/*
 * 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/db/odbcappender.h>
#include <log4cxx/helpers/loglog.h>
#include <log4cxx/helpers/optionconverter.h>
#include <log4cxx/helpers/stringhelper.h>
#include <log4cxx/helpers/transcoder.h>
#include <log4cxx/patternlayout.h>
#include <apr_strings.h>

#if !defined(LOG4CXX)
	#define LOG4CXX 1
#endif
#include <log4cxx/private/log4cxx_private.h>
#if LOG4CXX_HAVE_ODBC
	#if defined(WIN32) || defined(_WIN32)
		#include <windows.h>
	#endif
	#include <sqlext.h>
#endif


using namespace log4cxx;
using namespace log4cxx::helpers;
using namespace log4cxx::db;
using namespace log4cxx::spi;

SQLException::SQLException(short fHandleType,
	void* hInput, const char* prolog,
	log4cxx::helpers::Pool& p)
	: Exception(formatMessage(fHandleType, hInput, prolog, p))
{
}


SQLException::SQLException(const char* msg)
	: Exception(msg)
{
}

SQLException::SQLException(const SQLException& src)
	: Exception(src)
{
}

const char* SQLException::formatMessage(short fHandleType,
	void* hInput, const char* prolog, log4cxx::helpers::Pool& p)
{
	std::string strReturn(prolog);
	strReturn.append(" - ");
#if LOG4CXX_HAVE_ODBC
	SQLCHAR       SqlState[6];
	SQLCHAR       Msg[SQL_MAX_MESSAGE_LENGTH];
	SQLINTEGER    NativeError;
	SQLSMALLINT   i;
	SQLSMALLINT   MsgLen;
	SQLRETURN     rc2;

	// Get the status records.
	i = 1;

	while ((rc2 = SQLGetDiagRecA(fHandleType, hInput, i, SqlState, &NativeError,
					Msg, sizeof(Msg), &MsgLen)) != SQL_NO_DATA)
	{
		strReturn.append((char*) Msg);
		i++;
	}

#else
	strReturn.append("log4cxx built without ODBC support");
#endif

	return apr_pstrdup((apr_pool_t*) p.getAPRPool(), strReturn.c_str());
}


IMPLEMENT_LOG4CXX_OBJECT(ODBCAppender)


ODBCAppender::ODBCAppender()
	: connection(0), env(0), bufferSize(1)
{
}

ODBCAppender::~ODBCAppender()
{
	finalize();
}

void ODBCAppender::setOption(const LogString& option, const LogString& value)
{
	if (StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("BUFFERSIZE"), LOG4CXX_STR("buffersize")))
	{
		setBufferSize((size_t)OptionConverter::toInt(value, 1));
	}
	else if (StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("PASSWORD"), LOG4CXX_STR("password")))
	{
		setPassword(value);
	}
	else if (StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("SQL"), LOG4CXX_STR("sql")))
	{
		setSql(value);
	}
	else if (StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("URL"), LOG4CXX_STR("url"))
		|| StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("DSN"), LOG4CXX_STR("dsn"))
		|| StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("CONNECTIONSTRING"), LOG4CXX_STR("connectionstring"))  )
	{
		setURL(value);
	}
	else if (StringHelper::equalsIgnoreCase(option, LOG4CXX_STR("USER"), LOG4CXX_STR("user")))
	{
		setUser(value);
	}
	else
	{
		AppenderSkeleton::setOption(option, value);
	}
}

void ODBCAppender::activateOptions(log4cxx::helpers::Pool&)
{
#if !LOG4CXX_HAVE_ODBC
	LogLog::error(LOG4CXX_STR("Can not activate ODBCAppender unless compiled with ODBC support."));
#endif
}


void ODBCAppender::append(const spi::LoggingEventPtr& event, log4cxx::helpers::Pool& p)
{
#if LOG4CXX_HAVE_ODBC
	buffer.push_back(event);

	if (buffer.size() >= bufferSize)
	{
		flushBuffer(p);
	}

#endif
}

LogString ODBCAppender::getLogStatement(const spi::LoggingEventPtr& event, log4cxx::helpers::Pool& p) const
{
	LogString sbuf;
	getLayout()->format(sbuf, event, p);
	return sbuf;
}

void ODBCAppender::execute(const LogString& sql, log4cxx::helpers::Pool& p)
{
#if LOG4CXX_HAVE_ODBC
	SQLRETURN ret;
	SQLHDBC con = SQL_NULL_HDBC;
	SQLHSTMT stmt = SQL_NULL_HSTMT;

	try
	{
		con = getConnection(p);

		ret = SQLAllocHandle( SQL_HANDLE_STMT, con, &stmt);

		if (ret < 0)
		{
			throw SQLException( SQL_HANDLE_DBC, con, "Failed to allocate sql handle.", p);
		}

		SQLWCHAR* wsql;
		encode(&wsql, sql, p);
		ret = SQLExecDirectW(stmt, wsql, SQL_NTS);

		if (ret < 0)
		{
			throw SQLException(SQL_HANDLE_STMT, stmt, "Failed to execute sql statement.", p);
		}
	}
	catch (SQLException& e)
	{
		if (stmt != SQL_NULL_HSTMT)
		{
			SQLFreeHandle(SQL_HANDLE_STMT, stmt);
		}

		throw;
	}

	SQLFreeHandle(SQL_HANDLE_STMT, stmt);
	closeConnection(con);
#else
	throw SQLException("log4cxx build without ODBC support");
#endif
}

/* The default behavior holds a single connection open until the appender
is closed (typically when garbage collected).*/
void ODBCAppender::closeConnection(ODBCAppender::SQLHDBC /* con */)
{
}


ODBCAppender::SQLHDBC ODBCAppender::getConnection(log4cxx::helpers::Pool& p)
{
#if LOG4CXX_HAVE_ODBC
	SQLRETURN ret;

	if (env == SQL_NULL_HENV)
	{
		ret = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);

		if (ret < 0)
		{
			SQLException ex(SQL_HANDLE_ENV, env, "Failed to allocate SQL handle.", p);
			env = SQL_NULL_HENV;
			throw ex;
		}

		ret = SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC3, SQL_IS_INTEGER);

		if (ret < 0)
		{
			SQLException ex(SQL_HANDLE_ENV, env, "Failed to set odbc version.", p);
			SQLFreeHandle(SQL_HANDLE_ENV, env);
			env = SQL_NULL_HENV;
			throw ex;
		}
	}

	if (connection == SQL_NULL_HDBC)
	{
		ret = SQLAllocHandle(SQL_HANDLE_DBC, env, &connection);

		if (ret < 0)
		{
			SQLException ex(SQL_HANDLE_DBC, connection, "Failed to allocate sql handle.", p);
			connection = SQL_NULL_HDBC;
			throw ex;
		}


		SQLWCHAR* wURL, *wUser, *wPwd;
		encode(&wURL, databaseURL, p);
		encode(&wUser, databaseUser, p);
		encode(&wPwd, databasePassword, p);

		ret = SQLConnectW( connection,
				wURL, SQL_NTS,
				wUser, SQL_NTS,
				wPwd, SQL_NTS);


		if (ret < 0)
		{
			SQLException ex(SQL_HANDLE_DBC, connection, "Failed to connect to database.", p);
			SQLFreeHandle(SQL_HANDLE_DBC, connection);
			connection = SQL_NULL_HDBC;
			throw ex;
		}
	}

	return connection;
#else
	return 0;
#endif
}

void ODBCAppender::close()
{
	if (closed)
	{
		return;
	}

	Pool p;

	try
	{
		flushBuffer(p);
	}
	catch (SQLException& e)
	{
		errorHandler->error(LOG4CXX_STR("Error closing connection"),
			e, ErrorCode::GENERIC_FAILURE);
	}

#if LOG4CXX_HAVE_ODBC

	if (connection != SQL_NULL_HDBC)
	{
		SQLDisconnect(connection);
		SQLFreeHandle(SQL_HANDLE_DBC, connection);
	}

	if (env != SQL_NULL_HENV)
	{
		SQLFreeHandle(SQL_HANDLE_ENV, env);
	}

#endif
	this->closed = true;
}

void ODBCAppender::flushBuffer(Pool& p)
{
	std::list<spi::LoggingEventPtr>::iterator i;

	for (i = buffer.begin(); i != buffer.end(); i++)
	{
		try
		{
			const LoggingEventPtr& logEvent = *i;
			LogString sql = getLogStatement(logEvent, p);
			execute(sql, p);
		}
		catch (SQLException& e)
		{
			errorHandler->error(LOG4CXX_STR("Failed to execute sql"), e,
				ErrorCode::FLUSH_FAILURE);
		}
	}

	// clear the buffer of reported events
	buffer.clear();
}

void ODBCAppender::setSql(const LogString& s)
{
	sqlStatement = s;

	if (getLayout() == 0)
	{
		this->setLayout(new PatternLayout(s));
	}
	else
	{
		PatternLayoutPtr patternLayout = this->getLayout();

		if (patternLayout != 0)
		{
			patternLayout->setConversionPattern(s);
		}
	}
}

void ODBCAppender::encode(wchar_t** dest, const LogString& src, Pool& p)
{
	*dest = Transcoder::wencode(src, p);
}

void ODBCAppender::encode(unsigned short** dest,
	const LogString& src, Pool& p)
{
	//  worst case double number of characters from UTF-8 or wchar_t
	*dest = (unsigned short*)
		p.palloc((src.size() + 1) * 2 * sizeof(unsigned short));
	unsigned short* current = *dest;

	for (LogString::const_iterator i = src.begin();
		i != src.end();)
	{
		unsigned int sv = Transcoder::decode(src, i);

		if (sv < 0x10000)
		{
			*current++ = (unsigned short) sv;
		}
		else
		{
			unsigned char u = (unsigned char) (sv >> 16);
			unsigned char w = (unsigned char) (u - 1);
			unsigned short hs = (0xD800 + ((w & 0xF) << 6) + ((sv & 0xFFFF) >> 10));
			unsigned short ls = (0xDC00 + (sv & 0x3FF));
			*current++ = (unsigned short) hs;
			*current++ = (unsigned short) ls;
		}
	}

	*current = 0;
}