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


#include "Widgets/BagShapeGridWidget.h"

const float SBagShapeGridWidget::CellSize = 32.0f;
const float SBagShapeGridWidget::SeparatorWidth = 2.0f;
void SBagShapeGridWidget::Construct(const FArguments& InArgs)
{
	BagShapeAsset = InArgs._BagShapeAsset;
	OnSlotClicked = InArgs._OnSlotClicked;
}

void SBagShapeGridWidget::UpdateBagShapeAsset(UBagShapeAsset* InBagShapeAsset)
{
	BagShapeAsset = InBagShapeAsset;
	Invalidate(EInvalidateWidget::Paint);
}

FReply SBagShapeGridWidget::OnMouseButtonDown(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
{
	if (MouseEvent.GetEffectingButton() == EKeys::LeftMouseButton && BagShapeAsset.IsValid())
	{
		FVector2D LocalPosition = MyGeometry.AbsoluteToLocal(MouseEvent.GetScreenSpacePosition());
		FVector2D GridCell = GetGridCellFromPosition(LocalPosition);
        
		int32 GridX = FMath::FloorToInt(GridCell.X);
		int32 GridY = FMath::FloorToInt(GridCell.Y);

		if (IsValidGridPosition(GridX, GridY))
		{
			OnSlotClicked.ExecuteIfBound(GridX, GridY);
			return FReply::Handled();
		}
	}

	return FReply::Unhandled();
}

int32 SBagShapeGridWidget::OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry,
                                   const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId,
                                   const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const
{
 if (!BagShapeAsset.IsValid())
    {
        return LayerId;
    }

    // Calculate grid dimensions with separators
    float Scale = CellSize + SeparatorWidth;
    float GridWidth = BagShapeAsset->BagWidth * Scale - SeparatorWidth;
    float GridHeight = BagShapeAsset->BagHeight * Scale - SeparatorWidth;
    
    // Center the grid in the available space
    FVector2D GridStartPos = FVector2D(
        (AllottedGeometry.GetLocalSize().X - GridWidth) * 0.5f,
        (AllottedGeometry.GetLocalSize().Y - GridHeight) * 0.5f
    );

    // Draw background
    FSlateDrawElement::MakeBox(
        OutDrawElements,
        LayerId,
        AllottedGeometry.ToPaintGeometry(AllottedGeometry.GetLocalSize(), FSlateLayoutTransform()),
        FCoreStyle::Get().GetBrush("WhiteBrush"),
        ESlateDrawEffect::None,
        FLinearColor(0.1f, 0.1f, 0.1f, 1.0f)
    );

    // Draw cells
    for (int32 Y = 0; Y < BagShapeAsset->BagHeight; Y++)
    {
        for (int32 X = 0; X < BagShapeAsset->BagWidth; X++)
        {
            FVector2D CellPos = GridStartPos + FVector2D(X * Scale, Y * Scale);
            bool bIsActive = BagShapeAsset->IsSlotActive(X, Y);
            
            // Draw cell background
            FLinearColor CellColor = bIsActive ? FLinearColor(0.2f, 0.8f, 0.2f, 1.0f) : FLinearColor(0.15f, 0.15f, 0.15f, 1.0f);
            FSlateDrawElement::MakeBox(
                OutDrawElements,
                LayerId + 1,
                AllottedGeometry.ToPaintGeometry(FVector2D(CellSize, CellSize), FSlateLayoutTransform(CellPos)),
                FCoreStyle::Get().GetBrush("WhiteBrush"),
                ESlateDrawEffect::None,
                CellColor
            );
        }
    }
    
    // Draw vertical separators
    for (int32 X = 1; X < BagShapeAsset->BagWidth; X++)
    {
        float SeparatorX = GridStartPos.X + X * Scale - SeparatorWidth;
        FSlateDrawElement::MakeBox(
            OutDrawElements,
            LayerId + 2,
            AllottedGeometry.ToPaintGeometry(FVector2D(SeparatorWidth, GridHeight), FSlateLayoutTransform(FVector2D(SeparatorX, GridStartPos.Y))),
            FCoreStyle::Get().GetBrush("WhiteBrush"),
            ESlateDrawEffect::None,
            FLinearColor::White
        );
    }
    
    // Draw horizontal separators
    for (int32 Y = 1; Y < BagShapeAsset->BagHeight; Y++)
    {
        float SeparatorY = GridStartPos.Y + Y * Scale - SeparatorWidth;
        FSlateDrawElement::MakeBox(
            OutDrawElements,
            LayerId + 2,
            AllottedGeometry.ToPaintGeometry(FVector2D(GridWidth, SeparatorWidth), FSlateLayoutTransform(FVector2D(GridStartPos.X, SeparatorY))),
            FCoreStyle::Get().GetBrush("WhiteBrush"),
            ESlateDrawEffect::None,
            FLinearColor::White
        );
    }

    // Draw outer border
    FSlateDrawElement::MakeBox(
        OutDrawElements,
        LayerId + 3,
        AllottedGeometry.ToPaintGeometry(FVector2D(GridWidth, GridHeight), FSlateLayoutTransform(GridStartPos)),
        FCoreStyle::Get().GetBrush("Border"),
        ESlateDrawEffect::None,
        FLinearColor::White
    );

    return LayerId + 4;
}

FVector2D SBagShapeGridWidget::ComputeDesiredSize(float X) const
{
	if (!BagShapeAsset.IsValid())
	{
		return FVector2D(200, 200);
	}

	float Scale = CellSize + SeparatorWidth;
	return FVector2D(
		BagShapeAsset->BagWidth * Scale - SeparatorWidth + 20.0f, // Add padding
		BagShapeAsset->BagHeight * Scale - SeparatorWidth + 20.0f
	);
}

FVector2D SBagShapeGridWidget::GetGridCellFromPosition(const FVector2D& Position) const
{
	if (!BagShapeAsset.IsValid())
	{
		return FVector2D(-1, -1);
	}

	float Scale = CellSize + SeparatorWidth;
	float GridWidth = BagShapeAsset->BagWidth * Scale - SeparatorWidth;
	float GridHeight = BagShapeAsset->BagHeight * Scale - SeparatorWidth;
    
	FVector2D GridStartPos = FVector2D(
		(GetCachedGeometry().GetLocalSize().X - GridWidth) * 0.5f,
		(GetCachedGeometry().GetLocalSize().Y - GridHeight) * 0.5f
	);

	FVector2D RelativePos = Position - GridStartPos;
    
	return FVector2D(
		RelativePos.X / Scale,
		RelativePos.Y / Scale
	);
}

bool SBagShapeGridWidget::IsValidGridPosition(int32 X, int32 Y) const
{
	if (!BagShapeAsset.IsValid())
	{
		return false;
	}
	return X >= 0 && X < BagShapeAsset->BagWidth && Y >= 0 && Y < BagShapeAsset->BagHeight;
}