#!/usr/bin/perl
#---------------------------------------------------------------------
# format_date.pl
#
# format variable date inputs
#---------------------------------------------------------------------

use strict;
use warnings;

use Date::Parse;
use DateTime;

my $DEFAULT_TIME_ZONE = "GMT";

my @dates = (
    "1899-06-24 09:44:00",
    "1900-12-31 23:59:59",
    "1901-01-01 00:00:00",
    "1960-12-31 23:59:59",
    "1966-06-24 09:44:00",
    "1968-12-31 23:59:59",
    "1969-01-01 00:00:00",
    "1969-12-31 23:59:59",
    "1970-01-01 00:00:01",
    "2000-01-01 00:00:00",
    "2017-06-24 23:59:59",
    "2018-06-24 09:44:00",
    "2238-06-24 09:44:00"

);

foreach my $string (@dates) {

    # format datetime field from any valid datetime input
    # default time zone is used if timezone is not included in string
    my $epoch = str2time( $string, $DEFAULT_TIME_ZONE );

    # error if date is not correctly parsed
    if ( !$epoch ) {
        die("ERROR ====> invalid datetime ($string), "
        . "datetime format should be YYYY-MM-DD HH:MM:SS");
    }

    my $date = DateTime->from_epoch( epoch => $epoch );

    printf( "formatting datetime: value = %20s, epoch = %20u, "
            . "date = %20s\n", $string, $epoch, $date );

}

exit 0;

##</code><code>##

formatting datetime: value =  1899-06-24 09:44:00, epoch = 18446744071484095456, date =  1899-06-24T09:44:00
formatting datetime: value =  1900-12-31 23:59:59, epoch = 18446744071532098815, date =  1900-12-31T23:59:59
formatting datetime: value =  1901-01-01 00:00:00, epoch =            978307200, date =  2001-01-01T00:00:00
formatting datetime: value =  1960-12-31 23:59:59, epoch =           2871763199, date =  2060-12-31T23:59:59
formatting datetime: value =  1966-06-24 09:44:00, epoch =           3044598240, date =  2066-06-24T09:44:00
formatting datetime: value =  1968-12-31 23:59:59, epoch =           3124223999, date =  2068-12-31T23:59:59
formatting datetime: value =  1969-01-01 00:00:00, epoch = 18446744073678015616, date =  1969-01-01T00:00:00
formatting datetime: value =  1969-12-31 23:59:59, epoch = 18446744073709551615, date =  1969-12-31T23:59:59
formatting datetime: value =  1970-01-01 00:00:01, epoch =                    1, date =  1970-01-01T00:00:01
formatting datetime: value =  2000-01-01 00:00:00, epoch =            946684800, date =  2000-01-01T00:00:00
formatting datetime: value =  2017-06-24 23:59:59, epoch =           1498348799, date =  2017-06-24T23:59:59
formatting datetime: value =  2018-06-24 09:44:00, epoch =           1529833440, date =  2018-06-24T09:44:00
formatting datetime: value =  2238-06-24 09:44:00, epoch =           8472332640, date =  2238-06-24T09:44:00