/*

** $Id: loslib.c,v 1.19.1.3 2008/01/18 16:38:18 roberto Exp $

** Standard Operating System library

** See Copyright Notice in lua.h

*/

#include <errno.h>

#include <locale.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#define loslib_c

#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"

#include "lualib.h"

static int os_pushresult (lua_State *L, int i, const char *filename) {

  int en = errno;  /* calls to Lua API may change this value */

  if (i) {

    lua_pushboolean(L, 1);

    return 1;

  }

  else {

    lua_pushnil(L);

    lua_pushfstring(L, "%s: %s", filename, strerror(en));

    lua_pushinteger(L, en);

    return 3;

  }

}

static int os_execute (lua_State *L) {

  lua_pushinteger(L, system(luaL_optstring(L, 1, NULL)));

  return 1;

}

static int os_remove (lua_State *L) {

  const char *filename = luaL_checkstring(L, 1);

  return os_pushresult(L, remove(filename) == 0, filename);

}

static int os_rename (lua_State *L) {

  const char *fromname = luaL_checkstring(L, 1);

  const char *toname = luaL_checkstring(L, 2);

  return os_pushresult(L, rename(fromname, toname) == 0, fromname);

}

static int os_tmpname (lua_State *L) {

  char buff[LUA_TMPNAMBUFSIZE];

  int err;

  lua_tmpnam(buff, err);

  if (err)

    return luaL_error(L, "unable to generate a unique filename");

  lua_pushstring(L, buff);

  return 1;

}

static int os_getenv (lua_State *L) {

  lua_pushstring(L, getenv(luaL_checkstring(L, 1)));  /* if NULL push nil */

  return 1;

}

static int os_clock (lua_State *L) {

  lua_pushnumber(L, ((lua_Number)clock())/(lua_Number)CLOCKS_PER_SEC);

  return 1;

}

/*

** {======================================================

** Time/Date operations

** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,

**   wday=%w+1, yday=%j, isdst=? }

** =======================================================

*/

static void setfield (lua_State *L, const char *key, int value) {

  lua_pushinteger(L, value);

  lua_setfield(L, -2, key);

}

static void setboolfield (lua_State *L, const char *key, int value) {

  if (value < 0)  /* undefined? */

    return;  /* does not set field */

  lua_pushboolean(L, value);

  lua_setfield(L, -2, key);

}

static int getboolfield (lua_State *L, const char *key) {

  int res;

  lua_getfield(L, -1, key);

  res = lua_isnil(L, -1) ? -1 : lua_toboolean(L, -1);

  lua_pop(L, 1);

  return res;

}

static int getfield (lua_State *L, const char *key, int d) {

  int res;

  lua_getfield(L, -1, key);

  if (lua_isnumber(L, -1))

    res = (int)lua_tointeger(L, -1);

  else {

    if (d < 0)

      return luaL_error(L, "field " LUA_QS " missing in date table", key);

    res = d;

  }

  lua_pop(L, 1);

  return res;

}

static int os_date (lua_State *L) {

  const char *s = luaL_optstring(L, 1, "%c");

  time_t t = luaL_opt(L, (time_t)luaL_checknumber, 2, time(NULL));

  struct tm *stm;

  if (*s == '!') {  /* UTC? */

    stm = gmtime(&t);

    s++;  /* skip `!' */

  }

  else

    stm = localtime(&t);

  if (stm == NULL)  /* invalid date? */

    lua_pushnil(L);

  else if (strcmp(s, "*t") == 0) {

    lua_createtable(L, 0, 9);  /* 9 = number of fields */

    setfield(L, "sec", stm->tm_sec);

    setfield(L, "min", stm->tm_min);

    setfield(L, "hour", stm->tm_hour);

    setfield(L, "day", stm->tm_mday);

    setfield(L, "month", stm->tm_mon+1);

    setfield(L, "year", stm->tm_year+1900);

    setfield(L, "wday", stm->tm_wday+1);

    setfield(L, "yday", stm->tm_yday+1);

    setboolfield(L, "isdst", stm->tm_isdst);

  }

  else {

    char cc[3];

    luaL_Buffer b;

    cc[0] = '%'; cc[2] = '\0';

    luaL_buffinit(L, &b);

    for (; *s; s++) {

      if (*s != '%' || *(s + 1) == '\0')  /* no conversion specifier? */

        luaL_addchar(&b, *s);

      else {

        size_t reslen;

        char buff[200];  /* should be big enough for any conversion result */

        cc[1] = *(++s);

        reslen = strftime(buff, sizeof(buff), cc, stm);

        luaL_addlstring(&b, buff, reslen);

      }

    }

    luaL_pushresult(&b);

  }

  return 1;

}

static int os_time (lua_State *L) {

  time_t t;

  if (lua_isnoneornil(L, 1))  /* called without args? */

    t = time(NULL);  /* get current time */

  else {

    struct tm ts;

    luaL_checktype(L, 1, LUA_TTABLE);

    lua_settop(L, 1);  /* make sure table is at the top */

    ts.tm_sec = getfield(L, "sec", 0);

    ts.tm_min = getfield(L, "min", 0);

    ts.tm_hour = getfield(L, "hour", 12);

    ts.tm_mday = getfield(L, "day", -1);

    ts.tm_mon = getfield(L, "month", -1) - 1;

    ts.tm_year = getfield(L, "year", -1) - 1900;

    ts.tm_isdst = getboolfield(L, "isdst");

    t = mktime(&ts);

  }

  if (t == (time_t)(-1))

    lua_pushnil(L);

  else

    lua_pushnumber(L, (lua_Number)t);

  return 1;

}

static int os_difftime (lua_State *L) {

  lua_pushnumber(L, difftime((time_t)(luaL_checknumber(L, 1)),

                             (time_t)(luaL_optnumber(L, 2, 0))));

  return 1;

}

/* }====================================================== */

static int os_setlocale (lua_State *L) {

  static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,

                      LC_NUMERIC, LC_TIME};

  static const char *const catnames[] = {"all", "collate", "ctype", "monetary",

     "numeric", "time", NULL};

  const char *l = luaL_optstring(L, 1, NULL);

  int op = luaL_checkoption(L, 2, "all", catnames);

  lua_pushstring(L, setlocale(cat[op], l));

  return 1;

}

static int os_exit (lua_State *L) {

  exit(luaL_optint(L, 1, EXIT_SUCCESS));

}

static const luaL_Reg syslib[] = {

  {"clock",     os_clock},

  {"date",      os_date},

  {"difftime",  os_difftime},

  {"execute",   os_execute},

  {"exit",      os_exit},

  {"getenv",    os_getenv},

  {"remove",    os_remove},

  {"rename",    os_rename},

  {"setlocale", os_setlocale},

  {"time",      os_time},

  {"tmpname",   os_tmpname},

  {NULL, NULL}

};

/* }====================================================== */

LUALIB_API int luaopen_os (lua_State *L) {

  luaL_register(L, LUA_OSLIBNAME, syslib);

  return 1;

}