// ***************************************************************************
//
// Reality - The Matrix Online Server Emulator
// Copyright (C) 2006-2010 Rajko Stojadinovic
// http://mxoemu.info
//
// ---------------------------------------------------------------------------
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
// ---------------------------------------------------------------------------
//
// ***************************************************************************

#include "DatabaseEnv.h"
#include "../Log.h"
#include "../Util.h"
#include "../Threading/Threading.h"

SQLCallbackBase::~SQLCallbackBase()
{

}

Database::Database() : ThreadContext()
{
	_counter=0;
	ThreadRunning = true;
}

Database::~Database()
{
	Shutdown();
}

bool Database::Initialize(const char* Hostname, unsigned int port, const char* Username, const char* Password, const char* DatabaseName, uint32 ConnectionCount, uint32 BufferSize)
{
	uint32 i;
	MYSQL * temp, * temp2;
	my_bool my_true = true;

	mHostname = string(Hostname);
	mUsername = string(Username);
	mPassword = string(Password);
	mDatabaseName = string(DatabaseName);

	INFO_LOG(format("MySQLDatabase Connecting to `%1%`, database `%2%`...") % Hostname % DatabaseName);

	for( i = 0; i < ConnectionCount; ++i )
	{
		temp = mysql_init( NULL );
		if(mysql_options(temp, MYSQL_SET_CHARSET_NAME, "utf8"))
			WARNING_LOG("MySQLDatabase Could not set utf8 character set.");

		if (mysql_options(temp, MYSQL_OPT_RECONNECT, &my_true))
			WARNING_LOG("MYSQL_OPT_RECONNECT could not be set, connection drops may occur but will be counteracted.");

		temp2 = mysql_real_connect( temp, Hostname, Username, Password, DatabaseName, port, NULL, 0 );
		if( temp2 == NULL )
		{
			CRITICAL_LOG(format("MySQLDatabase Connection failed due to: `%1%`") % mysql_error( temp ) );
			return false;
		}

		m_connections.push_back(DatabaseConnection(temp2));
	}

	// Spawn Database thread
	ThreadPool.ExecuteTask(this);

	// launch the query thread
	qt = new QueryThread(this);
	ThreadPool.ExecuteTask(qt);

	return true;
}

DatabaseConnection &Database::GetFreeConnection()
{
	uint32 i = 0;
	for(;;)
	{
		DatabaseConnection &con = m_connections[ ((i++) % m_connections.size()) ];
		if(con.Busy.AttemptAcquire())
			return con;

		// sleep every 20 iterations, otherwise this can cause 100% cpu if the db link goes dead
		if( !(i % 20) )
		{
			Sleep(10);
		}
	}

	// shouldn't be reached
	throw(exception());
}

QueryResult *Database::Query( string QueryString )
{	
	// Send the query
	QueryResult * qResult = NULL;
	DatabaseConnection &con = GetFreeConnection();

	if( _SendQuery( con, QueryString.c_str(), false ) )
		qResult = _StoreQueryResult( con );

	con.Busy.Release();
	return qResult;
}

QueryResult * Database::FQuery( string QueryString, DatabaseConnection &con)
{	
	// Send the query
	QueryResult * qResult = NULL;
	if( _SendQuery( con, QueryString.c_str(), false ) )
		qResult = _StoreQueryResult( con );

	return qResult;
}

void Database::FWaitExecute( string QueryString, DatabaseConnection &con)
{	
	// Send the query
	_SendQuery( con, QueryString.c_str(), false );
}

void QueryBuffer::AddQuery(string fmt)
{
	queries.push_back(fmt);
}

void Database::PerformQueryBuffer(QueryBuffer * b, DatabaseConnection &con)
{
	if(!b->queries.size())
		return;

	while (b->queries.size() > 0)
	{
		string &currQuery = b->queries.front();
		_SendQuery(con, currQuery.c_str(), false);
		b->queries.pop_front();
	}
}

void Database::PerformQueryBuffer(QueryBuffer * b)
{
	if(!b->queries.size())
		return;

	DatabaseConnection &con = GetFreeConnection();

	while (b->queries.size() > 0)
	{
		string &currQuery = b->queries.front();
		_SendQuery(con, currQuery.c_str(), false);
		b->queries.pop_front();
	}

	con.Busy.Release();
}


bool Database::Execute( string QueryString)
{
	if(!ThreadRunning)
		return WaitExecute(QueryString);

	queries_queue.push(new string(QueryString));
	return true;
}

//this will wait for completion
bool Database::WaitExecute( string QueryString)
{
	DatabaseConnection &con = GetFreeConnection();
	bool Result = _SendQuery(con, QueryString.c_str(), false);
	con.Busy.Release();
	return Result;
}

bool Database::run()
{
	SetThreadName("Database Executor");
	ThreadRunning = true;
	string *query = queries_queue.pop();
	DatabaseConnection &con = GetFreeConnection();
	while(query)
	{
		_SendQuery( con, query->c_str(), false );
		delete query;
		if(!m_threadRunning)
			break;

		query = queries_queue.pop();
	}

	con.Busy.Release();

	if(queries_queue.get_size() > 0)
	{
		// execute all the remaining queries
		query = queries_queue.pop_nowait();
		while(query)
		{
			DatabaseConnection &con = GetFreeConnection();
			_SendQuery( con, query->c_str(), false );
			con.Busy.Release();
			delete query;
			query=queries_queue.pop_nowait();
		}
	}

	ThreadRunning = false;
	return false;
}

void AsyncQuery::AddQuery( string fmt )
{
	AsyncQueryResult res;
	res.query = NULL;
	res.result = NULL;
	size_t len = fmt.length();
	if(len>0)
	{
		res.query = new char[len+1];
		res.query[len] = 0;
		memcpy(res.query, fmt.c_str(), len);
		queries.push_back(res);
	}
}

void AsyncQuery::Perform()
{
	DatabaseConnection &conn = db->GetFreeConnection();
	for(vector<AsyncQueryResult>::iterator itr = queries.begin(); itr != queries.end(); ++itr)
		itr->result = db->FQuery(itr->query, conn);

	conn.Busy.Release();
	func->run(queries);

	delete this;
}

AsyncQuery::~AsyncQuery()
{
	delete func;
	for(vector<AsyncQueryResult>::iterator itr = queries.begin(); itr != queries.end(); ++itr)
	{
		if(itr->result)
			delete itr->result;

		delete[] itr->query;
	}
	queries.clear();
}

void Database::EndThreads()
{
	Terminate();
	while(ThreadRunning || qt)
	{
		if(query_buffer.get_size() == 0)
			query_buffer.GetCond().Broadcast();

		if(queries_queue.get_size() == 0)
			queries_queue.GetCond().Broadcast();


		Sleep(100);
		if(!ThreadRunning)
			break;

		Sleep(1000);
	}
}

bool QueryThread::run( )
{
	db->thread_proc_query( );
	return true;
}

QueryThread::~QueryThread()
{
	db->qt = NULL;
}

void Database::thread_proc_query()
{
	QueryBuffer * q;
	DatabaseConnection &con = GetFreeConnection();

	q = query_buffer.pop( );
	while( q != NULL )
	{
		PerformQueryBuffer( q, con );
		delete q;

		if( !m_threadRunning )
			break;

		q = query_buffer.pop( );
	}

	con.Busy.Release();

	// kill any queries
	q = query_buffer.pop_nowait( );
	while( q != NULL )
	{
		PerformQueryBuffer( q );
		delete q;

		q = query_buffer.pop_nowait( );
	}
}

void Database::QueueAsyncQuery(AsyncQuery * query)
{
	query->db = this;
	/*if(qt == NULL)
	{
	query->Perform();
	return;
	}

	qqueries_queue.push(query);*/
	query->Perform();
}

void Database::AddQueryBuffer(QueryBuffer * b)
{
	if( qt != NULL )
		query_buffer.push( b );
	else
	{
		PerformQueryBuffer( b );
		delete b;
	}
}

void Database::FreeQueryResult(QueryResult * p)
{
	delete p;
}

string Database::EscapeString(std::string Escape)
{
	char a2[16384] = {0};

	DatabaseConnection &con = GetFreeConnection();
	const char * ret;
	if(mysql_real_escape_string(con.conn, a2, Escape.c_str(), (unsigned long)Escape.length()) == 0)
		ret = Escape.c_str();
	else
		ret = a2;

	con.Busy.Release();
	return string(ret);
}

void Database::EscapeLongString(const char * str, uint32 len, stringstream& out)
{
	char a2[65536*3] = {0};

	DatabaseConnection &con = GetFreeConnection();
	const char * ret;
	if(mysql_real_escape_string(con.conn, a2, str, (unsigned long)len) == 0)
		ret = str;
	else
		ret = a2;

	out.write(a2, (std::streamsize)strlen(a2));
	con.Busy.Release();
}

string Database::EscapeString(const char * esc, DatabaseConnection * con)
{
	char a2[16384] = {0};
	const char * ret;
	if(mysql_real_escape_string(con->conn, a2, (char*)esc, (unsigned long)strlen(esc)) == 0)
		ret = esc;
	else
		ret = a2;

	return string(ret);
}

bool Database::_SendQuery(DatabaseConnection &con, const char* Sql, bool Self)
{
	//dunno what it does ...leaving untouched 
	int result = mysql_query(con.conn, Sql);
	if(result > 0)
	{
		if( Self == false && _HandleError(con, mysql_errno( con.conn ) ) )
		{
			// Re-send the query, the connection was successful.
			// The true on the end will prevent an endless loop here, as it will
			// stop after sending the query twice.
			result = _SendQuery(con, Sql, true);
		}
		else
			ERROR_LOG(format("Sql query failed due to [%1%], Query: [%2%]\n") % mysql_error( con.conn ) % Sql);
	}

	return (result == 0 ? true : false);
}

bool Database::_HandleError(DatabaseConnection &con, uint32 ErrorNumber)
{
	// Handle errors that should cause a reconnect to the Database.
	switch(ErrorNumber)
	{
	case 2006:  // Mysql server has gone away
	case 2008:  // Client ran out of memory
	case 2013:  // Lost connection to sql server during query
	case 2055:  // Lost connection to sql server - system error
		{
			// Let's instruct a reconnect to the db when we encounter these errors.
			return _Reconnect( con );
		}break;
	}

	return false;
}

QueryResult::QueryResult(MYSQL_RES *res, uint32 fields, uint32 rows) : mResult(res), mFieldCount(fields), mRowCount(rows)
{
	mCurrentRow = new Field[fields];
}

QueryResult::~QueryResult()
{
	mysql_free_result(mResult);
	delete [] mCurrentRow;
}

bool QueryResult::NextRow()
{
	MYSQL_ROW row = mysql_fetch_row(mResult);
	if(row == NULL)
		return false;

	for(uint32 i = 0; i < mFieldCount; ++i)
		mCurrentRow[i].SetValue(row[i]);

	return true;
}

QueryResult * Database::_StoreQueryResult(DatabaseConnection &con)
{
	QueryResult *res;
	MYSQL_RES * pRes = mysql_store_result( con.conn );
	uint32 uRows = (uint32)mysql_affected_rows( con.conn );
	uint32 uFields = (uint32)mysql_field_count( con.conn );

	if( uRows == 0 || uFields == 0 || pRes == 0 )
	{
		if( pRes != NULL )
			mysql_free_result( pRes );

		return NULL;
	}

	res = new QueryResult( pRes, uFields, uRows );
	res->NextRow();

	return res;
}

bool Database::_Reconnect(DatabaseConnection &conn)
{
	MYSQL * temp, *temp2;

	temp = mysql_init( NULL );
	temp2 = mysql_real_connect( temp, mHostname.c_str(), mUsername.c_str(), mPassword.c_str(), mDatabaseName.c_str(), mPort, NULL , 0 );
	if( temp2 == NULL )
	{
		CRITICAL_LOG(format("Could not reconnect to database because of `%1%`") % mysql_error( temp ) );
		mysql_close( temp );
		return false;
	}

	if( conn.conn != NULL )
		mysql_close( conn.conn );

	conn.conn = temp;
	return true;
}

void Database::CleanupLibs()
{
	mysql_library_end();
}

Database *Database::Create()
{
	return new Database();
}

void Database::Shutdown()
{
	for(connectionsList::iterator it=m_connections.begin();it!=m_connections.end();++it)
	{
		if( it->conn != NULL )
		{
			mysql_close(it->conn);
			it->conn = NULL;
		}
	}
	m_connections.clear();
}