#include "ext/LinearPotential.h"
#include <tmathutil.h>
#include <algorithm>
#include "tstroke.h"

using namespace std;

//-----------------------------------------------------------------------------

void ToonzExt::LinearPotential::setParameters_(const TStroke *ref,
											   double par,
											   double al)
{
	ref_ = ref;
	par_ = par;
	actionLength_ = al;

	strokeLength_ = ref->getLength();
	lenghtAtParam_ = ref->getLength(par);

	// lunghezza dal pto di click all'inizio della curva
	leftFactor_ = lenghtAtParam_;

	// lunghezza dal pto di click alla fine
	rightFactor_ = strokeLength_ - lenghtAtParam_;

	// considero come intervallo di mapping [-range,range].
	//  4 ha come valore c.a. 10exp-6
	//  cioé sposterei un pixel su un movimento di un milione di pixel
	range_ = 2.8;
}

//-----------------------------------------------------------------------------

ToonzExt::LinearPotential::~LinearPotential()
{
}

//-----------------------------------------------------------------------------

double
ToonzExt::LinearPotential::value_(double value2test) const
{
	assert(0.0 <= value2test &&
		   value2test <= 1.0);
	return this->compute_value(value2test);
}

//-----------------------------------------------------------------------------

// normalization of parameter in range interval
double ToonzExt::LinearPotential::compute_shape(double value2test) const
{
	double x = ref_->getLength(value2test);
	double shape = this->actionLength_ * 0.5;
	if (isAlmostZero(shape))
		shape = 1.0;
	x = ((x - lenghtAtParam_) * range_) / shape;
	return x;
}

//-----------------------------------------------------------------------------

double
ToonzExt::LinearPotential::compute_value(double value2test) const
{
	// use
	//
	//  1-x
	//

	double x = 0.0;
	double res = 0.0;

	// lenght  at parameter
	x = ref_->getLength(value2test);

	double tmp_al = actionLength_ * 0.5;

	if (isAlmostZero(par_) ||
		areAlmostEqual(par_, 1.0))
		tmp_al = actionLength_;

	// this is ckecked from wrapper class
	assert(tmp_al != 0.0);

	// compute correct parameter considering offset
	// try to have a square curve like shape
	//
	//  m = x
	//
	if (leftFactor_ == 0.0)
		x = 1.0 - x / tmp_al;
	else if (rightFactor_ == 0.0)
		x = (x - (strokeLength_ - tmp_al)) / tmp_al;
	else {
		if (x <= lenghtAtParam_ &&
			((lenghtAtParam_ - x) <= leftFactor_))
			x = (x - (lenghtAtParam_ - leftFactor_)) / leftFactor_;
		else if (x > lenghtAtParam_ &&
				 ((x - lenghtAtParam_) < rightFactor_))
			x = (rightFactor_ - (x - lenghtAtParam_)) / rightFactor_;
		else
			x = -1;
	}

	if (x < 0.0)
		return 0.0;
	//assert( 0.0 <= x &&
	//  x <= 1.0 + TConsts::epsilon );
	res = x;

	return res;
}

//-----------------------------------------------------------------------------

ToonzExt::Potential *
ToonzExt::LinearPotential::clone()
{
	return new LinearPotential;
}

//-----------------------------------------------------------------------------
//  End Of File
//-----------------------------------------------------------------------------