package org.madore.ephem;

import java.util.List;
import java.util.ArrayList;
import java.util.EnumMap;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;

public final class Smart97 {

    public static enum Variable {
	PSI("psi"), OMEGA("omega"), PHI("phi"),
	P("p"), EPSILON("epsilon"), CHI("chi"), SIDTIME("sidtime");
	final String name;
	Variable(String name) { this.name = name; }
    }

    // The argument is in Julian millennia (value is in radians).
    public static Comput.Polynomial[] lambdas = new Comput.Polynomial[] {
	new Comput.Polynomial(4.40260867435, 26088.1469432237), // Mercury
	new Comput.Polynomial(3.17614652884, 10213.5293478605), // Venus
	new Comput.Polynomial(1.75347029148, 6283.3196527950),  // Earth
	new Comput.Polynomial(6.20347594486, 3340.8562283493),  // Mars
	new Comput.Polynomial(0.59954632934, 529.9347667441),   // Jupiter
	new Comput.Polynomial(0.87401658845, 213.5428970875),   // Saturn
	new Comput.Polynomial(5.48129370354, 75.0254002168),    // Uranus
	new Comput.Polynomial(5.31188611871, 38.3768372873),    // Neptune
	new Comput.Polynomial(5.19846640063, 77713.7714481804), // Delaunay D
	new Comput.Polynomial(1.62790513602, 84334.6615717837), // Delaunay F
	new Comput.Polynomial(2.35555563875, 83286.9142477147), // Delaunay l
	new Comput.Polynomial(4.89496121282, 2301216.7536515365), // phi
    };

    private static EnumMap<Variable, Comput.SumPoisson2Terms> data = new EnumMap<Variable, Comput.SumPoisson2Terms>(Variable.class);

    public static Comput.SumPoisson2Terms getFunc(Variable v) {
	if ( ! data.containsKey(v) ) {
	    List<Comput.Poisson2Term> series = new ArrayList<Comput.Poisson2Term>();
	    try {
		InputStream str = Smart97.class.getResourceAsStream("smart97.dat");
		BufferedReader in = new BufferedReader(new InputStreamReader(str, "utf-8"));
		String s;
		while ( ( s = in.readLine() ) != null ) {
		    String[] fields = s.split("\t");
		    if ( ! fields[1].equals(v.name) )
			continue;
		    int deg = Integer.parseInt(fields[2]);
		    String[] subfields = fields[3].split(",");
		    double[] om = new double[12];
		    for ( int j=0 ; j<12 ; j++ )
			om[j] = Double.parseDouble(subfields[j]);
		    double b = Double.parseDouble(fields[4]);
		    double a = Double.parseDouble(fields[5]);
		    series.add(Comput.Poisson2Term.ab(deg, a, b, om, lambdas));
		}
	    } catch ( Exception e ) {
		throw new RuntimeException(e);
	    }
	    data.put(v, new Comput.SumPoisson2Terms(series));
	}
	return data.get(v);
    }

}