// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#include "Blueprint/WidgetTree.h"
#include "Components/Visual.h"
#include "Components/Widget.h"
#include "Blueprint/UserWidget.h"

/////////////////////////////////////////////////////
// UWidgetTree

UWidgetTree::UWidgetTree(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
}

UWorld* UWidgetTree::GetWorld() const
{
	// The outer of a widget tree should be a user widget
	if ( UUserWidget* OwningWidget = Cast<UUserWidget>(GetOuter()) )
	{
		return OwningWidget->GetWorld();
	}

	return nullptr;
}

UWidget* UWidgetTree::FindWidget(const FName& Name) const
{
	UWidget* FoundWidget = nullptr;

	ForEachWidget([&] (UWidget* Widget) {
		if ( Widget->GetFName() == Name )
		{
			FoundWidget = Widget;
		}
	});

	return FoundWidget;
}

UWidget* UWidgetTree::FindWidget(TSharedRef<SWidget> InWidget) const
{
	UWidget* FoundWidget = nullptr;

	ForEachWidget([&] (UWidget* Widget) {
		if ( Widget->GetCachedWidget() == InWidget )
		{
			FoundWidget = Widget;
		}
	});

	return FoundWidget;
}

UPanelWidget* UWidgetTree::FindWidgetParent(UWidget* Widget, int32& OutChildIndex)
{
	UPanelWidget* Parent = Widget->GetParent();
	if ( Parent != nullptr )
	{
		OutChildIndex = Parent->GetChildIndex(Widget);
	}
	else
	{
		OutChildIndex = 0;
	}

	return Parent;
}

bool UWidgetTree::RemoveWidget(UWidget* InRemovedWidget)
{
	bool bRemoved = false;

	UPanelWidget* InRemovedWidgetParent = InRemovedWidget->GetParent();
	if ( InRemovedWidgetParent )
	{
		if ( InRemovedWidgetParent->RemoveChild(InRemovedWidget) )
		{
			bRemoved = true;
		}
	}
	// If the widget being removed is the root, null it out.
	else if ( InRemovedWidget == RootWidget )
	{
		RootWidget = NULL;
		bRemoved = true;
	}

	return bRemoved;
}

bool UWidgetTree::TryMoveWidgetToNewTree(UWidget* Widget, UWidgetTree* DestinationTree)
{
	bool bWidgetMoved = false;

	// A Widget's Outer is always a WidgetTree
	UWidgetTree* OriginalTree = Widget ? Cast<UWidgetTree>(Widget->GetOuter()) : nullptr;

	if (DestinationTree && OriginalTree && OriginalTree != DestinationTree)
	{
		bWidgetMoved = Widget->Rename(*Widget->GetName(), DestinationTree, REN_ForceNoResetLoaders | REN_DontCreateRedirectors);
	}

	return bWidgetMoved;
}

void UWidgetTree::GetAllWidgets(TArray<UWidget*>& Widgets) const
{
	ForEachWidget([&Widgets] (UWidget* Widget) {
		Widgets.Add(Widget);
	});
}

void UWidgetTree::GetChildWidgets(UWidget* Parent, TArray<UWidget*>& Widgets)
{
	ForWidgetAndChildren(Parent, [&Widgets] (UWidget* Widget) {
		Widgets.Add(Widget);
	});
}

void UWidgetTree::ForEachWidget(TFunctionRef<void(UWidget*)> Predicate) const
{
	if ( RootWidget )
	{
		Predicate(RootWidget);

		ForWidgetAndChildren(RootWidget, Predicate);
	}
}

void UWidgetTree::ForEachWidgetAndDescendants(TFunctionRef<void(UWidget*)> Predicate) const
{
	if ( RootWidget )
	{
		Predicate(RootWidget);

		ForWidgetAndChildren(RootWidget, [&Predicate] (UWidget* Child) {
			if ( UUserWidget* UserWidgetChild = Cast<UUserWidget>(Child) )
			{
				if ( UserWidgetChild->WidgetTree )
				{
					UserWidgetChild->WidgetTree->ForEachWidgetAndDescendants(Predicate);
				}
			}
			else
			{
				Predicate(Child);
			}
		});
	}
}

void UWidgetTree::ForWidgetAndChildren(UWidget* Widget, TFunctionRef<void(UWidget*)> Predicate)
{
	// Search for any named slot with content that we need to dive into.
	if ( INamedSlotInterface* NamedSlotHost = Cast<INamedSlotInterface>(Widget) )
	{
		TArray<FName> SlotNames;
		NamedSlotHost->GetSlotNames(SlotNames);

		for ( FName SlotName : SlotNames )
		{
			if ( UWidget* SlotContent = NamedSlotHost->GetContentForSlot(SlotName) )
			{
				Predicate(SlotContent);

				ForWidgetAndChildren(SlotContent, Predicate);
			}
		}
	}

	// Search standard children.
	if ( UPanelWidget* PanelParent = Cast<UPanelWidget>(Widget) )
	{
		for ( int32 ChildIndex = 0; ChildIndex < PanelParent->GetChildrenCount(); ChildIndex++ )
		{
			if ( UWidget* ChildWidget = PanelParent->GetChildAt(ChildIndex) )
			{
				Predicate(ChildWidget);

				ForWidgetAndChildren(ChildWidget, Predicate);
			}
		}
	}
}

void UWidgetTree::PreSave(const class ITargetPlatform* TargetPlatform)
{
	AllWidgets.Empty();

	GetAllWidgets(AllWidgets);

	Super::PreSave( TargetPlatform);
}

void UWidgetTree::PostLoad()
{
	Super::PostLoad();
	AllWidgets.Empty();
}