/**

  * vim: set ts=4 sw=4 tw=99 noet :

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

  * SourceMod

  * Copyright (C) 2004-2010 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 "EventManager.h"

 #include "ForwardSys.h"

 #include "HandleSys.h"

 #include "PluginSys.h"

 #include "sm_stringutil.h"

 EventManager g_EventManager;

 SH_DECL_HOOK2(IGameEventManager2, FireEvent, SH_NOATTRIB, 0, bool, IGameEvent *, bool);

 const ParamType GAMEEVENT_PARAMS[] = {Param_Cell, Param_String, Param_Cell};

 typedef List<EventHook *> EventHookList;

 class EventForwardFilter : public IForwardFilter

 {

 	EventInfo *pEventInfo;

 public:

 	EventForwardFilter(EventInfo *pEventInfo) : pEventInfo(pEventInfo)

 	{

 	}

 	void Preprocess(IPluginFunction *fun, FwdParamInfo *params)

 	{

 		params[2].val = pEventInfo->bDontBroadcast ? 1 : 0;

 	}

 };

 EventManager::EventManager() : m_EventType(0)

 {

 	/* Create an event lookup trie */

 	m_EventHooks = sm_trie_create();

 }

 EventManager::~EventManager()

 {

 	sm_trie_destroy(m_EventHooks);

 	/* Free memory used by EventInfo structs if any */

 	CStack<EventInfo *>::iterator iter;

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

 	{

 		delete (*iter);

 	}

 	m_FreeEvents.popall();

 }

 void EventManager::OnSourceModAllInitialized()

 {

 	/* Add a hook for IGameEventManager2::FireEvent() */

 	SH_ADD_HOOK_MEMFUNC(IGameEventManager2, FireEvent, gameevents, this, &EventManager::OnFireEvent, false);

 	SH_ADD_HOOK_MEMFUNC(IGameEventManager2, FireEvent, gameevents, this, &EventManager::OnFireEvent_Post, true);

 	HandleAccess sec;

 	/* Handle access security for 'GameEvent' handle type */

 	sec.access[HandleAccess_Read] = 0;

 	sec.access[HandleAccess_Delete] = HANDLE_RESTRICT_IDENTITY | HANDLE_RESTRICT_OWNER;

 	sec.access[HandleAccess_Clone] = HANDLE_RESTRICT_IDENTITY | HANDLE_RESTRICT_OWNER;

 	/* Create the 'GameEvent' handle type */

 	m_EventType = g_HandleSys.CreateType("GameEvent", this, 0, NULL, &sec, g_pCoreIdent, NULL);

 }

 void EventManager::OnSourceModShutdown()

 {

 	/* Remove hook for IGameEventManager2::FireEvent() */

 	SH_REMOVE_HOOK_MEMFUNC(IGameEventManager2, FireEvent, gameevents, this, &EventManager::OnFireEvent, false);

 	SH_REMOVE_HOOK_MEMFUNC(IGameEventManager2, FireEvent, gameevents, this, &EventManager::OnFireEvent_Post, true);

 	/* Remove the 'GameEvent' handle type */

 	g_HandleSys.RemoveType(m_EventType, g_pCoreIdent);

 	/* Remove ourselves as listener for events */

 	gameevents->RemoveListener(this);

 }

 void EventManager::OnHandleDestroy(HandleType_t type, void *object)

 {

 	EventInfo *pInfo = static_cast<EventInfo *>(object);

 	/* Should only free event when created by a plugin */

 	if (pInfo->pOwner)

 	{

 		/* Free IGameEvent */

 		gameevents->FreeEvent(pInfo->pEvent);

 		/* Add EventInfo struct to free event stack */

 		m_FreeEvents.push(pInfo);

 	}

 }

 void EventManager::OnPluginUnloaded(IPlugin *plugin)

 {

 	EventHookList *pHookList;

 	EventHookList::iterator iter;

 	EventHook *pHook;

 	// If plugin has an event hook list...

 	if (plugin->GetProperty("EventHooks", reinterpret_cast<void **>(&pHookList), true))

 	{

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

 		{

 			pHook = (*iter);

 			if (--pHook->refCount == 0)

 			{

 				if (pHook->pPreHook)

 				{

 					g_Forwards.ReleaseForward(pHook->pPreHook);

 				}

 				if (pHook->pPostHook)

 				{

 					g_Forwards.ReleaseForward(pHook->pPostHook);

 				}

 				delete pHook;

 			}

 		}

 		delete pHookList;

 	}

 }

 /* IGameEventListener2::FireGameEvent */

 void EventManager::FireGameEvent(IGameEvent *pEvent)

 {

 	/* Not going to do anything here.

 	   Just need to add ourselves as a listener to make our hook on IGameEventManager2::FireEvent work */

 }

 #if SOURCE_ENGINE >= SE_LEFT4DEAD

 int EventManager::GetEventDebugID()

 {

 	return EVENT_DEBUG_ID_INIT;

 }

 #endif

 EventHookError EventManager::HookEvent(const char *name, IPluginFunction *pFunction, EventHookMode mode)

 {

 	EventHook *pHook;

 	/* If we aren't listening to this event... */

 	if (!gameevents->FindListener(this, name))

 	{

 		/* Then add ourselves */

 		if (!gameevents->AddListener(this, name, true))

 		{

 			/* If event doesn't exist... */

 			return EventHookErr_InvalidEvent;

 		}

 	}

 	/* If a hook structure does not exist... */

 	if (!sm_trie_retrieve(m_EventHooks, name, (void **)&pHook))

 	{

 		EventHookList *pHookList;

 		IPlugin *plugin = g_PluginSys.GetPluginByCtx(pFunction->GetParentContext()->GetContext());

 		/* Check plugin for an existing EventHook list */

 		if (!plugin->GetProperty("EventHooks", (void **)&pHookList))

 		{

 			pHookList = new EventHookList();

 			plugin->SetProperty("EventHooks", pHookList);

 		}

 		/* Create new GameEventHook structure */

 		pHook = new EventHook();

 		if (mode == EventHookMode_Pre)

 		{

 			/* Create forward for a pre hook */

 			pHook->pPreHook = g_Forwards.CreateForwardEx(NULL, ET_Hook, 3, GAMEEVENT_PARAMS);

 			/* Add to forward list */

 			pHook->pPreHook->AddFunction(pFunction);

 		} else {

 			/* Create forward for a post hook */

 			pHook->pPostHook = g_Forwards.CreateForwardEx(NULL, ET_Ignore, 3, GAMEEVENT_PARAMS);

 			/* Should we copy data from a pre hook to the post hook? */

 			pHook->postCopy = (mode == EventHookMode_Post);

 			/* Add to forward list */

 			pHook->pPostHook->AddFunction(pFunction);

 		}

 		/* Cache the name for post hooks */

 		pHook->name = sm_strdup(name);

 		/* Increase reference count */

 		pHook->refCount++;

 		/* Add hook structure to hook lists */

 		pHookList->push_back(pHook);

 		sm_trie_insert(m_EventHooks, name, pHook);

 		return EventHookErr_Okay;

 	}

 	/* Hook structure already exists at this point */

 	if (mode == EventHookMode_Pre)

 	{

 		/* Create pre hook forward if necessary */

 		if (!pHook->pPreHook)

 		{

 			pHook->pPreHook = g_Forwards.CreateForwardEx(NULL, ET_Event, 3, GAMEEVENT_PARAMS);

 		}

 		/* Add plugin function to forward list */

 		pHook->pPreHook->AddFunction(pFunction);

 	} else {

 		/* Create post hook forward if necessary */

 		if (!pHook->pPostHook)

 		{

 			pHook->pPostHook = g_Forwards.CreateForwardEx(NULL, ET_Ignore, 3, GAMEEVENT_PARAMS);

 		}

 		/* If postCopy is false, then we may want to set it to true */

 		if (!pHook->postCopy)

 		{

 			pHook->postCopy = (mode == EventHookMode_Post);

 		}

 		/* Add plugin function to forward list */

 		pHook->pPostHook->AddFunction(pFunction);

 	}

 	/* Increase reference count */

 	pHook->refCount++;

 	return EventHookErr_Okay;

 }

 EventHookError EventManager::UnhookEvent(const char *name, IPluginFunction *pFunction, EventHookMode mode)

 {

 	EventHook *pHook;

 	IChangeableForward **pEventForward;

 	/* If hook does not exist at all */

 	if (!sm_trie_retrieve(m_EventHooks, name, (void **)&pHook))

 	{

 		return EventHookErr_NotActive;

 	}

 	/* One forward to rule them all */

 	if (mode == EventHookMode_Pre)

 	{

 		pEventForward = &pHook->pPreHook;

 	} else {

 		pEventForward = &pHook->pPostHook;

 	}

 	/* Remove function from forward's list */

 	if (*pEventForward == NULL || !(*pEventForward)->RemoveFunction(pFunction))

 	{

 		return EventHookErr_InvalidCallback;

 	}

 	/* If forward's list contains 0 functions now, free it */

 	if ((*pEventForward)->GetFunctionCount() == 0)

 	{

 		g_Forwards.ReleaseForward(*pEventForward);

 		*pEventForward = NULL;

 	}

 	/* Decrement reference count */

 	if (--pHook->refCount == 0)

 	{

 		/* If reference count is now 0, free hook structure */

 		EventHookList *pHookList;

 		IPlugin *plugin = g_PluginSys.GetPluginByCtx(pFunction->GetParentContext()->GetContext());

 		/* Get plugin's event hook list */

 		if (!plugin->GetProperty("EventHooks", (void**)&pHookList))

 		{

 			return EventHookErr_NotActive;

 		}

 		/* Make sure the event was actually being hooked */

 		if (pHookList->find(pHook) == pHookList->end())

 		{

 			return EventHookErr_NotActive;

 		}

 		/* Remove current structure from plugin's list */

 		pHookList->remove(pHook);

 		/* Delete entry in trie */

 		sm_trie_delete(m_EventHooks, name);

 		/* Free the cached name */

 		delete pHook->name;

 		/* And finally free structure memory */

 		delete pHook;

 	}

 	return EventHookErr_Okay;

 }

 EventInfo *EventManager::CreateEvent(IPluginContext *pContext, const char *name, bool force)

 {

 	EventInfo *pInfo;

 	IGameEvent *pEvent = gameevents->CreateEvent(name, force);

 	if (pEvent)

 	{

 		if (m_FreeEvents.empty())

 		{

 			pInfo = new EventInfo();

 		} else {

 			pInfo = m_FreeEvents.front();

 			m_FreeEvents.pop();

 		}

 		pInfo->pEvent = pEvent;

 		pInfo->pOwner = pContext->GetIdentity();

 		pInfo->bDontBroadcast = false;

 		return pInfo;

 	}

 	return NULL;

 }

 void EventManager::FireEvent(EventInfo *pInfo, bool bDontBroadcast)

 {

 	/* Actually fire event now */

 	gameevents->FireEvent(pInfo->pEvent, bDontBroadcast);

 	/* IGameEvent is free at this point, so no one owns this */

 	pInfo->pOwner = NULL;

 	/* Add EventInfo struct to free event stack */

 	m_FreeEvents.push(pInfo);

 }

 void EventManager::CancelCreatedEvent(EventInfo *pInfo)

 {

 	/* Free event from IGameEventManager2 */

 	gameevents->FreeEvent(pInfo->pEvent);

 	/* IGameEvent is free at this point, so no one owns this */

 	pInfo->pOwner = NULL;

 	/* Add EventInfo struct to free event stack */

 	m_FreeEvents.push(pInfo);

 }

 /* IGameEventManager2::FireEvent hook */

 bool EventManager::OnFireEvent(IGameEvent *pEvent, bool bDontBroadcast)

 {

 	EventHook *pHook;

 	IChangeableForward *pForward;

 	const char *name;

 	cell_t res = Pl_Continue;

 	bool broadcast = bDontBroadcast;

 	/* The engine accepts NULL without crashing, so to prevent a crash in SM we ignore these */

 	if (!pEvent)

 	{

 		RETURN_META_VALUE(MRES_IGNORED, false);

 	}

 	name = pEvent->GetName();

 	if (sm_trie_retrieve(m_EventHooks, name, reinterpret_cast<void **>(&pHook)))

 	{

 		/* Push the event onto the event stack.  The reference count is increased to make sure 

 		 * the structure is not garbage collected in between now and the post hook.

 		 */

 		pHook->refCount++;

 		m_EventStack.push(pHook);

 		pForward = pHook->pPreHook;

 		if (pForward)

 		{

 			EventInfo info(pEvent, NULL);

 			HandleSecurity sec(NULL, g_pCoreIdent);

 			Handle_t hndl = g_HandleSys.CreateHandle(m_EventType, &info, NULL, g_pCoreIdent, NULL);

 			info.bDontBroadcast = bDontBroadcast;

 			EventForwardFilter filter(&info);

 			pForward->PushCell(hndl);

 			pForward->PushString(name);

 			pForward->PushCell(bDontBroadcast);

 			pForward->Execute(&res, &filter);

 			broadcast = info.bDontBroadcast;

 			g_HandleSys.FreeHandle(hndl, &sec);

 		}

 		if (pHook->postCopy)

 		{

 			m_EventCopies.push(gameevents->DuplicateEvent(pEvent));

 		}

 		if (res)

 		{

 			gameevents->FreeEvent(pEvent);

 			RETURN_META_VALUE(MRES_SUPERCEDE, false);

 		}

 	}

 	else

 	{

 		m_EventStack.push(NULL);

 	}

 	if (broadcast != bDontBroadcast)

 		RETURN_META_VALUE_NEWPARAMS(MRES_IGNORED, true, &IGameEventManager2::FireEvent, (pEvent, broadcast));

 	RETURN_META_VALUE(MRES_IGNORED, true);

 }

 /* IGameEventManager2::FireEvent post hook */

 bool EventManager::OnFireEvent_Post(IGameEvent *pEvent, bool bDontBroadcast)

 {

 	EventHook *pHook;

 	EventInfo info;

 	IChangeableForward *pForward;

 	Handle_t hndl = 0;

 	/* The engine accepts NULL without crashing, so to prevent a crash in SM we ignore these */

 	if (!pEvent)

 	{

 		RETURN_META_VALUE(MRES_IGNORED, false);

 	}

 	pHook = m_EventStack.front();

 	if (pHook != NULL)

 	{

 		pForward = pHook->pPostHook;

 		if (pForward)

 		{

 			if (pHook->postCopy)

 			{

 				info.bDontBroadcast = bDontBroadcast;

 				info.pEvent = m_EventCopies.front();

 				info.pOwner = NULL;

 				hndl = g_HandleSys.CreateHandle(m_EventType, &info, NULL, g_pCoreIdent, NULL);

 				pForward->PushCell(hndl);

 			} else {

 				pForward->PushCell(BAD_HANDLE);

 			}

 			pForward->PushString(pHook->name);

 			pForward->PushCell(bDontBroadcast);

 			pForward->Execute(NULL);

 			if (pHook->postCopy)

 			{

 				/* Free handle */

 				HandleSecurity sec(NULL, g_pCoreIdent);

 				g_HandleSys.FreeHandle(hndl, &sec);

 				/* Free event structure */

 				gameevents->FreeEvent(info.pEvent);

 				m_EventCopies.pop();

 			}

 		}

 		/* Decrement reference count, check if a delayed delete is needed */

 		if (--pHook->refCount == 0)

 		{

 			assert(pHook->pPostHook == NULL);

 			assert(pHook->pPreHook == NULL);

 			sm_trie_delete(m_EventHooks, pHook->name);

 			delete pHook->name;

 			delete pHook;

 		}

 	}

 	m_EventStack.pop();

 	RETURN_META_VALUE(MRES_IGNORED, true);

 }