#!/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 = (
	"0618-01-01 00:00:00",
	"1066-10-14 00:00:00",
	"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"

);

# define format for printf statements
my $pstr = "%-19s  %02s,%02s,%02s,%02s,%02s,%04s,%01s  %-19s\n";
my $pfrm =  "%19s  %02u,%02u,%02u,%02u,%02u,%04u,%01u  %19s\n";

printf( $pstr, "value", "ss", "mm", "hh", "dy", "mo", "year", "z", "date" );

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 @datetime = strptime( $string, $DEFAULT_TIME_ZONE );

	# error if date is not correctly parsed
	if ( scalar @datetime == 0 ) {
		die( "ERROR ====> invalid datetime ($string), " 
                    . "datetime format should be YYYY-MM-DD HH:MM:SS" );
	}

	my ( $ss, $mm, $hh, $day, $month, $year, $zone ) = @datetime;

	if ( $year < 1000 ) { $year += 1900; }

	my %datetimehash = (
		year       => $year,
		month      => $month + 1,
		day        => $day,
		hour       => $hh,
		minute     => $mm,
		second     => $ss,
		nanosecond => 0,
		time_zone  => $zone,
	);

	my $date = DateTime->new(%datetimehash);

	printf( $pfrm, $string, $ss, $mm, $hh, $day, $month, $year, $zone, $date );

}

exit 0;