/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.security.ec.point;

import sun.security.util.math.*;

/**

 * Elliptic curve point in projective coordinates (X, Y, Z) where

 * an affine point (x, y) is represented using any (X, Y, Z) s.t.

 * x = X/Z and y = Y/Z.

 */

public abstract class ProjectivePoint

    <T extends IntegerModuloP> implements Point {

    protected final T x;

    protected final T y;

    protected final T z;

    protected ProjectivePoint(T x, T y, T z) {

        this.x = x;

        this.y = y;

        this.z = z;

    }

    @Override

    public IntegerFieldModuloP getField() {

        return this.x.getField();

    }

    @Override

    public Immutable fixed() {

        return new Immutable(x.fixed(), y.fixed(), z.fixed());

    }

    @Override

    public Mutable mutable() {

        return new Mutable(x.mutable(), y.mutable(), z.mutable());

    }

    public T getX() {

        return x;

    }

    public T getY() {

        return y;

    }

    public T getZ() {

        return z;

    }

    public AffinePoint asAffine() {

        IntegerModuloP zInv = z.multiplicativeInverse();

        return new AffinePoint(x.multiply(zInv), y.multiply(zInv));

    }

    public static class Immutable

        extends ProjectivePoint<ImmutableIntegerModuloP>

        implements ImmutablePoint {

        public Immutable(ImmutableIntegerModuloP x,

                         ImmutableIntegerModuloP y,

                         ImmutableIntegerModuloP z) {

            super(x, y, z);

        }

    }

    public static class Mutable

        extends ProjectivePoint<MutableIntegerModuloP>

        implements MutablePoint {

        public Mutable(MutableIntegerModuloP x,

                       MutableIntegerModuloP y,

                       MutableIntegerModuloP z) {

            super(x, y, z);

        }

        public Mutable(IntegerFieldModuloP field) {

            super(field.get0().mutable(),

                field.get0().mutable(),

                field.get0().mutable());

        }

        @Override

        public Mutable conditionalSet(Point p, int set) {

            if (!(p instanceof ProjectivePoint)) {

                throw new RuntimeException("Incompatible point");

            }

            @SuppressWarnings("unchecked")

            ProjectivePoint<IntegerModuloP> pp =

                (ProjectivePoint<IntegerModuloP>) p;

            return conditionalSet(pp, set);

        }

        private <T extends IntegerModuloP>

        Mutable conditionalSet(ProjectivePoint<T> pp, int set) {

            x.conditionalSet(pp.x, set);

            y.conditionalSet(pp.y, set);

            z.conditionalSet(pp.z, set);

            return this;

        }

        @Override

        public Mutable setValue(AffinePoint p) {

            x.setValue(p.getX());

            y.setValue(p.getY());

            z.setValue(p.getX().getField().get1());

            return this;

        }

        @Override

        public Mutable setValue(Point p) {

            if (!(p instanceof ProjectivePoint)) {

                throw new RuntimeException("Incompatible point");

            }

            @SuppressWarnings("unchecked")

            ProjectivePoint<IntegerModuloP> pp =

                (ProjectivePoint<IntegerModuloP>) p;

            return setValue(pp);

        }

        private <T extends IntegerModuloP>

        Mutable setValue(ProjectivePoint<T> pp) {

            x.setValue(pp.x);

            y.setValue(pp.y);

            z.setValue(pp.z);

            return this;

        }

    }

}