package org.bouncycastle.x509;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;
import java.security.cert.X509Certificate;
import java.util.Date;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Vector;

import javax.security.auth.x500.X500Principal;

import org.bouncycastle.asn1.*;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.asn1.x509.TBSCertificateStructure;
import org.bouncycastle.asn1.x509.Time;
import org.bouncycastle.asn1.x509.V3TBSCertificateGenerator;
import org.bouncycastle.asn1.x509.X509CertificateStructure;
import org.bouncycastle.asn1.x509.X509Extension;
import org.bouncycastle.asn1.x509.X509Extensions;
import org.bouncycastle.asn1.x509.X509Name;
import org.bouncycastle.jce.X509Principal;
import org.bouncycastle.jce.provider.X509CertificateObject;

/**
 * class to produce an X.509 Version 3 certificate.
 */
public class X509V3CertificateGenerator
{
    private V3TBSCertificateGenerator   tbsGen;
    private DERObjectIdentifier         sigOID;
    private AlgorithmIdentifier         sigAlgId;
    private String                      signatureAlgorithm;
    private Hashtable                   extensions = null;
    private Vector                      extOrdering = null;

    public X509V3CertificateGenerator()
    {
        tbsGen = new V3TBSCertificateGenerator();
    }

    /**
     * reset the generator
     */
    public void reset()
    {
        tbsGen = new V3TBSCertificateGenerator();
        extensions = null;
        extOrdering = null;
    }

    /**
     * set the serial number for the certificate.
     */
    public void setSerialNumber(
        BigInteger      serialNumber)
    {
        tbsGen.setSerialNumber(new DERInteger(serialNumber));
    }

    /**
     * Set the issuer distinguished name - the issuer is the entity whose private key is used to sign the
     * certificate.
     */
    public void setIssuerDN(
        X500Principal   issuer)
    {
        try
        {
            tbsGen.setIssuer(new X509Principal(issuer.getEncoded()));
        }
        catch (IOException e)
        {
            throw new IllegalArgumentException("can't process principal: " + e);
        }
    }
    
    /**
     * Set the issuer distinguished name - the issuer is the entity whose private key is used to sign the
     * certificate.
     */
    public void setIssuerDN(
        X509Name   issuer)
    {
        tbsGen.setIssuer(issuer);
    }

    public void setNotBefore(
        Date    date)
    {
        tbsGen.setStartDate(new Time(date));
    }

    public void setNotAfter(
        Date    date)
    {
        tbsGen.setEndDate(new Time(date));
    }

    /**
     * Set the subject distinguished name. The subject describes the entity associated with the public key.
     */
    public void setSubjectDN(
        X500Principal   subject)
    {
        try
        {
            tbsGen.setSubject(new X509Principal(subject.getEncoded()));
        }
        catch (IOException e)
        {
            throw new IllegalArgumentException("can't process principal: " + e);
        }
    }
    
    /**
     * Set the subject distinguished name. The subject describes the entity associated with the public key.
     */
    public void setSubjectDN(
        X509Name   subject)
    {
        tbsGen.setSubject(subject);
    }

    public void setPublicKey(
        PublicKey       key)
    {
        try
        {
            tbsGen.setSubjectPublicKeyInfo(new SubjectPublicKeyInfo((ASN1Sequence)new ASN1InputStream(
                                new ByteArrayInputStream(key.getEncoded())).readObject()));
        }
        catch (Exception e)
        {
            throw new IllegalArgumentException("unable to process key - " + e.toString());
        }
    }

    /**
     * Set the signature algorithm. This can be either a name or an OID, names
     * are treated as case insensitive.
     * 
     * @param signatureAlgorithm string representation of the algorithm name.
     */
    public void setSignatureAlgorithm(
        String  signatureAlgorithm)
    {
        this.signatureAlgorithm = signatureAlgorithm;

        try
        {
            sigOID = X509Util.getAlgorithmOID(signatureAlgorithm);
        }
        catch (Exception e)
        {
            throw new IllegalArgumentException("Unknown signature type requested");
        }

        sigAlgId = new AlgorithmIdentifier(this.sigOID, new DERNull());

        tbsGen.setSignature(sigAlgId);
    }

    /**
     * add a given extension field for the standard extensions tag (tag 3)
     */
    public void addExtension(
        String          OID,
        boolean         critical,
        DEREncodable    value)
    {
        this.addExtension(new DERObjectIdentifier(OID), critical, value);
    }

    /**
     * add a given extension field for the standard extensions tag (tag 3)
     */
    public void addExtension(
        DERObjectIdentifier OID,
        boolean             critical,
        DEREncodable        value)
    {
        if (extensions == null)
        {
            extensions = new Hashtable();
            extOrdering = new Vector();
        }

        ByteArrayOutputStream   bOut = new ByteArrayOutputStream();
        DEROutputStream         dOut = new DEROutputStream(bOut);

        try
        {
            dOut.writeObject(value);
        }
        catch (IOException e)
        {
            throw new IllegalArgumentException("error encoding value: " + e);
        }

        this.addExtension(OID, critical, bOut.toByteArray());
    }

    /**
     * add a given extension field for the standard extensions tag (tag 3)
     * The value parameter becomes the contents of the octet string associated
     * with the extension.
     */
    public void addExtension(
        String          OID,
        boolean         critical,
        byte[]          value)
    {
        this.addExtension(new DERObjectIdentifier(OID), critical, value);
    }

    /**
     * add a given extension field for the standard extensions tag (tag 3)
     */
    public void addExtension(
        DERObjectIdentifier OID,
        boolean             critical,
        byte[]              value)
    {
        if (extensions == null)
        {
            extensions = new Hashtable();
            extOrdering = new Vector();
        }

        extensions.put(OID, new X509Extension(critical, new DEROctetString(value)));
        extOrdering.addElement(OID);
    }

    /**
     * generate an X509 certificate, based on the current issuer and subject
     * using the default provider "BC".
     */
    public X509Certificate generateX509Certificate(
        PrivateKey      key)
        throws SecurityException, SignatureException, InvalidKeyException
    {
        try
        {
            return generateX509Certificate(key, "BC", null);
        }
        catch (NoSuchProviderException e)
        {
            throw new SecurityException("BC provider not installed!");
        }
    }

    /**
     * generate an X509 certificate, based on the current issuer and subject
     * using the default provider "BC", and the passed in source of randomness
     * (if required).
     */
    public X509Certificate generateX509Certificate(
        PrivateKey      key,
        SecureRandom    random)
        throws SecurityException, SignatureException, InvalidKeyException
    {
        try
        {
            return generateX509Certificate(key, "BC", random);
        }
        catch (NoSuchProviderException e)
        {
            throw new SecurityException("BC provider not installed!");
        }
    }

    /**
     * generate an X509 certificate, based on the current issuer and subject,
     * using the passed in provider for the signing.
     */
    public X509Certificate generateX509Certificate(
        PrivateKey      key,
        String          provider)
        throws NoSuchProviderException, SecurityException, SignatureException, InvalidKeyException
    {
        return generateX509Certificate(key, provider, null);
    }

    /**
     * generate an X509 certificate, based on the current issuer and subject,
     * using the passed in provider for the signing and the supplied source
     * of randomness, if required.
     */
    public X509Certificate generateX509Certificate(
        PrivateKey      key,
        String          provider,
        SecureRandom    random)
        throws NoSuchProviderException, SecurityException, SignatureException, InvalidKeyException
    {
        Signature sig = null;

        if (sigOID == null)
        {
            throw new IllegalStateException("no signature algorithm specified");
        }

        try
        {
            sig = Signature.getInstance(sigOID.getId(), provider);
        }
        catch (NoSuchAlgorithmException ex)
        {
            try
            {
                sig = Signature.getInstance(signatureAlgorithm, provider);
            }
            catch (NoSuchAlgorithmException e)
            {
                throw new SecurityException("exception creating signature: " + e.toString());
            }
        }

        if (random != null)
        {
            sig.initSign(key, random);
        }
        else
        {
            sig.initSign(key);
        }

        if (extensions != null)
        {
            tbsGen.setExtensions(new X509Extensions(extOrdering, extensions));
        }

        TBSCertificateStructure tbsCert = tbsGen.generateTBSCertificate();

        try
        {
            ByteArrayOutputStream   bOut = new ByteArrayOutputStream();
            DEROutputStream         dOut = new DEROutputStream(bOut);

            dOut.writeObject(tbsCert);

            sig.update(bOut.toByteArray());
        }
        catch (Exception e)
        {
            throw new SecurityException("exception encoding TBS cert - " + e);
        }

        ASN1EncodableVector  v = new ASN1EncodableVector();

        v.add(tbsCert);
        v.add(sigAlgId);
        v.add(new DERBitString(sig.sign()));

        return new X509CertificateObject(new X509CertificateStructure(new DERSequence(v)));
    }
    
    /**
     * Return an iterator of the signature names supported by the generator.
     * 
     * @return an iterator containing recognised names.
     */
    public Iterator getSignatureAlgNames()
    {
        return X509Util.getAlgNames();
    }
}
