/**
 * 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: $Id$
 */

#ifndef _INCLUDE_SOURCEMOD_FORWARDSYSTEM_H_
#define _INCLUDE_SOURCEMOD_FORWARDSYSTEM_H_

#include <IForwardSys.h>
#include <IPluginSys.h>
#include "sm_globals.h"
#include <sh_list.h>
#include <sh_stack.h>
#include "sourcemod.h"

using namespace SourceHook;

typedef List<IPluginFunction *>::iterator FuncIter;

/* :TODO: a global name max define for sourcepawn, should mirror compiler's sNAMEMAX */
#define FORWARDS_NAME_MAX		64

struct ByrefInfo
{
	unsigned int cells;
	cell_t *orig_addr;
	int flags;
	int sz_flags;
};

struct FwdParamInfo
{
	cell_t val;
	ByrefInfo byref;
	ParamType pushedas;
};

class SourceMod::IForwardFilter
{
public:
	virtual void Preprocess(IPluginFunction *fun, FwdParamInfo *params)
	{
	}
};

class FuncIteratorGuard
{
	bool triggered;
	FuncIteratorGuard **pprev;
	FuncIter *iter;
	FuncIteratorGuard *next;
public:
	FuncIteratorGuard(FuncIteratorGuard **pprev, FuncIter *iter)
		: triggered(false), pprev(pprev), iter(iter), next(*pprev)
	{
		*pprev = this;
	}

	~FuncIteratorGuard()
	{
		*pprev = next;
	}

	inline bool Triggered()
	{
		bool t = triggered;
		triggered = false;
		return t;
	}

	/**
	 * This should not read from |this| before the NULL check, because FwdSys
	 * can call (NULL)->FixIteratorChain().
	 */
	void FixIteratorChain(FuncIter &other)
	{
		FuncIteratorGuard *guard = this;
		while (guard != NULL)
		{
			if (*guard->iter == other)
			{
				*(guard->iter) = ++(*(guard->iter));
				guard->triggered = true;
			}
			guard = guard->next;
		}
	}
};

class CForward : public IChangeableForward
{
public: //ICallable
	virtual int PushCell(cell_t cell);
	virtual int PushCellByRef(cell_t *cell, int flags);
	virtual int PushFloat(float number);
	virtual int PushFloatByRef(float *number, int flags);
	virtual int PushArray(cell_t *inarray, unsigned int cells, int flags);
	virtual int PushString(const char *string);
	virtual int PushStringEx(char *buffer, size_t length, int sz_flags, int cp_flags);
	virtual void Cancel();
public: //IForward
	virtual const char *GetForwardName();
	virtual unsigned int GetFunctionCount();
	virtual ExecType GetExecType();
	virtual int Execute(cell_t *result, IForwardFilter *filter);
public: //IChangeableForward
	virtual bool RemoveFunction(IPluginFunction *func);
	virtual unsigned int RemoveFunctionsOfPlugin(IPlugin *plugin);
	virtual bool AddFunction(IPluginFunction *func);
	virtual bool AddFunction(IPluginContext *ctx, funcid_t index);
	virtual bool RemoveFunction(IPluginContext *ctx, funcid_t index);
public:
	static CForward *CreateForward(const char *name, 
								   ExecType et, 
								   unsigned int num_params, 
								   const ParamType *types, 
								   va_list ap);
private:
	void _Int_PushArray(cell_t *inarray, unsigned int cells, int flags);
	void _Int_PushString(cell_t *inarray, unsigned int cells, int sz_flags, int cp_flags);
	inline int SetError(int err)
	{
		m_errstate = err;
		return err;
	}
protected:
	/* :TODO: I want a caching list type here.
	 * Destroying these things and using new/delete for their members feels bad.
	 */
	mutable List<IPluginFunction *> m_functions;
	mutable List<IPluginFunction *> m_paused;
	FuncIteratorGuard *m_IterGuard;

	/* Type and name information */
	FwdParamInfo m_params[SP_MAX_EXEC_PARAMS];
	ParamType m_types[SP_MAX_EXEC_PARAMS];
	char m_name[FORWARDS_NAME_MAX+1];
	unsigned int m_numparams;
	unsigned int m_varargs;
	ExecType m_ExecType;

	/* State information */
	unsigned int m_curparam;
	int m_errstate;
};

class CForwardManager : 
	public IForwardManager,
	public IPluginsListener,
	public SMGlobalClass
{
	friend class CForward;
public:
	~CForwardManager();
public: //IForwardManager
	IForward *CreateForward(const char *name, 
		ExecType et, 
		unsigned int num_params, 
		const ParamType *types, 
		...);
	IChangeableForward *CreateForwardEx(const char *name, 
		ExecType et, 
		int num_params, 
		const ParamType *types, 
		...);
	IForward *FindForward(const char *name, IChangeableForward **ifchng);
	void ReleaseForward(IForward *forward);
public: //IPluginsListener
	void OnPluginLoaded(IPlugin *plugin);
	void OnPluginUnloaded(IPlugin *plugin);
	void OnPluginPauseChange(IPlugin *plugin, bool paused);
public: //SMGlobalClass
	void OnSourceModAllInitialized();
protected:
	CForward *ForwardMake();
	void ForwardFree(CForward *fwd);
private:
	CStack<CForward *> m_FreeForwards;
	List<CForward *> m_managed;
	List<CForward *> m_unmanaged;
};

extern CForwardManager g_Forwards;

#endif //_INCLUDE_SOURCEMOD_FORWARDSYSTEM_H_