// Copyright Epic Games, Inc. All Rights Reserved.

#include "EditorDragTools.h"
#include "InputCoreTypes.h"
#include "EditorViewportClient.h"
#include "Editor.h"
#include "SnappingUtils.h"

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// FDragTool
//
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

FDragTool::FDragTool(FEditorModeTools* InModeTools)
    : bConvertDelta(true), ModeTools(InModeTools), Start(FVector::ZeroVector), End(FVector::ZeroVector), EndWk(FVector::ZeroVector), bUseSnapping(false), bIsDragging(false)
{
}

void FDragTool::AddDelta(const FVector& InDelta)
{
    EndWk += InDelta;

    End = EndWk;

    // Snap to constraints.
    if (bUseSnapping)
    {
        const float GridSize = GEditor->GetGridSize();
        const FVector GridBase(GridSize, GridSize, GridSize);
        FSnappingUtils::SnapPointToGrid(End, GridBase);
    }
}

void FDragTool::StartDrag(FEditorViewportClient* InViewportClient, const FVector& InStart, const FVector2D& StartScreen)
{
    Start       = InStart;
    bIsDragging = true;

    // Snap to constraints.
    if (bUseSnapping)
    {
        const float GridSize = GEditor->GetGridSize();
        const FVector GridBase(GridSize, GridSize, GridSize);
        FSnappingUtils::SnapPointToGrid(Start, GridBase);
    }
    End = EndWk = Start;

    // Store button state when the drag began.
    bAltDown               = InViewportClient->IsAltPressed();
    bShiftDown             = InViewportClient->IsShiftPressed();
    bControlDown           = InViewportClient->IsCtrlPressed();
    bLeftMouseButtonDown   = InViewportClient->Viewport->KeyState(EKeys::LeftMouseButton);
    bRightMouseButtonDown  = InViewportClient->Viewport->KeyState(EKeys::RightMouseButton);
    bMiddleMouseButtonDown = InViewportClient->Viewport->KeyState(EKeys::MiddleMouseButton);
}

void FDragTool::EndDrag()
{
    Start = End = EndWk = FVector::ZeroVector;
    bIsDragging         = false;
}