// Fill out your copyright notice in the Description page of Project Settings.


#include "SUpdatableImage.h"

#include "SlateApplication.h"
#include "SlateOptMacros.h"

BEGIN_SLATE_FUNCTION_BUILD_OPTIMIZATION

SUpdatableImage::SUpdatableImage()
{
	LastSize = FIntPoint::ZeroValue;
	SetVolatilePrepass(false);
}

void SUpdatableImage::Construct(const FArguments& InArgs)
{
	FixedWidth = InArgs._FixedWidth;
	FixedHeight = InArgs._FixedHeight;
	MaxWidth = InArgs._MaxWidth;
	MaxHeight = InArgs._MaxHeight;
	
	Texture = MakeShareable(new FUpdatableTexture(FIntPoint(16, 16)));
	Texture->RedrawImage = InArgs._OnPostResize;
}

void SUpdatableImage::NeedRedraw()
{
	Invalidate(EInvalidateWidgetReason::Paint);
	ForceRedraw = true;
}

void SUpdatableImage::Resize(FIntPoint NewSize, bool Immediate)
{
	if (Immediate)
	{
		if (FixedHeight.IsSet())
			NewSize.Y = FixedHeight.GetValue();
		if (FixedWidth.IsSet())
			NewSize.X = FixedWidth.GetValue();
		if (MaxHeight.IsSet())
			NewSize.Y = FMath::Min(NewSize.Y, MaxHeight.GetValue());
		if (MaxWidth.IsSet())
			NewSize.X = FMath::Min(NewSize.X, MaxWidth.GetValue());
		Texture->Resize(NewSize);
	}
}

void SUpdatableImage::AsyncUpdate() const
{
	Texture->Resize(FIntPoint(LastSize.X, LastSize.Y));
	Texture->RequestUpdate(true);
}

int32 SUpdatableImage::OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const
{
	const auto& CurrentSize = AllottedGeometry.GetAbsoluteSize();
	FIntPoint CurrentSizeInt(CurrentSize.X, CurrentSize.Y);

	if (FixedHeight.IsSet())
		CurrentSizeInt.Y = FixedHeight.GetValue();
	if (FixedWidth.IsSet())
		CurrentSizeInt.X = FixedWidth.GetValue();
	if (MaxHeight.IsSet())
		CurrentSizeInt.Y = FMath::Min(CurrentSizeInt.Y, MaxHeight.GetValue());
	if (MaxWidth.IsSet())
		CurrentSizeInt.X = FMath::Min(CurrentSizeInt.X, MaxWidth.GetValue());
	
	if (ForceRedraw || LastSize != CurrentSizeInt)
	{
		LastSize = CurrentSizeInt;
		ForceRedraw = false;
		AsyncUpdate();
	}
	FSlateDrawElement::MakeViewport(OutDrawElements, LayerId, AllottedGeometry.ToPaintGeometry(), Texture, ESlateDrawEffect::None, FLinearColor::White);
	return ++LayerId;
}

END_SLATE_FUNCTION_BUILD_OPTIMIZATION