//=============================================================================
//
//   File : libkvirot13.cpp
//   Creation date : Fri Jan 30 2002 09:25:15 GMT by Aeriana
//
//   This file is part of the KVIrc IRC client distribution
//   Copyright (C) 2009 Aeriana (aeriana at quasarnet dot org)
//   Copyright (C) 2002-2010 Szymon Stefanek (pragma at kvirc dot net)
//
//   This program is FREE software. You can redistribute it and/or
//   modify it under the terms of the GNU General Public License
//   as published by the Free Software Foundation; either version 2
//   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 General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program. If not, write to the Free Software Foundation,
//   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
//=============================================================================

#include "libkvirot13.h"

#include "KviModule.h"
#include "kvi_debug.h"
#include "KviLocale.h"

/*
	@doc: rot13
	@type:
		module
	@short:
		The ROT13 text transformation engine
	@title:
		The ROT13 module
	@body:
		Performs the "rotate by 13 places" substitution.
*/

#ifdef COMPILE_CRYPT_SUPPORT

#include "KviMemory.h"
#include "KviPointerList.h"
#include "KviCryptEngineDescription.h"

static KviPointerList<KviCryptEngine> * g_pEngineList = nullptr;

KviRot13Engine::KviRot13Engine()
    : KviCryptEngine()
{
	g_pEngineList->append(this);
}

KviRot13Engine::~KviRot13Engine()
{
	g_pEngineList->removeRef(this);
}

bool KviRot13Engine::init(const char *, int, const char *, int)
{
	return true;
}

KviCryptEngine::EncryptResult KviRot13Engine::encrypt(const char * plainText, KviCString & outBuffer)
{
	outBuffer = plainText;
	unsigned char * aux = (unsigned char *)outBuffer.ptr();
	while(*aux)
	{
		if(isalpha(*aux))
		{
			char l = toupper(*aux);
			if(l >= 'N' && l <= 'Z')
				*aux = *aux - 13;
			else if(l >= 'A' && l <= 'M')
				*aux = *aux + 13;
		}
		aux++;
	}

	return KviCryptEngine::Encoded;
}

KviCryptEngine::DecryptResult KviRot13Engine::decrypt(const char * inBuffer, KviCString & plainText)
{
	plainText = inBuffer;
	return KviCryptEngine::DecryptOkWasPlainText;
}

static KviCryptEngine * allocRot13Engine()
{
	return new KviRot13Engine();
}

static void deallocRot13Engine(KviCryptEngine * e)
{
	delete e;
}

#endif

///////////////////////////////////////////////////////////////////////////////
// module routines
///////////////////////////////////////////////////////////////////////////////

static bool rot13_module_init(KviModule * m)
{
#ifdef COMPILE_CRYPT_SUPPORT
	g_pEngineList = new KviPointerList<KviCryptEngine>;
	g_pEngineList->setAutoDelete(false);

	KviCryptEngineDescription * d = new KviCryptEngineDescription;
	d->m_szName = "ROT13";
	d->m_szAuthor = "Aeriana";
	d->m_szDescription = __tr2qs("The simple Caesar-cypher encryption that replaces each letter with the one 13 places forward or back along the alphabet; it is used to enclose the text in a sealed wrapper that the reader must choose to open - e.g. for posting things that might offend some readers, or spoilers.");
	d->m_iFlags = KviCryptEngine::CanEncrypt;
	d->m_allocFunc = allocRot13Engine;
	d->m_deallocFunc = deallocRot13Engine;
	m->registerCryptEngine(d);

	return true;
#else
	return false;
#endif
}

static bool rot13_module_cleanup(KviModule * m)
{
#ifdef COMPILE_CRYPT_SUPPORT
	while(g_pEngineList->first())
		delete g_pEngineList->first();
	delete g_pEngineList;
	g_pEngineList = nullptr;
	m->unregisterCryptEngines();
	return true;
#else
	return false;
#endif
}

static bool rot13_module_can_unload(KviModule *)
{
#ifdef COMPILE_CRYPT_SUPPORT
	return g_pEngineList->isEmpty();
#else
	return true;
#endif
}

KVIRC_MODULE(
    "ROT13 crypt engine",
    "4.0.0",
    "Aeriana <aeriana at quasarnet dot org>",
    "Exports the ROT13 text transformation engine",
    rot13_module_init,
    rot13_module_can_unload,
    0,
    rot13_module_cleanup,
    0)