package sansmodels;

public class PolyCoreShell extends SANSModel{
 
    private double scale, coreRadius, thickness, background;
    private double rhoCore, rhoShell, rhoSolvent, corePolyDisp;

    //Default constructor
    public PolyCoreShell() {
        scale = 1.0;
        coreRadius = 60.0;
        corePolyDisp = 0.2;
        thickness = 10.0;
        rhoCore = 1.e-6;
        rhoShell = 2.e-6;
        rhoSolvent = 3.e-6;
        background = 0.000;
        setNumberOfParameters(8);
        String[] parameters = {"Scale", "Core Radius (A)",
            "Core Polydisp. (0-1)", "Shell Thickness (A)", 
            "Core SLD (A-2)", "Shell SLD (A-2)",
            "Solvent SLD (A-2)", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public PolyCoreShell(double inScale, 
                     double inCoreRadius,
                     double inCorePolyDisp,
                     double inThickness,
                     double inRhoCore,
                     double inRhoShell,
                     double inRhoSolvent,
                     double inBackground) {
        scale = inScale; 
        coreRadius = inCoreRadius;
        corePolyDisp = inCorePolyDisp;
        thickness = inThickness;
        rhoCore = inRhoCore;
        rhoShell = inRhoShell;
        rhoSolvent = inRhoSolvent;
        background = inBackground;
        setNumberOfParameters(8);
        String[] parameters = {"Scale", "Core Radius (A)",
            "Core Polydisp. (0-1)", "Shell Thickness (A)", 
            "Core SLD (A-2)", "Shell SLD (A-2)",
            "Solvent SLD (A-2)", "Background (cm-1)"};
        setParametersText(parameters);
    }

    public double getFormFactor(double inX) {
        double zz, drho1, drho2;
        double d, g, form;
        double x, y, c1, c2, c3, c4, c5, c6, c7, c8, c9, t1, t2, t3;
        double t4, t5, tb, cy, sy, tb1, tb2, tb3, c2y, zp1, zp2;
        double zp3,vpoly;
        double s2y, arg1, arg2, arg3;
        
        if(corePolyDisp <= 0.0) corePolyDisp = 0.0001;
        if(corePolyDisp >= 1.0) corePolyDisp = 1.0;
        zz = 1.0/corePolyDisp/corePolyDisp - 1.0;
        drho1 = rhoCore - rhoShell;
        if(Math.abs(drho1) <= 1.e-10) drho1 = 1.e-10;
        drho2 = rhoShell - rhoSolvent;
        g = (-1.0)*drho2/drho1;
        zp1 = zz + 1;
        zp2 = zz + 2;
        zp3 = zz + 3;
        vpoly = 4.0*Math.PI/3.0*zp3*zp2/zp1/zp1
                *Math.pow((coreRadius+thickness),3.0);
        y = inX * thickness;
        x = inX * coreRadius;
        d = Math.atan(x*2.0/zp1); 
        arg1 = zp1 * d;
        arg2 = zp2 * d;
        arg3 = zp3 * d;
        sy = Math.sin(y);
        cy = Math.cos(y);
        s2y = Math.sin(2.*y);
        c2y = Math.cos(2.*y);
        c1 = .5 - g * (cy + y * sy) + g * g * .5 * (y * y + 1.);
        c2 = g * y * (g - cy);
        c3 = (g * g + 1.) * .5 - g * cy;
        c4 = g * g * (y * cy - sy) * (y * cy - sy) - c1;
        c5 = g * 2. * sy * (1. - g * (y * sy + cy)) + c2;
        c6 = c3 - g * g * sy * sy;
        c7 = g * sy - g * .5 * g * (y * y + 1.) * s2y - c5;
        c8 = c4 - .5 + g * cy - g * .5 * g * (y * y + 1.) * c2y;
        c9 = g * sy * (1. - g * cy);

        tb = Math.log(zp1 * zp1 / (zp1 * zp1 + x * 4. * x));
        tb1 = Math.exp(zp1 * .5 * tb);
        tb2 = Math.exp(zp2 * .5 * tb);
        tb3 = Math.exp(zp3 * .5 * tb);

        t1 = c1 + c2 * x + c3 * x * x * zp2 / zp1;
        t2 = tb1 * (c4 * Math.cos(arg1) + c7 * Math.sin(arg1));
        t3 = x * tb2 * (c5 * Math.cos(arg2) + c8 * Math.sin(arg2));
        t4 = zp2 / zp1 * x * x * tb3 * (c6 * Math.cos(arg3) + c9 
             * Math.sin(arg3));
        t5 = t1 + t2 + t3 + t4;
        form = t5 * 16. * Math.PI * Math.PI * drho1 * drho1 / Math.pow(inX,6.0);
        
        return form/vpoly*1.0e8*scale*getStructureFactor().calculate(inX)
            + background;
    }


    public void setParameters(double[] inParameters) {
        scale = inParameters[0];
        coreRadius = inParameters[1];
        corePolyDisp = inParameters[2];
        thickness = inParameters[3];
        rhoCore = inParameters[4];
        rhoShell = inParameters[5];
        rhoSolvent = inParameters[6];
        background = inParameters[7];
    }
 
    public double[] getParameters() {
        double[] outParameters = new double[8];
        outParameters[0] = scale;
        outParameters[1] = coreRadius;
        outParameters[2] = corePolyDisp;
        outParameters[3] = thickness;
        outParameters[4] = rhoCore;
        outParameters[5] = rhoShell;
        outParameters[6] = rhoSolvent;
        outParameters[7] = background;
        return outParameters;
    }
}