package org.bouncycastle.jce.provider;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPublicKeySpec;
import java.security.spec.EllipticCurve;

import org.bouncycastle.asn1.ASN1BitString;
import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
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.EC5Util;
import org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil;
import org.bouncycastle.jcajce.provider.asymmetric.util.KeyUtil;
import org.bouncycastle.jce.ECGOST3410NamedCurveTable;
import org.bouncycastle.jce.interfaces.ECPointEncoder;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveSpec;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.util.Strings;

public class JCEECPublicKey
    implements ECPublicKey, org.bouncycastle.jce.interfaces.ECPublicKey, ECPointEncoder
{
    private String                  algorithm = "EC";
    private org.bouncycastle.math.ec.ECPoint q;
    private ECParameterSpec         ecSpec;
    private boolean                 withCompression;
    private GOST3410PublicKeyAlgParameters       gostParams;

    public JCEECPublicKey(
        String              algorithm,
        JCEECPublicKey      key)
    {
        this.algorithm = algorithm;
        this.q = key.q;
        this.ecSpec = key.ecSpec;
        this.withCompression = key.withCompression;
        this.gostParams = key.gostParams;
    }
    
    public JCEECPublicKey(
        String              algorithm,
        ECPublicKeySpec     spec)
    {
        this.algorithm = algorithm;
        this.ecSpec = spec.getParams();
        this.q = EC5Util.convertPoint(ecSpec, spec.getW());
    }

    public JCEECPublicKey(
        String              algorithm,
        org.bouncycastle.jce.spec.ECPublicKeySpec     spec)
    {
        this.algorithm = algorithm;
        this.q = spec.getQ();

        if (spec.getParams() != null) // can be null if implictlyCa
        {
            ECCurve curve = spec.getParams().getCurve();
            EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getParams().getSeed());

            this.ecSpec = EC5Util.convertSpec(ellipticCurve, spec.getParams());
        }
        else
        {
            if (q.getCurve() == null)
            {
                org.bouncycastle.jce.spec.ECParameterSpec s = BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa();

                q = s.getCurve().createPoint(q.getAffineXCoord().toBigInteger(), q.getAffineYCoord().toBigInteger());
            }               
            this.ecSpec = null;
        }
    }
    
    public JCEECPublicKey(
        String                  algorithm,
        ECPublicKeyParameters   params,
        ECParameterSpec         spec)
    {
        ECDomainParameters      dp = params.getParameters();

        this.algorithm = algorithm;
        this.q = params.getQ();

        if (spec == null)
        {
            EllipticCurve ellipticCurve = EC5Util.convertCurve(dp.getCurve(), dp.getSeed());

            this.ecSpec = createSpec(ellipticCurve, dp);
        }
        else
        {
            this.ecSpec = spec;
        }
    }

    public JCEECPublicKey(
        String                  algorithm,
        ECPublicKeyParameters   params,
        org.bouncycastle.jce.spec.ECParameterSpec         spec)
    {
        ECDomainParameters      dp = params.getParameters();

        this.algorithm = algorithm;
        this.q = params.getQ();

        if (spec == null)
        {
            EllipticCurve ellipticCurve = EC5Util.convertCurve(dp.getCurve(), dp.getSeed());

            this.ecSpec = createSpec(ellipticCurve, dp);
        }
        else
        {
            EllipticCurve ellipticCurve = EC5Util.convertCurve(spec.getCurve(), spec.getSeed());

            this.ecSpec = EC5Util.convertSpec(ellipticCurve, spec);
        }
    }

    /*
     * called for implicitCA
     */
    public JCEECPublicKey(
        String                  algorithm,
        ECPublicKeyParameters   params)
    {
        this.algorithm = algorithm;
        this.q = params.getQ();
        this.ecSpec = null;
    }

    private ECParameterSpec createSpec(EllipticCurve ellipticCurve, ECDomainParameters dp)
    {
        return new ECParameterSpec(
            ellipticCurve,
            EC5Util.convertPoint(dp.getG()),
            dp.getN(),
            dp.getH().intValue());
    }

    public JCEECPublicKey(
        ECPublicKey     key)
    {
        this.algorithm = key.getAlgorithm();
        this.ecSpec = key.getParams();
        this.q = EC5Util.convertPoint(this.ecSpec, key.getW());
    }

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

    private void populateFromPubKeyInfo(SubjectPublicKeyInfo info)
    {
        AlgorithmIdentifier algID = info.getAlgorithm();

        if (algID.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[] x9Encoding = new byte[65];
            x9Encoding[0] = 0x04;
            for (int i = 1; i <= 32; ++i)
            {
                x9Encoding[i     ] = keyEnc[32 - i];
                x9Encoding[i + 32] = keyEnc[64 - i];
            }

            gostParams = GOST3410PublicKeyAlgParameters.getInstance(algID.getParameters());

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

            ECCurve curve = spec.getCurve();
            EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getSeed());

            this.q = curve.decodePoint(x9Encoding);

            ecSpec = new ECNamedCurveSpec(
                ECGOST3410NamedCurves.getName(gostParams.getPublicKeyParamSet()),
                ellipticCurve,
                EC5Util.convertPoint(spec.getG()),
                spec.getN(),
                spec.getH());
        }
        else
        {
            X962Parameters params = X962Parameters.getInstance(algID.getParameters());
            ECCurve                 curve;
            EllipticCurve           ellipticCurve;

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

                curve = ecP.getCurve();
                ellipticCurve = EC5Util.convertCurve(curve, ecP.getSeed());

                ecSpec = new ECNamedCurveSpec(
                    ECUtil.getCurveName(oid),
                    ellipticCurve,
                    EC5Util.convertPoint(ecP.getG()),
                    ecP.getN(),
                    ecP.getH());
            }
            else if (params.isImplicitlyCA())
            {
                ecSpec = null;
                curve = BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa().getCurve();
            }
            else
            {
                X9ECParameters ecP = X9ECParameters.getInstance(params.getParameters());

                curve = ecP.getCurve();
                ellipticCurve = EC5Util.convertCurve(curve, ecP.getSeed());

                this.ecSpec = new ECParameterSpec(
                    ellipticCurve,
                    EC5Util.convertPoint(ecP.getG()),
                    ecP.getN(),
                    ecP.getH().intValue());
            }

            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);

            this.q = derQ.getPoint();
        }
    }

    public String getAlgorithm()
    {
        return algorithm;
    }

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

    public byte[] getEncoded()
    {
        ASN1Encodable        params;
        SubjectPublicKeyInfo info;

        if (algorithm.equals("ECGOST3410"))
        {
            if (gostParams != null)
            {
                params = gostParams;
            }
            else
            {
                if (ecSpec instanceof ECNamedCurveSpec)
                {
                    params = new GOST3410PublicKeyAlgParameters(
                                   ECGOST3410NamedCurves.getOID(((ECNamedCurveSpec)ecSpec).getName()),
                                   CryptoProObjectIdentifiers.gostR3411_94_CryptoProParamSet);
                }
                else
                {   // strictly speaking this may not be applicable...
                    ECCurve curve = EC5Util.convertCurve(ecSpec.getCurve());

                    X9ECParameters ecP = new X9ECParameters(
                        curve,
                        new X9ECPoint(EC5Util.convertPoint(curve, ecSpec.getGenerator()), withCompression),
                        ecSpec.getOrder(),
                        BigInteger.valueOf(ecSpec.getCofactor()),
                        ecSpec.getCurve().getSeed());

                    params = new X962Parameters(ecP);
                }
            }

            BigInteger bX = this.q.getAffineXCoord().toBigInteger();
            BigInteger bY = this.q.getAffineYCoord().toBigInteger();

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

            try
            {
                info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(CryptoProObjectIdentifiers.gostR3410_2001, params), new DEROctetString(encKey));
            }
            catch (IOException e)
            {
                return null;
            }
        }
        else
        {
            if (ecSpec instanceof ECNamedCurveSpec)
            {
                ASN1ObjectIdentifier curveOid = ECUtil.getNamedCurveOid(((ECNamedCurveSpec)ecSpec).getName());
                if (curveOid == null)
                {
                    curveOid = new ASN1ObjectIdentifier(((ECNamedCurveSpec)ecSpec).getName());
                }
                params = new X962Parameters(curveOid);
            }
            else if (ecSpec == null)
            {
                params = new X962Parameters(DERNull.INSTANCE);
            }
            else
            {
                ECCurve curve = EC5Util.convertCurve(ecSpec.getCurve());

                X9ECParameters ecP = new X9ECParameters(
                    curve,
                    new X9ECPoint(EC5Util.convertPoint(curve, ecSpec.getGenerator()), withCompression),
                    ecSpec.getOrder(),
                    BigInteger.valueOf(ecSpec.getCofactor()),
                    ecSpec.getCurve().getSeed());

                params = new X962Parameters(ecP);
            }

            byte[] pubKeyOctets = this.getQ().getEncoded(withCompression);

            info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(X9ObjectIdentifiers.id_ecPublicKey, params), pubKeyOctets);
        }

        return KeyUtil.getEncodedSubjectPublicKeyInfo(info);
    }

    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];
        }
    }

    public ECParameterSpec getParams()
    {
        return ecSpec;
    }

    public org.bouncycastle.jce.spec.ECParameterSpec getParameters()
    {
        if (ecSpec == null)     // implictlyCA
        {
            return null;
        }

        return EC5Util.convertSpec(ecSpec);
    }

    public ECPoint getW()
    {
        return EC5Util.convertPoint(q);
    }

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

        return q;
    }

    public org.bouncycastle.math.ec.ECPoint engineGetQ()
    {
        return q;
    }

    org.bouncycastle.jce.spec.ECParameterSpec engineGetSpec()
    {
        if (ecSpec != null)
        {
            return EC5Util.convertSpec(ecSpec);
        }

        return BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa();
    }

    public String toString()
    {
        StringBuffer    buf = new StringBuffer();
        String          nl = Strings.lineSeparator();

        buf.append("EC Public Key").append(nl);
        buf.append("            X: ").append(this.q.getAffineXCoord().toBigInteger().toString(16)).append(nl);
        buf.append("            Y: ").append(this.q.getAffineYCoord().toBigInteger().toString(16)).append(nl);

        return buf.toString();

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

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

        JCEECPublicKey other = (JCEECPublicKey)o;

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

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

    private void readObject(
        ObjectInputStream in)
        throws IOException, ClassNotFoundException
    {
        byte[] enc = (byte[])in.readObject();

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

        this.algorithm = (String)in.readObject();
        this.withCompression = in.readBoolean();
    }

    private void writeObject(
        ObjectOutputStream out)
        throws IOException
    {
        out.writeObject(this.getEncoded());
        out.writeObject(algorithm);
        out.writeBoolean(withCompression);
    }
}
