// Copyright (C) 2012-2015 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of Nova libraries. 
// For conditions of distribution and use, see copying.txt file in root folder.

#include "nv/lib/lua.hh"

#if defined( NV_LUA_DYNAMIC )

#include "nv/core/library.hh"

#if NV_LUA_VERSION == NV_LUA_52
#	undef luaL_loadfile
#	undef luaL_loadbuffer
#	undef luaL_prepbuffer
#	undef lua_tonumber
#	undef lua_tointeger
#	undef lua_tounsigned
#	undef lua_call
#	undef lua_pcall
#	undef lua_yield
#endif

#define NV_LUA_FUN( rtype, fname, fparams ) rtype (*fname) fparams = nullptr;
#if NV_LUA_VERSION == NV_LUA_52
#	define NV_LUA_FUN_51( rtype, fname, fparams )
#	define NV_LUA_FUN_52 NV_LUA_FUN
#elif NV_LUA_VERSION == NV_LUA_51
#	define NV_LUA_FUN_51 NV_LUA_FUN
#	define NV_LUA_FUN_52( rtype, fname, fparams ) 
#else
#	define NV_LUA_FUN_51( rtype, fname, fparams )
#	define NV_LUA_FUN_52( rtype, fname, fparams ) 
#endif

#include <nv/lib/detail/lua_functions.inc>

#undef NV_LUA_FUN
#undef NV_LUA_FUN_51
#undef NV_LUA_FUN_52

#if NV_LUA_VERSION == NV_LUA_5C
#	define NV_LUA_COMPAT_FUN( rt, fn, fp,u1,u2,u3,u4,u5 ) rt (*fn) fp = nullptr;
#	include <nv/lib/detail/lua_functions_compat.inc>
#	undef NV_LUA_COMPAT_FUN
int LUA_UPVALUEINDEX  = 0;
int LUA_REGISTRYINDEX = 0;
int LUA_VERSION_NUM   = 0;
size_t (*lua_rawlen)        (lua_State *L, int idx) = nullptr;
int    (*lua_absindex)      (lua_State *L, int idx) = nullptr;
void   (*lua_getglobal)     (lua_State *L, const char *var) = nullptr;
void   (*lua_setglobal)     (lua_State *L, const char *var) = nullptr;
void   (*luaL_requiref)     (lua_State *L, const char *modname, lua_CFunction openf, int glb) = nullptr;
void   (*luaL_setmetatable) (lua_State *L, const char *tname) = nullptr;
void*  (*luaL_testudata)    (lua_State *L, int ud, const char *tname) = nullptr;
void   (*lua_copy)          (lua_State *L, int fromidx, int toidx) = nullptr;
int    (*lua_compare)       (lua_State *L, int idx1, int idx2, int op) = nullptr;
void   (*lua_rawgetp)       (lua_State *L, int idx, const void *p) = nullptr;
void   (*lua_rawsetp)       (lua_State *L, int idx, const void *p) = nullptr;
void   (*lua_pushglobaltable)(lua_State* L) = nullptr;
void   (*luaL_setfuncs)     (lua_State *L, const luaL_Reg *l, int nup) = nullptr;
int    (*luaL_getsubtable)  (lua_State *L, int idx, const char *fname) = nullptr;

const lua_Number* (*lua_version) (lua_State *L) = nullptr;

// only loaded in 5.1 mode to implement lua_compare
static int    (*lua_equal)        (lua_State *L, int idx1, int idx2) = nullptr;
static int    (*lua_lessthan)     (lua_State *L, int idx1, int idx2) = nullptr;


#	define NV_LUA_COMPAT_FUN( u1,u2,u3,rt2,fn2,fp2,u4,u5 ) static rt2 (*fn2##_compat) fp2 = nullptr;
#	include <nv/lib/detail/lua_functions_compat.inc>
#	undef NV_LUA_COMPAT_FUN

#	define NV_LUA_COMPAT_FUN( rt, fn, fp, rt2, fn2, fp2,arg,ret ) \
		static rt call_##fn2##_compat fp { ret fn2##_compat arg; } 
#	include <nv/lib/detail/lua_functions_compat.inc>
#	undef NV_LUA_COMPAT_FUN

#	define LUAI_MAXSTACK_52		    1000000
#	define LUAI_FIRSTPSEUDOIDX_52	(-LUAI_MAXSTACK_52 - 1000)
#	define LUA_REGISTRYINDEX_52	    LUAI_FIRSTPSEUDOIDX_52
#	define LUA_GLOBALSINDEX_51      (-10002)
#	define LUA_GLOBALSINDEX_52      2
#	define LUA_REGISTRYINDEX_51     (-10000)

static int lua_absindex_51 (lua_State *L, int idx) { return (idx > 0 ? idx : idx + lua_gettop(L) + 1); };
static void lua_getglobal_51 (lua_State *L, const char *var) { lua_getfield(L, LUA_GLOBALSINDEX_51, var ); };
static void lua_setglobal_51 (lua_State *L, const char *var) { lua_setfield(L, LUA_GLOBALSINDEX_51, var ); };
static void luaL_requiref_51 (lua_State *L, const char *modname, lua_CFunction openf, int glb)
{
	lua_pushcfunction(L, openf);
	lua_pushstring(L, modname);
	lua_call(L, 1, 1);
	if (glb != 0)
	{
		lua_pushvalue( L, LUA_GLOBALSINDEX_51 );
		lua_pushvalue(L, -2); 
		lua_setfield(L, -2, modname); 
		lua_pop(L, 1); 
	}
}

static void luaL_setmetatable_51 (lua_State *L, const char *tname)
{
	luaL_getmetatable(L, tname);
	lua_setmetatable(L, -2);
}

static void *luaL_testudata_51 (lua_State *L, int ud, const char *tname)
{
	void *p = lua_touserdata(L, ud);
	if (p != NULL) 
	{  
		if (lua_getmetatable(L, ud)) 
		{
			luaL_getmetatable(L, tname); 
			if ( !lua_rawequal(L, -1, -2))
				p = NULL;  
			lua_pop(L, 2); 
			return p;
		}
	}
	return NULL;
}

static const lua_Number *lua_version_51 (lua_State*) 
{
	static const lua_Number version = lua_Number( LUA_VERSION_NUM );
	return &version;
}

static void lua_copy_51 (lua_State *L, int fromidx, int toidx)
{
	toidx = lua_absindex( L, toidx );
	lua_pushvalue( L, fromidx );
	lua_replace( L, toidx );
}

static int lua_compare_51(lua_State *L, int idx1, int idx2, int op)
{
	switch (op)
	{
	case LUA_OPEQ : return lua_equal( L, idx1, idx2 );
	case LUA_OPLT : return lua_lessthan( L, idx1, idx2 );
	case LUA_OPLE : return lua_lessthan( L, idx1, idx2 ) || lua_equal( L, idx1, idx2 );
	default:
		return 0;
	}
}

static void lua_rawgetp_51(lua_State *L, int idx, const void *p)
{
	idx = lua_absindex( L, idx );
	void* pp = const_cast<void *>(p); // EVIL
	lua_pushlightuserdata( L, pp );
	lua_rawget( L, idx );
}

static void lua_rawsetp_51(lua_State *L, int idx, const void *p)
{
	idx = lua_absindex( L, idx );
	void* pp = const_cast<void *>(p); // EVIL
	lua_pushlightuserdata( L, pp );
	lua_insert( L, -1 );
	lua_rawset( L, idx );
}

static int luaL_getsubtable_51(lua_State *L, int idx, const char *fname)
{
	lua_getfield(L, idx, fname);
	if ( lua_istable(L, -1) ) return 1;
	else {
		idx = lua_absindex(L, idx);
		lua_pop(L, 1);
		lua_newtable(L);
		lua_pushvalue(L, -1);
		lua_setfield(L, idx, fname); 
		return 0; 
	}
}

static void luaL_setfuncs_51(lua_State *L, const luaL_Reg *l, int nup)
{
	luaL_checkstack(L, nup, "too many upvalues");
	for (; l->name != NULL; l++) 
	{
		for (int i = 0; i < nup; i++)
		{
			lua_pushvalue(L, -nup);
		}
		lua_pushcclosure(L, l->func, nup);
		lua_setfield(L, -(nup + 2), l->name);
	}
	lua_pop(L, nup);
}

static void lua_pushglobaltable_51(lua_State* L)
{
	lua_pushvalue( L, LUA_GLOBALSINDEX_51 );
}

static void lua_pushglobaltable_52(lua_State* L)
{
	lua_rawgeti( L, LUA_REGISTRYINDEX_52, LUA_GLOBALSINDEX_52 );
}

#endif

bool nv::load_lua_library( const char* path )
{
	static nv::library lua_library;
	if ( lua_library.is_open() ) return true;
#if NV_LUA_VERSION == NV_LUA_5C
	if ( path == nullptr )
	{
		if (!lua_library.try_open( NV_LUA_PATH_JIT ) &&
			!lua_library.try_open( NV_LUA_PATH_52 ) )
		{
			lua_library.open( NV_LUA_PATH_51 );
		}
	}
	else
#else
		lua_library.open( path );
#endif

#	define NV_LUA_FUN( rtype, fname, fparams ) void_assign( fname, lua_library.get(#fname) );
#	if NV_LUA_VERSION == NV_LUA_52
#		define NV_LUA_FUN_51( rtype, fname, fparams )
#		define NV_LUA_FUN_52 NV_LUA_FUN
#	elif NV_LUA_VERSION == NV_LUA_51
#		define NV_LUA_FUN_51 NV_LUA_FUN
#		define NV_LUA_FUN_52( rtype, fname, fparams ) 
#	else
#		define NV_LUA_FUN_51( rtype, fname, fparams )
#		define NV_LUA_FUN_52( rtype, fname, fparams ) 
#	endif

#	include <nv/lib/detail/lua_functions.inc>

#	undef NV_LUA_FUN
#	undef NV_LUA_FUN_51
#	undef NV_LUA_FUN_52

#if NV_LUA_VERSION == NV_LUA_5C
#	define NV_LUA_LOAD( fname ) void_assign( fname, lua_library.get(#fname) );
#	define NV_LUA_LOAD_AS( fname,fname2 ) void_assign( fname, lua_library.get(#fname2) );
	bool version_52 = lua_library.try_get("luaL_checkversion_") != nullptr;
	if (version_52)
	{
#	define NV_LUA_COMPAT_FUN( u1, fn, u2, u3, fn2, u5, u6, u7 ) \
	void_assign( fn2##_compat, lua_library.get(#fn2) ); \
	fn = call_##fn2##_compat; 
#	include <nv/lib/detail/lua_functions_compat.inc>
#	undef NV_LUA_COMPAT_FUN
		NV_LUA_LOAD( lua_rawlen );
		NV_LUA_LOAD( lua_absindex );
		NV_LUA_LOAD( lua_getglobal );
		NV_LUA_LOAD( lua_setglobal );
		NV_LUA_LOAD( luaL_setmetatable );
		NV_LUA_LOAD( luaL_testudata );
		NV_LUA_LOAD( lua_version );
		NV_LUA_LOAD( lua_copy );
		NV_LUA_LOAD( lua_compare );
		NV_LUA_LOAD( lua_rawgetp );
		NV_LUA_LOAD( lua_rawsetp );
		NV_LUA_LOAD( luaL_setfuncs );
		NV_LUA_LOAD( luaL_getsubtable );
		NV_LUA_LOAD( luaL_requiref );

		lua_pushglobaltable = lua_pushglobaltable_52;

		LUA_UPVALUEINDEX  = LUA_REGISTRYINDEX_52;
		LUA_REGISTRYINDEX = LUA_REGISTRYINDEX_52;
		LUA_VERSION_NUM   = 502;
	}
	else
	{
#	define NV_LUA_COMPAT_FUN( u1, fn, u2, u3, u4, u5, u6, u7 ) \
		void_assign(fn, lua_library.get(#fn) );
#	include <nv/lib/detail/lua_functions_compat.inc>
#	undef NV_LUA_COMPAT_FUN
		NV_LUA_LOAD_AS( lua_rawlen, lua_objlen )
		lua_absindex        = lua_absindex_51;
		lua_getglobal       = lua_getglobal_51;
		lua_setglobal       = lua_setglobal_51;
		luaL_setmetatable   = luaL_setmetatable_51;
		luaL_testudata      = luaL_testudata_51;
		lua_version         = lua_version_51;
		lua_copy            = lua_copy_51;
		lua_rawgetp         = lua_rawgetp_51;
		lua_rawsetp         = lua_rawsetp_51;
		lua_pushglobaltable = lua_pushglobaltable_51;
		luaL_setfuncs       = luaL_setfuncs_51;
		luaL_getsubtable    = luaL_getsubtable_51;
		luaL_requiref       = luaL_requiref_51;

		NV_LUA_LOAD( lua_lessthan );
		NV_LUA_LOAD( lua_equal );
		lua_compare       = lua_compare_51;
		LUA_UPVALUEINDEX  = LUA_GLOBALSINDEX_51;
		LUA_REGISTRYINDEX = LUA_REGISTRYINDEX_51;
		LUA_VERSION_NUM   = 501;
	}
#	undef NV_LUA_LOAD
#endif

	return true;
}

#endif