// Copyright 1998-2014 Epic Games, Inc. All Rights Reserved.

#include "ComponentVisualizersPrivatePCH.h"
#include "SplineComponentVisualizer.h"

IMPLEMENT_HIT_PROXY(HSplineVisProxy, HComponentVisProxy);
IMPLEMENT_HIT_PROXY(HSplineKeyProxy, HSplineVisProxy);

#define LOCTEXT_NAMESPACE "SplineComponentVisualizer"


/** Define commands for the spline component visualizer */
class FSplineComponentVisualizerCommands : public TCommands<FSplineComponentVisualizerCommands>
{
public:
	FSplineComponentVisualizerCommands() : TCommands <FSplineComponentVisualizerCommands>
	(
		"SplineComponentVisualizer",	// Context name for fast lookup
		LOCTEXT("SplineComponentVisualizer", "Spline Component Visualizer"),	// Localized context name for displaying
		NAME_None,	// Parent
		FEditorStyle::GetStyleSetName()
	)
	{
	}

	virtual void RegisterCommands() override
	{
		UI_COMMAND(DeleteKey, "Delete key", "Delete the currently selected key.", EUserInterfaceActionType::Button, FInputGesture(EKeys::Delete));
		UI_COMMAND(DuplicateKey, "Duplicate key", "Duplicates the currently selected key.", EUserInterfaceActionType::Button, FInputGesture());
		UI_COMMAND(ResetToAutomaticTangent, "Reset to Automatic Tangent", "Specify that the tangent for this key will be reset to its default auto-generated value.", EUserInterfaceActionType::Button, FInputGesture());
	}

public:
	/** Delete key */
	TSharedPtr<FUICommandInfo> DeleteKey;

	/** Duplicate key */
	TSharedPtr<FUICommandInfo> DuplicateKey;

	/** Reset to automatic tangent */
	TSharedPtr<FUICommandInfo> ResetToAutomaticTangent;
};



FSplineComponentVisualizer::FSplineComponentVisualizer()
	: FComponentVisualizer()
	, SelectedKeyIndex(INDEX_NONE)
	, bAllowDuplication(true)
{
	FSplineComponentVisualizerCommands::Register();

	SplineComponentVisualizerActions = MakeShareable(new FUICommandList);
}

void FSplineComponentVisualizer::OnRegister()
{
	const auto& Commands = FSplineComponentVisualizerCommands::Get();

	SplineComponentVisualizerActions->MapAction(
		Commands.DeleteKey,
		FExecuteAction::CreateSP(this, &FSplineComponentVisualizer::OnDeleteKey),
		FCanExecuteAction::CreateSP(this, &FSplineComponentVisualizer::IsSelectionValid));

	SplineComponentVisualizerActions->MapAction(
		Commands.DuplicateKey,
		FExecuteAction::CreateSP(this, &FSplineComponentVisualizer::OnDuplicateKey),
		FCanExecuteAction::CreateSP(this, &FSplineComponentVisualizer::IsSelectionValid));

	SplineComponentVisualizerActions->MapAction(
		Commands.ResetToAutomaticTangent,
		FExecuteAction::CreateSP(this, &FSplineComponentVisualizer::OnResetToAutomaticTangent),
		FCanExecuteAction::CreateSP(this, &FSplineComponentVisualizer::CanResetToAutomaticTangent));
}

FSplineComponentVisualizer::~FSplineComponentVisualizer()
{
	FSplineComponentVisualizerCommands::Unregister();
}

void FSplineComponentVisualizer::DrawVisualization(const UActorComponent* Component, const FSceneView* View, FPrimitiveDrawInterface* PDI)
{
	if (const USplineComponent* SplineComp = Cast<const USplineComponent>(Component))
	{
		const FColor DrawColor(255, 255, 255);
		const FColor SelectedColor(255, 0, 0);
		const float GrabHandleSize = 12.0f;

		const FInterpCurveVector& SplineInfo = SplineComp->SplineInfo;

		/*
		// Debug draw keys on the SplineReparamTable
		const FInterpCurveFloat& SplineReparamTable = SplineComp->SplineReparamTable;
		for (const auto& Point : SplineReparamTable.Points)
		{
			const float Value = Point.OutVal;
			FVector KeyPos = SplineComp->ComponentToWorld.TransformPosition(SplineInfo.Eval(Value, FVector::ZeroVector));
			PDI->DrawPoint(KeyPos, FColor(255, 0, 255), 5.f, SDPG_World);
		}
		*/

		FVector OldKeyPos(0);
		float OldKeyTime = 0.f;
		for (int32 KeyIdx = 0; KeyIdx<SplineInfo.Points.Num(); KeyIdx++)
		{
			float NewKeyTime = SplineInfo.Points[KeyIdx].InVal;
			FVector NewKeyPos = SplineComp->ComponentToWorld.TransformPosition( SplineInfo.Eval(NewKeyTime, FVector::ZeroVector) );

			USplineComponent* EditedSplineComp = GetEditedSplineComponent();
			const FColor KeyColor = (SplineComp == EditedSplineComp && KeyIdx == SelectedKeyIndex) ? SelectedColor : DrawColor;

			// Draw the keypoint
			PDI->SetHitProxy(new HSplineKeyProxy(Component, KeyIdx));

			PDI->DrawPoint(NewKeyPos, KeyColor, GrabHandleSize, SDPG_Foreground);

			PDI->SetHitProxy(NULL);


			// If not the first keypoint, draw a line to the previous keypoint.
			if (KeyIdx>0)
			{
				// For constant interpolation - don't draw ticks - just draw dotted line.
				if (SplineInfo.Points[KeyIdx - 1].InterpMode == CIM_Constant)
				{
					DrawDashedLine(PDI, OldKeyPos, NewKeyPos, DrawColor, 20, SDPG_World);
				}
				else
				{
					int32 NumSteps = FMath::CeilToInt((NewKeyTime - OldKeyTime) / 0.02f);
					float DrawSubstep = (NewKeyTime - OldKeyTime) / NumSteps;

					// Find position on first keyframe.
					float OldTime = OldKeyTime;
					FVector OldPos = OldKeyPos;

					// Then draw a line for each substep.
					for (int32 StepIdx = 1; StepIdx<NumSteps + 1; StepIdx++)
					{
						float NewTime = OldKeyTime + StepIdx*DrawSubstep;
						FVector NewPos = SplineComp->ComponentToWorld.TransformPosition( SplineInfo.Eval(NewTime, FVector::ZeroVector) );

						PDI->DrawLine(OldPos, NewPos, DrawColor, SDPG_Foreground);

						// Don't draw point for last one - its the keypoint drawn above.
						if (false)// (StepIdx != NumSteps)
						{
							PDI->DrawPoint(NewPos, DrawColor, 3.f, SDPG_Foreground);
						}

						OldTime = NewTime;
						OldPos = NewPos;
					}
				}
			}

			OldKeyTime = NewKeyTime;
			OldKeyPos = NewKeyPos;
		}
	}
}

bool FSplineComponentVisualizer::VisProxyHandleClick(HComponentVisProxy* VisProxy)
{
	bool bEditing = false;

	if(VisProxy && VisProxy->Component.IsValid())
	{
		const USplineComponent* SplineComp = CastChecked<const USplineComponent>(VisProxy->Component.Get());

		SplineCompPropName = GetComponentPropertyName(SplineComp);
		if(SplineCompPropName != NAME_None)
		{
			SplineOwningActor = SplineComp->GetOwner();

			if (VisProxy->IsA(HSplineKeyProxy::StaticGetType()))
			{
				HSplineKeyProxy* KeyProxy = (HSplineKeyProxy*)VisProxy;
				SelectedKeyIndex = KeyProxy->KeyIndex;
				bEditing = true;
			}
		}
		else
		{
			SplineOwningActor = NULL;
		}
	}

	return bEditing;
}

USplineComponent* FSplineComponentVisualizer::GetEditedSplineComponent() const
{
	return Cast<USplineComponent>(GetComponentFromPropertyName(SplineOwningActor.Get(), SplineCompPropName));
}


bool FSplineComponentVisualizer::GetWidgetLocation(FVector& OutLocation) const
{
	USplineComponent* SplineComp = GetEditedSplineComponent();
	if (SplineComp && SelectedKeyIndex != INDEX_NONE)
	{
		if (SelectedKeyIndex < SplineComp->SplineInfo.Points.Num())
		{
			OutLocation = SplineComp->ComponentToWorld.TransformPosition( SplineComp->SplineInfo.Points[SelectedKeyIndex].OutVal );
			return true;
		}
	}

	return false;
}


bool FSplineComponentVisualizer::HandleInputDelta(FLevelEditorViewportClient* ViewportClient, FViewport* Viewport, FVector& DeltaTranslate, FRotator& DeltaRotate, FVector& DeltaScale)
{
	USplineComponent* SplineComp = GetEditedSplineComponent();
	if( SplineComp && 
		SelectedKeyIndex != INDEX_NONE &&
		SelectedKeyIndex < SplineComp->SplineInfo.Points.Num() )
	{
		if (ViewportClient->IsAltPressed() && bAllowDuplication)
		{
			OnDuplicateKey();
			// Don't duplicate again until we release LMB
			bAllowDuplication = false;
		}

		FInterpCurvePoint<FVector>& EditedPoint = SplineComp->SplineInfo.Points[SelectedKeyIndex];

		if (!DeltaTranslate.IsZero())
		{
			// Find key position in world space
			FVector CurrentWorldPos = SplineComp->ComponentToWorld.TransformPosition(EditedPoint.OutVal);
			// Move in world space
			FVector NewWorldPos = CurrentWorldPos + DeltaTranslate;
			// Convert back to local space
			EditedPoint.OutVal = SplineComp->ComponentToWorld.InverseTransformPosition(NewWorldPos);
		}

		if (!DeltaRotate.IsZero())
		{
			// Set point tangent as user controlled
			EditedPoint.InterpMode = CIM_CurveUser;

			// Rotate tangent according to delta rotation
			const FVector NewTangent = DeltaRotate.RotateVector(EditedPoint.LeaveTangent);
			EditedPoint.LeaveTangent = NewTangent;
			EditedPoint.ArriveTangent = NewTangent;
		}

		if (!DeltaScale.IsZero())
		{
			// Set point tangent as user controlled
			EditedPoint.InterpMode = CIM_CurveUser;

			// Break tangent into direction and length so we can change its scale (the 'tension')
			// independently of its direction.
			FVector Direction;
			float Length;
			EditedPoint.LeaveTangent.ToDirectionAndLength(Direction, Length);

			// Figure out which component has changed, and use it
			float DeltaScaleValue = (DeltaScale.X != 0.0f) ? DeltaScale.X : ((DeltaScale.Y != 0.0f) ? DeltaScale.Y : DeltaScale.Z);

			// Change scale, avoiding singularity by never allowing a scale of 0, hence preserving direction.
			Length += DeltaScaleValue * 10.0f;
			if (Length == 0.0f)
			{
				Length = SMALL_NUMBER;
			}

			const FVector NewTangent = Direction * Length;
			EditedPoint.LeaveTangent = NewTangent;
			EditedPoint.ArriveTangent = NewTangent;
		}

		NotifyComponentModified();

		return true;
	}

	return false;
}

bool FSplineComponentVisualizer::HandleInputKey(FLevelEditorViewportClient* ViewportClient, FViewport* Viewport, FKey Key, EInputEvent Event)
{
	// TODO: find a way to make this work with ProcessCommandBindings(FKeyboardEvent&)

	bool bHandled = false;

	if(Key == EKeys::LeftMouseButton && Event == IE_Released)
	{
		// Reset duplication flag on LMB release
		bAllowDuplication = true;
	}
	else if(Key == EKeys::Delete && Event == IE_Pressed)
	{
		// Delete selected key
		if (IsSelectionValid())
		{
			OnDeleteKey();
			bHandled = true; // consume key input
		}
	}

	return bHandled;
}


void FSplineComponentVisualizer::EndEditing()
{
	SplineOwningActor = NULL;
	SplineCompPropName = NAME_None;
	SelectedKeyIndex = INDEX_NONE;
}


void FSplineComponentVisualizer::OnDuplicateKey()
{
	USplineComponent* SplineComp = GetEditedSplineComponent();

	FInterpCurvePoint<FVector> KeyToDupe = SplineComp->SplineInfo.Points[SelectedKeyIndex];
	KeyToDupe.InterpMode = CIM_CurveAuto;
	int32 NewKeyIndex = SplineComp->SplineInfo.Points.Insert(KeyToDupe, SelectedKeyIndex);
	// move selection to 'next' key
	SelectedKeyIndex++;

	// Update Input value for all keys
	SplineComp->RefreshSplineInputs();

	NotifyComponentModified();
}

void FSplineComponentVisualizer::OnDeleteKey()
{
	USplineComponent* SplineComp = GetEditedSplineComponent();

	SplineComp->SplineInfo.Points.RemoveAt(SelectedKeyIndex);

	SplineComp->RefreshSplineInputs(); // update input value for each key
	SelectedKeyIndex = INDEX_NONE; // deselect any keys

	NotifyComponentModified();
}

bool FSplineComponentVisualizer::IsSelectionValid() const
{
	USplineComponent* SplineComp = GetEditedSplineComponent();
	return (SplineComp &&
		SelectedKeyIndex != INDEX_NONE &&
		SelectedKeyIndex < SplineComp->SplineInfo.Points.Num());
}


void FSplineComponentVisualizer::OnResetToAutomaticTangent()
{
	USplineComponent* SplineComp = GetEditedSplineComponent();
	SplineComp->SplineInfo.Points[SelectedKeyIndex].InterpMode = CIM_CurveAuto;

	NotifyComponentModified();
}

bool FSplineComponentVisualizer::CanResetToAutomaticTangent() const
{
	USplineComponent* SplineComp = GetEditedSplineComponent();
	return (SplineComp &&
		SelectedKeyIndex != INDEX_NONE &&
		SelectedKeyIndex < SplineComp->SplineInfo.Points.Num() &&
		SplineComp->SplineInfo.Points[SelectedKeyIndex].InterpMode != CIM_CurveAuto);
}


TSharedPtr<SWidget> FSplineComponentVisualizer::GenerateContextMenu() const
{
	FMenuBuilder MenuBuilder(true, SplineComponentVisualizerActions);
	{
		MenuBuilder.BeginSection("SplineKeyEdit");
		{
			MenuBuilder.AddMenuEntry(FSplineComponentVisualizerCommands::Get().DeleteKey);
			MenuBuilder.AddMenuEntry(FSplineComponentVisualizerCommands::Get().DuplicateKey);
			MenuBuilder.AddMenuEntry(FSplineComponentVisualizerCommands::Get().ResetToAutomaticTangent);
		}
		MenuBuilder.EndSection();
	}

	TSharedPtr<SWidget> MenuWidget = MenuBuilder.MakeWidget();
	return MenuWidget;
}

void FSplineComponentVisualizer::NotifyComponentModified()
{
	USplineComponent* SplineComp = GetEditedSplineComponent();

	// Update tangents and reparam table
	SplineComp->SplineInfo.AutoSetTangents();
	SplineComp->UpdateSplineReparamTable();

	// Notify that the spline info has been modified
	UProperty* SplineInfoProperty = FindField<UProperty>(USplineComponent::StaticClass(), GET_MEMBER_NAME_CHECKED(USplineComponent, SplineInfo));
	FPropertyChangedEvent PropertyChangedEvent(SplineInfoProperty);
	SplineComp->PostEditChangeProperty(PropertyChangedEvent);

	// Notify of change so any CS is re-run
	if (SplineOwningActor.IsValid())
	{
		SplineOwningActor.Get()->PostEditMove(true);
	}

	GEditor->RedrawLevelEditingViewports(true);
}

#undef LOCTEXT_NAMESPACE