#include "StraightEdge.h"
#include <math.h>

// ---------------------------------------------------------------------------------
//		¥ CreateStraightEdgeFit [static]
// ---------------------------------------------------------------------------------

FitFunction *
StraightEdgeFit::CreateStraightEdgeFit( )
{
	return NEW StraightEdgeFit();
}

FitFunction *
StraightEdgeFit::CreateStraightEdgeMoveDetectorFit( )
{
	StraightEdgeFit *p = NEW StraightEdgeFit();
	p->moveBlade = false;
	return p;
}

StraightEdgeFit::StraightEdgeFit() : FitFunction(false, true), moveBlade( true )
{
	// Add the parameters
	
	FitParameter *fp;
	
	// The functional form is
	
	AddParameter( NEW FitParameter("Baseline", 0.01) );						// Param(1)
	AddParameter( NEW FitParameter("Intensity", 1) );						// Param(2)
	AddParameter( NEW FitParameter("Edge Position (mm)", 10) );				// Param(3)
	AddParameter( NEW FitParameter("Source Distance (mm)", 300) );			// Param(4)

	AddParameter( fp = NEW FitParameter("Image Distance (mm)", 2000) );		// Param(5)
	fp->Lock();
	
	AddParameter( fp = NEW FitParameter("Wavelength", 0.0006328) );			// Param(6)
	fp->Lock();
}

StraightEdgeFit::~StraightEdgeFit()
{
}


// Remember that fit parameters are 1-based


REAL StraightEdgeFit::CalcFitFunction(REAL x)
{
	REAL result = 0;

	// arg = (x - x0) sqrt(2/image * (1/source + 1/lambda))
	x -= Param(3)();							// the edge position parameter
	REAL argument = x * sqrt(2 / Param(6)() 	
		* (1.0 / Param(4)() + 1.0 / Param(5)()));
	
	if ( !moveBlade )
		argument *= Param(4)() / ( Param(4)() + Param(5)() );
	
	FLOAT C, S;
	fresnelIntegral.Evaluate(argument, C, S);
	C += 0.5;
	S += 0.5;
	
	result = Param(1)() 						// baseline
		+ 0.5 * Param(2)()						// amplitude
		* (C*C + S*S);							// squared amplitude of the Fresnel integral
	
	return result;
}