/*
** Compat-5.1
** Copyright Kepler Project 2004-2006 (http://www.keplerproject.org/compat)
** $Id$

Copyright © 2004-2006 The Kepler Project.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
IN THE SOFTWARE.

*/

#include <stdio.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "compat-5.1.h"

static void getfield(lua_State *L, int idx, const char *name) {
    const char *end = strchr(name, '.');
    lua_pushvalue(L, idx);
    while (end) {
        lua_pushlstring(L, name, end - name);
        lua_gettable(L, -2);
        lua_remove(L, -2);
        if (lua_isnil(L, -1)) return;
        name = end+1;
        end = strchr(name, '.');
    }
    lua_pushstring(L, name);
    lua_gettable(L, -2);
    lua_remove(L, -2);
}

static void setfield(lua_State *L, int idx, const char *name) {
    const char *end = strchr(name, '.');
    lua_pushvalue(L, idx);
    while (end) {
        lua_pushlstring(L, name, end - name);
        lua_gettable(L, -2);
        /* create table if not found */
        if (lua_isnil(L, -1)) {
            lua_pop(L, 1);
            lua_newtable(L);
            lua_pushlstring(L, name, end - name);
            lua_pushvalue(L, -2);
            lua_settable(L, -4);
        }
        lua_remove(L, -2);
        name = end+1;
        end = strchr(name, '.');
    }
    lua_pushstring(L, name);
    lua_pushvalue(L, -3);
    lua_settable(L, -3);
    lua_pop(L, 2);
}

LUALIB_API void luaL_module(lua_State *L, const char *libname,
                              const luaL_reg *l, int nup) {
  if (libname) {
    getfield(L, LUA_GLOBALSINDEX, libname);  /* check whether lib already exists */
    if (lua_isnil(L, -1)) { 
      int env, ns;
      lua_pop(L, 1); /* get rid of nil */
      lua_pushliteral(L, "require");
      lua_gettable(L, LUA_GLOBALSINDEX); /* look for require */
      lua_getfenv(L, -1); /* getfenv(require) */
      lua_remove(L, -2); /* remove function require */
      env = lua_gettop(L);

      lua_newtable(L); /* create namespace for lib */
      ns = lua_gettop(L);
      getfield(L, env, "package.loaded"); /* get package.loaded table */
      if (lua_isnil(L, -1)) { /* create package.loaded table */
          lua_pop(L, 1); /* remove previous result */
          lua_newtable(L);
          lua_pushvalue(L, -1);
          setfield(L, env, "package.loaded");
      }
      else if (!lua_istable(L, -1))
        luaL_error(L, "name conflict for library `%s'", libname);
      lua_pushstring(L, libname);
      lua_pushvalue(L, ns); 
      lua_settable(L, -3); /* package.loaded[libname] = ns */
      lua_pop(L, 1); /* get rid of package.loaded table */
      lua_pushvalue(L, ns); /* copy namespace */
      setfield(L, LUA_GLOBALSINDEX, libname);
      lua_remove (L, env); /* remove env */
    }
    lua_insert(L, -(nup+1));  /* move library table to below upvalues */
  }
  for (; l->name; l++) {
    int i;
    lua_pushstring(L, l->name);
    for (i=0; i<nup; i++)  /* copy upvalues to the top */
      lua_pushvalue(L, -(nup+1));
    lua_pushcclosure(L, l->func, nup);
    lua_settable(L, -(nup+3));
  }
  lua_pop(L, nup);  /* remove upvalues */
}