/* $Id$ */

/** @file squirrel_helper.hpp declarations and parts of the implementation of the class for convert code */

#ifndef SQUIRREL_HELPER_HPP
#define SQUIRREL_HELPER_HPP

#include <squirrel.h>
#include "core/math_func.hpp"
#include "economy_type.h"
#include "misc/smallvec.h"
#include "squirrel_helper_type.hpp"

/**
 * The Squirrel convert routines
 */
namespace SQConvert {
	/**
	 * Pointers assigned to this class will be free'd when this instance
	 *  comes out of scope. Useful to make sure you can use strdup(),
	 *  without leaking memory.
	 */
	struct SQAutoFreePointers : SmallVector<void *, 1> {
		~SQAutoFreePointers()
		{
			for (uint i = 0; i < this->items; i++) free(this->data[i]);
		}
	};

	template <bool Y> struct YesT {
		static const bool Yes = Y;
		static const bool No = !Y;
	};

	/**
	 * Helper class to recognize if the given type is void. Usage: 'IsVoidT<T>::Yes'
	 */
	template <typename T> struct IsVoidT : YesT<false> {};
	template <> struct IsVoidT<void> : YesT<true> {};

	/**
	 * Helper class to recognize if the function/method return type is void.
	 */
	template <typename Tfunc> struct HasVoidReturnT;
	/* functions */
	template <typename Tretval> struct HasVoidReturnT<Tretval (*)()> : IsVoidT<Tretval> {};
	template <typename Tretval, typename Targ1> struct HasVoidReturnT<Tretval (*)(Targ1)> : IsVoidT<Tretval> {};
	template <typename Tretval, typename Targ1, typename Targ2> struct HasVoidReturnT<Tretval (*)(Targ1, Targ2)> : IsVoidT<Tretval> {};
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3> struct HasVoidReturnT<Tretval (*)(Targ1, Targ2, Targ3)> : IsVoidT<Tretval> {};
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4> struct HasVoidReturnT<Tretval (*)(Targ1, Targ2, Targ3, Targ4)> : IsVoidT<Tretval> {};
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5> struct HasVoidReturnT<Tretval (*)(Targ1, Targ2, Targ3, Targ4, Targ5)> : IsVoidT<Tretval> {};
	/* methods */
	template <class Tcls, typename Tretval> struct HasVoidReturnT<Tretval (Tcls::*)()> : IsVoidT<Tretval> {};
	template <class Tcls, typename Tretval, typename Targ1> struct HasVoidReturnT<Tretval (Tcls::*)(Targ1)> : IsVoidT<Tretval> {};
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2> struct HasVoidReturnT<Tretval (Tcls::*)(Targ1, Targ2)> : IsVoidT<Tretval> {};
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3> struct HasVoidReturnT<Tretval (Tcls::*)(Targ1, Targ2, Targ3)> : IsVoidT<Tretval> {};
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4> struct HasVoidReturnT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4)> : IsVoidT<Tretval> {};
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5> struct HasVoidReturnT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4, Targ5)> : IsVoidT<Tretval> {};


	/**
	 * Special class to make it possible for the compiler to pick the correct GetParam().
	 */
	template <typename T> class ForceType { };

	/**
	 * To return a value to squirrel, we call this function. It converts to the right format.
	 */
	template <typename T> static int Return(HSQUIRRELVM vm, T t);

	template <> inline int Return<uint8>       (HSQUIRRELVM vm, uint8 res)       { sq_pushinteger(vm, (int32)res); return 1; }
	template <> inline int Return<uint16>      (HSQUIRRELVM vm, uint16 res)      { sq_pushinteger(vm, (int32)res); return 1; }
	template <> inline int Return<uint32>      (HSQUIRRELVM vm, uint32 res)      { sq_pushinteger(vm, (int32)res); return 1; }
	template <> inline int Return<int8>        (HSQUIRRELVM vm, int8 res)        { sq_pushinteger(vm, res); return 1; }
	template <> inline int Return<int16>       (HSQUIRRELVM vm, int16 res)       { sq_pushinteger(vm, res); return 1; }
	template <> inline int Return<int32>       (HSQUIRRELVM vm, int32 res)       { sq_pushinteger(vm, res); return 1; }
	template <> inline int Return<int64>       (HSQUIRRELVM vm, int64 res)       { sq_pushinteger(vm, ClampToI32(res)); return 1; }
	template <> inline int Return<Money>       (HSQUIRRELVM vm, Money res)       { sq_pushinteger(vm, ClampToI32(res)); return 1; }
	template <> inline int Return<bool>        (HSQUIRRELVM vm, bool res)        { sq_pushbool   (vm, res); return 1; }
	template <> inline int Return<char *>      (HSQUIRRELVM vm, char *res)       { if (res == NULL) sq_pushnull(vm); else sq_pushstring (vm, OTTD2FS(res), strlen(res)); free(res); return 1; }
	template <> inline int Return<const char *>(HSQUIRRELVM vm, const char *res) { if (res == NULL) sq_pushnull(vm); else sq_pushstring (vm, OTTD2FS(res), strlen(res)); return 1; }
	template <> inline int Return<void *>      (HSQUIRRELVM vm, void *res)       { sq_pushuserpointer(vm, res); return 1; }

	/**
	 * To get a param from squirrel, we call this function. It converts to the right format.
	 */
	template <typename T> static T GetParam(ForceType<T>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr);

	template <> inline uint8       GetParam(ForceType<uint8>       , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline uint16      GetParam(ForceType<uint16>      , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline uint32      GetParam(ForceType<uint32>      , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline int8        GetParam(ForceType<int8>        , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline int16       GetParam(ForceType<int16>       , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline int32       GetParam(ForceType<int32>       , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger     tmp; sq_getinteger    (vm, index, &tmp); return tmp; }
	template <> inline bool        GetParam(ForceType<bool>        , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQBool        tmp; sq_getbool       (vm, index, &tmp); return tmp != 0; }
	template <> inline const char *GetParam(ForceType<const char *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { const SQChar *tmp; sq_getstring     (vm, index, &tmp); char *tmp_str = strdup(FS2OTTD(tmp)); *ptr->Append() = (void *)tmp_str; return tmp_str; }
	template <> inline void       *GetParam(ForceType<void *>      , HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer tmp; sq_getuserpointer(vm, index, &tmp); return tmp; }

	template <> inline Array      *GetParam(ForceType<Array *>,      HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr)
	{
		SQObject obj;
		sq_getstackobj(vm, index, &obj);
		sq_pushobject(vm, obj);
		sq_pushnull(vm);

		SmallVector<int32, 2> data;

		while (SQ_SUCCEEDED(sq_next(vm, -2))) {
			SQInteger tmp;
			if (SQ_SUCCEEDED(sq_getinteger(vm, -1, &tmp))) {
				*data.Append() = (int32)tmp;
			} else {
				// TODO: handle following error properly: "array member is not numeric; ignoring member"
			}

			sq_pop(vm, 2);
		}
		sq_pop(vm, 2);

		Array *arr = (Array*)MallocT<byte>(sizeof(Array) + sizeof(int32) * data.Length());
		arr->size = data.Length();
		memcpy(arr->array, data.Begin(), sizeof(int32) * data.Length());

		*ptr->Append() = arr;
		return arr;
	}

	/**
	* Helper class to recognize the function type (retval type, args) and use the proper specialization
	* for SQ callback. The partial specializations for the second arg (Tis_void_retval) are not possible
	* on the function. Therefore the class is used instead.
	*/
	template <typename Tfunc, bool Tis_void_retval = HasVoidReturnT<Tfunc>::Yes> struct HelperT;

	/**
	 * The real C++ caller for function with return value and 0 params.
	 */
	template <typename Tretval>
	struct HelperT<Tretval (*)(), false> {
		static int SQCall(void *instance, Tretval (*func)(), HSQUIRRELVM vm)
		{
			return Return(vm, (*func)());
		}
	};

	/**
	 * The real C++ caller for function with no return value and 0 params.
	 */
	template <typename Tretval>
	struct HelperT<Tretval (*)(), true> {
		static int SQCall(void *instance, Tretval (*func)(), HSQUIRRELVM vm)
		{
			(*func)();
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 0 params.
	 */
	template <class Tcls, typename Tretval>
	struct HelperT<Tretval (Tcls::*)(), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(), HSQUIRRELVM vm)
		{
			return Return(vm, (instance->*func)());
		}
	};

	/**
	 * The real C++ caller for method with no return value and 0 params.
	 */
	template <class Tcls, typename Tretval>
	struct HelperT<Tretval (Tcls::*)(), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(), HSQUIRRELVM vm)
		{
			(instance->*func)();
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(), HSQUIRRELVM vm)
		{
			return new Tcls();
		}
	};

	/**
	 * The real C++ caller for function with return value and 1 param.
	 */
	template <typename Tretval, typename Targ1>
	struct HelperT<Tretval (*)(Targ1), false> {
		static int SQCall(void *instance, Tretval (*func)(Targ1), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr)
			);
			sq_pop(vm, 1);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for function with no return value and 1 param.
	 */
	template <typename Tretval, typename Targ1>
	struct HelperT<Tretval (*)(Targ1), true> {
		static int SQCall(void *instance, Tretval (*func)(Targ1), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr)
			);
			sq_pop(vm, 1);
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 1 param.
	 */
	template <class Tcls, typename Tretval, typename Targ1>
	struct HelperT<Tretval (Tcls::*)(Targ1), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr)
			);
			sq_pop(vm, 1);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for method with no return value and 1 param.
	 */
	template <class Tcls, typename Tretval, typename Targ1>
	struct HelperT<Tretval (Tcls::*)(Targ1), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr)
			);
			sq_pop(vm, 1);
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(Targ1), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tcls *inst = new Tcls(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr)
			);

			return inst;
		}
	};

	/**
	 * The real C++ caller for function with return value and 2 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2>
	struct HelperT<Tretval (*)(Targ1, Targ2), false> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr)
			);
			sq_pop(vm, 2);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for function with no return value and 2 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2>
	struct HelperT<Tretval (*)(Targ1, Targ2), true> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr)
			);
			sq_pop(vm, 2);
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 2 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr)
			);
			sq_pop(vm, 2);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for method with no return value and 2 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr)
			);
			sq_pop(vm, 2);
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tcls *inst = new Tcls(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr)
			);

			return inst;
		}
	};

	/**
	 * The real C++ caller for function with return value and 3 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3), false> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr)
			);
			sq_pop(vm, 3);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for function with no return value and 3 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3), true> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr)
			);
			sq_pop(vm, 3);
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 3 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr)
			);
			sq_pop(vm, 3);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for method with no return value and 3 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr)
			);
			sq_pop(vm, 3);
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tcls *inst = new Tcls(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr)
			);

			return inst;
		}
	};

	/**
	 * The real C++ caller for function with return value and 4 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3, Targ4), false> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3, Targ4), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr)
			);
			sq_pop(vm, 4);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for function with no return value and 4 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3, Targ4), true> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3, Targ4), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr)
			);
			sq_pop(vm, 4);
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 4 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr)
			);
			sq_pop(vm, 4);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for method with no return value and 4 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr)
			);
			sq_pop(vm, 4);
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tcls *inst = new Tcls(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr)
			);

			return inst;
		}
	};

	/**
	 * The real C++ caller for function with return value and 5 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3, Targ4, Targ5), false> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3, Targ4, Targ5), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr),
				GetParam(ForceType<Targ5>(), vm, 6, &ptr)
			);
			sq_pop(vm, 5);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for function with no return value and 5 params.
	 */
	template <typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5>
	struct HelperT<Tretval (*)(Targ1, Targ2, Targ3, Targ4, Targ5), true> {
		static int SQCall(void *instance, Tretval (*func)(Targ1, Targ2, Targ3, Targ4, Targ5), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr),
				GetParam(ForceType<Targ5>(), vm, 6, &ptr)
			);
			sq_pop(vm, 5);
			return 0;
		}
	};

	/**
	 * The real C++ caller for method with return value and 5 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4, Targ5), false> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4, Targ5), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tretval ret = (instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr),
				GetParam(ForceType<Targ5>(), vm, 6, &ptr)
			);
			sq_pop(vm, 5);
			return Return(vm, ret);
		}
	};

	/**
	 * The real C++ caller for method with no return value and 5 params.
	 */
	template <class Tcls, typename Tretval, typename Targ1, typename Targ2, typename Targ3, typename Targ4, typename Targ5>
	struct HelperT<Tretval (Tcls::*)(Targ1, Targ2, Targ3, Targ4, Targ5), true> {
		static int SQCall(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4, Targ5), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			(instance->*func)(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr),
				GetParam(ForceType<Targ5>(), vm, 6, &ptr)
			);
			sq_pop(vm, 5);
			return 0;
		}

		static Tcls *SQConstruct(Tcls *instance, Tretval (Tcls::*func)(Targ1, Targ2, Targ3, Targ4, Targ5), HSQUIRRELVM vm)
		{
			SQAutoFreePointers ptr;
			Tcls *inst = new Tcls(
				GetParam(ForceType<Targ1>(), vm, 2, &ptr),
				GetParam(ForceType<Targ2>(), vm, 3, &ptr),
				GetParam(ForceType<Targ3>(), vm, 4, &ptr),
				GetParam(ForceType<Targ4>(), vm, 5, &ptr),
				GetParam(ForceType<Targ5>(), vm, 6, &ptr)
			);

			return inst;
		}
	};


	/**
	 * A general template for all non-static method callbacks from Squirrel.
	 *  In here the function_proc is recovered, and the SQCall is called that
	 *  can handle this exact amount of params.
	 */
	template <typename Tcls, typename Tmethod>
	inline SQInteger DefSQNonStaticCallback(HSQUIRRELVM vm)
	{
		/* Find the amount of params we got */
		int nparam = sq_gettop(vm);
		SQUserPointer ptr = NULL;
		SQUserPointer real_instance = NULL;
		HSQOBJECT instance;

		/* Get the 'SQ' instance of this class */
		Squirrel::GetInstance(vm, &instance);

		/* Protect against calls to a non-static method in a static way */
		sq_pushroottable(vm);
		sq_pushstring(vm, OTTD2FS(Tcls::GetClassName()), -1);
		sq_get(vm, -2);
		sq_pushobject(vm, instance);
		if (sq_instanceof(vm) != SQTrue) return sq_throwerror(vm, _SC("class method is non-static"));
		sq_pop(vm, 3);

		/* Get the 'real' instance of this class */
		sq_getinstanceup(vm, 1, &real_instance, 0);
		/* Get the real function pointer */
		sq_getuserdata(vm, nparam, &ptr, 0);
		if (real_instance == NULL) return sq_throwerror(vm, _SC("couldn't detect real instance of class for non-static call"));
		/* Remove the userdata from the stack */
		sq_pop(vm, 1);

		/* Delegate it to a template that can handle this specific function */
		return HelperT<Tmethod>::SQCall((Tcls *)real_instance, *(Tmethod *)ptr, vm);
	}

	/**
	 * A general template for all non-static advanced method callbacks from Squirrel.
	 *  In here the function_proc is recovered, and the SQCall is called that
	 *  can handle this exact amount of params.
	 */
	template <typename Tcls, typename Tmethod>
	inline SQInteger DefSQAdvancedNonStaticCallback(HSQUIRRELVM vm)
	{
		/* Find the amount of params we got */
		int nparam = sq_gettop(vm);
		SQUserPointer ptr = NULL;
		SQUserPointer real_instance = NULL;
		HSQOBJECT instance;

		/* Get the 'SQ' instance of this class */
		Squirrel::GetInstance(vm, &instance);

		/* Protect against calls to a non-static method in a static way */
		sq_pushroottable(vm);
		sq_pushstring(vm, OTTD2FS(Tcls::GetClassName()), -1);
		sq_get(vm, -2);
		sq_pushobject(vm, instance);
		if (sq_instanceof(vm) != SQTrue) return sq_throwerror(vm, _SC("class method is non-static"));
		sq_pop(vm, 3);

		/* Get the 'real' instance of this class */
		sq_getinstanceup(vm, 1, &real_instance, 0);
		/* Get the real function pointer */
		sq_getuserdata(vm, nparam, &ptr, 0);
		if (real_instance == NULL) return sq_throwerror(vm, _SC("couldn't detect real instance of class for non-static call"));
		/* Remove the userdata from the stack */
		sq_pop(vm, 1);

		/* Call the function, which its only param is always the VM */
		return (SQInteger)(((Tcls *)real_instance)->*(*(Tmethod *)ptr))(vm);
	}

	/**
	 * A general template for all function/static method callbacks from Squirrel.
	 *  In here the function_proc is recovered, and the SQCall is called that
	 *  can handle this exact amount of params.
	 */
	template <typename Tcls, typename Tmethod>
	inline SQInteger DefSQStaticCallback(HSQUIRRELVM vm)
	{
		/* Find the amount of params we got */
		int nparam = sq_gettop(vm);
		SQUserPointer ptr = NULL;

		/* Get the real function pointer */
		sq_getuserdata(vm, nparam, &ptr, 0);

		/* Delegate it to a template that can handle this specific function */
		return HelperT<Tmethod>::SQCall((Tcls *)NULL, *(Tmethod *)ptr, vm);
	}

	/**
	 * A general template for the destructor of SQ instances. This is needed
	 *  here as it has to be in the same scope as DefSQConstructorCallback.
	 */
	template <typename Tcls>
	static SQInteger DefSQDestructorCallback(SQUserPointer p, SQInteger size)
	{
		/* Remove the real instance too */
		if (p != NULL) ((Tcls *)p)->Release();
		return 0;
	}

	/**
	 * A general template to handle creating of instance with any amount of
	 *  params. It creates the instance in C++, and it sets all the needed
	 *  settings in SQ to register the instance.
	 */
	template <typename Tcls, typename Tmethod, int Tnparam>
	inline SQInteger DefSQConstructorCallback(HSQUIRRELVM vm)
	{
		/* Create the real instance */
		Tcls *instance = HelperT<Tmethod>::SQConstruct((Tcls *)NULL, (Tmethod)NULL, vm);
		sq_setinstanceup(vm, -Tnparam, instance);
		sq_setreleasehook(vm, -Tnparam, DefSQDestructorCallback<Tcls>);
		instance->AddRef();
		return 0;
	}

}; // namespace SQConvert

#endif /* SQUIRREL_HELPER_HPP */