package C4::ClassSortRoutine::Dewey;

# Copyright (C) 2007 LibLime
# 
# 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;



=head1 NAME 

C4::ClassSortRoutine::Dewey - generic call number sorting key routine

=head1 SYNOPSIS

use C4::ClassSortRoutine qw( GetClassSortKey );

my $cn_sort = GetClassSortKey('Dewey', $cn_class, $cn_item);

=head1 FUNCTIONS

=head2 get_class_sort_key

  my $cn_sort = C4::ClassSortRoutine::Dewey::Dewey($cn_class, $cn_item);

Generates sorting key using the following rules:

* Concatenates class and item part.
* Converts to uppercase.
* Removes leading and trailing whitespace and '/'
* Separates alphabetic prefix from the rest of the call number
* Splits into tokens on whitespaces and periods.
* Leaves first digit group as is.
* Converts second digit group to 15-digit long group, padded on right with zeroes.
* Converts each run of whitespace to an underscore.
* Removes any remaining non-alphabetical, non-numeric, non-underscore characters.

=cut

sub get_class_sort_key {
    my ($cn_class, $cn_item) = @_;

    $cn_class = '' unless defined $cn_class;
    $cn_item  = '' unless defined $cn_item;
    my $init = uc "$cn_class $cn_item";
    $init =~ s/^\s+//;
    $init =~ s/\s+$//;
    $init =~ s/\// /g;
    $init =~ s!/!!g;
    $init =~ s/^([\p{IsAlpha}]+)/$1 /;
    my @tokens = split /\.|\s+/, $init;
    my $digit_group_count = 0;
    my $first_digit_group_idx;
    for (my $i = 0; $i <= $#tokens; $i++) {
        if ($tokens[$i] =~ /^\d+$/) {
            $digit_group_count++;
            if (1 == $digit_group_count) {
                $first_digit_group_idx = $i;
            }
            if (2 == $digit_group_count) {
               if ($i - $first_digit_group_idx == 1) {
                    $tokens[$i] = sprintf("%-15.15s", $tokens[$i]);
                    $tokens[$i] =~ tr/ /0/;
                } else {
                    $tokens[$first_digit_group_idx] .= '_000000000000000'
                }
            }
        }
    }
    # Pad the first digit_group if there was only one
    if (1 == $digit_group_count) {
        $tokens[$first_digit_group_idx] .= '_000000000000000'
    }
    my $key = join("_", @tokens);
    $key =~ s/[^\p{IsAlnum}_]//g;

    return $key;

}

1;

=head1 AUTHOR

Koha Development Team <http://koha-community.org/>

=cut