/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#include <tools/datetime.hxx>

#include <tools/duration.hxx>

#include <rtl/math.hxx>

#include <sal/log.hxx>

#include <compare>

#include <systemdatetime.hxx>

DateTime::DateTime(DateTimeInitSystem)

    : Date( Date::EMPTY )

    , Time( Time::EMPTY )

{

    sal_Int32 nD = 0;

    sal_Int64 nT = 0;

    if ( GetSystemDateTime( &nD, &nT ) )

    {

        Date::operator=( Date( nD ) );

        SetTime( nT );

    }

    else

        Date::operator=( Date( 1, 1, 1900 ) ); // Time::nTime is already 0

}

DateTime::DateTime( const css::util::DateTime& rDateTime )

  : Date( rDateTime.Day, rDateTime.Month, rDateTime.Year ),

    Time( rDateTime.Hours, rDateTime.Minutes, rDateTime.Seconds, rDateTime.NanoSeconds )

{

}

DateTime& DateTime::operator =( const css::util::DateTime& rUDateTime )

{

    Date::operator=( Date( rUDateTime.Day, rUDateTime.Month, rUDateTime.Year));

    Time::operator=( Time( rUDateTime));

    return *this;

}

bool DateTime::IsBetween( const DateTime& rFrom, const DateTime& rTo ) const

{

    return (*this >= rFrom) && (*this <= rTo);

}

sal_Int64 DateTime::GetSecFromDateTime( const Date& rDate ) const

{

    if (*this < rDate)

        return 0;

    else

    {

        sal_Int64 nSec = Date( *this ) - rDate;

        nSec *= 24UL*60*60;

        sal_Int64 nHour = GetHour();

        sal_Int64 nMin  = GetMin();

        nSec += (nHour*3600)+(nMin*60)+GetSec();

        return nSec;

    }

}

void DateTime::NormalizeTimeRemainderAndApply( tools::Time& rTime )

{

    sal_uInt16 nHours = rTime.GetHour();

    if ( rTime.GetTime() > 0 )

    {

        if (nHours >= 24)

        {

            AddDays( nHours / 24 );

            nHours %= 24;

            rTime.SetHour( nHours );

        }

    }

    else if ( rTime.GetTime() != 0 )

    {

        if (nHours >= 24)

        {

            AddDays( -static_cast<sal_Int32>(nHours) / 24 );

            nHours %= 24;

            rTime.SetHour( nHours );

        }

        Date::operator--();

        rTime = Time( 24, 0, 0 ) + rTime;

    }

    tools::Time::operator=( rTime );

}

DateTime& DateTime::operator +=( const tools::Time& rTime )

{

    tools::Time aTime = *this;

    aTime += rTime;

    NormalizeTimeRemainderAndApply(aTime);

    return *this;

}

DateTime& DateTime::operator -=( const tools::Time& rTime )

{

    tools::Time aTime = *this;

    aTime -= rTime;

    NormalizeTimeRemainderAndApply(aTime);

    return *this;

}

DateTime& DateTime::operator +=( const tools::Duration& rDuration )

{

    AddDays(rDuration.GetDays());

    operator+=(rDuration.GetTime());

    return *this;

}

DateTime operator +( const DateTime& rDateTime, sal_Int32 nDays )

{

    DateTime aDateTime( rDateTime );

    aDateTime.AddDays( nDays );

    return aDateTime;

}

DateTime operator -( const DateTime& rDateTime, sal_Int32 nDays )

{

    DateTime aDateTime( rDateTime );

    aDateTime.AddDays( -nDays );

    return aDateTime;

}

DateTime operator +( const DateTime& rDateTime, const tools::Time& rTime )

{

    DateTime aDateTime( rDateTime );

    aDateTime += rTime;

    return aDateTime;

}

DateTime operator -( const DateTime& rDateTime, const tools::Time& rTime )

{

    DateTime aDateTime( rDateTime );

    aDateTime -= rTime;

    return aDateTime;

}

DateTime operator +( const DateTime& rDateTime, const tools::Duration& rDuration )

{

    DateTime aDateTime(rDateTime);

    aDateTime.AddDays( rDuration.GetDays());

    aDateTime += rDuration.GetTime();

    return aDateTime;

}

void DateTime::AddTime( double fTimeInDays )

{

    // Use Duration to diminish floating point accuracy errors.

    tools::Duration aDuration(fTimeInDays);

    operator+=(aDuration);

}

DateTime operator +( const DateTime& rDateTime, double fTimeInDays )

{

    DateTime aDateTime( rDateTime );

    aDateTime.AddTime( fTimeInDays );

    return aDateTime;

}

tools::Duration operator -( const DateTime& rDateTime1, const DateTime& rDateTime2 )

{

    return tools::Duration( rDateTime2, rDateTime1);

}

// static

double DateTime::Sub( const DateTime& rDateTime1, const DateTime& rDateTime2 )

{

    if (static_cast<const tools::Time&>(rDateTime1) != static_cast<const tools::Time&>(rDateTime2))

    {

        // Use Duration to diminish floating point accuracy errors.

        const tools::Duration aDuration( rDateTime2, rDateTime1);

        return aDuration.GetInDays();

    }

    return static_cast<const Date&>(rDateTime1) - static_cast<const Date&>(rDateTime2);

}

void DateTime::GetWin32FileDateTime( sal_uInt32 & rLower, sal_uInt32 & rUpper ) const

{

    const sal_Int64 a100nPerSecond = SAL_CONST_INT64( 10000000 );

    const sal_Int64 a100nPerDay = a100nPerSecond * sal_Int64( 60 * 60 * 24 );

    // FILETIME is indirectly documented as uint64, see

    // https://msdn.microsoft.com/en-us/library/windows/desktop/ms724284.aspx

    // mentioning the ULARGE_INTEGER structure.

    // https://msdn.microsoft.com/en-us/library/windows/desktop/ms724280.aspx

    // mentions that if FILETIME is not less than 0x8000000000000000 then the

    // FileTimeToSystemTime function fails, which is another indicator.

    // Unless there's evidence that FILETIME can represent a signed offset from

    // 1601-01-01 truncate at 0. (reading part below in

    // CreateFromWin32FileDateTime() would had to be adapted to signed as

    // well).

    sal_Int16 nYear = GetYear();

    SAL_WARN_IF( nYear < 1601, "tools.datetime", "DateTime::GetWin32FileDateTime - year < 1601: " << nYear);

    sal_Int64 aTime = (nYear < 1601 ? 0 : (

        a100nPerDay * (*this - Date(1,1,1601)) +

        GetNSFromTime()/100));

    rLower = sal_uInt32( aTime % SAL_CONST_UINT64( 0x100000000 ) );

    rUpper = sal_uInt32( aTime / SAL_CONST_UINT64( 0x100000000 ) );

}

DateTime DateTime::CreateFromWin32FileDateTime( sal_uInt32 rLower, sal_uInt32 rUpper )

{

    // (rUpper|rLower) = 100-nanosecond intervals since 1601-01-01 00:00

    const sal_uInt64 a100nPerSecond = SAL_CONST_UINT64( 10000000 );

    const sal_uInt64 a100nPerDay = a100nPerSecond * sal_uInt64( 60 * 60 * 24 );

    sal_uInt64 aTime =

            sal_uInt64( rUpper ) * SAL_CONST_UINT64( 0x100000000 ) +

            sal_uInt64( rLower );

    SAL_WARN_IF( static_cast<sal_Int64>(aTime) < 0, "tools.datetime",

            "DateTime::CreateFromWin32FileDateTime - absurdly high value expected?");

    sal_uInt64 nDays = aTime / a100nPerDay;

    Date aDate(1,1,1601);

    // (0xffffffffffffffff / a100nPerDay = 21350398) fits into sal_Int32

    // (0x7fffffff = 2147483647)

    aDate.AddDays(nDays);

    SAL_WARN_IF( aDate - Date(1,1,1601) != static_cast<sal_Int32>(nDays), "tools.datetime",

            "DateTime::CreateFromWin32FileDateTime - date truncated to max");

    sal_uInt64 nNanos = (aTime - (nDays * a100nPerDay)) * 100;

    return DateTime( aDate, tools::Time(

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerHour)   % sal_uInt64( 24 )),

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerMinute) % sal_uInt64( 60 )),

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerSec)    % sal_uInt64( 60 )),

                static_cast<sal_uInt64>( nNanos % tools::Time::nanoSecPerSec)));

}

DateTime DateTime::CreateFromUnixTime(const double fSecondsSinceEpoch)

{

    double fValue = fSecondsSinceEpoch / Time::secondPerDay;

    const sal_Int32 nDays = static_cast <sal_Int32>(::rtl::math::approxFloor(fValue));

    Date aDate (1, 1, 1970);

    aDate.AddDays(nDays);

    SAL_WARN_IF(aDate - Date(1, 1, 1970) != nDays, "tools.datetime",

                "DateTime::CreateFromUnixTime - date truncated to max");

    fValue -= nDays;

    const sal_uInt64 nNanos = fValue * tools::Time::nanoSecPerDay;

    return DateTime( aDate, tools::Time(

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerHour)   % sal_uInt64( 24 )),

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerMinute) % sal_uInt64( 60 )),

                static_cast<sal_uInt32>((nNanos / tools::Time::nanoSecPerSec)    % sal_uInt64( 60 )),

                static_cast<sal_uInt64>( nNanos % tools::Time::nanoSecPerSec)));

}

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