#!/usr/bin/env perl

=head1 NAME

Move Division

=head1 SYNOPSIS

Moves all prints from a given list of divisions to a destination division.

=head1 AUTHOR

Robert Berry <robert.berry@liverpool.ac.uk>

=cut

use FindBin;
use lib "$FindBin::Bin/../perl_lib";
use EPrints;
use Getopt::Long;
use strict;

# Minimum number of CL arguments
use constant MIN_ARGUMENTS => 3;

# Default Session noise level
use constant DEFAULT_NOISE => 1;

# Error code for invalid usage
use constant ERRNO_USAGE => 1;

# Error code for incorrect session name
use constant ERRNO_BAD_SESSION => 2;

=head1 METHODS

=method usage

Returns usage information and exits.

=cut

sub usage {
    print "$0 <repository_id> <from...> <to> [--quiet] [--force]\n";
    exit ERRNO_USAGE;
}

=method session_from_args

Returns an EPrints session from the CL arguments.

=cut

sub session_from_args {
    my $noise;

    if (@_ == 1) {
        $noise = shift @_;
    } else {
        $noise = DEFAULT_NOISE;
    }

    EPrints::Session->new(1, $ARGV[0], $noise);
}

=method main

Moves all of the given divisions in the argument list to the destination division.

=cut

sub main {
    my $quiet = 0;
    my $verbose = 0;
    my $force = 0;

    GetOptions(
        'quiet+' => \$quiet,
        'force+' => \$force
    ) || usage();

    usage() if scalar @ARGV < MIN_ARGUMENTS;

    $verbose = 1 - $quiet;
    our $noise = 1 + $verbose;
    my $session = session_from_args $noise;

    unless (defined $session) {
        print STDERR "Unable to load session for $ARGV[0]. Is this a valid repository?\n";
        exit ERRNO_BAD_SESSION;
    }

    my (@divisions) = @ARGV[1..@ARGV-1];
    my $destination = pop @divisions;

    my $moved = 0;

    for my $division (@divisions) {
        my $prints = prints_for_division($session, $division);
        my $count = $prints->count;

        next unless $force or yes_or_no("Move $count prints from $division to $destination");
        if ($verbose) {
            print "Moving $count prints from $division ... ";
        }
        move_prints($prints, $destination);
        $moved += $count;
        print "Done!\n";
    }

    if ($verbose) {
        print "Moved $moved prints.\n";
        print "*********************************\n";
        print "WARNING: Run bin/generate_views - your repository views will be out of date.\n";
        print "*********************************\n";
    }
}

=method move_print

Moves an EPrint to the given division.

=cut

sub move_print {
    my ($print, $destination) = @_;

    $print->set_value("divisions", [$destination]);
    $print->commit;
}

=method move_prints

Moves all prints from a given EPrints result set to the destination division.

=cut

sub move_prints {
    my ($prints, $destination) = @_;

    $prints->map(sub {
        my (undef, undef, $eprint) = @_;
        move_print($eprint, $destination);
    });
}

=method yes_or_no

Asks a yes or no question, returns the answer as a boolean.

=cut

sub yes_or_no {
    my $question = shift;

    print $question;
    print " (yes or no)?: ";

    while (1) {
        my $answer = <STDIN>;
        if ($answer =~ m/y(?:es)?/i) {
            return 1;
        } elsif ($answer =~ m/no?/i) {
            return 0;
        }
        print "Please enter 'yes' or 'no': ";
    }
}

=method prints_for_division

Returns an EPrints results set for all prints in a given division.

=cut

sub prints_for_division {
    my ($session, $division) = @_;

    my $dataset = $session->get_repository->get_dataset("eprint");

    my $search = EPrints::Search->new(
        session => $session,
        dataset => $dataset,
        satisfy_all => 1);

    $search->add_field(
        $dataset->get_field("divisions"),
        $division);

    return $search->perform_search;
}

main unless caller;

=COPYRIGHT

Copyright (c) 2012 The University of Liverpool

This program 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.

This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

=cut