package org.jboss.resteasy.security.smime;

import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
import org.bouncycastle.cms.CMSTypedData;
import org.bouncycastle.cms.jcajce.JcaSignerInfoGeneratorBuilder;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.OperatorCreationException;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
import org.bouncycastle.operator.jcajce.JcaDigestCalculatorProviderBuilder;
import org.jboss.resteasy.plugins.providers.ProviderHelper;
import org.jboss.resteasy.security.BouncyIntegration;
import org.jboss.resteasy.security.doseta.i18n.Messages;
import org.jboss.resteasy.specimpl.MultivaluedMapImpl;
import org.jboss.resteasy.spi.AsyncMessageBodyWriter;
import org.jboss.resteasy.spi.AsyncOutputStream;
import org.jboss.resteasy.spi.WriterException;

import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.Providers;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.cert.CertificateEncodingException;
import java.util.concurrent.CompletionStage;

Author:
Bill Burke
Version:
$Revision: 1 $/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
@Provider
@Produces("application/pkcs7-signature")
public class PKCS7SignatureWriter implements AsyncMessageBodyWriter<SignedOutput>
{
   static
   {
      BouncyIntegration.init();
   }

   @Context
   protected Providers providers;

   @Override
   public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return SignedOutput.class.isAssignableFrom(type);
   }

   @Override
   public long getSize(SignedOutput smimeOutput, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return -1;
   }

   @Override
   public void writeTo(SignedOutput out, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> headers, OutputStream os) throws IOException, WebApplicationException
   {
      try
      {
         byte[] encoded = sign(providers, out);
         headers.putSingle("Content-Type", "application/pkcs7-signature;micalg=\"sha1\"");
         os.write(encoded);

      }
      catch (Exception e)
      {
         throw new WriterException(e);
      }
   }

   @Override
   public CompletionStage<Void> asyncWriteTo(SignedOutput out, Class<?> type, Type genericType, Annotation[] annotations,
                                             MediaType mediaType, MultivaluedMap<String, Object> headers,
                                             AsyncOutputStream entityStream) {
       try
       {
          byte[] encoded = sign(providers, out);
          headers.putSingle("Content-Type", "application/pkcs7-signature;micalg=\"sha1\"");
          return entityStream.asyncWrite(encoded);
       }
       catch (Exception e)
       {
          return ProviderHelper.completedException(new WriterException(e));
       }
   }

   @SuppressWarnings(value = "unchecked")
   public static byte[] sign(Providers providers, SignedOutput out) throws IOException, NoSuchAlgorithmException, NoSuchProviderException, CMSException, OperatorCreationException, CertificateEncodingException {
      ByteArrayOutputStream bodyOs = new ByteArrayOutputStream();
      MessageBodyWriter writer = providers.getMessageBodyWriter(out.getType(), out.getGenericType(), null, out.getMediaType());
      if (writer == null)
      {
         throw new WriterException(Messages.MESSAGES.failedToFindWriter(out.getType().getName()));
      }
      MultivaluedMapImpl<String, Object> bodyHeaders = new MultivaluedMapImpl<String, Object>();
      bodyHeaders.add("Content-Type",  out.getMediaType().toString());
      writer.writeTo(out.getEntity(), out.getType(), out.getGenericType(), null, out.getMediaType(), bodyHeaders, bodyOs);
      CMSSignedDataGenerator signGen = new CMSSignedDataGenerator();


      ContentSigner sha1Signer = new JcaContentSignerBuilder("SHA1withRSA").setProvider("BC").build(out.getPrivateKey());

      signGen.addSignerInfoGenerator(
                              new JcaSignerInfoGeneratorBuilder(
                                   new JcaDigestCalculatorProviderBuilder().setProvider("BC").build())
                           .build(sha1Signer, out.getCertificate()));

      CMSTypedData content = new CMSProcessableByteArray(bodyOs.toByteArray());

      CMSSignedData signedData = signGen.generate(content, true);

      return signedData.getEncoded();
   }
}