// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software 
 * Foundation.  See file COPYING.
 * 
 */

#ifndef CEPH_UTIME_H
#define CEPH_UTIME_H

#include <math.h>
#include <sys/time.h>
#include <time.h>
#include <errno.h>

#if defined(WITH_SEASTAR)
#include <seastar/core/lowres_clock.hh>
#endif

#include "include/compat.h"
#include "include/types.h"
#include "include/timegm.h"
#include "common/strtol.h"
#include "common/ceph_time.h"
#include "common/safe_io.h"
#include "common/SubProcess.h"
#include "include/denc.h"


// --------
// utime_t

inline __u32 cap_to_u32_max(__u64 t) {
  return std::min(t, (__u64)std::numeric_limits<uint32_t>::max());
}
/* WARNING: If add member in utime_t, please make sure the encode/decode function
 * work well. For little-endian machine, we should make sure there is no padding
 * in 32-bit machine and 64-bit machine.
 * You should also modify the padding_check function.
 */
class utime_t {
public:
  struct {
    __u32 tv_sec, tv_nsec;
  } tv;

 public:
  bool is_zero() const {
    return (tv.tv_sec == 0) && (tv.tv_nsec == 0);
  }

  void normalize() {
    if (tv.tv_nsec > 1000000000ul) {
      tv.tv_sec = cap_to_u32_max(tv.tv_sec + tv.tv_nsec / (1000000000ul));
      tv.tv_nsec %= 1000000000ul;
    }
  }

  // cons
  utime_t() { tv.tv_sec = 0; tv.tv_nsec = 0; }
  utime_t(time_t s, int n) { tv.tv_sec = s; tv.tv_nsec = n; normalize(); }
  utime_t(const struct ceph_timespec &v) {
    decode_timeval(&v);
  }
  utime_t(const struct timespec v)
  {
    // NOTE: this is used by ceph_clock_now() so should be kept
    // as thin as possible.
    tv.tv_sec = v.tv_sec;
    tv.tv_nsec = v.tv_nsec;
  }
  // conversion from ceph::real_time/coarse_real_time
  template <typename Clock, typename std::enable_if_t<
            ceph::converts_to_timespec_v<Clock>>* = nullptr>
  explicit utime_t(const std::chrono::time_point<Clock>& t)
    : utime_t(Clock::to_timespec(t)) {} // forward to timespec ctor

  template<class Rep, class Period>
  explicit utime_t(const std::chrono::duration<Rep, Period>& dur) {
    using common_t = std::common_type_t<Rep, int>;
    tv.tv_sec = std::max<common_t>(std::chrono::duration_cast<std::chrono::seconds>(dur).count(), 0);
    tv.tv_nsec = std::max<common_t>((std::chrono::duration_cast<std::chrono::nanoseconds>(dur) %
				     std::chrono::seconds(1)).count(), 0);
  }
#if defined(WITH_SEASTAR)
  explicit utime_t(const seastar::lowres_system_clock::time_point& t) {
    tv.tv_sec = std::chrono::duration_cast<std::chrono::seconds>(
        t.time_since_epoch()).count();
    tv.tv_nsec = std::chrono::duration_cast<std::chrono::nanoseconds>(
        t.time_since_epoch() % std::chrono::seconds(1)).count();
  }
  explicit operator seastar::lowres_system_clock::time_point() const noexcept {
    using clock_t = seastar::lowres_system_clock;
    return clock_t::time_point{std::chrono::duration_cast<clock_t::duration>(
      std::chrono::seconds{tv.tv_sec} + std::chrono::nanoseconds{tv.tv_nsec})};
  }
#endif

  utime_t(const struct timeval &v) {
    set_from_timeval(&v);
  }
  utime_t(const struct timeval *v) {
    set_from_timeval(v);
  }
  void to_timespec(struct timespec *ts) const {
    ts->tv_sec = tv.tv_sec;
    ts->tv_nsec = tv.tv_nsec;
  }
  void set_from_double(double d) {
    tv.tv_sec = (__u32)trunc(d);
    tv.tv_nsec = (__u32)((d - (double)tv.tv_sec) * 1000000000.0);
  }

  ceph::real_time to_real_time() const {
    ceph_timespec ts;
    encode_timeval(&ts);
    return ceph::real_clock::from_ceph_timespec(ts);
  }

  // accessors
  time_t        sec()  const { return tv.tv_sec; }
  long          usec() const { return tv.tv_nsec/1000; }
  int           nsec() const { return tv.tv_nsec; }

  // ref accessors/modifiers
  __u32&         sec_ref()  { return tv.tv_sec; }
  __u32&         nsec_ref() { return tv.tv_nsec; }

  uint64_t to_nsec() const {
    return (uint64_t)tv.tv_nsec + (uint64_t)tv.tv_sec * 1000000000ull;
  }
  uint64_t to_msec() const {
    return (uint64_t)tv.tv_nsec / 1000000ull + (uint64_t)tv.tv_sec * 1000ull;
  }

  void copy_to_timeval(struct timeval *v) const {
    v->tv_sec = tv.tv_sec;
    v->tv_usec = tv.tv_nsec/1000;
  }
  void set_from_timeval(const struct timeval *v) {
    tv.tv_sec = v->tv_sec;
    tv.tv_nsec = v->tv_usec*1000;
  }
  void padding_check() {
    static_assert(
      sizeof(utime_t) ==
        sizeof(tv.tv_sec) +
        sizeof(tv.tv_nsec)
      ,
      "utime_t have padding");
  }
  void encode(ceph::buffer::list &bl) const {
#if defined(CEPH_LITTLE_ENDIAN)
    bl.append((char *)(this), sizeof(__u32) + sizeof(__u32));
#else
    using ceph::encode;
    encode(tv.tv_sec, bl);
    encode(tv.tv_nsec, bl);
#endif
  }
  void decode(ceph::buffer::list::const_iterator &p) {
#if defined(CEPH_LITTLE_ENDIAN)
    p.copy(sizeof(__u32) + sizeof(__u32), (char *)(this));
#else
    using ceph::decode;
    decode(tv.tv_sec, p);
    decode(tv.tv_nsec, p);
#endif
  }

  DENC(utime_t, v, p) {
    denc(v.tv.tv_sec, p);
    denc(v.tv.tv_nsec, p);
  }

  void dump(ceph::Formatter *f) const;
  static void generate_test_instances(std::list<utime_t*>& o);
  
  void encode_timeval(struct ceph_timespec *t) const {
    t->tv_sec = tv.tv_sec;
    t->tv_nsec = tv.tv_nsec;
  }
  void decode_timeval(const struct ceph_timespec *t) {
    tv.tv_sec = t->tv_sec;
    tv.tv_nsec = t->tv_nsec;
  }

  utime_t round_to_minute() {
    struct tm bdt;
    time_t tt = sec();
    localtime_r(&tt, &bdt);
    bdt.tm_sec = 0;
    tt = mktime(&bdt);
    return utime_t(tt, 0);
  }

  utime_t round_to_hour() {
    struct tm bdt;
    time_t tt = sec();
    localtime_r(&tt, &bdt);
    bdt.tm_sec = 0;
    bdt.tm_min = 0;
    tt = mktime(&bdt);
    return utime_t(tt, 0);
  }

  utime_t round_to_day() {
    struct tm bdt;
    time_t tt = sec();
    localtime_r(&tt, &bdt);
    bdt.tm_sec = 0;
    bdt.tm_min = 0;
    bdt.tm_hour = 0;
    tt = mktime(&bdt);
    return utime_t(tt, 0);
  }

  // cast to double
  operator double() const {
    return (double)sec() + ((double)nsec() / 1000000000.0L);
  }
  operator ceph_timespec() const {
    ceph_timespec ts;
    ts.tv_sec = sec();
    ts.tv_nsec = nsec();
    return ts;
  }

  void sleep() const {
    struct timespec ts;
    to_timespec(&ts);
    nanosleep(&ts, NULL);
  }

  // output
  std::ostream& gmtime(std::ostream& out, bool legacy_form=false) const {
    out.setf(std::ios::right);
    char oldfill = out.fill();
    out.fill('0');
    if (sec() < ((time_t)(60*60*24*365*10))) {
      // raw seconds.  this looks like a relative time.
      out << (long)sec() << "." << std::setw(6) << usec();
    } else {
      // this looks like an absolute time.
      //  conform to http://en.wikipedia.org/wiki/ISO_8601
      struct tm bdt;
      time_t tt = sec();
      gmtime_r(&tt, &bdt);
      out << std::setw(4) << (bdt.tm_year+1900)  // 2007 -> '07'
	  << '-' << std::setw(2) << (bdt.tm_mon+1)
	  << '-' << std::setw(2) << bdt.tm_mday;
      if (legacy_form) {
	out << ' ';
      } else {
	out << 'T';
      }
      out << std::setw(2) << bdt.tm_hour
	  << ':' << std::setw(2) << bdt.tm_min
	  << ':' << std::setw(2) << bdt.tm_sec;
      out << "." << std::setw(6) << usec();
      out << "Z";
    }
    out.fill(oldfill);
    out.unsetf(std::ios::right);
    return out;
  }

  // output
  std::ostream& gmtime_nsec(std::ostream& out) const {
    out.setf(std::ios::right);
    char oldfill = out.fill();
    out.fill('0');
    if (sec() < ((time_t)(60*60*24*365*10))) {
      // raw seconds.  this looks like a relative time.
      out << (long)sec() << "." << std::setw(6) << usec();
    } else {
      // this looks like an absolute time.
      //  conform to http://en.wikipedia.org/wiki/ISO_8601
      struct tm bdt;
      time_t tt = sec();
      gmtime_r(&tt, &bdt);
      out << std::setw(4) << (bdt.tm_year+1900)  // 2007 -> '07'
	  << '-' << std::setw(2) << (bdt.tm_mon+1)
	  << '-' << std::setw(2) << bdt.tm_mday
	  << 'T'
	  << std::setw(2) << bdt.tm_hour
	  << ':' << std::setw(2) << bdt.tm_min
	  << ':' << std::setw(2) << bdt.tm_sec;
      out << "." << std::setw(9) << nsec();
      out << "Z";
    }
    out.fill(oldfill);
    out.unsetf(std::ios::right);
    return out;
  }

  // output
  std::ostream& asctime(std::ostream& out) const {
    out.setf(std::ios::right);
    char oldfill = out.fill();
    out.fill('0');
    if (sec() < ((time_t)(60*60*24*365*10))) {
      // raw seconds.  this looks like a relative time.
      out << (long)sec() << "." << std::setw(6) << usec();
    } else {
      // this looks like an absolute time.
      struct tm bdt;
      time_t tt = sec();
      gmtime_r(&tt, &bdt);

      char buf[128];
      asctime_r(&bdt, buf);
      int len = strlen(buf);
      if (buf[len - 1] == '\n')
        buf[len - 1] = '\0';
      out << buf;
    }
    out.fill(oldfill);
    out.unsetf(std::ios::right);
    return out;
  }

  std::ostream& localtime(std::ostream& out, bool legacy_form=false) const {
    out.setf(std::ios::right);
    char oldfill = out.fill();
    out.fill('0');
    if (sec() < ((time_t)(60*60*24*365*10))) {
      // raw seconds.  this looks like a relative time.
      out << (long)sec() << "." << std::setw(6) << usec();
    } else {
      // this looks like an absolute time.
      //  conform to http://en.wikipedia.org/wiki/ISO_8601
      struct tm bdt;
      time_t tt = sec();
      localtime_r(&tt, &bdt);
      out << std::setw(4) << (bdt.tm_year+1900)  // 2007 -> '07'
	  << '-' << std::setw(2) << (bdt.tm_mon+1)
	  << '-' << std::setw(2) << bdt.tm_mday;
      if (legacy_form) {
	out << ' ';
      } else {
	out << 'T';
      }
      out << std::setw(2) << bdt.tm_hour
	  << ':' << std::setw(2) << bdt.tm_min
	  << ':' << std::setw(2) << bdt.tm_sec;
      out << "." << std::setw(6) << usec();
      if (!legacy_form) {
	char buf[32] = { 0 };
	strftime(buf, sizeof(buf), "%z", &bdt);
	out << buf;
      }
    }
    out.fill(oldfill);
    out.unsetf(std::ios::right);
    return out;
  }

  static int invoke_date(const std::string& date_str, utime_t *result) {
     char buf[256];

     SubProcess bin_date("/bin/date", SubProcess::CLOSE, SubProcess::PIPE,
			 SubProcess::KEEP);
     bin_date.add_cmd_args("-d", date_str.c_str(), "+%s %N", NULL);

     int r = bin_date.spawn();
     if (r < 0) return r;

     ssize_t n = safe_read(bin_date.get_stdout(), buf, sizeof(buf));

     r = bin_date.join();
     if (r || n <= 0) return -EINVAL;

     uint64_t epoch, nsec;
     std::istringstream iss(buf);

     iss >> epoch;
     iss >> nsec;

     *result = utime_t(epoch, nsec);

     return 0;
  }


  static int parse_date(const std::string& date, uint64_t *epoch, uint64_t *nsec,
                        std::string *out_date=nullptr,
			std::string *out_time=nullptr) {
    struct tm tm;
    memset(&tm, 0, sizeof(tm));

    if (nsec)
      *nsec = 0;

    const char *p = strptime(date.c_str(), "%Y-%m-%d", &tm);
    if (p) {
      if (*p == ' ' || *p == 'T') {
	p++;
	// strptime doesn't understand fractional/decimal seconds, and
	// it also only takes format chars or literals, so we have to
	// get creative.
	char fmt[32] = {0};
	strncpy(fmt, p, sizeof(fmt) - 1);
	fmt[0] = '%';
	fmt[1] = 'H';
	fmt[2] = ':';
	fmt[3] = '%';
	fmt[4] = 'M';
	fmt[6] = '%';
	fmt[7] = 'S';
	const char *subsec = 0;
	char *q = fmt + 8;
	if (*q == '.') {
	  ++q;
	  subsec = p + 9;
	  q = fmt + 9;
	  while (*q && isdigit(*q)) {
	    ++q;
	  }
	}
	// look for tz...
	if (*q == '-' || *q == '+') {
	  *q = '%';
	  *(q+1) = 'z';
	  *(q+2) = 0;
	}
	p = strptime(p, fmt, &tm);
	if (!p) {
	  return -EINVAL;
	}
        if (nsec && subsec) {
          unsigned i;
          char buf[10]; /* 9 digit + null termination */
          for (i = 0; (i < sizeof(buf) - 1) && isdigit(*subsec); ++i, ++subsec) {
            buf[i] = *subsec;
          }
          for (; i < sizeof(buf) - 1; ++i) {
            buf[i] = '0';
          }
          buf[i] = '\0';
	  std::string err;
          *nsec = (uint64_t)strict_strtol(buf, 10, &err);
          if (!err.empty()) {
            return -EINVAL;
          }
        }
      }
    } else {
      int sec, usec;
      int r = sscanf(date.c_str(), "%d.%d", &sec, &usec);
      if (r != 2) {
        return -EINVAL;
      }

      time_t tt = sec;
      gmtime_r(&tt, &tm);

      if (nsec) {
        *nsec = (uint64_t)usec * 1000;
      }
    }

    #ifndef _WIN32
    // apply the tm_gmtoff manually below, since none of mktime,
    // gmtime, and localtime seem to do it.  zero it out here just in
    // case some other libc *does* apply it.  :(
    auto gmtoff = tm.tm_gmtoff;
    tm.tm_gmtoff = 0;
    #else
    auto gmtoff = _timezone;
    #endif /* _WIN32 */

    time_t t = internal_timegm(&tm);
    if (epoch)
      *epoch = (uint64_t)t;

    *epoch -= gmtoff;

    if (out_date) {
      char buf[32];
      strftime(buf, sizeof(buf), "%Y-%m-%d", &tm);
      *out_date = buf;
    }
    if (out_time) {
      char buf[32];
      strftime(buf, sizeof(buf), "%H:%M:%S", &tm);
      *out_time = buf;
    }

    return 0;
  }

  bool parse(const std::string& s) {
    uint64_t epoch, nsec;
    int r = parse_date(s, &epoch, &nsec);
    if (r < 0) {
      return false;
    }
    *this = utime_t(epoch, nsec);
    return true;
  }
};
WRITE_CLASS_ENCODER(utime_t)
WRITE_CLASS_DENC(utime_t)

// arithmetic operators
inline utime_t operator+(const utime_t& l, const utime_t& r) {
  __u64 sec = (__u64)l.sec() + r.sec();
  return utime_t(cap_to_u32_max(sec), l.nsec() + r.nsec());
}
inline utime_t& operator+=(utime_t& l, const utime_t& r) {
  l.sec_ref() = cap_to_u32_max((__u64)l.sec() + r.sec());
  l.nsec_ref() += r.nsec();
  l.normalize();
  return l;
}
inline utime_t& operator+=(utime_t& l, double f) {
  double fs = trunc(f);
  double ns = (f - fs) * 1000000000.0;
  l.sec_ref() = cap_to_u32_max(l.sec() + (__u64)fs);
  l.nsec_ref() += (long)ns;
  l.normalize();
  return l;
}

inline utime_t operator-(const utime_t& l, const utime_t& r) {
  return utime_t( l.sec() - r.sec() - (l.nsec()<r.nsec() ? 1:0),
                  l.nsec() - r.nsec() + (l.nsec()<r.nsec() ? 1000000000:0) );
}
inline utime_t& operator-=(utime_t& l, const utime_t& r) {
  l.sec_ref() -= r.sec();
  if (l.nsec() >= r.nsec())
    l.nsec_ref() -= r.nsec();
  else {
    l.nsec_ref() += 1000000000L - r.nsec();
    l.sec_ref()--;
  }
  return l;
}
inline utime_t& operator-=(utime_t& l, double f) {
  double fs = trunc(f);
  double ns = (f - fs) * 1000000000.0;
  l.sec_ref() -= (long)fs;
  long nsl = (long)ns;
  if (nsl) {
    l.sec_ref()--;
    l.nsec_ref() = 1000000000L + l.nsec_ref() - nsl;
  }
  l.normalize();
  return l;
}


// comparators
inline bool operator>(const utime_t& a, const utime_t& b)
{
  return (a.sec() > b.sec()) || (a.sec() == b.sec() && a.nsec() > b.nsec());
}
inline bool operator<=(const utime_t& a, const utime_t& b)
{
  return !(operator>(a, b));
}
inline bool operator<(const utime_t& a, const utime_t& b)
{
  return (a.sec() < b.sec()) || (a.sec() == b.sec() && a.nsec() < b.nsec());
}
inline bool operator>=(const utime_t& a, const utime_t& b)
{
  return !(operator<(a, b));
}

inline bool operator==(const utime_t& a, const utime_t& b)
{
  return a.sec() == b.sec() && a.nsec() == b.nsec();
}
inline bool operator!=(const utime_t& a, const utime_t& b)
{
  return a.sec() != b.sec() || a.nsec() != b.nsec();
}


// output

// ostream
inline std::ostream& operator<<(std::ostream& out, const utime_t& t)
{
  return t.localtime(out);
}

inline std::string utimespan_str(const utime_t& age) {
  auto age_ts = ceph::timespan(age.nsec()) + std::chrono::seconds(age.sec());
  return ceph::timespan_str(age_ts);
}

#endif