/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 */
#include <sys/time.h>
#include <rtthread.h>

/* days per month -- nonleap! */
const short __spm[13] =
{
    0,
    (31),
    (31 + 28),
    (31 + 28 + 31),
    (31 + 28 + 31 + 30),
    (31 + 28 + 31 + 30 + 31),
    (31 + 28 + 31 + 30 + 31 + 30),
    (31 + 28 + 31 + 30 + 31 + 30 + 31),
    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31),
    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30),
    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31),
    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30),
    (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31),
};

/* seconds per day */
#define SPD 24*60*60

#ifdef RT_USING_DEVICE
int gettimeofday(struct timeval *tp, void *ignore)
{
    time_t time;
    rt_device_t device;

    device = rt_device_find("rtc");
    if (device != RT_NULL)
    {
        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
        if (tp != RT_NULL)
        {
            tp->tv_sec = time;
            tp->tv_usec = 0;
        }

        return time;
    }

    return 0;
}
#endif

/**
 * Returns the current time.
 *
 * @param time_t * t the timestamp pointer, if not used, keep NULL.
 *
 * @return time_t return timestamp current.
 *
 */
#pragma module_name = "?time"
#if _DLIB_TIME_ALLOW_64
__time64_t __time64(__time64_t *t)
#else
__time32_t __time32(__time32_t *t)
#endif
{
  time_t time_now = 0;
  
#ifdef RT_USING_RTC
  static rt_device_t device = RT_NULL;
  
  /* optimization: find rtc device only first. */
  if (device == RT_NULL)
  {
    device = rt_device_find("rtc");
  }
  
  /* read timestamp from RTC device. */
  if (device != RT_NULL)
  {
    if (rt_device_open(device, 0) == RT_EOK)
    {
      rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time_now);
      rt_device_close(device);
    }
  }
#endif /* RT_USING_RTC */
  
  /* if t is not NULL, write timestamp to *t */
  if (t != RT_NULL)
  {
    *t = time_now;
  }
  
  return time_now;
}

static int __isleap(int year)
{
    /* every fourth year is a leap year except for century years that are
     * not divisible by 400. */
    /*  return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); */
    return (!(year % 4) && ((year % 100) || !(year % 400)));
}

/**
 * This function will convert Time (Restartable)
 *
 * @param timep the timestamp
 * @param the structure to stores information
 *
 * @return the structure to stores information
 *
 */
struct tm *gmtime_r(const time_t *timep, struct tm *r)
{
    time_t i;
    register time_t work = *timep % (SPD);
    r->tm_sec = work % 60;
    work /= 60;
    r->tm_min = work % 60;
    r->tm_hour = work / 60;
    work = *timep / (SPD);
    r->tm_wday = (4 + work) % 7;
    for (i = 1970;; ++i)
    {
        register time_t k = __isleap(i) ? 366 : 365;
        if (work >= k)
            work -= k;
        else
            break;
    }
    r->tm_year = i - 1900;
    r->tm_yday = work;

    r->tm_mday = 1;
    if (__isleap(i) && (work > 58))
    {
        if (work == 59)
            r->tm_mday = 2; /* 29.2. */
        work -= 1;
    }

    for (i = 11; i && (__spm[i] > work); --i)
        ;
    r->tm_mon = i;
    r->tm_mday += work - __spm[i];
    return r;
}

RT_WEAK clock_t clock(void)
{
    return rt_tick_get();
}