package C4::Ratings;

# Copyright 2011 KohaAloha, NZ
# Parts copyright 2011, Catalyst IT, NZ.
#
# This file is part of Koha.
#
# Koha is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Koha 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. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Koha; if not, see <http://www.gnu.org/licenses>.

use strict;
use warnings;
use Carp;
use Exporter;
use POSIX;
use C4::Debug;
use C4::Context;

use Koha::Database;

use vars qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);

BEGIN {
    @ISA     = qw(Exporter);

    @EXPORT = qw(
      &GetRating
      &AddRating
      &ModRating
      &DelRating
    );
}

=head1 NAME

C4::Ratings - a module to manage user ratings of Koha biblios

=head1 DESCRIPTION

Ratings.pm provides simple functionality for a user to 'rate' a biblio, and to retrieve a biblio's rating info

the 4 subroutines allow a user to add, delete modify and retrieve rating info for a biblio.

The rating can be from 1 to 5 stars, (5 stars being the highest rating)

=head1 SYNOPSIS

Get a rating for a bib
 my $rating_hashref = GetRating( $biblionumber, undef );
 my $rating_hashref = GetRating( $biblionumber, $borrowernumber );

Add a rating for a bib
 my $rating_hashref = AddRating( $biblionumber, $borrowernumber, $rating_value );

Mod a rating for a bib
 my $rating_hashref = ModRating( $biblionumber, $borrowernumber, $rating_value );

Delete a rating for a bib
 my $rating_hashref = DelRating( $biblionumber, $borrowernumber );


All subroutines in Ratings.pm return a hashref which contain 4 keys

for example, after executing this statement below...

    my $rating_hashref = GetRating ( $biblionumber, $borrowernumber ) ;

$rating_hashref now contains a hashref that looks like this...

    $rating  = {
             rating_avg       => '2',
             rating_avg_int   => '2.3',
             rating_total     => '432',
             rating_value => '5'
    }

they 4 keys returned in the hashref are...

    rating_avg:            average rating of a biblio
    rating_avg_int:        average rating of a biblio, rounded to 1dp
    rating_total:          total number of ratings of a biblio
    rating_value:          logged-in user's rating of a biblio

=head1 BUGS

Please use bugs.koha-community.org for tracking bugs.

=head1 SOURCE AVAILABILITY

The source is available from the koha-community.org git server
L<http://git.koha-community.org>

=head1 AUTHOR

Original code: Mason James <mtj@kohaaloha.com>

=head1 COPYRIGHT

Copyright (c) 2011 Mason James <mtj@kohaaloha.com>

=head1 LICENSE

C4::Ratings is free software. You can redistribute it and/or
modify it under the same terms as Koha itself.

=head1 CREDITS

 Mason James <mtj@kohaaloha.com>
 Koha Dev Team <http://koha-community.org>


=head2 GetRating

    GetRating($biblionumber, [$borrowernumber])

Get a rating for a bib
 my $rating_hashref = GetRating( $biblionumber, undef );
 my $rating_hashref = GetRating( $biblionumber, $borrowernumber );

This returns the rating for the supplied biblionumber. It will also return
the rating that the supplied user gave to the provided biblio. If a particular
value can't be supplied, '0' is returned for that value.

=head3 RETURNS

A hashref containing:

=over

=item * rating_avg - average rating of a biblio

=item * rating_avg_int - average rating of a biblio, rounded to 1dp

=item * rating_total - total number of ratings of a biblio

=item * rating_value - logged-in user's rating of a biblio

=back

=cut

sub GetRating {
    my ( $biblionumber, $borrowernumber ) = @_;

    my $ratings = Koha::Database->new()->schema->resultset('Rating')->search(
        {
            biblionumber => $biblionumber,
        }
    );

    my $sum   = $ratings->get_column('rating_value')->sum();
    my $total = $ratings->count();

    my ( $avg, $avg_int ) = 0;

    if ( $sum and $total ) {
        eval { $avg = $sum / $total };
    }

    $avg_int = sprintf( "%.1f", $avg );
    $avg     = sprintf( "%.0f", $avg );

    my %rating_hash;
    $rating_hash{rating_total}   = $total   || 0;
    $rating_hash{rating_avg}     = $avg     || 0;
    $rating_hash{rating_avg_int} = $avg_int || 0;

    if ($borrowernumber) {
        my $rating = Koha::Database->new()->schema->resultset('Rating')->find(
            {
                biblionumber   => $biblionumber,
                borrowernumber => $borrowernumber,
            }
        );
        return unless $rating;
        $rating_hash{'rating_value'} = $rating->rating_value();
    }
    else {
        $rating_hash{rating_value}          = undef;
    }

    return \%rating_hash;
}

=head2 AddRating

    my $rating_hashref = AddRating( $biblionumber, $borrowernumber, $rating_value );

Add a rating for a bib

This adds or updates a rating for a particular user on a biblio. If the value
is 0, then the rating will be deleted. If the value is out of the range of
0-5, nothing will happen.

=cut

sub AddRating {
    my ( $biblionumber, $borrowernumber, $rating_value ) = @_;

    my $rating = Koha::Database->new()->schema->resultset('Rating')->create(
        {
            biblionumber   => $biblionumber,
            borrowernumber => $borrowernumber,
            rating_value   => $rating_value
        }
    );

    return GetRating( $biblionumber, $borrowernumber );
}

=head2 ModRating

    my $rating_hashref = ModRating( $biblionumber, $borrowernumber, $rating_value );

Mod a rating for a bib

=cut

sub ModRating {
    my ( $biblionumber, $borrowernumber, $rating_value ) = @_;

    my $rating = Koha::Database->new()->schema->resultset('Rating')->find(
        {
            borrowernumber => $borrowernumber,
            biblionumber   => $biblionumber
        }
    );

    $rating->update( { rating_value => $rating_value } );

    return GetRating( $biblionumber, $borrowernumber );
}

=head2 DelRating

    my $rating_hashref = DelRating( $biblionumber, $borrowernumber );

Delete a rating for a bib

=cut

sub DelRating {
    my ( $biblionumber, $borrowernumber ) = @_;

    my $rating = Koha::Database->new()->schema->resultset('Rating')->find(
        {
            borrowernumber => $borrowernumber,
            biblionumber   => $biblionumber
        }
    );

    $rating->delete() if $rating;

    return GetRating($biblionumber);
}

1;
__END__