/*  -*- c++ -*-

    KMime, the KDE Internet mail/usenet news message library.

    Copyright (c) 2001-2002 Marc Mutz <mutz@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/
/**
  @file
  This file is part of the API for handling MIME data and
  defines the Codec class.

  @brief
  Defines the Codec class.

  @authors Marc Mutz \<mutz@kde.org\>
*/

#include "kmime_codecs.h"
#include "kmime_util.h"
#include "kmime_codec_base64.h"
#include "kmime_codec_qp.h"
#include "kmime_codec_uuencode.h"
#include "kmime_codec_identity.h"

#include "kautodeletehash.h"

#include <kascii.h>
#include <kdebug.h>
#include <kglobal.h>

#include <QtCore/QCoreApplication>
#include <QtCore/QMutex>

#include <cassert>
#include <cstring>
#include <string.h>

using namespace KMime;

namespace KMime {

// global list of KMime::Codec's
//@cond PRIVATE
KAutoDeleteHash<QByteArray, Codec> *Codec::all = 0;
K_GLOBAL_STATIC( QMutex, dictLock )
//@endcond

void Codec::cleanupCodec()
{
    delete all;
    all = 0;
}

void Codec::fillDictionary()
{
  //all->insert( "7bit", new SevenBitCodec() );
  //all->insert( "8bit", new EightBitCodec() );
  all->insert( "base64", new Base64Codec() );
  all->insert( "quoted-printable", new QuotedPrintableCodec() );
  all->insert( "b", new Rfc2047BEncodingCodec() );
  all->insert( "q", new Rfc2047QEncodingCodec() );
  all->insert( "x-kmime-rfc2231", new Rfc2231EncodingCodec() );
  all->insert( "x-uuencode", new UUCodec() );
  //all->insert( "binary", new BinaryCodec() );
}

Codec *Codec::codecForName( const char *name )
{
  const QByteArray ba( name );
  return codecForName( ba );
}

Codec *Codec::codecForName( const QByteArray &name )
{
  dictLock->lock(); // protect "all"
  if ( !all ) {
    all = new KAutoDeleteHash<QByteArray, Codec>();
    qAddPostRoutine( cleanupCodec );
    fillDictionary();
  }
  QByteArray lowerName = name;
  kAsciiToLower( lowerName.data() );
  Codec *codec = ( *all )[ lowerName ]; // FIXME: operator[] adds an entry into the hash
  dictLock->unlock();

  if ( !codec ) {
    kDebug() << "Unknown codec \"" << name << "\" requested!";
  }

  return codec;
}

bool Codec::encode( const char* &scursor, const char * const send,
                    char* &dcursor, const char * const dend,
                    bool withCRLF ) const
{
  // get an encoder:
  Encoder *enc = makeEncoder( withCRLF );
  assert( enc );

  // encode and check for output buffer overflow:
  while ( !enc->encode( scursor, send, dcursor, dend ) ) {
    if ( dcursor == dend ) {
      delete enc;
      return false; // not enough space in output buffer
    }
  }

  // finish and check for output buffer overflow:
  while ( !enc->finish( dcursor, dend ) ) {
    if ( dcursor == dend ) {
      delete enc;
      return false; // not enough space in output buffer
    }
  }

  // cleanup and return:
  delete enc;
  return true; // successfully encoded.
}

QByteArray Codec::encode( const QByteArray &src, bool withCRLF ) const
{
  // allocate buffer for the worst case:
  QByteArray result;
  result.resize( maxEncodedSizeFor( src.size(), withCRLF ) );

  // set up iterators:
  QByteArray::ConstIterator iit = src.begin();
  QByteArray::ConstIterator iend = src.end();
  QByteArray::Iterator oit = result.begin();
  QByteArray::ConstIterator oend = result.end();

  // encode
  if ( !encode( iit, iend, oit, oend, withCRLF ) ) {
    kFatal() << name() << "codec lies about it's mEncodedSizeFor()";
  }

  // shrink result to actual size:
  result.truncate( oit - result.begin() );

  return result;
}

QByteArray Codec::decode( const QByteArray &src, bool withCRLF ) const
{
  // allocate buffer for the worst case:
  QByteArray result;
  result.resize( maxDecodedSizeFor( src.size(), withCRLF ) );

  // set up iterators:
  QByteArray::ConstIterator iit = src.begin();
  QByteArray::ConstIterator iend = src.end();
  QByteArray::Iterator oit = result.begin();
  QByteArray::ConstIterator oend = result.end();

  // decode
  if ( !decode( iit, iend, oit, oend, withCRLF ) ) {
    kFatal() << name() << "codec lies about it's maxDecodedSizeFor()";
  }

  // shrink result to actual size:
  result.truncate( oit - result.begin() );

  return result;
}

bool Codec::decode( const char* &scursor, const char * const send,
                    char* &dcursor, const char * const dend,
                    bool withCRLF ) const
{
  // get a decoder:
  Decoder *dec = makeDecoder( withCRLF );
  assert( dec );

  // decode and check for output buffer overflow:
  while ( !dec->decode( scursor, send, dcursor, dend ) ) {
    if ( dcursor == dend ) {
      delete dec;
      return false; // not enough space in output buffer
    }
  }

  // finish and check for output buffer overflow:
  while ( !dec->finish( dcursor, dend ) ) {
    if ( dcursor == dend ) {
      delete dec;
      return false; // not enough space in output buffer
    }
  }

  // cleanup and return:
  delete dec;
  return true; // successfully encoded.
}

// write as much as possible off the output buffer. Return true if
// flushing was complete, false if some chars could not be flushed.
bool Encoder::flushOutputBuffer( char* &dcursor, const char * const dend )
{
  int i;
  // copy output buffer to output stream:
  for ( i = 0 ; dcursor != dend && i < mOutputBufferCursor ; ++i ) {
    *dcursor++ = mOutputBuffer[i];
  }

  // calculate the number of missing chars:
  int numCharsLeft = mOutputBufferCursor - i;
  // push the remaining chars to the begin of the buffer:
  if ( numCharsLeft ) {
    ::memmove( mOutputBuffer, mOutputBuffer + i, numCharsLeft );
  }
  // adjust cursor:
  mOutputBufferCursor = numCharsLeft;

  return !numCharsLeft;
}

} // namespace KMime