BEGIN {
    $ENV{PERL_DATETIME_PP} = 1;
}

use strict;
use warnings;

use Test::More;
use Test::Fatal;

use DateTime;

{
    my $dt = DateTime->new(
        year      => 1996, month  => 11, day    => 22,
        hour      => 18,   minute => 30, second => 20,
        time_zone => 'UTC',
    );
    $dt->add( weeks => 8 );

    is( $dt->year,     1997,                  'year rollover' );
    is( $dt->month,    1,                     'month set on year rollover' );
    is( $dt->datetime, '1997-01-17T18:30:20', 'okay on year rollover' );

    $dt->add( weeks => 2 );
    is( $dt->datetime, '1997-01-31T18:30:20', 'Adding weeks' );

    $dt->add( seconds => 15 );
    is( $dt->datetime, '1997-01-31T18:30:35', 'Adding seconds' );

    $dt->add( minutes => 12 );
    is( $dt->datetime, '1997-01-31T18:42:35', 'Adding minutes' );

    $dt->add( minutes => 25, hours => 3, seconds => 7 );
    is( $dt->datetime, '1997-01-31T22:07:42', 'Adding h,m,s' );
}

{
    # Now, test the adding of durations
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( minutes => 1, seconds => 12 );
    is(
        $dt->datetime, '1986-01-28T16:39:12',
        'Adding durations with minutes and seconds works'
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( seconds => 30 );
    is(
        $dt->datetime, '1986-01-28T16:38:30',
        'Adding durations with seconds only works'
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( hours => 1, minutes => 10 );
    is(
        $dt->datetime, '1986-01-28T17:48:00',
        'Adding durations with hours and minutes works'
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( days => 3 );
    is(
        $dt->datetime, '1986-01-31T16:38:00',
        'Adding durations with days only works'
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( days => 3, hours => 2 );
    is(
        $dt->datetime, '1986-01-31T18:38:00',
        'Adding durations with days and hours works'
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( days => 3, hours => 2, minutes => 20, seconds => 15 );
    is(
        $dt->datetime, '1986-01-31T18:58:15',
        'Adding durations with days, hours, minutes, and seconds works'
    );
}

{
    # Add 15M - this test failed at one point in N::I::Time
    my $dt = DateTime->new(
        year      => 2001, month => 4, day => 5,
        hour      => 16,
        time_zone => 'UTC'
    );

    $dt->add( minutes => 15 );
    is(
        $dt->datetime, '2001-04-05T16:15:00',
        'Adding minutes to an ical string'
    );

    # Subtract a duration
    $dt->add( minutes => -15 );
    is( $dt->datetime, '2001-04-05T16:00:00', 'Back where we started' );
}

{
    # Syntactic sugar works as well
    my $dt = DateTime->new(
        year      => 2016, month => 11, day => 11,
        hour      => 17,
        time_zone => 'UTC'
    );
    my $duration = DateTime::Duration->new( years => 1 );
    $dt->add($duration);
    is(
        $dt->datetime, '2017-11-11T17:00:00',
        'Adding a Duration object via ->add works',
    );
    $duration = DateTime::Duration->new( months => 5, days => 1 );
    $dt->subtract($duration);
    is(
        $dt->datetime, '2017-06-10T17:00:00',
        'Subtracting a Duration object via ->subtract works',
    );
}

{
    my $dt = DateTime->new(
        year      => 1986, month  => 1, day => 28,
        hour      => 16,   minute => 38,
        time_zone => 'UTC'
    );

    $dt->add( seconds => 60 );
    is(
        $dt->datetime, '1986-01-28T16:39:00',
        'adding positive seconds with seconds works'
    );
    $dt->add( seconds => -120 );
    is(
        $dt->datetime, '1986-01-28T16:37:00',
        'adding negative seconds with seconds works'
    );
}

{
    # test sub months
    my $dt = DateTime->new(
        year      => 2001, month => 1, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-02-01', 'february 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 2, day => 28,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-03-01', 'march 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 3, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-04-01', 'april 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 4, day => 30,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-05-01', 'may 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 5, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-06-01', 'june 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 6, day => 30,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-07-01', 'july 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 7, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-08-01', 'august 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 8, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-09-01', 'september 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 9, day => 30,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-10-01', 'october 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 10, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-11-01', 'november 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 11, day => 30,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2001-12-01', 'december 1st' );
}

{
    my $dt = DateTime->new(
        year      => 2001, month => 12, day => 31,
        time_zone => 'UTC',
    );
    $dt->add( days => 1 );
    is( $dt->date, '2002-01-01', 'january 1st' );
}

{
    # Before leap day, not a leap year ...
    my $dt = DateTime->new(
        year      => 2001, month => 2, day => 28,
        time_zone => 'UTC',
    );
    $dt->add( years => 1 );
    is( $dt->date, '2002-02-28', 'Adding a year' );
    $dt->add( years => 17 );
    is( $dt->date, '2019-02-28', 'Adding 17 years' );
}

{
    # After leap day, not a leap year ...
    my $dt = DateTime->new(
        year      => 2001, month => 3, day => 28,
        time_zone => 'UTC',
    );
    $dt->add( years => 1 );
    is( $dt->date, '2002-03-28', 'Adding a year' );
    $dt->add( years => 17 );
    is( $dt->date, '2019-03-28', 'Adding 17 years' );
}

{
    # On leap day, in a leap year ...
    my $dt = DateTime->new(
        year      => 2000, month => 2, day => 29,
        time_zone => 'UTC',
    );
    $dt->add( years => 1 );
    is( $dt->date, '2001-03-01', 'Adding a year' );
    $dt->add( years => 17 );
    is( $dt->date, '2018-03-01', 'Adding 17 years' );
}

{
    # Before leap day, in a leap year ...
    my $dt = DateTime->new(
        year      => 2000, month => 2, day => 28,
        time_zone => 'UTC',
    );
    $dt->add( years => 1 );
    is( $dt->date, '2001-02-28', 'Adding a year' );
    $dt->add( years => 17 );
    is( $dt->date, '2018-02-28', 'Adding 17 years' );
}

{
    # After leap day, in a leap year ...
    my $dt = DateTime->new(
        year      => 2000, month => 3, day => 28,
        time_zone => 'UTC',
    );
    $dt->add( years => 1 );
    is( $dt->date, '2001-03-28', 'Adding a year' );
    $dt->add( years => 17 );
    is( $dt->date, '2018-03-28', 'Adding 17 years' );
}

{
    # Test a bunch of years, before leap day
    for ( 1 .. 99 ) {
        my $dt = DateTime->new(
            year      => 2000, month => 2, day => 28,
            time_zone => 'UTC',
        );
        $dt->add( years => $_ );
        my $x = sprintf '%02d', $_;
        is( $dt->date, "20${x}-02-28", "Adding $_ years" );
    }

    # Test a bunch of years, after leap day
    for ( 1 .. 99 ) {
        my $dt = DateTime->new(
            year      => 2000, month => 3, day => 28,
            time_zone => 'UTC',
        );
        $dt->add( years => $_ );
        my $x = sprintf '%02d', $_;
        is( $dt->date, "20${x}-03-28", "Adding $_ years" );
    }
}

# And more of the same, starting on a non-leap year

{
    # Test a bunch of years, before leap day
    for ( 1 .. 97 ) {
        my $dt = DateTime->new(
            year      => 2002, month => 2, day => 28,
            time_zone => 'UTC',
        );
        $dt->add( years => $_ );
        my $x = sprintf '%02d', $_ + 2;
        is( $dt->date, "20${x}-02-28", "Adding $_ years" );
    }

    # Test a bunch of years, after leap day
    for ( 1 .. 97 ) {
        my $dt = DateTime->new(
            year      => 2002, month => 3, day => 28,
            time_zone => 'UTC',
        );
        $dt->add( years => $_ );
        my $x = sprintf '%02d', $_ + 2;
        is( $dt->date, "20${x}-03-28", "Adding $_ years" );
    }
}

{
    # subtract years
    for ( 1 .. 97 ) {
        my $dt = DateTime->new(
            year      => 1999, month => 3, day => 1,
            time_zone => 'UTC',
        );
        $dt->add( years => -$_ );
        my $x = sprintf '%02d', 99 - $_;
        is( $dt->date, "19${x}-03-01", "Subtracting $_ years" );
    }
}

# test some old bugs

{
    # bug adding months where current month + months added were > 25
    my $dt = DateTime->new(
        year      => 1997, month => 12, day => 1,
        time_zone => 'UTC',
    );
    $dt->add( months => 14 );
    is( $dt->date, '1999-02-01', 'Adding months--rollover year' );
}

{
    # bug subtracting months with year rollover
    my $dt = DateTime->new(
        year      => 1997, month => 1, day => 1,
        time_zone => 'UTC',
    );
    $dt->add( months => -1 );
    is( $dt->date, '1996-12-01', 'Subtracting months--rollover year' );

    my $new = $dt + DateTime::Duration->new( years => 2 );
    is( $new->date, '1998-12-01', 'test + overloading' );
}

{
    my $dt = DateTime->new(
        year       => 1997, month  => 1, day    => 1,
        hour       => 1,    minute => 1, second => 59,
        nanosecond => 500000000,
        time_zone  => 'UTC',
    );

    $dt->add( nanoseconds => 500000000 );
    is( $dt->second, 0, 'fractional second rollover' );
    $dt->add( nanoseconds => 123000000 );
    is( $dt->fractional_second, 0.123, 'as fractional_second' );
}

{
    my $dt = DateTime->new( year => 2003, month => 2, day => 28 );
    $dt->add( months => 1, days => 1 );

    is( $dt->ymd, '2003-04-01', 'order of units in date math' );
}

{
    my $dt = DateTime->new( year => 2003, hour => 12, minute => 1 );
    $dt->add( minutes => 30, seconds => -1 );

    is( $dt->hour,   12, 'hour is 12' );
    is( $dt->minute, 30, 'minute is 30' );
    is( $dt->second, 59, 'second is 59' );
}

{
    my $dt = DateTime->new(
        year      => 2014,
        month     => 7,
        day       => 1,
        time_zone => 'floating',
    );

    $dt->add( days => 2 );
    is( $dt->date, '2014-07-03', 'adding 2 days to a floating datetime' );
}

{
    my $dt = DateTime->new( year => 0, month => 1, day => 1 );
    my $dt2;
    is(
        exception { $dt2 = $dt->clone->add( days => 268_526_345 ) },
        undef,
        'no exception adding 268,526,345 days to 0000-01-01'
    );

    if ($dt2) {
        is(
            $dt2->ymd(),
            '735200-02-29',
            'adding 268,526,345 days produces 735200-02-29'
        );
    }
}

done_testing();