/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * 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, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#include "UserMessages.h"

#include "sm_stringutil.h"

UserMessages g_UserMsgs;

#if SOURCE_ENGINE == SE_LEFT4DEAD

SH_DECL_HOOK3(IVEngineServer, UserMessageBegin, SH_NOATTRIB, 0, bf_write *, IRecipientFilter *, int, const char *);

#else

SH_DECL_HOOK2(IVEngineServer, UserMessageBegin, SH_NOATTRIB, 0, bf_write *, IRecipientFilter *, int);

#endif

SH_DECL_HOOK0_void(IVEngineServer, MessageEnd, SH_NOATTRIB, 0);

UserMessages::UserMessages() : m_InterceptBuffer(m_pBase, 2500)

{

	m_Names = sm_trie_create();

	m_HookCount = 0;

	m_InExec = false;

	m_InHook = false;

	m_CurFlags = 0;

	m_CurId = INVALID_MESSAGE_ID;

}

UserMessages::~UserMessages()

{

	sm_trie_destroy(m_Names);

	CStack<ListenerInfo *>::iterator iter;

	for (iter=m_FreeListeners.begin(); iter!=m_FreeListeners.end(); iter++)

	{

		delete (*iter);

	}

	m_FreeListeners.popall();

}

void UserMessages::OnSourceModStartup(bool late)

{

	/* -1 means SourceMM was unable to get the user message list */

	m_FallbackSearch = (g_SMAPI->GetUserMessageCount() == -1);

}

void UserMessages::OnSourceModAllInitialized()

{

	g_ShareSys.AddInterface(NULL, this);

}

void UserMessages::OnSourceModAllShutdown()

{

	if (m_HookCount)

	{

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Pre, false);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Post, true);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Pre, false);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Post, true);

	}

	m_HookCount = 0;

}

int UserMessages::GetMessageIndex(const char *msg)

{

	int msgid;

	if (!sm_trie_retrieve(m_Names, msg, reinterpret_cast<void **>(&msgid)))

	{

		if (m_FallbackSearch)

		{

			char msgbuf[64];

			int size;

			msgid = 0;

			while (gamedll->GetUserMessageInfo(msgid, msgbuf, sizeof(msgbuf), size))

			{

				if (strcmp(msgbuf, msg) == 0)

				{

					sm_trie_insert(m_Names, msg, reinterpret_cast<void *>(msgid));

					return msgid;

				}

				msgid++;

			}

		}

		msgid = g_SMAPI->FindUserMessage(msg);

		if (msgid != INVALID_MESSAGE_ID)

		{

			sm_trie_insert(m_Names, msg, reinterpret_cast<void *>(msgid));

		}

	}

	return msgid;

}

bool UserMessages::GetMessageName(int msgid, char *buffer, size_t maxlength) const

{

	if (m_FallbackSearch)

	{

		int size;

		return gamedll->GetUserMessageInfo(msgid, buffer, maxlength, size);

	}

	const char *msg = g_SMAPI->GetUserMessage(msgid);

	if (msg)

	{

		strncopy(buffer, msg, maxlength);

		return true;

	}

	return false;

}

bf_write *UserMessages::StartMessage(int msg_id, const cell_t players[], unsigned int playersNum, int flags)

{

	bf_write *buffer;

	if (m_InExec || m_InHook)

	{

		return NULL;

	}

	if (msg_id < 0 || msg_id >= 255)

	{

		return NULL;

	}

	m_CellRecFilter.Initialize(players, playersNum);

	m_CurFlags = flags;

	if (m_CurFlags & USERMSG_INITMSG)

	{

		m_CellRecFilter.SetToInit(true);

	}

	if (m_CurFlags & USERMSG_RELIABLE)

	{

		m_CellRecFilter.SetToReliable(true);

	}

	m_InExec = true;

	if (m_CurFlags & USERMSG_BLOCKHOOKS)

	{

#if SOURCE_ENGINE == SE_LEFT4DEAD

		buffer = ENGINE_CALL(UserMessageBegin)(static_cast<IRecipientFilter *>(&m_CellRecFilter), msg_id, g_SMAPI->GetUserMessage(msg_id));

#else

		buffer = ENGINE_CALL(UserMessageBegin)(static_cast<IRecipientFilter *>(&m_CellRecFilter), msg_id);

#endif

	} else {

#if SOURCE_ENGINE == SE_LEFT4DEAD

		buffer = engine->UserMessageBegin(static_cast<IRecipientFilter *>(&m_CellRecFilter), msg_id, g_SMAPI->GetUserMessage(msg_id));

#else

		buffer = engine->UserMessageBegin(static_cast<IRecipientFilter *>(&m_CellRecFilter), msg_id);

#endif

	}

	return buffer;

}

bool UserMessages::EndMessage()

{

	if (!m_InExec)

	{

		return false;

	}

	if (m_CurFlags & USERMSG_BLOCKHOOKS)

	{

		ENGINE_CALL(MessageEnd)();

	} else {

		engine->MessageEnd();

	}

	m_InExec = false;

	m_CurFlags = 0;

	m_CellRecFilter.Reset();

	return true;

}

bool UserMessages::HookUserMessage2(int msg_id,

									IUserMessageListener *pListener,

									bool intercept)

{

	return InternalHook(msg_id, pListener, intercept, true);

}

bool UserMessages::UnhookUserMessage2(int msg_id,

									  IUserMessageListener *pListener,

									  bool intercept)

{

	return InternalUnhook(msg_id, pListener, intercept, true);

}

bool UserMessages::HookUserMessage(int msg_id, IUserMessageListener *pListener, bool intercept)

{

	return InternalHook(msg_id, pListener, intercept, false);

}

bool UserMessages::UnhookUserMessage(int msg_id, IUserMessageListener *pListener, bool intercept)

{	

	return InternalUnhook(msg_id, pListener, intercept, false);

}

bool UserMessages::InternalHook(int msg_id, IUserMessageListener *pListener, bool intercept, bool isNew)

{

	if (msg_id < 0 || msg_id >= 255)

	{

		return false;

	}

	ListenerInfo *pInfo;

	if (m_FreeListeners.empty())

	{

		pInfo = new ListenerInfo;

	} else {

		pInfo = m_FreeListeners.front();

		m_FreeListeners.pop();

	}

	pInfo->Callback = pListener;

	pInfo->IsHooked = false;

	pInfo->KillMe = false;

	pInfo->IsNew = isNew;

	if (!m_HookCount++)

	{

		SH_ADD_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Pre, false);

		SH_ADD_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Post, true);

		SH_ADD_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Pre, false);

		SH_ADD_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Post, true);

	}

	if (intercept)

	{

		m_msgIntercepts[msg_id].push_back(pInfo);

	} else {

		m_msgHooks[msg_id].push_back(pInfo);

	}

	return true;

}

bool UserMessages::InternalUnhook(int msg_id, IUserMessageListener *pListener, bool intercept, bool isNew)

{

	MsgList *pList;

	MsgIter iter;

	ListenerInfo *pInfo;

	bool deleted = false;

	if (msg_id < 0 || msg_id >= 255)

	{

		return false;

	}

	pList = (intercept) ? &m_msgIntercepts[msg_id] : &m_msgHooks[msg_id];

	for (iter=pList->begin(); iter!=pList->end(); iter++)

	{

		pInfo = (*iter);

		if (pInfo->Callback == pListener && pInfo->IsNew == isNew)

		{

			if (pInfo->IsHooked)

			{

				pInfo->KillMe = true;

				return true;

			}

			pList->erase(iter);

			deleted = true;

			break;

		}

	}

	if (deleted)

	{

		_DecRefCounter();

	}

	return deleted;

}

void UserMessages::_DecRefCounter()

{

	if (--m_HookCount == 0)

	{

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Pre, false);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, UserMessageBegin, engine, this, &UserMessages::OnStartMessage_Post, true);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Pre, false);

		SH_REMOVE_HOOK_MEMFUNC(IVEngineServer, MessageEnd, engine, this, &UserMessages::OnMessageEnd_Post, true);

	}

}

#if SOURCE_ENGINE == SE_LEFT4DEAD

bf_write *UserMessages::OnStartMessage_Pre(IRecipientFilter *filter, int msg_type, const char *msg_name)

#else

bf_write *UserMessages::OnStartMessage_Pre(IRecipientFilter *filter, int msg_type)

#endif

{

	bool is_intercept_empty = m_msgIntercepts[msg_type].empty();

	bool is_hook_empty = m_msgHooks[msg_type].empty();

	if ((is_intercept_empty && is_hook_empty)

		|| (m_InExec && (m_CurFlags & USERMSG_BLOCKHOOKS)))

	{

		m_InHook = false;

		RETURN_META_VALUE(MRES_IGNORED, NULL);

	}

	m_CurId = msg_type;

	m_CurRecFilter = filter;

	m_InHook = true;

	m_BlockEndPost = false;

	if (!is_intercept_empty)

	{

		m_InterceptBuffer.Reset();

		RETURN_META_VALUE(MRES_SUPERCEDE, &m_InterceptBuffer);

	}

	RETURN_META_VALUE(MRES_IGNORED, NULL);

}

#if SOURCE_ENGINE == SE_LEFT4DEAD

bf_write *UserMessages::OnStartMessage_Post(IRecipientFilter *filter, int msg_type, const char *msg_name)

#else

bf_write *UserMessages::OnStartMessage_Post(IRecipientFilter *filter, int msg_type)

#endif

{

	if (!m_InHook)

	{

		RETURN_META_VALUE(MRES_IGNORED, NULL);

	}

	m_OrigBuffer = META_RESULT_ORIG_RET(bf_write *);

	RETURN_META_VALUE(MRES_IGNORED, NULL);

}

void UserMessages::OnMessageEnd_Post()

{

	if (!m_InHook)

	{

		RETURN_META(MRES_IGNORED);

	}

	MsgList *pList;

	MsgIter iter;

	ListenerInfo *pInfo;

	m_InHook = false;

	pList = &m_msgIntercepts[m_CurId];

	for (iter=pList->begin(); iter!=pList->end(); )

	{

		pInfo = (*iter);

		if (m_BlockEndPost && !pInfo->IsNew)

		{

			continue;

		}

		pInfo->IsHooked = true;

		pInfo->Callback->OnUserMessageSent(m_CurId);

		if (pInfo->IsNew)

		{

			pInfo->Callback->OnPostUserMessage(m_CurId, !m_BlockEndPost);

		}

		if (pInfo->KillMe)

		{

			iter = pList->erase(iter);

			m_FreeListeners.push(pInfo);

			_DecRefCounter();

			continue;

		}

		pInfo->IsHooked = false;

		iter++;

	}

	pList = &m_msgHooks[m_CurId];

	for (iter=pList->begin(); iter!=pList->end(); )

	{

		pInfo = (*iter);

		if (m_BlockEndPost && !pInfo->IsNew)

		{

			continue;

		}

		pInfo->IsHooked = true;

		pInfo->Callback->OnUserMessageSent(m_CurId);

		if (pInfo->IsNew)

		{

			pInfo->Callback->OnPostUserMessage(m_CurId, !m_BlockEndPost);

		}

		if (pInfo->KillMe)

		{

			iter = pList->erase(iter);

			m_FreeListeners.push(pInfo);

			_DecRefCounter();

			continue;

		}

		pInfo->IsHooked = false;

		iter++;

	}

}

void UserMessages::OnMessageEnd_Pre()

{

	if (!m_InHook)

	{

		RETURN_META(MRES_IGNORED);

	}

	MsgList *pList;

	MsgIter iter;

	ListenerInfo *pInfo;

	ResultType res;

	bool intercepted = false;

	bool handled = false;

	pList = &m_msgIntercepts[m_CurId];

	for (iter=pList->begin(); iter!=pList->end(); )

	{

		pInfo = (*iter);

		pInfo->IsHooked = true;

		res = pInfo->Callback->InterceptUserMessage(m_CurId, &m_InterceptBuffer, m_CurRecFilter);

		intercepted = true;

		switch (res)

		{

		case Pl_Stop:

			{

				if (pInfo->KillMe)

				{

					pList->erase(iter);

					m_FreeListeners.push(pInfo);

					_DecRefCounter();

					goto supercede;

				}

				pInfo->IsHooked = false;

				goto supercede;

			}

		case Pl_Handled:

			{

				handled = true;

				if (pInfo->KillMe)

				{

					iter = pList->erase(iter);

					m_FreeListeners.push(pInfo);

					_DecRefCounter();

					continue;

				}

				break;

			}

		default:

			{

				if (pInfo->KillMe)

				{

					iter = pList->erase(iter);

					m_FreeListeners.push(pInfo);

					_DecRefCounter();

					continue;

				}

				break;

			}

		}

		pInfo->IsHooked = false;

		iter++;

	}

	if (handled)

	{

		goto supercede;

	}

	if (intercepted)

	{

		bf_write *engine_bfw;

#if SOURCE_ENGINE == SE_LEFT4DEAD

		engine_bfw = ENGINE_CALL(UserMessageBegin)(m_CurRecFilter, m_CurId, g_SMAPI->GetUserMessage(m_CurId));

#else

		engine_bfw = ENGINE_CALL(UserMessageBegin)(m_CurRecFilter, m_CurId);

#endif

		m_ReadBuffer.StartReading(m_InterceptBuffer.GetBasePointer(), m_InterceptBuffer.GetNumBytesWritten());

		engine_bfw->WriteBitsFromBuffer(&m_ReadBuffer, m_InterceptBuffer.GetNumBitsWritten());

		ENGINE_CALL(MessageEnd)();

	}

	pList = &m_msgHooks[m_CurId];

	for (iter=pList->begin(); iter!=pList->end(); )

	{

		pInfo = (*iter);

		pInfo->IsHooked = true;

		pInfo->Callback->OnUserMessage(m_CurId, m_OrigBuffer, m_CurRecFilter);

		if (pInfo->KillMe)

		{

			iter = pList->erase(iter);

			m_FreeListeners.push(pInfo);

			_DecRefCounter();

			continue;

		}

		pInfo->IsHooked = false;

		iter++;

	}

	RETURN_META((intercepted) ? MRES_SUPERCEDE : MRES_IGNORED);

supercede:

	m_BlockEndPost = true;

	RETURN_META(MRES_SUPERCEDE);

}