#!/usr/bin/perl

package C4::ShelfBrowser;

# Copyright 2010 Catalyst IT

#

# 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 2 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, write to the Free Software Foundation, Inc.,

# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

use strict;

use warnings;

use C4::Biblio;

use C4::Branch;

use C4::Context;

use C4::Koha;

use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);

BEGIN {

	$VERSION = 3.02;

	require Exporter;

	@ISA    = qw(Exporter);

	@EXPORT = qw(

	    &GetNearbyItems

    );

    @EXPORT_OK = qw(

    );

}

=head1 NAME

C4::ShelfBrowser - functions that deal with the shelf browser feature found in

the OPAC.

=head1 SYNOPSIS

  use C4::ShelfBrowser;

=head1 DESCRIPTION

This module provides functions to get items nearby to another item, for use

in the shelf browser function.

'Nearby' is controlled by a handful of system preferences that specify what

to take into account.

=head1 FUNCTIONS

=head2 GetNearbyItems($itemnumber, [$num_each_side])

  $nearby = GetNearbyItems($itemnumber, [$num_each_side]);

  @next = @{ $nearby->{next} };

  @prev = @{ $nearby->{prev} };

  foreach (@next) {

      # These won't format well like this, but here are the fields

  	  print $_->{title};

  	  print $_->{biblionumber};

  	  print $_->{itemnumber};

  	  print $_->{browser_normalized_upc};

  	  print $_->{browser_normalized_oclc};

  	  print $_->{browser_normalized_isbn};

  }

  # This is the information required to scroll the browser to the next left

  # or right set. Can be derived from next/prev, but it's here for convenience.

  print $nearby->{prev_itemnumber};

  print $nearby->{next_itemnumber};

  print $nearby->{prev_biblionumber};

  print $nearby->{next_biblionumber};

  # These will be undef if the values are not used to calculate the 

  # nearby items.

  print $nearby->{starting_homebranch}->{code};

  print $nearby->{starting_homebranch}->{description};

  print $nearby->{starting_location}->{code};

  print $nearby->{starting_location}->{description};

  print $nearby->{starting_ccode}->{code};

  print $nearby->{starting_ccode}->{description};

  print $nearby->{starting_itemnumber};

This finds the items that are nearby to the supplied item, and supplies

those previous and next, along with the other useful information for displaying

the shelf browser.

It automatically applies the following user preferences to work out how to

calculate things: C<ShelfBrowserUsesLocation>, C<ShelfBrowserUsesHomeBranch>, 

C<ShelfBrowserUsesCcode>.

The option C<$num_each_side> value determines how many items will be fetched

each side of the supplied item. Note that the item itself is the first entry

in the 'next' set, and counts towards this limit (this is to keep the

behaviour consistant with the code that this is a refactor of.) Default is

3.

This will throw an exception if something went wrong.

=cut

sub GetNearbyItems {

	my ($itemnumber, $num_each_side) = @_;

	$num_each_side ||= 3;

    my $dbh         = C4::Context->dbh;

    my $marcflavour = C4::Context->preference("marcflavour");

    my $branches = GetBranches();

    my $sth_get_item_details = $dbh->prepare("SELECT cn_sort,homebranch,location,ccode from items where itemnumber=?");

    $sth_get_item_details->execute($itemnumber);

    my $item_details_result = $sth_get_item_details->fetchrow_hashref();

    die "Unable to find item '$itemnumber' for shelf browser" if (!$sth_get_item_details);

    my $start_cn_sort = $item_details_result->{'cn_sort'};

    my ($start_homebranch, $start_location, $start_ccode);

    if (C4::Context->preference('ShelfBrowserUsesHomeBranch') && 

    	defined($item_details_result->{'homebranch'})) {

        $start_homebranch->{code} = $item_details_result->{'homebranch'};

        $start_homebranch->{description} = $branches->{$item_details_result->{'homebranch'}}{branchname};

    }

    if (C4::Context->preference('ShelfBrowserUsesLocation') && 

    	defined($item_details_result->{'location'})) {

        $start_location->{code} = $item_details_result->{'location'};

        $start_location->{description} = GetAuthorisedValueDesc('','',$item_details_result->{'location'},'','','LOC','opac');

    }

    if (C4::Context->preference('ShelfBrowserUsesCcode') && 

    	defined($item_details_result->{'ccode'})) {

        $start_ccode->{code} = $item_details_result->{'ccode'};

        $start_ccode->{description} = GetAuthorisedValueDesc('', '', $item_details_result->{'ccode'}, '', '', 'CCODE', 'opac');

    }

    # Build the query for previous and next items

    my $prev_query ='

        SELECT *

        FROM items

        WHERE

            ((cn_sort = ? AND itemnumber < ?) OR cn_sort < ?) ';

    my $next_query ='

        SELECT *

        FROM items

        WHERE

            ((cn_sort = ? AND itemnumber >= ?) OR cn_sort > ?) ';

    my @params;

    my $query_cond;

    push @params, ($start_cn_sort, $itemnumber, $start_cn_sort);

    if ($start_homebranch) {

    	$query_cond .= 'AND homebranch = ? ';

    	push @params, $start_homebranch->{code};

    }

    if ($start_location) {

    	$query_cond .= 'AND location = ? ';

    	push @params, $start_location->{code};

    }

    if ($start_ccode) {

    	$query_cond .= 'AND ccode = ? ';

    	push @params, $start_ccode->{code};

    }

    my $sth_prev_items = $dbh->prepare($prev_query . $query_cond . ' ORDER BY cn_sort DESC, itemnumber LIMIT ?');

    my $sth_next_items = $dbh->prepare($next_query . $query_cond . ' ORDER BY cn_sort, itemnumber LIMIT ?');

    push @params, $num_each_side;

    $sth_prev_items->execute(@params);

    $sth_next_items->execute(@params);

    # Now we have the query run, suck out the data like marrow

    my @prev_items = reverse GetShelfInfo($sth_prev_items, $marcflavour);

    my @next_items = GetShelfInfo($sth_next_items, $marcflavour);

    my $next_itemnumber = $next_items[-1]->{itemnumber} if @next_items;

    my $next_biblionumber = $next_items[-1]->{biblionumber} if @next_items;

    my $prev_itemnumber = $prev_items[0]->{itemnumber} if @prev_items;

    my $prev_biblionumber = $prev_items[0]->{biblionumber} if @prev_items;

    my %result = (

        next                => \@next_items,

        prev                => \@prev_items,

        next_itemnumber     => $next_itemnumber,

        next_biblionumber   => $next_biblionumber,

        prev_itemnumber     => $prev_itemnumber,

        prev_biblionumber   => $prev_biblionumber,   

        starting_itemnumber => $itemnumber,

    );

    $result{starting_homebranch} = $start_homebranch if $start_homebranch;

    $result{starting_location}   = $start_location   if $start_location;

    $result{starting_ccode}         = $start_ccode      if $start_ccode;

    return \%result;

}

# This runs through a statement handle and pulls out all the items in it, fills

# them up with additional info that shelves want, and returns those as a list.

# Not really intended to be exported.

sub GetShelfInfo {

    my ($sth, $marcflavour) = @_;

    my @items;

    while (my $this_item = $sth->fetchrow_hashref()) {

        my $this_biblio = GetBibData($this_item->{biblionumber});

        next if (!defined($this_biblio));

        $this_item->{'title'} = $this_biblio->{'title'};

        my $this_record = GetMarcBiblio($this_biblio->{'biblionumber'});

        $this_item->{'browser_normalized_upc'} = GetNormalizedUPC($this_record,$marcflavour);

        $this_item->{'browser_normalized_oclc'} = GetNormalizedOCLCNumber($this_record,$marcflavour);

        $this_item->{'browser_normalized_isbn'} = GetNormalizedISBN(undef,$this_record,$marcflavour);

        push @items, $this_item;

    }

    return @items;

}

# Fetches some basic biblio data needed by the shelf stuff

sub GetBibData {

	my ($bibnum) = @_;

    my $dbh         = C4::Context->dbh;

    my $sth = $dbh->prepare("SELECT biblionumber, title FROM biblio WHERE biblionumber=?");

    $sth->execute($bibnum);

    my $bib = $sth->fetchrow_hashref();

    return $bib;

}

1;

INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesLocation','1','Use the item location when finding items for the shelf browser.','1','YesNo');

INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesHomeBranch','1','Use the item home branch when finding items for the shelf browser.','1','YesNo');

INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesCcode','1','Use the item collection code when finding items for the shelf browser.','0','YesNo');

$DBversion = 'XXX';

if (C4::Context->preference("Version") < TransformToNum($DBversion)) {

    $dbh->do("INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesLocation','1','Use the item location when finding items for the shelf browser.','1','YesNo')");

    $dbh->do("INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesHomeBranch','1','Use the item home branch when finding items for the shelf browser.','1','YesNo')");

    $dbh->do("INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('ShelfBrowserUsesCcode','0','Use the item collection code when finding items for the shelf browser.','1','YesNo')");

    print "Upgrade to $DBversion done (Add flexible shelf browser constraints)\n";

    SetVersion ($DBversion);

}

    Shelf Browser:

        -

            - pref: OPACShelfBrowser

              choices:

                  yes: Show

                  no: "Don't show"

            - "a shelf browser on item details pages, allowing patrons to see what's near that item on the shelf. Note that this uses up a fairly large amount of resources on your server, and should be avoided if your collection has a large number of items."

        -

            - pref: ShelfBrowserUsesLocation

              default: 1

              choices:

                  yes: Use

                  no: "Don't use"

            - "the item location when finding items for the shelf browser."

        -

            - pref: ShelfBrowserUsesHomeBranch

              default: 1

              choices:

                  yes: Use

                  no: "Don't use"

            - "the item home branch when finding items for the shelf browser."      

        -

            - pref: ShelfBrowserUsesCcode

              default: 0

              choices:

                  yes: Use

                  no: "Don't use"

            - "the item collection code when finding items for the shelf browser."      

use C4::ShelfBrowser;