/*
 Copyright 2006 Jerry Huxtable

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

/*
 * This file was semi-automatically converted from the public-domain USGS PROJ source.
 */
package org.meteoinfo.projection.proj4j.proj;

import org.meteoinfo.projection.proj4j.ProjCoordinate;
import org.meteoinfo.projection.proj4j.ProjectionException;
import org.meteoinfo.projection.proj4j.util.ProjectionMath;

public class RobinsonProjection extends PseudoCylindricalProjection {

    private final static double X[] = {
        1, -5.67239e-12, -7.15511e-05, 3.11028e-06,
        0.9986, -0.000482241, -2.4897e-05, -1.33094e-06,
        0.9954, -0.000831031, -4.4861e-05, -9.86588e-07,
        0.99, -0.00135363, -5.96598e-05, 3.67749e-06,
        0.9822, -0.00167442, -4.4975e-06, -5.72394e-06,
        0.973, -0.00214869, -9.03565e-05, 1.88767e-08,
        0.96, -0.00305084, -9.00732e-05, 1.64869e-06,
        0.9427, -0.00382792, -6.53428e-05, -2.61493e-06,
        0.9216, -0.00467747, -0.000104566, 4.8122e-06,
        0.8962, -0.00536222, -3.23834e-05, -5.43445e-06,
        0.8679, -0.00609364, -0.0001139, 3.32521e-06,
        0.835, -0.00698325, -6.40219e-05, 9.34582e-07,
        0.7986, -0.00755337, -5.00038e-05, 9.35532e-07,
        0.7597, -0.00798325, -3.59716e-05, -2.27604e-06,
        0.7186, -0.00851366, -7.0112e-05, -8.63072e-06,
        0.6732, -0.00986209, -0.000199572, 1.91978e-05,
        0.6213, -0.010418, 8.83948e-05, 6.24031e-06,
        0.5722, -0.00906601, 0.000181999, 6.24033e-06,
        0.5322, 0., 0., 0.
    };
    private final static double Y[] = {
        0, 0.0124, 3.72529e-10, 1.15484e-09,
        0.062, 0.0124001, 1.76951e-08, -5.92321e-09,
        0.124, 0.0123998, -7.09668e-08, 2.25753e-08,
        0.186, 0.0124008, 2.66917e-07, -8.44523e-08,
        0.248, 0.0123971, -9.99682e-07, 3.15569e-07,
        0.31, 0.0124108, 3.73349e-06, -1.1779e-06,
        0.372, 0.0123598, -1.3935e-05, 4.39588e-06,
        0.434, 0.0125501, 5.20034e-05, -1.00051e-05,
        0.4958, 0.0123198, -9.80735e-05, 9.22397e-06,
        0.5571, 0.0120308, 4.02857e-05, -5.2901e-06,
        0.6176, 0.0120369, -3.90662e-05, 7.36117e-07,
        0.6769, 0.0117015, -2.80246e-05, -8.54283e-07,
        0.7346, 0.0113572, -4.08389e-05, -5.18524e-07,
        0.7903, 0.0109099, -4.86169e-05, -1.0718e-06,
        0.8435, 0.0103433, -6.46934e-05, 5.36384e-09,
        0.8936, 0.00969679, -6.46129e-05, -8.54894e-06,
        0.9394, 0.00840949, -0.000192847, -4.21023e-06,
        0.9761, 0.00616525, -0.000256001, -4.21021e-06,
        1., 0., 0., 0
    };
    private final int NODES = 18;
    private final static double FXC = 0.8487;
    private final static double FYC = 1.3523;
    private final static double C1 = 11.45915590261646417544;
    private final static double RC1 = 0.08726646259971647884;
    private final static double ONEEPS = 1.000001;
    private final static double EPS = 1e-8;

    public RobinsonProjection() {
        proj4Name = "robin";
        name = "Robinson";
    }

    private double poly(double[] array, int offset, double z) {
        return (array[offset] + z * (array[offset + 1] + z * (array[offset + 2] + z * array[offset + 3])));
    }

    @Override
    public ProjCoordinate project(double lplam, double lpphi, ProjCoordinate xy) {
        double phi = Math.abs(lpphi);
        int i = (int) Math.floor(phi * C1);
        if (i >= NODES) {
            i = NODES - 1;
        }
        phi = Math.toDegrees(phi - RC1 * i);
        i *= 4;
        xy.x = poly(X, i, phi) * FXC * lplam;
        xy.y = poly(Y, i, phi) * FYC;
        if (lpphi < 0.0) {
            xy.y = -xy.y;
        }
        return xy;
    }

    @Override
    public ProjCoordinate projectInverse(double x, double y, ProjCoordinate lp) {
        int i;
        double t, t1;

        lp.x = x / FXC;
        lp.y = Math.abs(y / FYC);
        if (lp.y >= 1.0) {
            if (lp.y > 1.000001) {
                throw new ProjectionException();
            } else {
                lp.y = y < 0. ? -ProjectionMath.HALFPI : ProjectionMath.HALFPI;
                lp.x /= X[4 * NODES];
            }
        } else {
            for (i = 4 * (int) Math.floor(lp.y * NODES);;) {
                if (Y[i] > lp.y) {
                    i -= 4;
                } else if (Y[i + 4] <= lp.y) {
                    i += 4;
                } else {
                    break;
                }
            }
            t = 5. * (lp.y - Y[i]) / (Y[i + 4] - Y[i]);
            double Tc0 = Y[i];
            double Tc1 = Y[i + 1];
            double Tc2 = Y[i + 2];
            double Tc3 = Y[i + 3];
            t = 5. * (lp.y - Tc0) / (Y[i + 1] - Tc0);
            Tc0 -= lp.y;
            for (;;) { // Newton-Raphson
                t -= t1 = (Tc0 + t * (Tc1 + t * (Tc2 + t * Tc3))) / (Tc1 + t * (Tc2 + Tc2 + t * 3. * Tc3));
                if (Math.abs(t1) < EPS) {
                    break;
                }
            }
            lp.y = Math.toRadians(5 * i + t);
            if (y < 0.) {
                lp.y = -lp.y;
            }
            lp.x /= poly(X, i, t);
        }
        return lp;
    }

    @Override
    public boolean hasInverse() {
        return true;
    }

    @Override
    public String toString() {
        return "Robinson";
    }
}
