// Copyright (c) 2012 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

#include "butil/time/time.h"

#include <limits>

#include <ostream>

#include "butil/float_util.h"

#include "butil/lazy_instance.h"

#include "butil/logging.h"

namespace butil {

// TimeDelta ------------------------------------------------------------------

// static

TimeDelta TimeDelta::Max() {

  return TimeDelta(std::numeric_limits<int64_t>::max());

}

int TimeDelta::InDays() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);

}

int TimeDelta::InHours() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerHour);

}

int TimeDelta::InMinutes() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute);

}

double TimeDelta::InSecondsF() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond;

}

int64_t TimeDelta::InSeconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_ / Time::kMicrosecondsPerSecond;

}

double TimeDelta::InMillisecondsF() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMilliseconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_ / Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMillisecondsRoundedUp() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return (delta_ + Time::kMicrosecondsPerMillisecond - 1) /

      Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMicroseconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_;

}

// Time -----------------------------------------------------------------------

// static

Time Time::Max() {

  return Time(std::numeric_limits<int64_t>::max());

}

// static

Time Time::FromTimeT(time_t tt) {

  if (tt == 0)

    return Time();  // Preserve 0 so we can tell it doesn't exist.

  if (tt == std::numeric_limits<time_t>::max())

    return Max();

  return Time((tt * kMicrosecondsPerSecond) + kTimeTToMicrosecondsOffset);

}

time_t Time::ToTimeT() const {

  if (is_null())

    return 0;  // Preserve 0 so we can tell it doesn't exist.

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<time_t>::max();

  }

  if (std::numeric_limits<int64_t>::max() - kTimeTToMicrosecondsOffset <= us_) {

    DLOG(WARNING) << "Overflow when converting butil::Time with internal " <<

                     "value " << us_ << " to time_t.";

    return std::numeric_limits<time_t>::max();

  }

  return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;

}

// static

Time Time::FromDoubleT(double dt) {

  if (dt == 0 || IsNaN(dt))

    return Time();  // Preserve 0 so we can tell it doesn't exist.

  if (dt == std::numeric_limits<double>::infinity())

    return Max();

  return Time(static_cast<int64_t>((dt *

                                  static_cast<double>(kMicrosecondsPerSecond)) +

                                 kTimeTToMicrosecondsOffset));

}

double Time::ToDoubleT() const {

  if (is_null())

    return 0;  // Preserve 0 so we can tell it doesn't exist.

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /

          static_cast<double>(kMicrosecondsPerSecond));

}

#if defined(OS_POSIX)

// static

Time Time::FromTimeSpec(const timespec& ts) {

  return FromDoubleT(ts.tv_sec +

                     static_cast<double>(ts.tv_nsec) /

                         butil::Time::kNanosecondsPerSecond);

}

#endif

// static

Time Time::FromJsTime(double ms_since_epoch) {

  // The epoch is a valid time, so this constructor doesn't interpret

  // 0 as the null time.

  if (ms_since_epoch == std::numeric_limits<double>::infinity())

    return Max();

  return Time(static_cast<int64_t>(ms_since_epoch * kMicrosecondsPerMillisecond) +

              kTimeTToMicrosecondsOffset);

}

double Time::ToJsTime() const {

  if (is_null()) {

    // Preserve 0 so the invalid result doesn't depend on the platform.

    return 0;

  }

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /

          kMicrosecondsPerMillisecond);

}

int64_t Time::ToJavaTime() const {

  if (is_null()) {

    // Preserve 0 so the invalid result doesn't depend on the platform.

    return 0;

  }

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return ((us_ - kTimeTToMicrosecondsOffset) /

          kMicrosecondsPerMillisecond);

}

// static

Time Time::UnixEpoch() {

  Time time;

  time.us_ = kTimeTToMicrosecondsOffset;

  return time;

}

Time Time::LocalMidnight() const {

  Exploded exploded;

  LocalExplode(&exploded);

  exploded.hour = 0;

  exploded.minute = 0;

  exploded.second = 0;

  exploded.millisecond = 0;

  return FromLocalExploded(exploded);

}

// static

bool Time::FromStringInternal(const char* time_string,

                              bool is_local,

                              Time* parsed_time) {

  // TODO(zhujiashun): after removing nspr, this function

  // is left unimplemented.

  return false;

}

// Local helper class to hold the conversion from Time to TickTime at the

// time of the Unix epoch.

class UnixEpochSingleton {

 public:

  UnixEpochSingleton()

      : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}

  TimeTicks unix_epoch() const { return unix_epoch_; }

 private:

  const TimeTicks unix_epoch_;

  DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);

};

static LazyInstance<UnixEpochSingleton>::Leaky

    leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;

// Static

TimeTicks TimeTicks::UnixEpoch() {

  return leaky_unix_epoch_singleton_instance.Get().unix_epoch();

}

// Time::Exploded -------------------------------------------------------------

inline bool is_in_range(int value, int lo, int hi) {

  return lo <= value && value <= hi;

}

bool Time::Exploded::HasValidValues() const {

  return is_in_range(month, 1, 12) &&

         is_in_range(day_of_week, 0, 6) &&

         is_in_range(day_of_month, 1, 31) &&

         is_in_range(hour, 0, 23) &&

         is_in_range(minute, 0, 59) &&

         is_in_range(second, 0, 60) &&

         is_in_range(millisecond, 0, 999);

}

}  // namespace butil