using System;

namespace Science.Mathematics.VectorCalculus
{
    public class SurfaceIntegral
    {
        private Surface s;
        private double res;
        private VectorField F;
        public SurfaceIntegral(Function.ToLastType<double[], double[]> function, Surface surface)
        {
            VectorField vf = new VectorField(function);
            F = vf;
            s = surface;
        }
        public SurfaceIntegral(VectorField vectorField, Surface surface)
        {
            F = vectorField;
            s = surface;
        }               
        public void Compute()
        {
            double[] f = { s.Parameter1StartValue, s.Parameter2StartValue };
            double[] t = { s.Parameter1EndValue, s.Parameter2EndValue };
            Function.ToLastType<double[], double> fdots
                = new Function.ToLastType<double[], double>(Func);
            IntegrationMultiD obj = new IntegrationMultiD(fdots, f, t);
            obj.NumberOfCall = nc;
            obj.Compute();
            res = obj.BestEstimation;
            tgral = obj.BestEstimation;
            sd = obj.StandardDeviation;
            chi2 = obj.ChiSQUARE;
        }
        private double Func(double[] u)
        {
            TangentVectorOnSurface tv
                = new TangentVectorOnSurface(s, u);
            tv.Compute();
            Vector n = tv.Result[0] % tv.Result[1];
            double[] x = s.Parametrization(u);
            Point at = new Point(x);
            F.FindComponents(at);
            return n*F;
        }
        public double Result
        {
            get { return res; }
        }
        private double tgral, sd, chi2;
        private ulong nc = 100000;
        public double BestEstimation
        {
            get { return tgral; }
        }
        public double StandardDeviation
        {
            get { return sd; }
        }
        public double ChiSQUARE
        {
            get { return chi2; }
        }
        public ulong NumberOfCall
        {
            set { nc = value; }
        }
    }
}