/* -*- 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 <rtl/math.hxx>

bool DateTime::IsBetween( const DateTime& rFrom, const DateTime& rTo ) const
{
    if ( (*this >= rFrom) && (*this <= rTo) )
        return true;
    else
        return false;
}

bool DateTime::operator >( const DateTime& rDateTime ) const
{
    if ( (Date::operator>( rDateTime )) ||
         (Date::operator==( rDateTime ) && Time::operator>( rDateTime )) )
        return true;
    else
        return false;
}

bool DateTime::operator <( const DateTime& rDateTime ) const
{
    if ( (Date::operator<( rDateTime )) ||
         (Date::operator==( rDateTime ) && Time::operator<( rDateTime )) )
        return true;
    else
        return false;
}

bool DateTime::operator >=( const DateTime& rDateTime ) const
{
    if ( (Date::operator>( rDateTime )) ||
         (Date::operator==( rDateTime ) && Time::operator>=( rDateTime )) )
        return true;
    else
        return false;
}

bool DateTime::operator <=( const DateTime& rDateTime ) const
{
    if ( (Date::operator<( rDateTime )) ||
         (Date::operator==( rDateTime ) && Time::operator<=( rDateTime )) )
        return true;
    else
        return false;
}

long DateTime::GetSecFromDateTime( const Date& rDate ) const
{
    if ( Date::operator<( rDate ) )
        return 0;
    else
    {
        long nSec = Date( *this ) - rDate;
        nSec *= 24UL*60*60;
        long nHour = GetHour();
        long nMin  = GetMin();
        nSec += (nHour*3600)+(nMin*60)+GetSec();
        return nSec;
    }
}

DateTime& DateTime::operator +=( const Time& rTime )
{
    Time aTime = *this;
    aTime += rTime;
    sal_uInt16 nHours = aTime.GetHour();
    if ( aTime.GetTime() > 0 )
    {
        while ( nHours >= 24 )
        {
            Date::operator++();
            nHours -= 24;
        }
        aTime.SetHour( nHours );
    }
    else if ( aTime.GetTime() != 0 )
    {
        while ( nHours >= 24 )
        {
            Date::operator--();
            nHours -= 24;
        }
        Date::operator--();
        aTime = Time( 24, 0, 0 )+aTime;
    }
    Time::operator=( aTime );

    return *this;
}

DateTime& DateTime::operator -=( const Time& rTime )
{
    Time aTime = *this;
    aTime -= rTime;
    sal_uInt16 nHours = aTime.GetHour();
    if ( aTime.GetTime() > 0 )
    {
        while ( nHours >= 24 )
        {
            Date::operator++();
            nHours -= 24;
        }
        aTime.SetHour( nHours );
    }
    else if ( aTime.GetTime() != 0 )
    {
        while ( nHours >= 24 )
        {
            Date::operator--();
            nHours -= 24;
        }
        Date::operator--();
        aTime = Time( 24, 0, 0 )+aTime;
    }
    Time::operator=( aTime );

    return *this;
}

DateTime operator +( const DateTime& rDateTime, long nDays )
{
    DateTime aDateTime( rDateTime );
    aDateTime += nDays;
    return aDateTime;
}

DateTime operator -( const DateTime& rDateTime, long nDays )
{
    DateTime aDateTime( rDateTime );
    aDateTime -= nDays;
    return aDateTime;
}

DateTime operator +( const DateTime& rDateTime, const Time& rTime )
{
    DateTime aDateTime( rDateTime );
    aDateTime += rTime;
    return aDateTime;
}

DateTime operator -( const DateTime& rDateTime, const Time& rTime )
{
    DateTime aDateTime( rDateTime );
    aDateTime -= rTime;
    return aDateTime;
}

DateTime& DateTime::operator +=( double fTimeInDays )
{
    double fInt, fFrac;
    if ( fTimeInDays < 0.0 )
    {
        fInt = ::rtl::math::approxCeil( fTimeInDays );
        fFrac = fInt <= fTimeInDays ? 0.0 : fTimeInDays - fInt;
    }
    else
    {
        fInt = ::rtl::math::approxFloor( fTimeInDays );
        fFrac = fInt >= fTimeInDays ? 0.0 : fTimeInDays - fInt;
    }
    Date::operator+=( long(fInt) );     // full days
    if ( fFrac )
    {
        Time aTime(0);  // default ctor calls system time, we don't need that
        fFrac *= ::Time::nanoSecPerDay;   // time expressed in nanoseconds
        aTime.MakeTimeFromNS( static_cast<sal_Int64>(fFrac) );    // method handles negative ns
        operator+=( aTime );
    }
    return *this;
}

DateTime operator +( const DateTime& rDateTime, double fTimeInDays )
{
    DateTime aDateTime( rDateTime );
    aDateTime += fTimeInDays;
    return aDateTime;
}

double operator -( const DateTime& rDateTime1, const DateTime& rDateTime2 )
{
    long nDays = (const Date&) rDateTime1 - (const Date&) rDateTime2;
    sal_Int64 nTime = rDateTime1.GetNSFromTime() - rDateTime2.GetNSFromTime();
    if ( nTime )
    {
        double fTime = double(nTime);
        fTime /= ::Time::nanoSecPerDay; // convert from nanoseconds to fraction
        if ( nDays < 0 && fTime > 0.0 )
            fTime = 1.0 - fTime;
        return double(nDays) + fTime;
    }
    return double(nDays);
}

void DateTime::GetWin32FileDateTime( sal_uInt32 & rLower, sal_uInt32 & rUpper )
{
    const sal_Int64 a100nPerSecond = SAL_CONST_INT64( 10000000 );
    const sal_Int64 a100nPerDay = a100nPerSecond * sal_Int64( 60 * 60 * 24 );

    sal_Int64 nYears = GetYear() - 1601;
    sal_Int64 nDays =
        nYears * 365 +
        nYears / 4 - nYears / 100 + nYears / 400 +
        GetDayOfYear() - 1;

    sal_Int64 aTime =
        a100nPerDay * nDays +
        GetNSFromTime()/100;

    rLower = sal_uInt32( aTime % SAL_CONST_UINT64( 0x100000000 ) );
    rUpper = sal_uInt32( aTime / SAL_CONST_UINT64( 0x100000000 ) );
}

DateTime DateTime::CreateFromWin32FileDateTime( const sal_uInt32 & rLower, const sal_uInt32 & rUpper )
{
    const sal_Int64 a100nPerSecond = SAL_CONST_INT64( 10000000 );
    const sal_Int64 a100nPerDay = a100nPerSecond * sal_Int64( 60 * 60 * 24 );

    sal_Int64 aTime = sal_Int64(
            sal_uInt64( rUpper ) * SAL_CONST_UINT64( 0x100000000 ) +
            sal_uInt64( rLower ) );

    sal_Int64 nDays = aTime / a100nPerDay;
    sal_Int64 nYears =
        ( nDays -
          ( nDays / ( 4 * 365 ) ) +
          ( nDays / ( 100 * 365 ) ) -
          ( nDays / ( 400 * 365 ) ) ) / 365;
    nDays -= nYears * 365 + nYears / 4 - nYears / 100 + nYears / 400;

    sal_uInt16 nMonths = 0;
    for( sal_Int64 nDaysCount = nDays; nDaysCount >= 0; )
    {
        nDays = nDaysCount;
        nMonths ++;
        nDaysCount -= Date(
            1, nMonths, sal::static_int_cast< sal_uInt16 >(1601 + nYears) ).
            GetDaysInMonth();
    }

    Date _aDate(
        (sal_uInt16)( nDays + 1 ), nMonths,
        sal::static_int_cast< sal_uInt16 >(nYears + 1601) );
    Time _aTime( sal_uIntPtr( ( aTime / ( a100nPerSecond * 60 * 60 ) ) % sal_Int64( 24 ) ),
                 sal_uIntPtr( ( aTime / ( a100nPerSecond * 60 ) )      % sal_Int64( 60 ) ),
                 sal_uIntPtr( ( aTime / ( a100nPerSecond ) )           % sal_Int64( 60 ) ),
                 (aTime % a100nPerSecond) * 100 );

    return DateTime( _aDate, _aTime );
}

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