/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program 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.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#define ALLOW_FORBID_FUNC
#define _BSD_SOURCE

#ifdef DARWIN
#define _XOPEN_SOURCE
#else
#define _XOPEN_SOURCE 500
#endif

#define _DEFAULT_SOURCE

#include "os.h"

#ifdef WINDOWS

#include <time.h>  
#include <stdlib.h>  
#include <string.h>
//#define TM_YEAR_BASE 1970 //origin
#define TM_YEAR_BASE 1900 //slguan
/*
* We do not implement alternate representations. However, we always
* check whether a given modifier is allowed for a certain conversion.
*/
#define ALT_E			0x01
#define ALT_O			0x02
#define	LEGAL_ALT(x)		{ if (alt_format & ~(x)) return (0); }


static int conv_num(const char **buf, int *dest, int llim, int ulim)
{
    int result = 0;

    /* The limit also determines the number of valid digits. */
    int rulim = ulim;

    if (**buf < '0' || **buf > '9')
        return (0);

    do {
        result *= 10;
        result += *(*buf)++ - '0';
        rulim /= 10;
    } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');

    if (result < llim || result > ulim)
        return (0);

    *dest = result;
    return (1);
}

static const char *day[7] = {
    "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
    "Friday", "Saturday"
};
static const char *abday[7] = {
    "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static const char *mon[12] = {
    "January", "February", "March", "April", "May", "June", "July",
    "August", "September", "October", "November", "December"
};
static const char *abmon[12] = {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char *am_pm[2] = {
    "AM", "PM"
};

#define BILLION                             (1E9)

static BOOL g_first_time = 1;
static LARGE_INTEGER g_counts_per_sec;

int clock_gettime(int dummy, struct timespec *ct)
{
    LARGE_INTEGER count;

    if (g_first_time)
    {
        g_first_time = 0;

        if (0 == QueryPerformanceFrequency(&g_counts_per_sec))
        {
            g_counts_per_sec.QuadPart = 0;
        }
    }

    if ((NULL == ct) || (g_counts_per_sec.QuadPart <= 0) ||
            (0 == QueryPerformanceCounter(&count)))
    {
        return -1;
    }

    ct->tv_sec = count.QuadPart / g_counts_per_sec.QuadPart;
    ct->tv_nsec = ((count.QuadPart % g_counts_per_sec.QuadPart) * BILLION) / g_counts_per_sec.QuadPart;

    return 0;
}

#else
#include <sys/time.h>
#endif

char *taosStrpTime(const char *buf, const char *fmt, struct tm *tm) {
#ifdef WINDOWS
    char c;
    const char *bp;
    size_t len = 0;
    int alt_format, i, split_year = 0;

    bp = buf;

    while ((c = *fmt) != '\0') {
        /* Clear `alternate' modifier prior to new conversion. */
        alt_format = 0;

        /* Eat up white-space. */
        if (isspace(c)) {
            while (isspace(*bp))
                bp++;

            fmt++;
            continue;
        }

        if ((c = *fmt++) != '%')
            goto literal;


    again:		switch (c = *fmt++) {
    case '%':	/* "%%" is converted to "%". */
        literal :
            if (c != *bp++)
                return (0);
        break;

        /*
        * "Alternative" modifiers. Just set the appropriate flag
        * and start over again.
        */
    case 'E':	/* "%E?" alternative conversion modifier. */
        LEGAL_ALT(0);
        alt_format |= ALT_E;
        goto again;

    case 'O':	/* "%O?" alternative conversion modifier. */
        LEGAL_ALT(0);
        alt_format |= ALT_O;
        goto again;

        /*
        * "Complex" conversion rules, implemented through recursion.
        */
    case 'c':	/* Date and time, using the locale's format. */
        LEGAL_ALT(ALT_E);
        if (!(bp = taosStrpTime(bp, "%x %X", tm)))
            return (0);
        break;

    case 'D':	/* The date as "%m/%d/%y". */
        LEGAL_ALT(0);
        if (!(bp = taosStrpTime(bp, "%m/%d/%y", tm)))
            return (0);
        break;

    case 'R':	/* The time as "%H:%M". */
        LEGAL_ALT(0);
        if (!(bp = taosStrpTime(bp, "%H:%M", tm)))
            return (0);
        break;

    case 'r':	/* The time in 12-hour clock representation. */
        LEGAL_ALT(0);
        if (!(bp = taosStrpTime(bp, "%I:%M:%S %p", tm)))
            return (0);
        break;

    case 'T':	/* The time as "%H:%M:%S". */
        LEGAL_ALT(0);
        if (!(bp = taosStrpTime(bp, "%H:%M:%S", tm)))
            return (0);
        break;

    case 'X':	/* The time, using the locale's format. */
        LEGAL_ALT(ALT_E);
        if (!(bp = taosStrpTime(bp, "%H:%M:%S", tm)))
            return (0);
        break;

    case 'x':	/* The date, using the locale's format. */
        LEGAL_ALT(ALT_E);
        if (!(bp = taosStrpTime(bp, "%m/%d/%y", tm)))
            return (0);
        break;

        /*
        * "Elementary" conversion rules.
        */
    case 'A':	/* The day of week, using the locale's form. */
    case 'a':
        LEGAL_ALT(0);
        for (i = 0; i < 7; i++) {
            /* Full name. */
            len = strlen(day[i]);
            if (strncmp(day[i], bp, len) == 0)
                break;

            /* Abbreviated name. */
            len = strlen(abday[i]);
            if (strncmp(abday[i], bp, len) == 0)
                break;
        }

        /* Nothing matched. */
        if (i == 7)
            return (0);

        tm->tm_wday = i;
        bp += len;
        break;

    case 'B':	/* The month, using the locale's form. */
    case 'b':
    case 'h':
        LEGAL_ALT(0);
        for (i = 0; i < 12; i++) {
            /* Full name. */
            len = strlen(mon[i]);
            if (strncmp(mon[i], bp, len) == 0)
                break;

            /* Abbreviated name. */
            len = strlen(abmon[i]);
            if (strncmp(abmon[i], bp, len) == 0)
                break;
        }

        /* Nothing matched. */
        if (i == 12)
            return (0);

        tm->tm_mon = i;
        bp += len;
        break;

    case 'C':	/* The century number. */
        LEGAL_ALT(ALT_E);
        if (!(conv_num(&bp, &i, 0, 99)))
            return (0);

        if (split_year) {
            tm->tm_year = (tm->tm_year % 100) + (i * 100);
        }
        else {
            tm->tm_year = i * 100;
            split_year = 1;
        }
        break;

    case 'd':	/* The day of month. */
    case 'e':
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
            return (0);
        break;

    case 'k':	/* The hour (24-hour clock representation). */
        LEGAL_ALT(0);
        /* FALLTHROUGH */
    case 'H':
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
            return (0);
        break;

    case 'l':	/* The hour (12-hour clock representation). */
        LEGAL_ALT(0);
        /* FALLTHROUGH */
    case 'I':
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
            return (0);
        if (tm->tm_hour == 12)
            tm->tm_hour = 0;
        break;

    case 'j':	/* The day of year. */
        LEGAL_ALT(0);
        if (!(conv_num(&bp, &i, 1, 366)))
            return (0);
        tm->tm_yday = i - 1;
        break;

    case 'M':	/* The minute. */
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
            return (0);
        break;

    case 'm':	/* The month. */
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &i, 1, 12)))
            return (0);
        tm->tm_mon = i - 1;
        break;

    case 'p':	/* The locale's equivalent of AM/PM. */
        LEGAL_ALT(0);
        /* AM? */
        if (strcmp(am_pm[0], bp) == 0) {
            if (tm->tm_hour > 11)
                return (0);

            bp += strlen(am_pm[0]);
            break;
        }
        /* PM? */
        else if (strcmp(am_pm[1], bp) == 0) {
            if (tm->tm_hour > 11)
                return (0);

            tm->tm_hour += 12;
            bp += strlen(am_pm[1]);
            break;
        }

        /* Nothing matched. */
        return (0);

    case 'S':	/* The seconds. */
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
            return (0);
        break;

    case 'U':	/* The week of year, beginning on sunday. */
    case 'W':	/* The week of year, beginning on monday. */
        LEGAL_ALT(ALT_O);
        /*
        * XXX This is bogus, as we can not assume any valid
        * information present in the tm structure at this
        * point to calculate a real value, so just check the
        * range for now.
        */
        if (!(conv_num(&bp, &i, 0, 53)))
            return (0);
        break;

    case 'w':	/* The day of week, beginning on sunday. */
        LEGAL_ALT(ALT_O);
        if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
            return (0);
        break;

    case 'Y':	/* The year. */
        LEGAL_ALT(ALT_E);
        if (!(conv_num(&bp, &i, 0, 9999)))
            return (0);

        tm->tm_year = i - TM_YEAR_BASE;
        break;

    case 'y':	/* The year within 100 years of the epoch. */
        LEGAL_ALT(ALT_E | ALT_O);
        if (!(conv_num(&bp, &i, 0, 99)))
            return (0);

        if (split_year) {
            tm->tm_year = ((tm->tm_year / 100) * 100) + i;
            break;
        }
        split_year = 1;
        if (i <= 68)
            tm->tm_year = i + 2000 - TM_YEAR_BASE;
        else
            tm->tm_year = i + 1900 - TM_YEAR_BASE;
        break;

        /*
        * Miscellaneous conversions.
        */
    case 'n':	/* Any kind of white-space. */
    case 't':
        LEGAL_ALT(0);
        while (isspace(*bp))
            bp++;
        break;


    default:	/* Unknown/unsupported conversion. */
        return (0);
    }


    }

    /* LINTED functional specification */
    return ((char *)bp);
#else
    return strptime(buf, fmt, tm);
#endif
}

FORCE_INLINE int32_t taosGetTimeOfDay(struct timeval *tv) {
#ifdef WINDOWS
  time_t t;
  t = taosGetTimestampSec();
  SYSTEMTIME st;
  GetLocalTime(&st);

  tv->tv_sec = (long)t;
  tv->tv_usec = st.wMilliseconds * 1000;

  return 0;
#else
  return gettimeofday(tv, NULL);
#endif
}

time_t taosTime(time_t *t) {
  return time(t);
}

time_t taosMktime(struct tm *timep) {
  return mktime(timep);
}

struct tm *taosLocalTime(const time_t *timep, struct tm *result) {
  if (result == NULL) {
    return localtime(timep);
  }
#ifdef WINDOWS
  localtime_s(result, timep);
#else
  localtime_r(timep, result);
#endif
  return result;
}

int32_t taosGetTimestampSec() { return (int32_t)time(NULL); }

int32_t taosClockGetTime(int clock_id, struct timespec *pTS) { return clock_gettime(clock_id, pTS); }