package org.bouncycastle.jcajce.provider.asymmetric.ecgost;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1BitString;
import org.bouncycastle.asn1.DERNull;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.cryptopro.CryptoProObjectIdentifiers;
import org.bouncycastle.asn1.cryptopro.ECGOST3410NamedCurves;
import org.bouncycastle.asn1.cryptopro.GOST3410PublicKeyAlgParameters;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.asn1.x9.X962Parameters;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.asn1.x9.X9ECPoint;
import org.bouncycastle.asn1.x9.X9IntegerConverter;
import org.bouncycastle.asn1.x9.X9ObjectIdentifiers;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil;
import org.bouncycastle.jcajce.provider.asymmetric.util.KeyUtil;
import org.bouncycastle.jcajce.provider.config.ProviderConfiguration;
import org.bouncycastle.jce.ECGOST3410NamedCurveTable;
import org.bouncycastle.jce.interfaces.ECPointEncoder;
import org.bouncycastle.jce.interfaces.ECPublicKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECParameterSpec;
import org.bouncycastle.jce.spec.ECPublicKeySpec;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil;

public class BCECGOST3410PublicKey
    implements ECPublicKey, ECPointEncoder
{
    private String                  algorithm = "ECGOST3410";
    private boolean                 withCompression;

    private transient ECPublicKeyParameters   ecPublicKey;
    private transient ECParameterSpec         ecSpec;
    private transient GOST3410PublicKeyAlgParameters       gostParams;

    public BCECGOST3410PublicKey(
        String              algorithm,
        BCECGOST3410PublicKey      key)
    {
        this.algorithm = algorithm;
        this.ecPublicKey = key.ecPublicKey;
        this.ecSpec = key.ecSpec;
        this.withCompression = key.withCompression;
        this.gostParams = key.gostParams;
    }

    public BCECGOST3410PublicKey(
        ECPublicKeySpec     spec,
        ProviderConfiguration configuration)
    {
        if (spec.getParams() != null)
        {
            this.ecSpec = spec.getParams();
            this.ecPublicKey = new ECPublicKeyParameters(spec.getQ(), ECUtil.getDomainParameters(configuration, spec.getParams()));

        }
        else
        {
            this.ecSpec = null;

            org.bouncycastle.jce.spec.ECParameterSpec s = configuration.getEcImplicitlyCa();

            this.ecPublicKey = new ECPublicKeyParameters(
                s.getCurve().createPoint(spec.getQ().getAffineXCoord().toBigInteger(), spec.getQ().getAffineYCoord().toBigInteger()),
                ECUtil.getDomainParameters(configuration, (ECParameterSpec)null));
        }
    }

    public BCECGOST3410PublicKey(
        String                  algorithm,
        ECPublicKeyParameters   params,
        ECParameterSpec         spec)
    {
        ECDomainParameters      dp = params.getParameters();

        this.algorithm = algorithm;
        this.ecPublicKey = params;

        if (spec == null)
        {
            this.ecSpec = new ECParameterSpec(
                            dp.getCurve(),
                            dp.getG(),
                            dp.getN(),
                            dp.getH(),
                            dp.getSeed());
        }
        else
        {
            this.ecSpec = spec;
        }
    }

    public BCECGOST3410PublicKey(
        String                  algorithm,
        ECPublicKeyParameters   params)
    {
        this.algorithm = algorithm;
        this.ecPublicKey = params;
        this.ecSpec = null;
    }

    BCECGOST3410PublicKey(
        ECPublicKey     key)
    {
        this.ecPublicKey = new ECPublicKeyParameters(key.getQ(), ECUtil.getDomainParameters(BouncyCastleProvider.CONFIGURATION, key.getParameters()));
        this.algorithm = key.getAlgorithm();
        this.ecSpec = key.getParameters();
    }

    BCECGOST3410PublicKey(
        String            algorithm,
        ECPoint           q,
        ECParameterSpec   ecSpec)
    {
        this.algorithm = algorithm;
        this.ecPublicKey = new ECPublicKeyParameters(q, ECUtil.getDomainParameters(BouncyCastleProvider.CONFIGURATION, ecSpec));
        this.ecSpec = ecSpec;
    }

    BCECGOST3410PublicKey(
        SubjectPublicKeyInfo    info)
    {
        populateFromPubKeyInfo(info);
    }

    private void populateFromPubKeyInfo(SubjectPublicKeyInfo info)
    {
        if (info.getAlgorithmId().getAlgorithm().equals(CryptoProObjectIdentifiers.gostR3410_2001))
        {
            ASN1BitString bits = info.getPublicKeyData();
            ASN1OctetString key;
            this.algorithm = "ECGOST3410";

            try
            {
                key = (ASN1OctetString)ASN1Primitive.fromByteArray(bits.getBytes());
            }
            catch (IOException ex)
            {
                throw new IllegalArgumentException("error recovering public key");
            }

            byte[]          keyEnc = key.getOctets();
            byte[]          x = new byte[32];
            byte[]          y = new byte[32];

            for (int i = 0; i != x.length; i++)
            {
                x[i] = keyEnc[32 - 1 - i];
            }

            for (int i = 0; i != y.length; i++)
            {
                y[i] = keyEnc[64 - 1 - i];
            }

            gostParams = GOST3410PublicKeyAlgParameters.getInstance(info.getAlgorithmId().getParameters());

            ECNamedCurveParameterSpec spec = ECGOST3410NamedCurveTable.getParameterSpec(ECGOST3410NamedCurves.getName(gostParams.getPublicKeyParamSet()));

            ecSpec = spec;

            ECPoint q = spec.getCurve().createPoint(new BigInteger(1, x), new BigInteger(1, y));

            this.ecPublicKey = new ECPublicKeyParameters(q, ECUtil.getDomainParameters(BouncyCastleProvider.CONFIGURATION, ecSpec));
        }
        else
        {
            X962Parameters          params = X962Parameters.getInstance(info.getAlgorithmId().getParameters());
            ECCurve                 curve;

            if (params.isNamedCurve())
            {
                ASN1ObjectIdentifier oid = ASN1ObjectIdentifier.getInstance(params.getParameters());
                X9ECParameters      ecP = ECUtil.getNamedCurveByOid(oid);

                ecSpec = new ECNamedCurveParameterSpec(
                                            ECUtil.getCurveName(oid),
                                            ecP.getCurve(),
                                            ecP.getG(),
                                            ecP.getN(),
                                            ecP.getH(),
                                            ecP.getSeed());
                curve = ((ECParameterSpec)ecSpec).getCurve();
            }
            else if (params.isImplicitlyCA())
            {
                ecSpec = null;
                curve = BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa().getCurve();
            }
            else
            {
                X9ECParameters ecP = X9ECParameters.getInstance(params.getParameters());
                ecSpec = new ECParameterSpec(
                                            ecP.getCurve(),
                                            ecP.getG(),
                                            ecP.getN(),
                                            ecP.getH(),
                                            ecP.getSeed());
                curve = ((ECParameterSpec)ecSpec).getCurve();
            }

            ASN1BitString    bits = info.getPublicKeyData();
            byte[]          data = bits.getBytes();
            ASN1OctetString key = new DEROctetString(data);

            //
            // extra octet string - one of our old certs...
            //
            if (data[0] == 0x04 && data[1] == data.length - 2
                && (data[2] == 0x02 || data[2] == 0x03))
            {
                int qLength = new X9IntegerConverter().getByteLength(curve);

                if (qLength >= data.length - 3)
                {
                    try
                    {
                        key = (ASN1OctetString)ASN1Primitive.fromByteArray(data);
                    }
                    catch (IOException ex)
                    {
                        throw new IllegalArgumentException("error recovering public key");
                    }
                }
            }

            X9ECPoint derQ = new X9ECPoint(curve, key);

            ECPoint q = derQ.getPoint();

            this.ecPublicKey = new ECPublicKeyParameters(q, ECUtil.getDomainParameters(BouncyCastleProvider.CONFIGURATION, ecSpec));
        }
    }

    public String getAlgorithm()
    {
        return algorithm;
    }

    public String getFormat()
    {
        return "X.509";
    }

    public byte[] getEncoded()
    {
        ASN1Encodable params = null;
        if (gostParams != null)
        {
            params = gostParams;
        }
        else if (ecSpec instanceof ECNamedCurveParameterSpec)
        {
            params = new GOST3410PublicKeyAlgParameters(
                ECGOST3410NamedCurves.getOID(((ECNamedCurveParameterSpec)ecSpec).getName()),
                CryptoProObjectIdentifiers.gostR3411_94_CryptoProParamSet);
        }
        else
        {
            ECParameterSpec p = (ECParameterSpec)ecSpec;

            X9ECParameters ecP = new X9ECParameters(
                p.getCurve(), new X9ECPoint(p.getG(), withCompression), p.getN(), p.getH(), p.getSeed());

            params = new X962Parameters(ecP);
        }

        BigInteger bX = getQ().getAffineXCoord().toBigInteger();
        BigInteger bY = getQ().getAffineYCoord().toBigInteger();

        byte[] encKey = new byte[64];
        extractBytes(encKey, 0, bX);
        extractBytes(encKey, 32, bY);

        SubjectPublicKeyInfo info;
        try
        {
            info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(CryptoProObjectIdentifiers.gostR3410_2001, params), new DEROctetString(encKey));
        }
        catch (IOException e)
        {
            return null;
        }

        return KeyUtil.getEncodedSubjectPublicKeyInfo(info);
    }

    public ECParameterSpec getParams()
    {
        return (ECParameterSpec)ecSpec;
    }

    public ECParameterSpec getParameters()
    {
        return (ECParameterSpec)ecSpec;
    }
    
    public org.bouncycastle.math.ec.ECPoint getQ()
    {
        if (ecSpec == null)
        {
            return ecPublicKey.getQ().getDetachedPoint();
        }

        return ecPublicKey.getQ();
    }

    ECPublicKeyParameters engineGetKeyParameters()
    {
        return ecPublicKey;
    }

    public String toString()
    {
        return ECUtil.publicKeyToString(algorithm, ecPublicKey.getQ(), engineGetSpec());
    }

    public void setPointFormat(String style)
    {
       withCompression = !("UNCOMPRESSED".equalsIgnoreCase(style));
    }

    ECParameterSpec engineGetSpec()
    {
        if (ecSpec != null)
        {
            return (ECParameterSpec)ecSpec;
        }

        return BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa();
    }

    public boolean equals(Object o)
    {
        if (!(o instanceof BCECGOST3410PublicKey))
        {
            return false;
        }

        BCECGOST3410PublicKey other = (BCECGOST3410PublicKey)o;

        return getQ().equals(other.getQ()) && (engineGetSpec().equals(other.engineGetSpec()));
    }

    public int hashCode()
    {
        return getQ().hashCode() ^ engineGetSpec().hashCode();
    }

    private void readObject(
        ObjectInputStream in)
        throws IOException, ClassNotFoundException
    {
        in.defaultReadObject();

        byte[] enc = (byte[])in.readObject();

        populateFromPubKeyInfo(SubjectPublicKeyInfo.getInstance(ASN1Primitive.fromByteArray(enc)));
    }

    private void writeObject(
        ObjectOutputStream out)
        throws IOException
    {
        out.defaultWriteObject();

        out.writeObject(this.getEncoded());
    }

    private void extractBytes(byte[] encKey, int offSet, BigInteger bI)
    {
        byte[] val = bI.toByteArray();
        if (val.length < 32)
        {
            byte[] tmp = new byte[32];
            System.arraycopy(val, 0, tmp, tmp.length - val.length, val.length);
            val = tmp;
        }

        for (int i = 0; i != 32; i++)
        {
            encKey[offSet + i] = val[val.length - 1 - i];
        }
    }
}
