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#!/usr/bin/env perl

use 5.008004;

use strict;
use warnings;

use Getopt::Long 2.33 qw{ :config auto_version };
use Pod::Usage;

our $VERSION = '0.910';

my %opt = (
    from	=> 'DateTime',
    to		=> 'DateTime::Fiction::JRRTolkien::Shire',
);

GetOptions( \%opt,
    qw{ from=s reverse! to=s },
    'instantiater=s'	=> \( my $instantiater = 'new' ),
    'serializer=s'	=> \( my $serializer ),
    help => sub { pod2usage( { -verbose => 2 } ) },
) or pod2usage( { -verbose => 0 } );

$opt{reverse}
    and @opt{ qw< to from > } = @opt{ qw< from to > };

foreach my $key ( qw{ from to } ) {
    local $@ = undef;
    eval "require $opt{$key}; 1"
	or die $@;
}

my $from = $opt{from}->$instantiater( @ARGV );

my $to = $opt{to}->from_object( object => $from );

my $calendar;
if ( my $code = $to->can( 'calendar_name' ) ) {
    $calendar = $code->( $to );
} else {
    ( $calendar = $opt{to} ) =~ s/ .* :: //smx
	or $calendar = 'Gregorian';
}

if ( $serializer ) {
    print $to->$serializer(), " $calendar\n";
} else {
    print "$to $calendar\n";
}

__END__

=head1 TITLE

date-convert - Convert dates from one calendar to another.

=head1 SYNOPSIS

 date-convert year 2016 month 4 day 1
 date-convert -reverse year 1419 holiday 3
 date-convert -help
 date-convert -version

=head1 OPTIONS

=head2 -from

This option specifies the class to be converted from.

The default is C<-from=DateTime>.

=head2 -help

This option displays the documentation for this script. The script then
exits.

=head2 -instantiater

This option specifies the name of the method used to instantiate the
object to be converted from.

The default is C<'new'>.

=head2 -reverse

If asserted, this Boolean option specifies that a reverse conversion is
to be done. It works by swapping the values of the C<-from> and C<-to>
options, whether specified or defaulted.

The default is C<-noreverse>.

=head2 serializer

This option specifies the name of the method to be used to serialize the
object converted to. This method must not take any arguments. If a false
value, the object is stringified.

The default is C<undef>.

=head2 -to

This option specifies the class to be converted to.

The default is C<-to=DateTime::Fiction::JRRTolkien::Shire>.

=head2 -version

This option displays the version of this script. The script then exits.

=head1 DETAILS

This Perl script uses L<DateTime|DateTime> modules to convert from one
calendar to another.

The command-line arguments are passed verbatim to the C<-from> class'
C<new()> method. The resultant object is passed to the C<-to> class'
C<from_object()> method, and the result of that method is stringified.

By default, this script converts from C<DateTime> to
C<DateTime::Fiction::JRRTolkien::Shire>, thus converting the given date
from Gregorian to Shire Reckoning.

=head1 AUTHOR

Thomas R. Wyant, III F<harryfmudd at comcast dot net>

=head1 COPYRIGHT AND LICENSE

Copyright (C) 2017-2022, 2025-2026 by Thomas R. Wyant, III

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl 5.10.0. For more details, see the full text
of the licenses in the files F<LICENSE-Artistic> and F<LICENSE-GPL>.

This program is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.

=cut

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