/*
** OS library.
** Copyright (C) 2005-2014 Mike Pall. See Copyright Notice in luajit.h
**
** Major portions taken verbatim or adapted from the Lua interpreter.
** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
*/

#include <errno.h>
#include <locale.h>
#include <time.h>

#define lib_os_c
#define LUA_LIB

#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"

#include "lj_obj.h"
#include "lj_err.h"
#include "lj_lib.h"

#if LJ_TARGET_POSIX
    #include <unistd.h>
#else
    #include <stdio.h>
#endif

/* ------------------------------------------------------------------------ */

#define LJLIB_MODULE_os

LJLIB_CF(os_clock)
{
    setnumV(L->top++,
            ((lua_Number)clock()) * (1.0 / (lua_Number)CLOCKS_PER_SEC));
    return 1;
}

/* ------------------------------------------------------------------------ */

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)
            lj_err_callerv(L, LJ_ERR_OSDATEF, key);
        res = d;
    }
    lua_pop(L, 1);
    return res;
}

LJLIB_CF(os_date)
{
    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 LJ_TARGET_POSIX
    struct tm rtm;
#endif
    if (*s == '!') { /* UTC? */
        s++;         /* Skip '!' */
#if LJ_TARGET_POSIX
        stm = gmtime_r(&t, &rtm);
#else
        stm = gmtime(&t);
#endif
    }
    else {
#if LJ_TARGET_POSIX
        stm = localtime_r(&t, &rtm);
#else
        stm = localtime(&t);
#endif
    }
    if (stm == NULL) { /* Invalid date? */
        setnilV(L->top - 1);
    }
    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;
}

LJLIB_CF(os_time)
{
    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;
}

LJLIB_CF(os_difftime)
{
    lua_pushnumber(L, difftime((time_t)(luaL_checknumber(L, 1)),
                               (time_t)(luaL_optnumber(L, 2, (lua_Number)0))));
    return 1;
}

/* ------------------------------------------------------------------------ */

#include "lj_libdef.h"

LUALIB_API int luaopen_os(lua_State *L)
{
    LJ_LIB_REG(L, LUA_OSLIBNAME, os);
    return 1;
}
