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

#pragma once

#include "MathStructCustomizations.h"

/** 
 * Helper class used to track the dirty state of a proxy value
 */
template< typename ObjectType >
class TProxyValue
{
public:
	TProxyValue()
		: Value()
		, bIsSet(false)
	{
	}

	TProxyValue(const ObjectType& InValue)
		: Value(InValue)
		, bIsSet(false)
	{
	}

	/** 
	 * Set the wrapped value
	 * @param	InValue	The value to set.
	 */
	void Set(const ObjectType& InValue)
	{
		Value = InValue;
		bIsSet = true;
	}

	/** 
	 * Get the wrapped value
	 * @return the wrapped value
	 */
	const ObjectType& Get() const
	{
		return Value;
	}

	/** 
	 * Get the wrapped value
	 * @return the wrapped value
	 */
	ObjectType& Get()
	{
		return Value;
	}

	/** 
	 * Check to see if the value is set.
	 * @return whether the value is set.
	 */
	bool IsSet() const
	{
		return bIsSet;
	}

	/** 
	 * Mark the value as if it was set.
	 */
	void MarkAsSet()
	{
		bIsSet = true;
	}

private:
	/** The value we are tracking */
	ObjectType Value;

	/** Whether the value is set */
	bool bIsSet;
};

/**
 * Helper class used to track the state of properties of proxy values.
 */
template< typename ObjectType, typename PropertyType >
class TProxyProperty
{
public:
	TProxyProperty(const TSharedRef< TProxyValue<ObjectType> >& InValue, PropertyType& InPropertyValue)
		: Value(InValue)
		, Property(InPropertyValue)
		, bIsSet(false)
	{
	}

	/**
	 * Set the value of this property
	 * @param	InPropertyValue		The value of the property to set
	 */
	void Set(const PropertyType& InPropertyValue)
	{
		Property = InPropertyValue;
		Value->MarkAsSet();
		bIsSet = true;
	}

	/**
	 * Get the value of this property
	 * @return The value of the property
	 */
	const PropertyType& Get() const
	{
		return Property;
	}

	/** 
	 * Check to see if the value is set.
	 * @return whether the value is set.
	 */
	bool IsSet() const
	{
		return bIsSet;
	}

private:
	/** The proxy value we are tracking */
	TSharedRef< TProxyValue<ObjectType> > Value;

	/** The property of the value we are tracking */
	PropertyType& Property;

	/** Whether the value is set */
	bool bIsSet;
};

/** 
 * Helper class to aid representing math structs to the user in an editable form
 * e.g. representing a quaternion as a set of euler angles
 */
class FMathStructProxyCustomization : public FMathStructCustomization
{
public:
	/** IPropertyTypeCustomization interface */
	virtual void CustomizeChildren( TSharedRef<class IPropertyHandle> StructPropertyHandle, class IDetailChildrenBuilder& StructBuilder, IPropertyTypeCustomizationUtils& StructCustomizationUtils ) OVERRIDE;

	/** FMathStructCustomization interface */
	virtual void MakeHeaderRow( TSharedRef<class IPropertyHandle>& InStructPropertyHandle, FDetailWidgetRow& Row ) OVERRIDE;

protected:

	/**
	 * Cache the values from the property to the proxy.
	 * @param	WeakHandlePtr	The property handle to get values from.
	 * @return true if values(s) were successfully cached
	 */
	virtual bool CacheValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const = 0;

	/**
	 * Flush the values from the proxy to the property.
	 * @param	WeakHandlePtr	The property handle to set values to.
	 * @return true if values(s) were successfully flushed
	 */
	virtual bool FlushValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const = 0;

	/** 
	 * Helper function to make a numeric property widget to edit a proxy value.
	 * @param	StructPropertyHandle	Property handle to the containing struct
	 * @param	ProxyValue				The value we will be editing in the proxy data.
	 * @param	Label					A label to use for this value.
	 * @return the newly created widget.
	 */
	template<typename ProxyType, typename NumericType>
	TSharedRef<SWidget> MakeNumericProxyWidget(TSharedRef<IPropertyHandle>& StructPropertyHandle, TSharedRef< TProxyProperty<ProxyType, NumericType> >& ProxyValue, const FText& Label, const FLinearColor& LabelColor = FCoreStyle::Get().GetColor("DefaultForeground"), const FLinearColor& LabelBackgroundColor = FCoreStyle::Get().GetColor("InvertedForeground"));

private:
	/**
	 * Gets the value as a float for the provided property handle
	 *
	 * @param WeakHandlePtr	Handle to the property to get the value from
	 * @param ProxyValue	Proxy value to get value from.
	 * @return The value or unset if it could not be accessed
	 */
	template<typename ProxyType, typename NumericType>
	TOptional<NumericType> OnGetValue( TWeakPtr<IPropertyHandle> WeakHandlePtr, TSharedRef< TProxyProperty<ProxyType, NumericType> > ProxyValue ) const;

	/**
	 * Called when the value is committed from the property editor
	 *
	 * @param NewValue		The new value of the property as a float
	 * @param CommitType	How the value was committed (unused)
	 * @param WeakHandlePtr	Handle to the property that the new value is for
	 */
	template<typename ProxyType, typename NumericType>
	void OnValueCommitted( NumericType NewValue, ETextCommit::Type CommitType, TWeakPtr<IPropertyHandle> WeakHandlePtr, TSharedRef< TProxyProperty<ProxyType, NumericType> > ProxyValue );
	
	/**
	 * Called when the value is changed in the property editor
	 *
	 * @param NewValue		The new value of the property as a float
	 * @param WeakHandlePtr	Handle to the property that the new value is for
	 */
	template<typename ProxyType, typename NumericType>
	void OnValueChanged( NumericType NewValue, TWeakPtr<IPropertyHandle> WeakHandlePtr, TSharedRef< TProxyProperty<ProxyType, NumericType> > ProxyValue );

	/** Called when a value starts to be changed by a slider */
	void OnBeginSliderMovement();

	/** Called when a value stops being changed by a slider */
	template<typename NumericType>
	void OnEndSliderMovement( NumericType NewValue );
};

/** 
 * Proxy struct customization that displays a matrix as a position, rotation & scale.
 */
class FMatrixStructCustomization : public FMathStructProxyCustomization
{
public:
	static TSharedRef<IPropertyTypeCustomization> MakeInstance();

public:
	FMatrixStructCustomization()
		: CachedRotation(MakeShareable( new TProxyValue<FRotator>(FRotator::ZeroRotator)))
		, CachedRotationYaw(MakeShareable( new TProxyProperty<FRotator, float>(CachedRotation, CachedRotation->Get().Yaw)))
		, CachedRotationPitch(MakeShareable( new TProxyProperty<FRotator, float>(CachedRotation, CachedRotation->Get().Pitch)))
		, CachedRotationRoll(MakeShareable( new TProxyProperty<FRotator, float>(CachedRotation, CachedRotation->Get().Roll)))
		, CachedTranslation(MakeShareable( new TProxyValue<FVector>(FVector::ZeroVector)))
		, CachedTranslationX(MakeShareable( new TProxyProperty<FVector, float>(CachedTranslation, CachedTranslation->Get().X)))
		, CachedTranslationY(MakeShareable( new TProxyProperty<FVector, float>(CachedTranslation, CachedTranslation->Get().Y)))
		, CachedTranslationZ(MakeShareable( new TProxyProperty<FVector, float>(CachedTranslation, CachedTranslation->Get().Z)))
		, CachedScale(MakeShareable( new TProxyValue<FVector>(FVector::ZeroVector)))
		, CachedScaleX(MakeShareable( new TProxyProperty<FVector, float>(CachedScale, CachedScale->Get().X)))
		, CachedScaleY(MakeShareable( new TProxyProperty<FVector, float>(CachedScale, CachedScale->Get().Y)))
		, CachedScaleZ(MakeShareable( new TProxyProperty<FVector, float>(CachedScale, CachedScale->Get().Z)))
	{
	}

	/** FMathStructCustomization interface */
	virtual void MakeHeaderRow( TSharedRef<class IPropertyHandle>& StructPropertyHandle, FDetailWidgetRow& Row ) OVERRIDE;

protected:
	/** FMathStructProxyCustomization interface */
	virtual bool CacheValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const OVERRIDE;
	virtual bool FlushValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const OVERRIDE;

protected:
	/** Cached rotation values */
	mutable TSharedRef< TProxyValue<FRotator> > CachedRotation;
	mutable TSharedRef< TProxyProperty<FRotator, float> > CachedRotationYaw;
	mutable TSharedRef< TProxyProperty<FRotator, float> > CachedRotationPitch;
	mutable TSharedRef< TProxyProperty<FRotator, float> > CachedRotationRoll;

	/** Cached translation values */
	mutable TSharedRef< TProxyValue<FVector> > CachedTranslation;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedTranslationX;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedTranslationY;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedTranslationZ;

	/** Cached scale values */
	mutable TSharedRef< TProxyValue<FVector> > CachedScale;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedScaleX;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedScaleY;
	mutable TSharedRef< TProxyProperty<FVector, float> > CachedScaleZ;
};

/** 
 * Proxy struct customization that displays an FTransform as a position, euler rotation & scale.
 */
class FTransformStructCustomization : public FMatrixStructCustomization
{
public:
	static TSharedRef<IPropertyTypeCustomization> MakeInstance();

protected:
	/** FMathStructProxyCustomization interface */
	virtual bool CacheValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const OVERRIDE;
	virtual bool FlushValues( TWeakPtr<IPropertyHandle> WeakHandlePtr ) const OVERRIDE;
};