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.