#!/usr/bin/perl
use warnings;
use strict;

use Getopt::Long;

# configuration hashref
my $conf  = {};
initialize($conf);

my %id;

open F, "<", $conf->{idfile};
while (<F>) {
	chomp;
	$id{$_} = 1;
}
close F;

my $M; my $I; my $S;
open $M, '<:utf8', $conf->{marcfile}
  or die "Can't open marcfile '",$conf->{marcfile},"'\n";
open $I, '>:utf8', $conf->{'output-import'}
  or die "Can't open import file '",$conf->{'output-import'},"'\n";
open $S, '>:utf8', $conf->{'output-shelved'}
  or die "Can't open shelf file '",$conf->{'output-shelve'},"'\n";

while (<$M>) {
    my $tag = $conf->{tag};
    my $sub = $conf->{subfield};

    /tag="$tag" ind1=" " ind2=" ">.*?<subfield code="$sub">(\d+)</;
    if ($conf->{mode} eq "exclude") {
        print $S $_ if ($id{$1});
        print $I $_ unless ($id{$1});;
    } else {
        print $S $_ unless ($id{$1});
        print $I $_ if ($id{$1});;
    }
    $conf->{count}++;

    unless ($conf->{count} % 100) {
        print STDERR "\rProcessed: ",$conf->{count};
    }
}

=head2 initialize

Performs boring script initialization. Handles argument parsing,
mostly.

=cut

sub initialize {
    my ($c) = @_;
    my @missing = ();

    # set mode on existing filehandles
    binmode(STDIN, ':utf8');

    my $rc = GetOptions( $c,
                         'mode=s',
                         'include',
                         'tag|t=i',
                         'subfield|s=s',
                         'idfile|i=s',
                         'marcfile|m=s',
                         'output-import|oi=s',
                         'output-shelved|os=s',
                         'help|h',
                       );
    show_help() unless $rc;
    show_help() if ($c->{help});

    my @keys = keys %{$c};
    for my $key ('mode', 'idfile', 'marcfile', 'tag', 'subfield',
                 'output-import', 'output-shelved')
      { push @missing, $key unless $c->{$key} }
    if (@missing) {
        print "Required option: ", join(', ', @missing), " missing!\n";
        show_help();
    }
    unless ($c->{mode} eq "include" or $c->{mode} eq "exclude") {
        print "Unknown run mode '", $c->{mode}, "'\n";
        show_help();
    }
}


=head2 show_help

Display usage message when things go wrong

=cut

sub show_help {
print <<HELP;
Usage is: $0 [ARGS]

  --mode=MODE           Runmode to use (exclude, include; usually exclude)
  --idfile         -i   File of record ids to use as source for matchpoints
  --marcfile       -m   MARCXML source file
  --tag            -t   MARC tag to use as matchpoint (903 when matching
                        incoming records, 901 when matching incumbents)
  --subfield       -s   Subfield of tag to use ('a' for incoming, 'c'
                        for incumbent)
  --output-import  -oi  Output MARCXML file for records to be imported
  --output-shelved -os  Output MARCXML file for records to be ignored

If '--mode=exclude' is specified, the record ids in the file specified
by -idfile will be used as EXCLUSION data.

That is, the given record ids will be treated as records which match
incumbent records, are being compressed into existing data, and so
WILL NOT be imported. The --output-import file will contain records
whose ids DO NOT occur in --idfile; --output-shelved will contain the
records which DO occur.

If '--mode=include' is specified, the reverse occurs.
HELP
exit 1;
}