/*
 * This file is a part of Winix
 * and is distributed under the 2-Clause BSD licence.
 * Author: Tomasz Sowa <t.sowa@ttmath.org>
 */

/* 
 * Copyright (c) 2008-2021, Tomasz Sowa
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 */

#include "core/sessionmanager.h"
#include "login.h"
#include "utf8/utf8.h"



namespace Winix
{


namespace Fun
{

Login::Login()
{
	fun.url  = L"login";
	need_ssl = true;
}


void Login::ClearTmpStruct()
{
	system->crypt.ClearString(pass_decrypted);
//	system->crypt.ClearString(up.pass);
//	system->crypt.ClearString(up.pass_encrypted);
//	system->crypt.ClearString(up2.pass);
//	system->crypt.ClearString(up2.pass_encrypted);
}



bool Login::CheckPasswords(User & user, const std::wstring & password)
{
	if( !user.pass_encrypted.empty() )
	{
		if( system->crypt.RSA(false, config->pass_rsa_private_key, user.pass_encrypted, pass_decrypted) )
		{
			pt::utf8_to_wide(pass_decrypted, user.password);
		}
		else
		{
			log << log1 << "Login: I cannot decrypt a stored password, login failure" << logend;
			return false;
		}
	}

	std::wstring password_from_db = user.password;
	user.password = password;

	if( user.pass_hash_salted )
		salt = config->pass_hash_salt;
	else
		salt.clear();

	if( !system->crypt.PassHash(salt, user) )
	{
		log << log1 << "Login: I cannot hash a password, login failure" << logend;
		return false;
	}

	// compare char by char until the end of the strings (time attacks)
	bool result = (user.password == password_from_db);

	if( !result )
		log << log2 << "Login: incorrect login/password" << logend;

return result;
}



/*
	this method is checking whether there is a person with that login and password
	in the database

	return true if it has found one and sets it user_id
*/
bool Login::CheckUserPass(const std::wstring & login, const std::wstring & password, long & user_id)
{
bool result;

	morm::Finder<User> finder(model_connector);

	User user = finder.
			select().
			where().
			eq(L"login", login).
			get();

	if( user.found() )
	{
		user_id = user.id;

		if( user.has_pass )
		{
			result = CheckPasswords(user, password);
		}
		else
		{
			log << log2 << "Login: this account has no a password set yet" << logend;
			result = false;
		}
	}
	else
	{
		log << log2 << "Login: there is no a user name: " << login << logend;
		result = false;
	}

	ClearTmpStruct();

return result;
}



void Login::CheckBan()
{
	IPBan * ip_ban = cur->session->ip_ban;

	if( !ip_ban )
	{
		ip_ban = &session_manager->AddIPToBanList(cur->request->ip, cur->request->start_time);
		cur->session->ip_ban = ip_ban;
	}

	if( ip_ban->incorrect_login_events < config->incorrect_login_cannot_login_treshold )
	{
		ip_ban->incorrect_login_events += 1;
	}
	else
	{
		log << log2 << "Login: too many incorrect login attempts from this IP" << logend;

		if( config->incorrect_login_cannot_login_mode == 0 )
		{
			time_t expires = cur->request->start_time + (time_t)config->incorrect_login_cannot_login_delay;

			if( ip_ban->expires < expires )
				ip_ban->expires = expires;

			pt::Date date(ip_ban->expires);
			log << log2 << "Login: logging from this IP address has been blocked until to: " << date << " UTC" << logend;
		}
		else
		{
			session_manager->IncrementBanLevel(ip_ban);
		}
	}
}


bool Login::ShouldUseCaptchaForCurrentIP()
{
	if( cur->session->ip_ban )
		return ShouldUseCaptchaFor(*cur->session->ip_ban);

return false;
}


bool Login::ShouldUseCaptchaFor(const IPBan & ipban)
{
	if( ipban.expires != 0 && cur->request->start_time >= ipban.expires )
		return false; // the 'ip block' has expired (but incorrect_login_events has the old value)

return ipban.incorrect_login_events >= config->incorrect_login_captcha_treshold;
}


bool Login::CannotLoginFromCurrentIP()
{
	if( cur->session->ip_ban )
		return CannotLoginFrom(*cur->session->ip_ban);

return false;
}


bool Login::CannotLoginFrom(const IPBan & ipban)
{
	if( ipban.IsIPBanned() )
		return true;

	/*
	 * if incorrect_login_cannot_login_mode is equal to one then we only
	 * block logging (there is no a ban actually -- neither the active flag is enabled
	 * nor any ban_level is set)
	 */
	if( ipban.expires != 0 &&
		cur->request->start_time < ipban.expires &&
		ipban.incorrect_login_events >= config->incorrect_login_cannot_login_treshold )
		return true;

return false;
}



bool Login::CheckAbuse()
{
	time_t diff = (time_t)config->incorrect_login_min_time_between_get_post;

	if( cur->session->last_time_get + diff > cur->request->start_time )
	{
		log << log2 << "Login: the minimum time between GET and POST have not passed" << logend;
		return false;
	}

	if( ShouldUseCaptchaForCurrentIP() )
	{
		if( !system->rebus.CheckRebus() )
		{
			return false;
		}
	}

return true;
}


// if you are logging not from a webbrowser but from an application
// then probably you need check_abuse to be false
bool Login::LoginUser(const std::wstring & login, const std::wstring & password, bool remember_me,
					  bool use_ses_log, bool check_abuse)
{
long user_id;

	if( cur->session->id == 0 )
	{
		log << log2 << "Login: can't login in a temporary session (skipped)" << logend;
		return false;
	}

	if( CannotLoginFromCurrentIP() )
	{
		log << log2 << "Login: you cannot login from this IP address" << logend;
		return false;
	}

	if( login.empty() )
	{
		log << log3 << "Login: login is empty (skipping)" << logend;
		return false;
	}

	if( check_abuse && !CheckAbuse() )
	{
		CheckBan();
		return false;
	}


	if( CheckUserPass(login, password, user_id) )
	{
		if( system->users.LoginUser(user_id, remember_me, use_ses_log) )
		{
			if( cur->session->ip_ban )
				cur->session->ip_ban->incorrect_login_events = 0;

			return true;
		}
	}
	else
	{
		CheckBan();
	}

return false;
}


void Login::MakePost()
{
	const std::wstring & login = cur->request->PostVar(L"login");
	const std::wstring & pass  = cur->request->PostVar(L"password");
	const std::wstring & remem = cur->request->PostVar(L"rememberme");

	if( LoginUser(login, pass, !remem.empty(), true, true) )
		system->RedirectToLastItem();
}


void Login::MakeGet()
{
}


} // namespace

} // namespace Winix