/*
 * This file is a part of Winix
 * and is not publicly distributed
 * 
 * Copyright (c) 2008-2012, Tomasz Sowa
 * All rights reserved.
 * 
 */
 
#include <sys/stat.h>
#include "sessionmanager.h"
#include "request.h"
#include "log.h"
#include "session.h"
#include "sessionparser.h"
#include "plugin.h"






SessionManager::SessionManager()
{
	temporary_session.id = 0;
	session = &temporary_session;
	session_tab.SetTmpSession(&temporary_session);

	// thread work mode
	work_mode = 1;
}


void SessionManager::SetCur(Cur * pcur)
{
	cur = pcur;
	session_tab.SetCur(pcur);
}


void SessionManager::SetConfig(Config * pconfig)
{
	config = pconfig;
	session_tab.SetConfig(pconfig);
}


void SessionManager::SetSystem(System * psystem)
{
	system = psystem;
}


void SessionManager::SetLastContainer(LastContainer * plast_container)
{
	last_container = plast_container;
}



size_t SessionManager::Size()
{
	return session_tab.Size();
}


bool SessionManager::IsSession(long id)
{
	if( session_tab.FindById(id) == session_tab.End() )
		return false;

return true;
}



long SessionManager::CreateSessionId()
{
long id;
	
	// make sure to call std::srand() somewhere at the beginning
	// id must be != 0 (0 is reserved)
	do
	{
		if( sizeof(long) == 8 )
		{
			id = ((unsigned long)std::rand()) << 32 + std::rand();
		}
		else
		{
			id = std::rand();
		}
		
		id += std::time(0);
		
		if( id < 0 )
			id = -id;
		
	}
	while( id == 0 ); // 0 reserved for a temporary session

	
return id;
}




void SessionManager::CreateSession()
{
int attempts = 100;
SessionContainer::Iterator i = session_tab.End();

	if( config->session_max == 0 || session_tab.Size() < config->session_max )
	{
		for( ; i == session_tab.End() && attempts > 0 ; --attempts )
		{
			long id = CreateSessionId();
			i = session_tab.AddSession(id);	
		}
	}
	else
	{
		log << log2 << "SM: sessions limit exceeded (" << config->session_max << ")" << logend;
	}

	if( i != session_tab.End() )
	{
		session = &(*i);
		session->new_session = true;
		session->SetTimesTo(cur->request->start_time);

		log << log2 << "SM: created a new session: " << session->id << logend;
	}
	else
	{
		// there is a problem with generating a new session id
		// we do not set a session cookie
		session = &temporary_session;
		session->Clear(false);
		session->SetTimesTo(cur->request->start_time);
		session->new_session = false; // temporary session was initialized at the beginning
		log << log1 << "SM: cannot create a session id (temporary used: with id 0)" << logend;
	}
}




bool SessionManager::SetSessionFromCookie(const std::string & cookie)
{
	long id = Tol(cookie.c_str());
	SessionContainer::Iterator s = session_tab.FindById(id);

	if( s == session_tab.End() || s->remove_me )
		return false;
	
	// that session is in the table
	session = &(*s);
	session->new_session = false;
	session->last_time   = cur->request->start_time;
	session->last_date   = cur->request->start_time;

	if( cur->request->method == Request::get )
		session->last_time_get = cur->request->start_time;

	log << log2 << "SM: session: " << session->id;
	
	if( session->puser )
		log << log2 << ", user: " << session->puser->name << ", id: " << session->puser->id;
		
	log << log2 << logend;

return true;
}



void SessionManager::SetSession()
{
	CookieTab::iterator i = cur->request->cookie_tab.find(config->http_session_id_name);

	if( i == cur->request->cookie_tab.end() )
	{
		CreateSession();
	}
	else
	{
		if( !SetSessionFromCookie(i->second) )
		{
			// there is no such a session
			// deleting the old cookie
			cur->request->cookie_tab.erase(i);

			// and creating a new one
			CreateSession();
		}
	}
}


Session * SessionManager::FindSession(long id)
{
	SessionContainer::Iterator i = session_tab.FindById(id);

	if( i != session_tab.End() )
		return &*i;

return 0;
}


SessionContainer::Iterator SessionManager::SessionBegin()
{
	return session_tab.Begin();
}



SessionContainer::Iterator SessionManager::SessionEnd()
{
	return session_tab.End();
}






void SessionManager::DeleteSessions()
{
	SessionContainer::Iterator i;

	for(i=session_tab.Begin() ; i!=session_tab.End() ; ++i)
	{
		if( i->puser && !i->remember_me )
		{
			plugin.Call(&(*i), WINIX_PREPARE_USER_TO_LOGOUT, i->puser);
			last_container->UserLogout(i->puser->id, i->id);
		}
	}

	session_tab.Clear();
}




/*
	don't change a session's id when a user is logged
	the session id is in last_container and the user would not be 
	correctly removed from the container
*/
bool SessionManager::ChangeSessionId(long old_id)
{
int attempts = 100;
bool changed = false;
long new_id;
SessionContainer::Iterator i = session_tab.FindById(old_id);

	if( i != session_tab.End() )
	{
		for( ; !changed && attempts > 0 ; --attempts )
		{
			new_id  = CreateSessionId();
			changed = session_tab.ChangeSessionId(i, new_id);
		}

		if( changed )
			plugin.Call(&(*i), WINIX_SESSION_CHANGED_ID, old_id, new_id);
		else
			log << log1 << "SM: I cannot create a new session id (still uses old one)" << logend;
	}
	else
	{
		log << log2 << "SM: there is no a session with id: " << old_id << logend;
	}

return changed;
}


void SessionManager::InitTmpSession()
{
	Session * old_session = cur->session;

	log << log4 << "SM: initializing temporary session" << logend;
	cur->session = &temporary_session;
	plugin.Call(WINIX_SESSION_CREATED);

	cur->session = old_session;
}



void SessionManager::UninitTmpSession()
{
	Session * old_session = cur->session;

	log << log4 << "SM: uninitializing temporary session" << logend;
	cur->session = &temporary_session;
	cur->session->plugin_data.DeleteAll(); // this will call plugin.Call(WINIX_PLUGIN_SESSION_DATA_REMOVE);
	cur->session->plugin_data.Resize(0);

	cur->session = old_session;
}



void SessionManager::LoadSessions()
{
SessionParser sp;
SessionContainer::Iterator i;

	// sessions will be overwritten (pointers are invalidated)
	cur->session = &temporary_session;

	sp.SetUsers(&system->users);
	sp.Parse(config->session_file, session_tab);

	for(i=session_tab.Begin() ; i != session_tab.End() ; ++i)
	{
		i->plugin_data.Resize(plugin.Size());
		plugin.Call(&(*i), WINIX_SESSION_CREATED);

		/*
			!! IMPROVE ME
			we do not add it to the last_container (we don't have IP address stored yet)
		*/

		if( i->puser )
			plugin.Call(&(*i), WINIX_USER_LOGGED);
	}

	cur->session = &temporary_session;
}





void SessionManager::SaveSessions()
{
	if( config->session_file.empty() )
		return;

	std::ofstream file(config->session_file.c_str());

	if( !file )
	{
		log << log1 << "SM: cannot open the session file for writing - sessions lost" << logend;
		return;
	}

	log << log2 << "SM: saving sessions" << logend;
	long len = 0;

	SessionContainer::Iterator i = session_tab.Begin();

	for( ; i!=session_tab.End() ; ++i )
	{
		if( i->id != 0 && i->puser && !i->remove_me )
		{
			file << i->id << ' ' << i->puser->id << ' ' << i->remember_me << ' ';
			file << (long)i->start_time << ' ' << (long)i->last_time << std::endl;

			++len;
		}
	}

	file.close();
	chmod(config->session_file.c_str(), 0600);

	log << log2 << "SM: saved " << len << " session(s)" << logend;
}




Session * SessionManager::GetTmpSession()
{
	return &temporary_session;
}


Session * SessionManager::GetCurSession()
{
	return session;
}


// returns how many sessions was marked to remove
size_t SessionManager::MarkAllSessionsToRemove(long user_id)
{
	size_t how_many = 0;
	SessionContainer::Iterator i;

	for(i=session_tab.Begin() ; i!=session_tab.End() ; ++i)
	{
		if( i->puser && i->puser->id == user_id )
		{
			plugin.Call(&(*i), WINIX_PREPARE_USER_TO_LOGOUT, i->puser);
			last_container->UserLogout(i->puser->id, i->id);
			i->remove_me = true;
			i->puser     = 0;
			how_many    += 1;
		}
	}

return how_many;
}




/*
 *
 *
 *  sessions gc (second thread)
 *  sessions are only removed here
 *  SessionContainer::IndexId can be removed from the other thread 
 *  (when ChangeSessionId() method is called)
 *
 */
void SessionManager::Work()
{
bool exit = false;
SessionContainer::Iterator i;

	deleted = 0;

	Lock();
	i = session_tab.Begin();
	Unlock();

	while( !exit )
	{
		Lock();

		CheckSession(i);
		exit = synchro->was_stop_signal;

		Unlock();
	}
}


// it's called from the other thread (with Lock and Unlock)
void SessionManager::CheckSession(SessionContainer::Iterator & i)
{
const int deleted_max_at_once = 10;

	if( i == session_tab.End() )
	{
		if( deleted > 0 )
		{
			deleted = 0;
			log << logsave;
		}

		i = session_tab.Begin();
		WaitForSignalSleep(10);
	}
	else
	{
		if( i->remove_me || IsSessionOutdated(*i) )
		{
			Session * ses = &(*i);
			++i;
			DeleteSession(ses);
			++deleted;
		}
		else
		{
			++i;
		}

		if( deleted >= deleted_max_at_once )
		{
			log << logsave;
			WaitForSignalSleep(1);
			deleted = 0;
		}
	}
}


// it's called from the other thread (with Lock and Unlock)
bool SessionManager::IsSessionOutdated(const Session & s) const
{
bool outdated;

	if( s.remember_me )
	{
		outdated = s.last_time < std::time(0) - config->session_remember_max_idle;
	}
	else
	{
		outdated = s.last_time < std::time(0) - config->session_max_idle;
	}

return outdated;
}



// it's called from the other thread (with Lock and Unlock)
void SessionManager::DeleteSession(Session * del_session)
{
	if( del_session->puser )
	{
		plugin.Call(del_session, WINIX_PREPARE_USER_TO_LOGOUT, del_session->puser);
		last_container->UserLogout(del_session->puser->id, del_session->id);
		del_session->puser = 0;
	}

	long id = del_session->id;

	plugin.Call(del_session, WINIX_PREPARE_SESSION_TO_REMOVE);
	session_tab.EraseById(del_session->id);
	plugin.Call((Session*)0, WINIX_SESSION_REMOVED, id);
}


/*
 *
 *
 *  end of sessions gc
 *
 *
 */