer
{
public:

	// Get the current instance (can change during hot-reloading).
	static FImGuiDelegatesContainer& Get() { return *InstancePtr; }

	// If this is an active container move its data to a destination and redirect all future calls to that instance.
	static void MoveContainer(FImGuiDelegatesContainer& Dst);

	// Get delegate to ImGui world early debug event from known world instance.
	FSimpleMulticastDelegate& OnWorldEarlyDebug(UWorld* World) { return OnWorldEarlyDebug(GetContextIndex(World)); }

	// Get delegate to ImGui world early debug event from known context index.
	FSimpleMulticastDelegate& OnWorldEarlyDebug(int32 ContextIndex) { return WorldEarlyDebugDelegates.FindOrAdd(ContextIndex); }

	// Get delegate to ImGui multi-context early debug event.
	FSimpleMulticastDelegate& OnMultiContextEarlyDebug() { return MultiContextEarlyDebugDelegate; }

	// Get delegate to ImGui world debug event from known world instance.
	FSimpleMulticastDelegate& OnWorldDebug(UWorld* World) { return OnWorldDebug(GetContextIndex(World)); }

	// Get delegate to ImGui world debug event from known context index.
	FSimpleMulticastDelegate& OnWorldDebug(int32 ContextIndex) { return WorldDebugDelegates.FindOrAdd(ContextIndex); }

	// Get delegate to ImGui multi-context debug event.
	FSimpleMulticastDelegate& OnMultiContextDebug() { return MultiContextDebugDelegate; }

private:

	int32 GetContextIndex(UWorld* World);

	void Clear();

	TMap<int32, FSimpleMulticastDelegate> WorldEarlyDebugDelegates;
	TMap<int32, FSimpleMulticastDelegate> WorldDebugDelegates;
	FSimpleMulticastDelegate MultiContextEarlyDebugDelegate;
	FSimpleMulticastDelegate MultiContextDebugDelegate;

	// Default container instance.
	static FImGuiDelegatesContainer DefaultInstance;

	// Pointer to the container instance that can be overwritten during hot-reloading.
	static FImGuiDelegatesContainer* InstancePtr;
};