/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <log4cxx/logstring.h>
#include <log4cxx/helpers/charsetencoder.h>
#include <log4cxx/helpers/bytebuffer.h>
#include <log4cxx/helpers/exception.h>
#include <apr_xlate.h>
#include <log4cxx/helpers/stringhelper.h>
#include <log4cxx/helpers/transcoder.h>

#if !defined(LOG4CXX)
	#define LOG4CXX 1
#endif

#include <log4cxx/private/log4cxx_private.h>
#include <apr_portable.h>

#ifdef LOG4CXX_HAS_WCSTOMBS
	#include <stdlib.h>
#endif

using namespace log4cxx;
using namespace log4cxx::helpers;

IMPLEMENT_LOG4CXX_OBJECT(CharsetEncoder)

namespace log4cxx
{

namespace helpers
{

#if APR_HAS_XLATE
/**
* A character encoder implemented using apr_xlate.
*/
class APRCharsetEncoder : public CharsetEncoder
{
	public:
        APRCharsetEncoder(const LogString& topage) : pool()
		{
#if LOG4CXX_LOGCHAR_IS_WCHAR
			const char* frompage = "WCHAR_T";
#endif
#if LOG4CXX_LOGCHAR_IS_UTF8
			const char* frompage = "UTF-8";
#endif
#if LOG4CXX_LOGCHAR_IS_UNICHAR
			const char* frompage = "UTF-16";
#endif
			std::string tpage(Transcoder::encodeCharsetName(topage));
			apr_status_t stat = apr_xlate_open(&convset,
					tpage.c_str(),
					frompage,
					pool.getAPRPool());

			if (stat != APR_SUCCESS)
			{
				throw IllegalArgumentException(topage);
			}
		}

		virtual ~APRCharsetEncoder()
		{
		}

		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			apr_status_t stat;
			size_t outbytes_left = out.remaining();
			size_t initial_outbytes_left = outbytes_left;
			size_t position = out.position();

			if (iter == in.end())
			{
				log4cxx::unique_lock<log4cxx::mutex> lock(mutex);
				stat = apr_xlate_conv_buffer(convset, NULL, NULL,
						out.data() + position, &outbytes_left);
			}
			else
			{
				LogString::size_type inOffset = (iter - in.begin());
				apr_size_t inbytes_left =
					(in.size() - inOffset) * sizeof(LogString::value_type);
				apr_size_t initial_inbytes_left = inbytes_left;
				{
					log4cxx::unique_lock<log4cxx::mutex> lock(mutex);
					stat = apr_xlate_conv_buffer(convset,
							(const char*) (in.data() + inOffset),
							&inbytes_left,
							out.data() + position,
							&outbytes_left);
				}
				iter += ((initial_inbytes_left - inbytes_left) / sizeof(LogString::value_type));
			}

			out.position(out.position() + (initial_outbytes_left - outbytes_left));
			return stat;
		}

	private:
		APRCharsetEncoder(const APRCharsetEncoder&);
		APRCharsetEncoder& operator=(const APRCharsetEncoder&);
		Pool pool;
		log4cxx::mutex mutex;
		apr_xlate_t* convset;
};
#endif

#if LOG4CXX_LOGCHAR_IS_WCHAR && LOG4CXX_HAS_WCSTOMBS
/**
 *  A character encoder implemented using wcstombs.
*/
class WcstombsCharsetEncoder : public CharsetEncoder
{
	public:
		WcstombsCharsetEncoder()
		{
		}

		/**
		 *   Converts a wchar_t to the default external multibyte encoding.
		 */
		log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			log4cxx_status_t stat = APR_SUCCESS;

			if (iter != in.end())
			{
				size_t outbytes_left = out.remaining();
				size_t position = out.position();
				std::wstring::size_type inOffset = (iter - in.begin());
				enum { BUFSIZE = 256 };
				wchar_t buf[BUFSIZE];
				size_t chunkSize = BUFSIZE - 1;

				if (chunkSize * MB_LEN_MAX > outbytes_left)
				{
					chunkSize = outbytes_left / MB_LEN_MAX;
				}

				if (chunkSize > in.length() - inOffset)
				{
					chunkSize = in.length() - inOffset;
				}

				memset(buf, 0, BUFSIZE * sizeof(wchar_t));
				memcpy(buf,
					in.data() + inOffset,
					chunkSize * sizeof(wchar_t));
				size_t converted = wcstombs(out.data() + position, buf, outbytes_left);

				if (converted == (size_t) -1)
				{
					stat = APR_BADARG;

					//
					//   if unconvertable character was encountered
					//       repeatedly halve source to get fragment that
					//       can be converted
					for (chunkSize /= 2;
						chunkSize > 0;
						chunkSize /= 2)
					{
						buf[chunkSize] = 0;
						converted = wcstombs(out.data() + position, buf, outbytes_left);

						if (converted != (size_t) -1)
						{
							iter += chunkSize;
							out.position(out.position() + converted);
							break;
						}
					}
				}
				else
				{
					iter += chunkSize;
					out.position(out.position() + converted);
				}
			}

			return stat;
		}


	private:
		WcstombsCharsetEncoder(const WcstombsCharsetEncoder&);
		WcstombsCharsetEncoder& operator=(const WcstombsCharsetEncoder&);
};
#endif


/**
*   Encodes a LogString to US-ASCII.
*/
class USASCIICharsetEncoder : public CharsetEncoder
{
	public:
		USASCIICharsetEncoder()
		{
		}

		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			log4cxx_status_t stat = APR_SUCCESS;

			if (iter != in.end())
			{
				while (out.remaining() > 0 && iter != in.end())
				{
					LogString::const_iterator prev(iter);
					unsigned int sv = Transcoder::decode(in, iter);

					if (sv <= 0x7F)
					{
						out.put((char) sv);
					}
					else
					{
						iter = prev;
						stat = APR_BADARG;
						break;
					}
				}
			}

			return stat;
		}

	private:
		USASCIICharsetEncoder(const USASCIICharsetEncoder&);
		USASCIICharsetEncoder& operator=(const USASCIICharsetEncoder&);
};

/**
*   Converts a LogString to ISO-8859-1.
*/
class ISOLatinCharsetEncoder : public CharsetEncoder
{
	public:
		ISOLatinCharsetEncoder()
		{
		}

		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			log4cxx_status_t stat = APR_SUCCESS;

			if (iter != in.end())
			{
				while (out.remaining() > 0 && iter != in.end())
				{
					LogString::const_iterator prev(iter);
					unsigned int sv = Transcoder::decode(in, iter);

					if (sv <= 0xFF)
					{
						out.put((char) sv);
					}
					else
					{
						iter = prev;
						stat = APR_BADARG;
						break;
					}
				}
			}

			return stat;
		}

	private:
		ISOLatinCharsetEncoder(const ISOLatinCharsetEncoder&);
		ISOLatinCharsetEncoder& operator=(const ISOLatinCharsetEncoder&);
};

/**
*   Encodes a LogString to a byte array when the encodings are identical.
*/
class TrivialCharsetEncoder : public CharsetEncoder
{
	public:
		TrivialCharsetEncoder()
		{
		}


		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			if (iter != in.end())
			{
				size_t requested = in.length() - (iter - in.begin());

				if (requested > out.remaining() / sizeof(logchar))
				{
					requested = out.remaining() / sizeof(logchar);
				}

				memcpy(out.current(),
					(const char*) in.data() + (iter - in.begin()),
					requested * sizeof(logchar));
				iter += requested;
				out.position(out.position() + requested * sizeof(logchar));
			}

			return APR_SUCCESS;
		}

	private:
		TrivialCharsetEncoder(const TrivialCharsetEncoder&);
		TrivialCharsetEncoder& operator=(const TrivialCharsetEncoder&);
};

#if LOG4CXX_LOGCHAR_IS_UTF8
typedef TrivialCharsetEncoder UTF8CharsetEncoder;
#else
/**
 *  Converts a LogString to UTF-8.
 */
class UTF8CharsetEncoder : public CharsetEncoder
{
	public:
		UTF8CharsetEncoder()
		{
		}

		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			while (iter != in.end() && out.remaining() >= 8)
			{
				unsigned int sv = Transcoder::decode(in, iter);

				if (sv == 0xFFFF)
				{
					return APR_BADARG;
				}

				Transcoder::encodeUTF8(sv, out);
			}

			return APR_SUCCESS;
		}

	private:
		UTF8CharsetEncoder(const UTF8CharsetEncoder&);
		UTF8CharsetEncoder& operator=(const UTF8CharsetEncoder&);
};
#endif

/**
 *   Encodes a LogString to UTF16-BE.
 */
class UTF16BECharsetEncoder : public CharsetEncoder
{
	public:
		UTF16BECharsetEncoder()
		{
		}

		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			while (iter != in.end() && out.remaining() >= 4)
			{
				unsigned int sv = Transcoder::decode(in, iter);

				if (sv == 0xFFFF)
				{
					return APR_BADARG;
				}

				Transcoder::encodeUTF16BE(sv, out);
			}

			return APR_SUCCESS;
		}

	private:
		UTF16BECharsetEncoder(const UTF16BECharsetEncoder&);
		UTF16BECharsetEncoder& operator=(const UTF16BECharsetEncoder&);
};

/**
 *   Encodes a LogString to UTF16-LE.
 */
class UTF16LECharsetEncoder : public CharsetEncoder
{
	public:
		UTF16LECharsetEncoder()
		{
		}


		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
			while (iter != in.end() && out.remaining() >= 4)
			{
				unsigned int sv = Transcoder::decode(in, iter);

				if (sv == 0xFFFF)
				{
					return APR_BADARG;
				}

				Transcoder::encodeUTF16LE(sv, out);
			}

			return APR_SUCCESS;
		}
	private:
		UTF16LECharsetEncoder(const UTF16LECharsetEncoder&);
		UTF16LECharsetEncoder& operator=(const UTF16LECharsetEncoder&);
};

/**
 *    Charset encoder that uses an embedded CharsetEncoder consistent
 *     with current locale settings.
 */
class LocaleCharsetEncoder : public CharsetEncoder
{
	public:
        LocaleCharsetEncoder() : pool(), encoder(), encoding()
		{
		}
		virtual ~LocaleCharsetEncoder()
		{
		}
		virtual log4cxx_status_t encode(const LogString& in,
			LogString::const_iterator& iter,
			ByteBuffer& out)
		{
#if !LOG4CXX_CHARSET_EBCDIC
			char* current = out.current();
			size_t remain = out.remaining();

			for (;
				iter != in.end() && ((unsigned int) *iter) < 0x80 && remain > 0;
				iter++, remain--, current++)
			{
				*current = *iter;
			}

			out.position(current - out.data());
#endif

			if (iter != in.end() && out.remaining() > 0)
			{
				Pool subpool;
				const char* enc = apr_os_locale_encoding(subpool.getAPRPool());
				{
					log4cxx::unique_lock<log4cxx::mutex> lock(mutex);

					if (enc == 0)
					{
						if (encoder == 0)
						{
							encoding = "C";
                            encoder.reset( new USASCIICharsetEncoder() );
						}
					}
					else if (encoding != enc)
					{
						encoding = enc;
						LogString ename;
						Transcoder::decode(encoding, ename);

						try
						{
							encoder = CharsetEncoder::getEncoder(ename);
						}
						catch (IllegalArgumentException&)
						{
                            encoder.reset( new USASCIICharsetEncoder() );
						}
					}
				}
				return encoder->encode(in, iter, out);
			}

			return APR_SUCCESS;
		}

	private:
		LocaleCharsetEncoder(const LocaleCharsetEncoder&);
		LocaleCharsetEncoder& operator=(const LocaleCharsetEncoder&);
		Pool pool;
		log4cxx::mutex mutex;
		CharsetEncoderPtr encoder;
		std::string encoding;
};


} // namespace helpers

}  //namespace log4cxx


CharsetEncoder::CharsetEncoder()
{
}

CharsetEncoder::~CharsetEncoder()
{
}

CharsetEncoderPtr CharsetEncoder::getDefaultEncoder()
{
	static CharsetEncoderPtr encoder(createDefaultEncoder());

	//
	//  if invoked after static variable destruction
	//     (if logging is called in the destructor of a static object)
	//     then create a new decoder.
	//
	if (encoder == 0)
	{
        return CharsetEncoderPtr( createDefaultEncoder() );
	}

	return encoder;
}

CharsetEncoder* CharsetEncoder::createDefaultEncoder()
{
#if LOG4CXX_CHARSET_UTF8
	return new UTF8CharsetEncoder();
#elif LOG4CXX_CHARSET_ISO88591
	return new ISOLatinCharsetEncoder();
#elif LOG4CXX_CHARSET_USASCII
	return new USASCIICharsetEncoder();
#elif LOG4CXX_LOGCHAR_IS_WCHAR && LOG4CXX_HAS_WCSTOMBS
	return new WcstombsCharsetEncoder();
#else
	return new LocaleCharsetEncoder();
#endif
}


CharsetEncoderPtr CharsetEncoder::getUTF8Encoder()
{
    return CharsetEncoderPtr( new UTF8CharsetEncoder() );
}


CharsetEncoderPtr CharsetEncoder::getEncoder(const LogString& charset)
{
	if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF-8"), LOG4CXX_STR("utf-8")))
	{
        return CharsetEncoderPtr( new UTF8CharsetEncoder() );
	}
	else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("C"), LOG4CXX_STR("c")) ||
		charset == LOG4CXX_STR("646") ||
		StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("US-ASCII"), LOG4CXX_STR("us-ascii")) ||
		StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO646-US"), LOG4CXX_STR("iso646-US")) ||
		StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ANSI_X3.4-1968"), LOG4CXX_STR("ansi_x3.4-1968")))
	{
        return CharsetEncoderPtr( new USASCIICharsetEncoder() );
	}
	else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO-8859-1"), LOG4CXX_STR("iso-8859-1")) ||
		StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO-LATIN-1"), LOG4CXX_STR("iso-latin-1")))
	{
        return CharsetEncoderPtr( new ISOLatinCharsetEncoder() );
	}
	else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF-16BE"), LOG4CXX_STR("utf-16be"))
		|| StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF-16"), LOG4CXX_STR("utf-16")))
	{
        return CharsetEncoderPtr( new UTF16BECharsetEncoder() );
	}
	else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF-16LE"), LOG4CXX_STR("utf-16le")))
	{
        return CharsetEncoderPtr( new UTF16LECharsetEncoder() );
	}

#if APR_HAS_XLATE
    return CharsetEncoderPtr( new APRCharsetEncoder(charset) );
#else
	throw IllegalArgumentException(charset);
#endif
}


void CharsetEncoder::reset()
{
}

void CharsetEncoder::flush(ByteBuffer& /* out */ )
{
}


void CharsetEncoder::encode(CharsetEncoderPtr& enc,
	const LogString& src,
	LogString::const_iterator& iter,
	ByteBuffer& dst)
{
	log4cxx_status_t stat = enc->encode(src, iter, dst);

	if (stat != APR_SUCCESS && iter != src.end())
	{
#if LOG4CXX_LOGCHAR_IS_WCHAR || LOG4CXX_LOGCHAR_IS_UNICHAR
		iter++;
#elif LOG4CXX_LOGCHAR_IS_UTF8

		//  advance past this character and all continuation characters
		while ((*(++iter) & 0xC0) == 0x80);

#else
#error logchar is unrecognized
#endif
		dst.put(Transcoder::LOSSCHAR);
	}
}