/* luastuff.c
   
   Copyright 2006-2009 Taco Hoekwater <taco@luatex.org>

   This file is part of LuaTeX.

   LuaTeX is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
   Software Foundation; either version 2 of the License, or (at your
   option) any later version.

   LuaTeX 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 Lesser General Public
   License for more details.

   You should have received a copy of the GNU General Public License along
   with LuaTeX; if not, see <http://www.gnu.org/licenses/>. */

static const char _svn_version[] =
    "$Id: luastuff.c 3217 2009-12-03 16:52:01Z taco $ "
    "$URL: http://foundry.supelec.fr/svn/luatex/tags/beta-0.50.0/source/texk/web2c/luatexdir/lua/luastuff.c $";

#include "lua/luatex-api.h"
#include <ptexlib.h>

lua_State *Luas = NULL;

extern char *startup_filename;
extern int safer_option;
extern int nosocket_option;

int luastate_bytes = 0;

int lua_active = 0;

void make_table(lua_State * L, char *tab, char *getfunc, char *setfunc)
{
    /* make the table *//* [{<tex>}] */
    lua_pushstring(L, tab);     /* [{<tex>},"dimen"] */
    lua_newtable(L);            /* [{<tex>},"dimen",{}] */
    lua_settable(L, -3);        /* [{<tex>}] */
    /* fetch it back */
    lua_pushstring(L, tab);     /* [{<tex>},"dimen"] */
    lua_gettable(L, -2);        /* [{<tex>},{<dimen>}] */
    /* make the meta entries */
    luaL_newmetatable(L, tab);  /* [{<tex>},{<dimen>},{<dimen_m>}] */
    lua_pushstring(L, "__index");       /* [{<tex>},{<dimen>},{<dimen_m>},"__index"] */
    lua_pushstring(L, getfunc); /* [{<tex>},{<dimen>},{<dimen_m>},"__index","getdimen"] */
    lua_gettable(L, -5);        /* [{<tex>},{<dimen>},{<dimen_m>},"__index",<tex.getdimen>]  */
    lua_settable(L, -3);        /* [{<tex>},{<dimen>},{<dimen_m>}]  */
    lua_pushstring(L, "__newindex");    /* [{<tex>},{<dimen>},{<dimen_m>},"__newindex"] */
    lua_pushstring(L, setfunc); /* [{<tex>},{<dimen>},{<dimen_m>},"__newindex","setdimen"] */
    lua_gettable(L, -5);        /* [{<tex>},{<dimen>},{<dimen_m>},"__newindex",<tex.setdimen>]  */
    lua_settable(L, -3);        /* [{<tex>},{<dimen>},{<dimen_m>}]  */
    lua_setmetatable(L, -2);    /* [{<tex>},{<dimen>}] : assign the metatable */
    lua_pop(L, 1);              /* [{<tex>}] : clean the stack */
}

static
const char *getS(lua_State * L, void *ud, size_t * size)
{
    LoadS *ls = (LoadS *) ud;
    (void) L;
    if (ls->size == 0)
        return NULL;
    *size = ls->size;
    ls->size = 0;
    return ls->s;
}

void *my_luaalloc(void *ud, void *ptr, size_t osize, size_t nsize)
{
    void *ret = NULL;
    (void) ud;                  /* for -Wunused */
    if (nsize == 0)
        free(ptr);
    else
        ret = realloc(ptr, nsize);
    luastate_bytes += (nsize - osize);
    return ret;
}

static int my_luapanic(lua_State * L)
{
    (void) L;                   /* to avoid warnings */
    fprintf(stderr, "PANIC: unprotected error in call to Lua API (%s)\n",
            lua_tostring(L, -1));
    return 0;
}

static const luaL_Reg lualibs[] = {
    {"", luaopen_base},
    {"package", luaopen_package},
    {"table", luaopen_table},
    {"io", luaopen_io},
    {"os", luaopen_os},
    {"string", luaopen_string},
    {"math", luaopen_math},
    {"debug", luaopen_debug},
    {"unicode", luaopen_unicode},
    {"zip", luaopen_zip},
    {"lpeg", luaopen_lpeg},
    {"md5", luaopen_md5},
    {"lfs", luaopen_lfs},
    {"profiler", luaopen_profiler},
    {NULL, NULL}
};


static void do_openlibs(lua_State * L)
{
    const luaL_Reg *lib = lualibs;
    for (; lib->func; lib++) {
        lua_pushcfunction(L, lib->func);
        lua_pushstring(L, lib->name);
        lua_call(L, 1, 0);
    }
}

void luainterpreter(void)
{
    lua_State *L;
    L = lua_newstate(my_luaalloc, NULL);
    if (L == NULL) {
        fprintf(stderr, "Can't create the Lua state.\n");
        return;
    }
    lua_atpanic(L, &my_luapanic);

    do_openlibs(L);             /* does all the 'simple' libraries */

    luatex_md5_lua_open(L);

    open_oslibext(L, safer_option);

    /* luasockets */
    /* socket and mime are a bit tricky to open because
     * they use a load-time  dependency that has to be 
     * worked around for luatex, where the C module is 
     * loaded way before the lua module.
     */
    if (!nosocket_option) {
        lua_getglobal(L, "package");
        lua_getfield(L, -1, "loaded");
        if (!lua_istable(L, -1)) {
            lua_newtable(L);
            lua_setfield(L, -2, "loaded");
            lua_getfield(L, -1, "loaded");
        }
        luaopen_socket_core(L);
        lua_setfield(L, -2, "socket.core");
        lua_pushnil(L);
        lua_setfield(L, -2, "socket");  /* package.loaded.socket = nil */

        luaopen_mime_core(L);
        lua_setfield(L, -2, "mime.core");
        lua_pushnil(L);
        lua_setfield(L, -2, "mime");    /* package.loaded.mime = nil */
        lua_pop(L, 2);          /* pop the tables */

        luatex_socketlua_open(L);       /* preload the pure lua modules */
    }
    /* zlib. slightly odd calling convention */
    luaopen_zlib(L);
    lua_setglobal(L, "zlib");
    luaopen_gzip(L);

    /* our own libraries */
    luaopen_ff(L);
    luaopen_tex(L);
    luaopen_token(L);
    luaopen_node(L);
    luaopen_texio(L);
    luaopen_kpse(L);
    luaopen_callback(L);
    luaopen_lua(L, startup_filename);
    luaopen_stats(L);
    luaopen_font(L);
    luaopen_lang(L);
    luaopen_mplib(L);

    /* luaopen_pdf(L); */
    /* environment table at LUA_ENVIRONINDEX needs to load this way: */
    lua_pushcfunction(L, luaopen_pdf);
    lua_pushstring(L, "pdf");
    lua_call(L, 1, 0);

    /* luaopen_img(L); */
    lua_pushcfunction(L, luaopen_img);
    lua_pushstring(L, "img");
    lua_call(L, 1, 0);

    lua_createtable(L, 0, 0);
    lua_setglobal(L, "texconfig");

    if (safer_option) {
        /* disable some stuff if --safer */
        (void) hide_lua_value(L, "os", "execute");
        (void) hide_lua_value(L, "os", "rename");
        (void) hide_lua_value(L, "os", "remove");
        (void) hide_lua_value(L, "io", "popen");
        /* make io.open only read files */
        luaL_checkstack(L, 2, "out of stack space");
        lua_getglobal(L, "io");
        lua_getfield(L, -1, "open_ro");
        lua_setfield(L, -2, "open");
        (void) hide_lua_value(L, "io", "tmpfile");
        (void) hide_lua_value(L, "io", "output");
        (void) hide_lua_value(L, "lfs", "chdir");
        (void) hide_lua_value(L, "lfs", "lock");
        (void) hide_lua_value(L, "lfs", "touch");
        (void) hide_lua_value(L, "lfs", "rmdir");
        (void) hide_lua_value(L, "lfs", "mkdir");
    }
    Luas = L;
}

int hide_lua_table(lua_State * L, char *name)
{
    int r = 0;
    lua_getglobal(L, name);
    if (lua_istable(L, -1)) {
        r = luaL_ref(L, LUA_REGISTRYINDEX);
        lua_pushnil(L);
        lua_setglobal(L, name);
    }
    return r;
}

void unhide_lua_table(lua_State * L, char *name, int r)
{
    lua_rawgeti(L, LUA_REGISTRYINDEX, r);
    lua_setglobal(L, name);
    luaL_unref(L, LUA_REGISTRYINDEX, r);
}

int hide_lua_value(lua_State * L, char *name, char *item)
{
    int r = 0;
    lua_getglobal(L, name);
    if (lua_istable(L, -1)) {
        lua_getfield(L, -1, item);
        r = luaL_ref(L, LUA_REGISTRYINDEX);
        lua_pushnil(L);
        lua_setfield(L, -2, item);
    }
    return r;
}

void unhide_lua_value(lua_State * L, char *name, char *item, int r)
{
    lua_getglobal(L, name);
    if (lua_istable(L, -1)) {
        lua_rawgeti(L, LUA_REGISTRYINDEX, r);
        lua_setfield(L, -2, item);
        luaL_unref(L, LUA_REGISTRYINDEX, r);
    }
}


int lua_traceback(lua_State * L)
{
    lua_getfield(L, LUA_GLOBALSINDEX, "debug");
    if (!lua_istable(L, -1)) {
        lua_pop(L, 1);
        return 1;
    }
    lua_getfield(L, -1, "traceback");
    if (!lua_isfunction(L, -1)) {
        lua_pop(L, 2);
        return 1;
    }
    lua_pushvalue(L, 1);        /* pass error message */
    lua_pushinteger(L, 2);      /* skip this function and traceback */
    lua_call(L, 2, 1);          /* call debug.traceback */
    return 1;
}

/**********************************************************************/

static void luacall(int p, int nameptr)
{
    LoadS ls;
    int i, l;
    char *lua_id;
    char *s = NULL;

    if (Luas == NULL) {
        luainterpreter();
    }
    l = 0;
    lua_active++;
    s = tokenlist_to_cstring(p, 1, &l);
    ls.s = s;
    ls.size = l;

    if (ls.size > 0) {
        if (nameptr > 0) {
            lua_id = tokenlist_to_cstring(nameptr, 1, &l);
        } else if (nameptr < 0) {
            char *tmp = get_lua_name((nameptr + 65536));
            if (tmp != NULL)
                lua_id = xstrdup(tmp);
            else
                lua_id = xstrdup("\\latelua ");
        } else {
            lua_id = xmalloc(20);
            snprintf((char *) lua_id, 20, "\\latelua ");
        }

        i = lua_load(Luas, getS, &ls, lua_id);
        if (i != 0) {
            Luas = luatex_error(Luas, (i == LUA_ERRSYNTAX ? 0 : 1));
        } else {
            int base = lua_gettop(Luas);        /* function index */
            lua_checkstack(Luas, 1);
            lua_pushcfunction(Luas, lua_traceback);     /* push traceback function */
            lua_insert(Luas, base);     /* put it under chunk  */
            i = lua_pcall(Luas, 0, 0, base);
            lua_remove(Luas, base);     /* remove traceback function */
            if (i != 0) {
                lua_gc(Luas, LUA_GCCOLLECT, 0);
                Luas = luatex_error(Luas, (i == LUA_ERRRUN ? 0 : 1));
            }
        }
        xfree(lua_id);
    }
    lua_active--;
}

void late_lua(PDF pdf, halfword p)
{
    (void) pdf;
    expand_macros_in_tokenlist(p);      /* sets def_ref */
    luacall(def_ref, late_lua_name(p));
    flush_list(def_ref);
}

/**********************************************************************/

void luatokencall(int p, int nameptr)
{
    LoadS ls;
    int i, l;
    char *s = NULL;
    char *lua_id;
    assert(Luas);
    l = 0;
    lua_active++;
    s = tokenlist_to_cstring(p, 1, &l);
    ls.s = s;
    ls.size = l;
    if (ls.size > 0) {
        if (nameptr > 0) {
            lua_id = tokenlist_to_cstring(nameptr, 1, &l);
        } else if (nameptr < 0) {
            char *tmp = get_lua_name((nameptr + 65536));
            if (tmp != NULL)
                lua_id = xstrdup(tmp);
            else
                lua_id = xstrdup("\\directlua ");
        } else {
            lua_id = xstrdup("\\directlua ");
        }
        i = lua_load(Luas, getS, &ls, lua_id);
        xfree(s);
        if (i != 0) {
            Luas = luatex_error(Luas, (i == LUA_ERRSYNTAX ? 0 : 1));
        } else {
            int base = lua_gettop(Luas);        /* function index */
            lua_checkstack(Luas, 1);
            lua_pushcfunction(Luas, lua_traceback);     /* push traceback function */
            lua_insert(Luas, base);     /* put it under chunk  */
            i = lua_pcall(Luas, 0, 0, base);
            lua_remove(Luas, base);     /* remove traceback function */
            if (i != 0) {
                lua_gc(Luas, LUA_GCCOLLECT, 0);
                Luas = luatex_error(Luas, (i == LUA_ERRRUN ? 0 : 1));
            }
        }
        xfree(lua_id);
    }
    lua_active--;
}

lua_State *luatex_error(lua_State * L, int is_fatal)
{

    const char *luaerr;
    size_t len = 0;
    char *err = NULL;
    if (lua_isstring(L, -1)) {
        luaerr = lua_tolstring(L, -1, &len);
        err = (char *) xmalloc(len + 1);
        len = snprintf(err, (len + 1), "%s", luaerr);
    }
    if (is_fatal > 0) {
        /* Normally a memory error from lua. 
           The pool may overflow during the maketexlstring(), but we 
           are crashing anyway so we may as well abort on the pool size */
        lua_fatal_error(err);
        /* never reached */
        xfree(err);
        lua_close(L);
        return (lua_State *) NULL;
    } else {
        lua_norm_error(err);
        xfree(err);
        return L;
    }
}
