// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.
#include "WorldBrowserPrivatePCH.h"

#include "Engine/WorldComposition.h"
#include "ModuleManager.h"
#include "StreamingLevels/StreamingLevelEdMode.h"
#include "Tiles/WorldTileCollectionModel.h"
#include "StreamingLevels/StreamingLevelCollectionModel.h"
#include "SWorldHierarchy.h"
#include "SWorldDetails.h"
#include "Tiles/SWorldComposition.h"


IMPLEMENT_MODULE( FWorldBrowserModule, WorldBrowser );

#define LOCTEXT_NAMESPACE "WorldBrowser"

void FWorldBrowserModule::StartupModule()
{
	FLevelCollectionCommands::Register();

	// register the editor mode
	FEditorModeRegistry::Get().RegisterMode<FStreamingLevelEdMode>(
		FBuiltinEditorModes::EM_StreamingLevel,
		NSLOCTEXT("WorldBrowser", "StreamingLevelMode", "Level Transform Editing"));

	if (ensure(GEngine))
	{
		GEngine->OnWorldAdded().AddRaw(this, &FWorldBrowserModule::OnWorldCreated);
		GEngine->OnWorldDestroyed().AddRaw(this, &FWorldBrowserModule::OnWorldDestroyed);
	}

	UWorldComposition::WorldCompositionChangedEvent.AddRaw(this, &FWorldBrowserModule::OnWorldCompositionChanged);
}

void FWorldBrowserModule::ShutdownModule()
{
	if (GEngine)
	{
		GEngine->OnWorldAdded().RemoveAll(this);
		GEngine->OnWorldDestroyed().RemoveAll(this);
	}

	UWorldComposition::WorldCompositionChangedEvent.RemoveAll(this);
	
	FLevelCollectionCommands::Unregister();

	// unregister the editor mode
	FEditorModeRegistry::Get().UnregisterMode(FBuiltinEditorModes::EM_StreamingLevel);
}

TSharedRef<SWidget> FWorldBrowserModule::CreateWorldBrowserHierarchy()
{
	UWorld* EditorWorld = GEditor->GetEditorWorldContext().World();
	return SNew(SWorldHierarchy).InWorld(EditorWorld);
}
	
TSharedRef<SWidget> FWorldBrowserModule::CreateWorldBrowserDetails()
{
	UWorld* EditorWorld = GEditor->GetEditorWorldContext().World();
	return SNew(SWorldDetails).InWorld(EditorWorld);
}

TSharedRef<SWidget> FWorldBrowserModule::CreateWorldBrowserComposition()
{
	UWorld* EditorWorld = GEditor->GetEditorWorldContext().World();
	return SNew(SWorldComposition).InWorld(EditorWorld);
}

void FWorldBrowserModule::OnWorldCreated(UWorld* InWorld)
{
	if (InWorld && 
		InWorld->WorldType == EWorldType::Editor)
	{
		OnBrowseWorld.Broadcast(InWorld);
	}
}

void FWorldBrowserModule::OnWorldCompositionChanged(UWorld* InWorld)
{
	if (InWorld && 
		InWorld->WorldType == EWorldType::Editor)
	{
		OnBrowseWorld.Broadcast(NULL);
		OnBrowseWorld.Broadcast(InWorld);
	}
}

void FWorldBrowserModule::OnWorldDestroyed(UWorld* InWorld)
{
	TSharedPtr<FLevelCollectionModel> SharedWorldModel = WorldModel.Pin();
	// Is there any editors alive?
	if (SharedWorldModel.IsValid())
	{
		UWorld* ManagedWorld = SharedWorldModel->GetWorld(/*bEvenIfPendingKill*/true);
		// Is it our world gets cleaned up?
		if (ManagedWorld == InWorld)
		{
			// Will reset all references to a shared world model
			OnBrowseWorld.Broadcast(NULL);
			// So we have to be the last owner of this model
			check(SharedWorldModel.IsUnique());
		}
	}
}

TSharedPtr<FLevelCollectionModel> FWorldBrowserModule::SharedWorldModel(UWorld* InWorld)
{
	TSharedPtr<FLevelCollectionModel> SharedWorldModel = WorldModel.Pin();
	if (!SharedWorldModel.IsValid() || SharedWorldModel->GetWorld() != InWorld)
	{
		if (InWorld)
		{
			if (InWorld->WorldComposition)
			{
				SharedWorldModel = FWorldTileCollectionModel::Create(GEditor, InWorld);
			}
			else
			{
				SharedWorldModel = FStreamingLevelCollectionModel::Create(GEditor, InWorld);
			}
		}

		// Hold weak reference to shared world model
		WorldModel = SharedWorldModel;
	}
	
	return SharedWorldModel;
}

#undef LOCTEXT_NAMESPACE