/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *
 * $Id: BinaryVerificator_1_0_0.java,v 1.3 2006/10/11 08:03:22 wprinz Exp $
 */
package at.gv.egiz.pdfas.impl.verificator.binary;

import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.log4j.Logger;

import at.gv.egiz.pdfas.exceptions.ErrorCode;
import at.gv.egiz.pdfas.framework.input.PdfDataSource;
import at.gv.egiz.pdfas.framework.verificator.Verificator;
import at.gv.egiz.pdfas.impl.input.CompoundPdfDataSourceImpl;
import at.gv.egiz.pdfas.impl.input.DelimitedPdfDataSource;
import at.gv.egiz.pdfas.impl.vfilter.helper.VerificationFilterBinaryHelper;
import at.knowcenter.wag.egov.egiz.PdfASID;
import at.knowcenter.wag.egov.egiz.cfg.ConfigLogger;
import at.knowcenter.wag.egov.egiz.cfg.SettingsReader;
import at.knowcenter.wag.egov.egiz.exceptions.PDFDocumentException;
import at.knowcenter.wag.egov.egiz.exceptions.PresentableException;
import at.knowcenter.wag.egov.egiz.framework.SignatorFactory;
import at.knowcenter.wag.egov.egiz.framework.VerificationFilter;
import at.knowcenter.wag.egov.egiz.pdf.BinaryBlockInfo;
import at.knowcenter.wag.egov.egiz.pdf.BinarySignature;
import at.knowcenter.wag.egov.egiz.pdf.BinarySignatureHolder;
import at.knowcenter.wag.egov.egiz.pdf.Placeholder;
import at.knowcenter.wag.egov.egiz.pdf.ReplaceInfo;
import at.knowcenter.wag.egov.egiz.pdf.StringInfo;
import at.knowcenter.wag.egov.egiz.sig.SignatureObject;
import at.knowcenter.wag.egov.egiz.sig.SignatureTypes;
import at.knowcenter.wag.exactparser.parsing.IndirectObjectReference;
import at.knowcenter.wag.exactparser.parsing.PDFUtils;
import at.knowcenter.wag.exactparser.parsing.results.ArrayParseResult;
import at.knowcenter.wag.exactparser.parsing.results.DictionaryParseResult;
import at.knowcenter.wag.exactparser.parsing.results.FooterParseResult;
import at.knowcenter.wag.exactparser.parsing.results.IndirectObjectReferenceParseResult;
import at.knowcenter.wag.exactparser.parsing.results.LiteralStringParseResult;
import at.knowcenter.wag.exactparser.parsing.results.NameParseResult;
import at.knowcenter.wag.exactparser.parsing.results.NumberParseResult;
import at.knowcenter.wag.exactparser.parsing.results.ObjectParseResult;
import at.knowcenter.wag.exactparser.parsing.results.ParseResult;

/**
 * The BinaryVerificator parses the EGIT Dictionary and extracts the signature
 * holder from it.
 * 
 * @author wprinz
 */
public class BinaryVerificator_1_0_0 implements Verificator
{
  /**
   * The Pdf-AS ID of this Verificator.
   */
  public static final PdfASID MY_ID = new PdfASID(SignatorFactory.VENDOR, SignatorFactory.TYPE_BINARY, SignatorFactory.VERSION_1_0_0);

  /**
   * Use this to override the MY_ID field.
   * 
   * @return Returns the Id of this Verificator.
   */
  protected PdfASID getMyId()
  {
    return MY_ID;
  }

  /**
   * The /ODS key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_ODS_NAME = new byte[] { 'O', 'D', 'S' };

  /**
   * The /ID key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_KZ_NAME = VerificationFilter.EGIZ_KZ_NAME;

  /**
   * The /ByteRange key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_BYTE_RANGE_NAME = new byte[] { 'B', 'y', 't', 'e', 'R', 'a', 'n', 'g', 'e' };

  /**
   * The /replaces key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_REPLACES_NAME = new byte[] { 'r', 'e', 'p', 'l', 'a', 'c', 'e', 's' };

  /**
   * The /encodings key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_ENCODINGS_NAME = new byte[] { 'e', 'n', 'c', 'o', 'd', 'i', 'n', 'g', 's' };

  /**
   * The /Cert key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_CERT_NAME = new byte[] { 'C', 'e', 'r', 't' };
  
  /**
   * The /TimeStamp key in the EGIZ Dict.
   */
  public static final byte[] EGIZ_TIMESTAMP_NAME = new byte[] { 'T', 'i', 'm', 'e', 'S', 't', 'a', 'm', 'p' };
  

  /**
   * The logger definition.
   */
  private static final Logger logger_ = ConfigLogger.getLogger(BinaryVerificator_1_0_0.class);

  /**
   * Default constructor.
   */
  public BinaryVerificator_1_0_0()
  {
    // Default constructor.
  }

  /**
   * @see at.gv.egiz.pdfas.framework.verificator.Verificator#parseBlock(at.gv.egiz.pdfas.framework.input.PdfDataSource,
   *      byte[],
   *      at.knowcenter.wag.exactparser.parsing.results.FooterParseResult, int)
   */
  public List parseBlock(PdfDataSource pdfDataSource, byte [] pdf, FooterParseResult block, int start_of_whole_block) throws PresentableException
  {
    // PERF: BinaryVerificator needs byte array.
    
    int egiz_index = PDFUtils.indexOfName(pdf, block.tpr.dpr.names, VerificationFilter.EGIZ_DICT_NAME);
    if (egiz_index < 0)
    {
      throw new PDFDocumentException(ErrorCode.COULDNT_VERIFY, "egiz_index = " + egiz_index);
    }

    IndirectObjectReferenceParseResult egiz_dict_iorpr = (IndirectObjectReferenceParseResult) block.tpr.dpr.values.get(egiz_index);

    IndirectObjectReference ior = egiz_dict_iorpr.ior;

    final int egiz_dict_offset = PDFUtils.getObjectOffsetFromXRefByIndirectObjectReference(block.xpr, ior);

    ObjectParseResult obj = PDFUtils.parseObject(pdf, egiz_dict_offset);
    DictionaryParseResult egiz_dict = (DictionaryParseResult) obj.object;

    NumberParseResult ods_npr = (NumberParseResult) getRequiredValueOfKey(pdf, egiz_dict, EGIZ_ODS_NAME);

    ArrayParseResult kz_apr = (ArrayParseResult) getRequiredValueOfKey(pdf, egiz_dict, EGIZ_KZ_NAME);
    PdfASID kz = null;
//    String kz_string = VerificationFilter.restoreKZ(pdf, kz_apr);
    String kz_string = VerificationFilterBinaryHelper.restoreKZ(pdf, kz_apr);  // dferbas hack baik test
    // TODO baik hack kz_string = "urn:pdfsigfilter:bka.gv.at:binaer:v1.0.0";
    kz = new PdfASID(kz_string);
    if (!kz_string.equals(getMyId().toString()))
    {
      logger_.warn("Warning: Kennzeichnung not recognized:" + kz_string);
    }

    ArrayParseResult byte_ranges_apr = (ArrayParseResult) getRequiredValueOfKey(pdf, egiz_dict, EGIZ_BYTE_RANGE_NAME);

    ArrayParseResult replaces_apr = (ArrayParseResult) getRequiredValueOfKey(pdf, egiz_dict, EGIZ_REPLACES_NAME);

    ArrayParseResult encodings_apr = (ArrayParseResult) getRequiredValueOfKey(pdf, egiz_dict, EGIZ_ENCODINGS_NAME);

    ArrayParseResult cert_apr = (ArrayParseResult) getValueOfKey(pdf, egiz_dict, EGIZ_CERT_NAME);
    byte[] cert = null;
    if (cert_apr != null && !cert_apr.elements.isEmpty())
    {
      LiteralStringParseResult lspr = (LiteralStringParseResult) cert_apr.elements.get(0);
      int str_length = lspr.content_end_index - lspr.content_start_index;
      byte[] encoded = new byte[str_length];
      System.arraycopy(pdf, lspr.content_start_index, encoded, 0, encoded.length);

      cert = Placeholder.unescapePDFString(encoded);
    }
    
    //timestamp
    ArrayParseResult timestamp_apr = (ArrayParseResult) getValueOfKey(pdf, egiz_dict, EGIZ_TIMESTAMP_NAME);
    byte[] timestamp = null;
    if (timestamp_apr != null) {
       logger_.debug("found /TimeStamp in egiz dict. Extracting...");    
       
       if (timestamp_apr != null && !timestamp_apr.elements.isEmpty())
       {
         LiteralStringParseResult lspr = (LiteralStringParseResult) timestamp_apr.elements.get(0);
         int str_length = lspr.content_end_index - lspr.content_start_index;
         byte[] encoded = new byte[str_length];
         System.arraycopy(pdf, lspr.content_start_index, encoded, 0, encoded.length);
   
         timestamp = Placeholder.unescapePDFString(encoded);
                  
       }
    }
    

    int num_byte_ranges = byte_ranges_apr.elements.size() / 2;
    List byte_ranges = new ArrayList();
    for (int i = 0; i < num_byte_ranges; i++)
    {
      NumberParseResult start_npr = (NumberParseResult) byte_ranges_apr.elements.get(2 * i);
      NumberParseResult length_npr = (NumberParseResult) byte_ranges_apr.elements.get(2 * i + 1);

      StringInfo si = new StringInfo();
      si.string_start = start_npr.number;
      si.string_length = length_npr.number;
      byte_ranges.add(si);
    }

    StringInfo sis[] = new StringInfo[num_byte_ranges - 1];
    for (int i = 0; i < num_byte_ranges - 1; i++)
    {
      StringInfo prev = (StringInfo) byte_ranges.get(i);
      StringInfo next = (StringInfo) byte_ranges.get(i + 1);

      StringInfo hole = new StringInfo();
      hole.string_start = prev.string_start + prev.string_length;
      hole.string_length = next.string_start - hole.string_start;

      sis[i] = hole;
    }

    int n = replaces_apr.elements.size();
    byte[][] brevs = new byte[n][];
    for (int i = 0; i < n; i++)
    {
      NameParseResult lspr = (NameParseResult) replaces_apr.elements.get(i);

      byte[] brev = new byte[3];
      System.arraycopy(pdf, lspr.name_start_index, brev, 0, brev.length);

      brevs[i] = brev; // SignatureTypes.convertBrevToType(brev);
    }

    n = encodings_apr.elements.size();
    byte[][] encodings = new byte[n][];
    for (int i = 0; i < n; i++)
    {
      NameParseResult lspr = (NameParseResult) encodings_apr.elements.get(i);

      byte[] enc = new byte[3];
      System.arraycopy(pdf, lspr.name_start_index, enc, 0, enc.length);
      encodings[i] = enc;
    }

    BinaryBlockInfo bbi = new BinaryBlockInfo();
    bbi.replaces = BinarySignature.reconstructReplaces(pdf, brevs, sis, encodings);
    bbi.signed_size = ods_npr.number;

    // BinaryBlockInfo bbi = BinarySignature.retrieveEgizDictInformation(pdf,
    // ior.object_number, ior.generation_number, egiz_dict_offset);

    // byte[] original_pdf = BinarySignature.restoreEgizDictInformation(pdf,
    // bbi);

    byte[] signed_pdf = BinarySignature.prepareDataToSign(pdf, byte_ranges);
    // String signed_text =
    // BinarySignature.retrieveSignableTextFromData(signed_pdf,
    // signed_pdf.length); // has been moved into the BinarySignatureHolder

    SignatureObject signature_object = new SignatureObject();
    String default_type = SettingsReader.getInstance().getValueFromKey(SignatureTypes.DEFAULT_TYPE);
    signature_object.setSigType(default_type);
    signature_object.initByType();

    signature_object.setKZ(kz);
    
    if (timestamp != null) {
       String ts = new String(trimZeroBytes(timestamp));
       signature_object.setTimeStamp(ts);
       if (logger_.isDebugEnabled()) {
          logger_.debug("extracted timestamp " + ts);
       }
    }

    if (cert != null)
    {
      try
      {
        // ByteArrayInputStream bais = new ByteArrayInputStream(cert);
        // CertificateFactory cf = CertificateFactory.getInstance("X.509");
        // X509Certificate certificate = (X509Certificate)
        // cf.generateCertificate(bais);

        // trim zero bytes. - the base 64 cert must not have zero bytes.
        byte[] b64 = trimZeroBytes(cert);

        signature_object.storeNewCertificateInLocalStore(b64);
      }
      catch (Exception e)
      {
         logger_.error(e.getMessage(), e);
      }

    }

    Iterator rit = bbi.replaces.iterator();
    while (rit.hasNext())
    {
      ReplaceInfo ri = (ReplaceInfo) rit.next();

      String type = SignatureTypes.convertBrevToType(ri.brev);
      
      if (type == null) {
         throw new PresentableException(ErrorCode.UNSUPPORTED_REPLACES_NAME, "Unsupported /replaces name.");
      }

      // signature_object.setSigValue(ri.type, ri.value);
      if (type.equals(SignatureTypes.SIG_DATE))
      {
        signature_object.setSignationDate(ri.value);
        continue;
      }

      if (type.equals(SignatureTypes.SIG_ISSUER))
      {
        signature_object.setSignationIssuer(ri.value);
        continue;
      }

      if (type.equals(SignatureTypes.SIG_VALUE))
      {
        signature_object.setSignationValue(ri.value);
        continue;
      }

      if (type.equals(SignatureTypes.SIG_NUMBER))
      {
        signature_object.setSignationSerialNumber(ri.value);
        continue;
      }

      if (type.equals(SignatureTypes.SIG_ID))
      {
        signature_object.setSignationIDs(ri.value);
        continue;
      }
      
      if (type.equals(SignatureTypes.SIG_ALG))
      {
        signature_object.setSigAlg(ri.value);
        continue;
      }      
    }

    int iu_length = signed_pdf.length - start_of_whole_block;
    byte [] iu_block = new byte [iu_length];
    System.arraycopy(signed_pdf, start_of_whole_block, iu_block, 0, iu_length);

    DelimitedPdfDataSource dpds = new DelimitedPdfDataSource(pdfDataSource, start_of_whole_block);
    PdfDataSource ds = new CompoundPdfDataSourceImpl(dpds, iu_block);
    
    //PdfDataSource dsByteArray = new ByteArrayPdfDataSourceImpl(signed_pdf, signed_pdf.length);
    
    BinarySignatureHolder signature_holder = new BinarySignatureHolder(ds, signature_object);

    List holders = new ArrayList();
    holders.add(signature_holder);
    return holders;
  }

   private byte[] trimZeroBytes(byte[] arr) {
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
        for (int i = 0; i < arr.length; i++)
        {
          if (arr[i] != 0)
          {
            baos.write(arr[i]);
          }
        }
        byte[] b64 = baos.toByteArray();
      return b64;
   }

  /**
   * Retrieves the value of the key from the dictionary.
   * 
   * @param pdf
   *          The PDF.
   * @param egiz_dict
   *          The dictionary.
   * @param name
   *          The name of the key.
   * @return Returns the value of the key. An exception is thrown if the key
   *         doesn't exist.
   * @throws PDFDocumentException
   *           Thrown, if the key doesn't exist in the dictionary.
   */
  protected ParseResult getRequiredValueOfKey(byte[] pdf, DictionaryParseResult egiz_dict, byte[] name) throws PDFDocumentException
  {
    final int index = PDFUtils.indexOfName(pdf, egiz_dict.names, name);
    checkIndex(index);
    ParseResult value = (ParseResult) egiz_dict.values.get(index);
    return value;
  }

  /**
   * Throws an excaption, if the index is lower than 0.
   * 
   * @param name_index
   *          The index.
   * @throws PDFDocumentException
   *           Thrown, if the index is lower than 0.
   */
  protected void checkIndex(int name_index) throws PDFDocumentException
  {
    if (name_index < 0)
    {
      throw new PDFDocumentException(ErrorCode.COULDNT_VERIFY, "The name wasn't found in the egiz dict.");
    }
  }

  /**
   * Retrieves the value of the key from the dictionary.
   * 
   * @param pdf
   *          The PDF.
   * @param egiz_dict
   *          The dictionary.
   * @param name
   *          The name of the key.
   * @return Returns the key's value, or null if the dictionary didn't contain
   *         that key.
   */
  protected ParseResult getValueOfKey(byte[] pdf, DictionaryParseResult egiz_dict, byte[] name)
  {
    final int index = PDFUtils.indexOfName(pdf, egiz_dict.names, name);
    if (index < 0)
    {
      return null;
    }
    ParseResult value = (ParseResult) egiz_dict.values.get(index);
    return value;
  }

}