package org.bouncycastle.pqc.jcajce.provider.rainbow;

import java.io.IOException;
import java.security.PrivateKey;
import java.util.Arrays;

import org.bouncycastle.asn1.DERNull;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.pqc.asn1.PQCObjectIdentifiers;
import org.bouncycastle.pqc.asn1.RainbowPrivateKey;
import org.bouncycastle.pqc.crypto.rainbow.Layer;
import org.bouncycastle.pqc.crypto.rainbow.RainbowPrivateKeyParameters;
import org.bouncycastle.pqc.crypto.rainbow.util.RainbowUtil;
import org.bouncycastle.pqc.jcajce.spec.RainbowPrivateKeySpec;

The Private key in Rainbow consists of the linear affine maps L1, L2 and the
map F, consisting of quadratic polynomials. In this implementation, we
denote: L1 = A1*x + b1 L2 = A2*x + b2

The coefficients of the polynomials in F are stored in 3-dimensional arrays
per layer. The indices of these arrays denote the polynomial, and the
variables.

More detailed information about the private key is to be found in the paper
of Jintai Ding, Dieter Schmidt: Rainbow, a New Multivariable Polynomial
Signature Scheme. ACNS 2005: 164-175 (http://dx.doi.org/10.1007/11496137_12)

/**
 * The Private key in Rainbow consists of the linear affine maps L1, L2 and the
 * map F, consisting of quadratic polynomials. In this implementation, we
 * denote: L1 = A1*x + b1 L2 = A2*x + b2
 * <p>
 * The coefficients of the polynomials in F are stored in 3-dimensional arrays
 * per layer. The indices of these arrays denote the polynomial, and the
 * variables.
 * </p><p>
 * More detailed information about the private key is to be found in the paper
 * of Jintai Ding, Dieter Schmidt: Rainbow, a New Multivariable Polynomial
 * Signature Scheme. ACNS 2005: 164-175 (http://dx.doi.org/10.1007/11496137_12)
 * </p>
 */
public class BCRainbowPrivateKey
    implements PrivateKey
{
    private static final long serialVersionUID = 1L;

    // the inverse of L1
    private short[][] A1inv;

    // translation vector element of L1
    private short[] b1;

    // the inverse of L2
    private short[][] A2inv;

    // translation vector of L2
    private short[] b2;

    /*
      * components of F
      */
    private Layer[] layers;

    // set of vinegar vars per layer.
    private int[] vi;


    
Constructor.
Params:
A1inv – 
b1 – 
A2inv – 
b2 – 
layers – /**
     * Constructor.
     *
     * @param A1inv
     * @param b1
     * @param A2inv
     * @param b2
     * @param layers
     */
    public BCRainbowPrivateKey(short[][] A1inv, short[] b1, short[][] A2inv,
                               short[] b2, int[] vi, Layer[] layers)
    {
        this.A1inv = A1inv;
        this.b1 = b1;
        this.A2inv = A2inv;
        this.b2 = b2;
        this.vi = vi;
        this.layers = layers;
    }

    
Constructor (used by the RainbowKeyFactorySpi). 
Params:
keySpec – a RainbowPrivateKeySpec/**
     * Constructor (used by the {@link RainbowKeyFactorySpi}).
     *
     * @param keySpec a {@link RainbowPrivateKeySpec}
     */
    public BCRainbowPrivateKey(RainbowPrivateKeySpec keySpec)
    {
        this(keySpec.getInvA1(), keySpec.getB1(), keySpec.getInvA2(), keySpec
            .getB2(), keySpec.getVi(), keySpec.getLayers());
    }

    public BCRainbowPrivateKey(
        RainbowPrivateKeyParameters params)
    {
        this(params.getInvA1(), params.getB1(), params.getInvA2(), params.getB2(), params.getVi(), params.getLayers());
    }

    
Getter for the inverse matrix of A1.
Returns:
the A1inv inverse/**
     * Getter for the inverse matrix of A1.
     *
     * @return the A1inv inverse
     */
    public short[][] getInvA1()
    {
        return this.A1inv;
    }

    
Getter for the translation part of the private quadratic map L1.
Returns:
b1 the translation part of L1/**
     * Getter for the translation part of the private quadratic map L1.
     *
     * @return b1 the translation part of L1
     */
    public short[] getB1()
    {
        return this.b1;
    }

    
Getter for the translation part of the private quadratic map L2.
Returns:
b2 the translation part of L2/**
     * Getter for the translation part of the private quadratic map L2.
     *
     * @return b2 the translation part of L2
     */
    public short[] getB2()
    {
        return this.b2;
    }

    
Getter for the inverse matrix of A2
Returns:
the A2inv/**
     * Getter for the inverse matrix of A2
     *
     * @return the A2inv
     */
    public short[][] getInvA2()
    {
        return this.A2inv;
    }

    
Returns the layers contained in the private key
Returns:
layers/**
     * Returns the layers contained in the private key
     *
     * @return layers
     */
    public Layer[] getLayers()
    {
        return this.layers;
    }

    
Returns the array of vi-s
Returns:
the vi/**
     * Returns the array of vi-s
     *
     * @return the vi
     */
    public int[] getVi()
    {
        return vi;
    }

    
Compare this Rainbow private key with another object.
Params:
other – the other object
Returns:
the result of the comparison/**
     * Compare this Rainbow private key with another object.
     *
     * @param other the other object
     * @return the result of the comparison
     */
    public boolean equals(Object other)
    {
        if (other == null || !(other instanceof BCRainbowPrivateKey))
        {
            return false;
        }
        BCRainbowPrivateKey otherKey = (BCRainbowPrivateKey)other;

        boolean eq = true;
        // compare using shortcut rule ( && instead of &)
        eq = eq && RainbowUtil.equals(A1inv, otherKey.getInvA1());
        eq = eq && RainbowUtil.equals(A2inv, otherKey.getInvA2());
        eq = eq && RainbowUtil.equals(b1, otherKey.getB1());
        eq = eq && RainbowUtil.equals(b2, otherKey.getB2());
        eq = eq && Arrays.equals(vi, otherKey.getVi());
        if (layers.length != otherKey.getLayers().length)
        {
            return false;
        }
        for (int i = layers.length - 1; i >= 0; i--)
        {
            eq &= layers[i].equals(otherKey.getLayers()[i]);
        }
        return eq;
    }

    public int hashCode()
    {
        int hash = layers.length;

        hash = hash * 37 + org.bouncycastle.util.Arrays.hashCode(A1inv);
        hash = hash * 37 + org.bouncycastle.util.Arrays.hashCode(b1);
        hash = hash * 37 + org.bouncycastle.util.Arrays.hashCode(A2inv);
        hash = hash * 37 + org.bouncycastle.util.Arrays.hashCode(b2);
        hash = hash * 37 + org.bouncycastle.util.Arrays.hashCode(vi);

        for (int i = layers.length - 1; i >= 0; i--)
        {
            hash = hash * 37 + layers[i].hashCode();
        }


        return hash;
    }

    
Returns:
name of the algorithm - "Rainbow"/**
     * @return name of the algorithm - "Rainbow"
     */
    public final String getAlgorithm()
    {
        return "Rainbow";
    }

    public byte[] getEncoded()
    {
        RainbowPrivateKey privateKey = new RainbowPrivateKey(A1inv, b1, A2inv, b2, vi, layers);

        PrivateKeyInfo pki;
        try
        {
            AlgorithmIdentifier algorithmIdentifier = new AlgorithmIdentifier(PQCObjectIdentifiers.rainbow, DERNull.INSTANCE);
            pki = new PrivateKeyInfo(algorithmIdentifier, privateKey);
        }
        catch (IOException e)
        {
            return null;
        }
        try
        {
            byte[] encoded = pki.getEncoded();
            return encoded;
        }
        catch (IOException e)
        {
            return null;
        }
    }

    public String getFormat()
    {
        return "PKCS#8";
    }
}