package DateTime::TimeZone::OffsetOnly;

use strict;

use vars qw ($VERSION);
$VERSION = 0.02;

use DateTime::TimeZone;
use base 'DateTime::TimeZone';

use DateTime::TimeZone::UTC;
use Params::Validate qw( validate SCALAR );

sub new
{
    my $class = shift;
    my %p = validate( @_, { offset => { type => SCALAR },
                          } );

    my $offset =
        DateTime::TimeZone::offset_as_seconds( $p{offset} );

    die "Invalid offset: $p{offset}\n" unless defined $offset;

    return DateTime::TimeZone::UTC->new unless $offset;

    my $self = { name   => DateTime::TimeZone::offset_as_string( $offset ),
                 offset => $offset,
               };

    return bless $self, $class;
}

sub is_dst_for_datetime { 0 }

sub offset_for_datetime { $_[0]->{offset} }
sub offset_for_local_datetime { $_[0]->{offset} }

sub is_utc { 0 }

sub short_name_for_datetime { $_[0]->name }

sub category { undef }


sub STORABLE_freeze
{
    my $self = shift;

    return $self->name;
}

sub STORABLE_thaw
{
    my $self = shift;
    my $cloning = shift;
    my $serialized = shift;

    my $class = ref $self || $self;

    my $obj;
    if ( $class->isa(__PACKAGE__) )
    {
        $obj = __PACKAGE__->new( offset => $serialized );
    }
    else
    {
        $obj = $class->new( offset => $serialized );
    }

    %$self = %$obj;

    return $self;
}


1;

__END__

=head1 NAME

DateTime::TimeZone::OffsetOnly - A DateTime::TimeZone object that just contains an offset

=head1 SYNOPSIS

  my $offset_tz = DateTime::TimeZone->new( name => '-0300' );

=head1 DESCRIPTION

This class is used to provide the DateTime::TimeZone API needed by
DateTime.pm, but with a fixed offset.  An object in this class always
returns the same offset as was given in its constructor, regardless of
the date.

=head1 USAGE

This class has the same methods as a real time zone object, but the
C<category()> method returns undef.

=head2 DateTime::TimeZone::OffsetOnly->new ( offset => $offset )

The value given to the offset parameter must be a string such as
"+0300".  Strings will be converted into numbers by the
C<DateTime::TimeZone::offset_as_seconds()> function.

=head2 $tz->offset_for_datetime( $datetime )

No matter what date is given, the offset provided to the constructor
is always used.

=head2 $tz->name()

=head2 $tz->short_name_for_datetime()

Both of these methods return the offset in string form.

=head1 AUTHOR

Dave Rolsky, <autarch@urth.org>

=head1 COPYRIGHT & LICENSE

Copyright (c) 2003-2008 David Rolsky.  All rights reserved.  This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included
with this module.

=cut
