#include "BsHandleSlider.h"
#include "BsCamera.h"
#include "BsHandleManager.h"

namespace BansheeEngine
{
	HandleSlider::HandleSlider(bool fixedScale)
		:mFixedScale(fixedScale), mScale(Vector3::ONE), mTransformDirty(true),
		mDistanceScale(1.0f), mDelta(0.0f), mHasLastPos(false)
	{

	}

	void HandleSlider::update(const HCamera& camera)
	{
		if (mFixedScale)
			mDistanceScale = HandleManager::instance().getHandleSize(camera, mPosition);
	}

	void HandleSlider::setPosition(const Vector3& position)
	{
		mPosition = position;
		mTransformDirty = true;
	}

	void HandleSlider::setRotation(const Quaternion& rotation)
	{
		mRotation = rotation;
		mTransformDirty = true;
	}

	void HandleSlider::setScale(const Vector3& scale)
	{
		mScale = scale;
		mTransformDirty = true;
	}

	const Matrix4& HandleSlider::getTransform() const
	{
		if (mTransformDirty)
			updateCachedTransform();

		return mTransform;
	}

	const Matrix4& HandleSlider::getTransformInv() const
	{
		if (mTransformDirty)
			updateCachedTransform();

		return mTransformInv;
	}

	void HandleSlider::updateCachedTransform() const
	{
		if (mFixedScale)
			mTransform.setTRS(mPosition, mRotation, mScale * mDistanceScale);
		else
			mTransform.setTRS(mPosition, mRotation, mScale);

		mTransformInv = mTransform.inverseAffine();
		mTransformDirty = false;
	}

	void HandleSlider::reset()
	{
		mDelta = 0.0f;
		mHasLastPos = false;
	}

	float HandleSlider::getDelta() const
	{
		return mDelta;
	}

	float HandleSlider::calcDelta(const HCamera& camera, const Vector3& position, const Vector3& direction,
		const Vector2I& pointerStart, const Vector2I& pointerEnd)
	{
		Vector2I handleStart2D = camera->worldToScreenPoint(position);
		Vector2I handleEnd2D = camera->worldToScreenPoint(position + direction);

		Vector2I handleDir2D = handleEnd2D - handleStart2D;
		INT32 sqrdMag = handleDir2D.squaredLength();

		if (sqrdMag == 0)
			return 0.0f;

		Vector2I diffStart = pointerStart - handleStart2D;
		Vector2I diffEnd = pointerEnd - handleStart2D;

		float tStart = handleDir2D.dot(diffStart) / (float)sqrdMag;
		float tEnd = handleDir2D.dot(diffEnd) / (float)sqrdMag;

		return tEnd - tStart;
	}
}