/*
 * Copyright (C) 2016 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include <optional>
#include <wtf/FastMalloc.h>
#include <wtf/MathExtras.h>

namespace WTF {

class ApproximateTime;
class ContinuousApproximateTime;
class ContinuousTime;
class MonotonicTime;
class PrintStream;
class TextStream;
class TimeWithDynamicClockType;
class WallTime;

class Seconds final {
    WTF_MAKE_FAST_ALLOCATED;
public:
    constexpr Seconds() { }
    
    explicit constexpr Seconds(double value)
        : m_value(value)
    {
    }
    
    constexpr double value() const { return m_value; }
    
    constexpr double minutes() const { return m_value / 60; }
    constexpr double seconds() const { return m_value; }
    constexpr double milliseconds() const { return seconds() * 1000; }
    constexpr double microseconds() const { return milliseconds() * 1000; }
    constexpr double nanoseconds() const { return microseconds() * 1000; }

    // Keep in mind that Seconds is held in double. If the value is not in range of 53bit integer, the result may not be precise.
    template<typename T> T minutesAs() const { static_assert(std::is_integral<T>::value); return clampToAccepting64<T>(minutes()); }
    template<typename T> T secondsAs() const { static_assert(std::is_integral<T>::value); return clampToAccepting64<T>(seconds()); }
    template<typename T> T millisecondsAs() const { static_assert(std::is_integral<T>::value); return clampToAccepting64<T>(milliseconds()); }
    template<typename T> T microsecondsAs() const { static_assert(std::is_integral<T>::value); return clampToAccepting64<T>(microseconds()); }
    template<typename T> T nanosecondsAs() const { static_assert(std::is_integral<T>::value); return clampToAccepting64<T>(nanoseconds()); }
    
    static constexpr Seconds fromMinutes(double minutes)
    {
        return Seconds(minutes * 60);
    }

    static constexpr Seconds fromHours(double hours)
    {
        return Seconds(hours * 3600);
    }

    static constexpr Seconds fromMilliseconds(double milliseconds)
    {
        return Seconds(milliseconds / 1000);
    }
    
    static constexpr Seconds fromMicroseconds(double microseconds)
    {
        return fromMilliseconds(microseconds / 1000);
    }
    
    static constexpr Seconds fromNanoseconds(double nanoseconds)
    {
        return fromMicroseconds(nanoseconds / 1000);
    }
    
    static constexpr Seconds infinity()
    {
        return Seconds(std::numeric_limits<double>::infinity());
    }

    static constexpr Seconds nan()
    {
        return Seconds(std::numeric_limits<double>::quiet_NaN());
    }

    static constexpr Seconds highTimePrecision()
    {
        return Seconds::fromMicroseconds(20);
    }
    
    bool isNaN() const { return std::isnan(m_value); }
    bool isInfinity() const { return std::isinf(m_value); }
    bool isFinite() const { return std::isfinite(m_value); }

    explicit constexpr operator bool() const { return !!m_value; }
    
    constexpr Seconds operator+(Seconds other) const
    {
        return Seconds(value() + other.value());
    }
    
    constexpr Seconds operator-(Seconds other) const
    {
        return Seconds(value() - other.value());
    }
    
    constexpr Seconds operator-() const
    {
        return Seconds(-value());
    }
    
    // It makes sense to consider scaling a duration, like, "I want to wait 5 times as long as
    // last time!".
    constexpr Seconds operator*(double scalar) const
    {
        return Seconds(value() * scalar);
    }
    
    constexpr Seconds operator/(double scalar) const
    {
        return Seconds(value() / scalar);
    }
    
    // It's reasonable to think about ratios between Seconds.
    constexpr double operator/(Seconds other) const
    {
        return value() / other.value();
    }
    
    Seconds operator%(double scalar) const
    {
        return Seconds(fmod(value(), scalar));
    }
    
    // This solves for r, where:
    //
    //     floor(this / other) + r / other = this / other
    //
    // Therefore, if this is Seconds then r is Seconds.
    Seconds operator%(Seconds other) const
    {
        return Seconds(fmod(value(), other.value()));
    }
    
    Seconds& operator+=(Seconds other)
    {
        return *this = *this + other;
    }
    
    Seconds& operator-=(Seconds other)
    {
        return *this = *this - other;
    }
    
    Seconds& operator*=(double scalar)
    {
        return *this = *this * scalar;
    }
    
    Seconds& operator/=(double scalar)
    {
        return *this = *this / scalar;
    }
    
    Seconds& operator%=(double scalar)
    {
        return *this = *this % scalar;
    }
    
    Seconds& operator%=(Seconds other)
    {
        return *this = *this % other;
    }
    
    WTF_EXPORT_PRIVATE WallTime operator+(WallTime) const;
    WTF_EXPORT_PRIVATE MonotonicTime operator+(MonotonicTime) const;
    WTF_EXPORT_PRIVATE ApproximateTime operator+(ApproximateTime) const;
    WTF_EXPORT_PRIVATE ContinuousTime operator+(ContinuousTime) const;
    WTF_EXPORT_PRIVATE ContinuousApproximateTime operator+(ContinuousApproximateTime) const;
    WTF_EXPORT_PRIVATE TimeWithDynamicClockType operator+(const TimeWithDynamicClockType&) const;
    
    WTF_EXPORT_PRIVATE WallTime operator-(WallTime) const;
    WTF_EXPORT_PRIVATE MonotonicTime operator-(MonotonicTime) const;
    WTF_EXPORT_PRIVATE ApproximateTime operator-(ApproximateTime) const;
    WTF_EXPORT_PRIVATE ContinuousTime operator-(ContinuousTime) const;
    WTF_EXPORT_PRIVATE ContinuousApproximateTime operator-(ContinuousApproximateTime) const;
    WTF_EXPORT_PRIVATE TimeWithDynamicClockType operator-(const TimeWithDynamicClockType&) const;
    
    friend constexpr bool operator==(Seconds, Seconds) = default;
    
    constexpr bool operator<(Seconds other) const
    {
        return m_value < other.m_value;
    }
    
    constexpr bool operator>(Seconds other) const
    {
        return m_value > other.m_value;
    }
    
    constexpr bool operator<=(Seconds other) const
    {
        return m_value <= other.m_value;
    }
    
    constexpr bool operator>=(Seconds other) const
    {
        return m_value >= other.m_value;
    }
    
    WTF_EXPORT_PRIVATE void dump(PrintStream&) const;
    
    Seconds isolatedCopy() const
    {
        return *this;
    }

    constexpr Seconds reduceTimeResolution(Seconds resolution)
    {
        double reduced = std::floor(seconds() / resolution.seconds()) * resolution.seconds();
        return Seconds(reduced);
    }

    struct MarkableTraits;

private:
    double m_value { 0 };
};

WTF_EXPORT_PRIVATE void sleep(Seconds);

struct Seconds::MarkableTraits {
    static bool isEmptyValue(Seconds seconds)
    {
        return seconds.isNaN();
    }

    static constexpr Seconds emptyValue()
    {
        return Seconds::nan();
    }
};

inline namespace seconds_literals {

constexpr Seconds operator""_min(long double minutes)
{
    return Seconds::fromMinutes(minutes);
}

constexpr Seconds operator""_h(long double hours)
{
    return Seconds::fromHours(hours);
}

constexpr Seconds operator""_s(long double seconds)
{
    return Seconds(seconds);
}

constexpr Seconds operator""_ms(long double milliseconds)
{
    return Seconds::fromMilliseconds(milliseconds);
}

constexpr Seconds operator""_us(long double microseconds)
{
    return Seconds::fromMicroseconds(microseconds);
}

constexpr Seconds operator""_ns(long double nanoseconds)
{
    return Seconds::fromNanoseconds(nanoseconds);
}

constexpr Seconds operator""_min(unsigned long long minutes)
{
    return Seconds::fromMinutes(minutes);
}

constexpr Seconds operator""_h(unsigned long long hours)
{
    return Seconds::fromHours(hours);
}

constexpr Seconds operator""_s(unsigned long long seconds)
{
    return Seconds(seconds);
}

constexpr Seconds operator""_ms(unsigned long long milliseconds)
{
    return Seconds::fromMilliseconds(milliseconds);
}

constexpr Seconds operator""_us(unsigned long long microseconds)
{
    return Seconds::fromMicroseconds(microseconds);
}

constexpr Seconds operator""_ns(unsigned long long nanoseconds)
{
    return Seconds::fromNanoseconds(nanoseconds);
}

} // inline seconds_literals

inline Seconds operator*(double scalar, Seconds seconds)
{
    return Seconds(scalar * seconds.value());
}

inline Seconds operator/(double scalar, Seconds seconds)
{
    return Seconds(scalar / seconds.value());
}

WTF_EXPORT_PRIVATE TextStream& operator<<(TextStream&, Seconds);

} // namespace WTF

using WTF::sleep;

using namespace WTF::seconds_literals;
using WTF::Seconds;