/*
** $Id: loslib.c,v 1.40 2012/10/19 15:54:02 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"


/*
** list of valid conversion specifiers for the 'strftime' function
*/
#if !defined(LUA_STRFTIMEOPTIONS)

#if !defined(LUA_USE_POSIX)
#define LUA_STRFTIMEOPTIONS { "aAbBcdHIjmMpSUwWxXyYz%", "" }
#else
#define LUA_STRFTIMEOPTIONS \
    { "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%", "" \
        "", "E", "cCxXyY",  \
        "O", "deHImMSuUVwWy" }
#endif

#endif



/*
** By default, Lua uses tmpnam except when POSIX is available, where it
** uses mkstemp.
*/
#if defined(LUA_USE_MKSTEMP)
#include <unistd.h>
#define LUA_TMPNAMBUFSIZE 32
#define lua_tmpnam(b,e) { \
        strcpy(b, "/tmp/lua_XXXXXX"); \
        e = mkstemp(b); \
        if (e != -1) close(e); \
        e = (e == -1); }

#elif !defined(lua_tmpnam)

#define LUA_TMPNAMBUFSIZE L_tmpnam
#define lua_tmpnam(b,e) { e = (tmpnam(b) == NULL); }

#endif


/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/
#if defined(LUA_USE_GMTIME_R)

#define l_gmtime(t,r)    gmtime_r(t,r)
#define l_localtime(t,r) localtime_r(t,r)

#elif !defined(l_gmtime)

#define l_gmtime(t,r)    ((void)r, gmtime(t))
#define l_localtime(t,r) ((void)r, localtime(t))

#endif



static int os_execute(lua_State *L) {
    const char *cmd = luaL_optstring(L, 1, NULL);
    int stat = system(cmd);
    if (cmd != NULL)
        return luaL_execresult(L, stat);
    else {
        lua_pushboolean(L, stat);  /* true if there is a shell */
        return 1;
    }
}


static int os_remove(lua_State *L) {
    const char *filename = luaL_checkstring(L, 1);
    return luaL_fileresult(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 luaL_fileresult(L, rename(fromname, toname) == 0, NULL);
}


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, isnum;
    lua_getfield(L, -1, key);
    res = (int)lua_tointegerx(L, -1, &isnum);
    if (!isnum) {
        if (d < 0)
            return luaL_error(L, "field " LUA_QS " missing in date table", key);
        res = d;
    }
    lua_pop(L, 1);
    return res;
}


static const char *checkoption(lua_State *L, const char *conv, char *buff) {
    static const char *const options[] = LUA_STRFTIMEOPTIONS;
    unsigned int i;
    for (i = 0; i < sizeof(options) / sizeof(options[0]); i += 2) {
        if (*conv != '\0' && strchr(options[i], *conv) != NULL) {
            buff[1] = *conv;
            if (*options[i + 1] == '\0') {  /* one-char conversion specifier? */
                buff[2] = '\0';  /* end buffer */
                return conv + 1;
            } else if (*(conv + 1) != '\0' &&
                       strchr(options[i + 1], *(conv + 1)) != NULL) {
                buff[2] = *(conv + 1);  /* valid two-char conversion specifier */
                buff[3] = '\0';  /* end buffer */
                return conv + 2;
            }
        }
    }
    luaL_argerror(L, 1,
                  lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));
    return conv;  /* to avoid warnings */
}


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 tmr, *stm;
    if (*s == '!') {  /* UTC? */
        stm = l_gmtime(&t, &tmr);
        s++;  /* skip `!' */
    } else
        stm = l_localtime(&t, &tmr);
    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[4];
        luaL_Buffer b;
        cc[0] = '%';
        luaL_buffinit(L, &b);
        while (*s) {
            if (*s != '%')  /* no conversion specifier? */
                luaL_addchar(&b, *s++);
            else {
                size_t reslen;
                char buff[200];  /* should be big enough for any conversion result */
                s = checkoption(L, s + 1, cc);
                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) {
    int status;
    if (lua_isboolean(L, 1))
        status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);
    else
        status = luaL_optint(L, 1, EXIT_SUCCESS);
    if (lua_toboolean(L, 2))
        lua_close(L);
    if (L) exit(status);  /* 'if' to avoid warnings for unreachable 'return' */
    return 0;
}


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}
};

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



LUAMOD_API int luaopen_os(lua_State *L) {
    luaL_newlib(L, syslib);
    return 1;
}