#!/usr/bin/perl
use strict;
use warnings;
use open ':utf8';

use Getopt::Long;

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

# build exclusion hash
open FP, '<', shift or die "Can't open matchset file: $!\n";
my %exclude = ();
while (<FP>) {
    my ($lead,$sub) = split /\t/;
    $exclude{$sub}  = 1 unless ($sub < $conf->{lowerbound});
}
close FP;

# strip exclusions from marcxml file
open MI, '<', $conf->{marc} or die "Can't open input file: $!\n";
open MO, '>', $conf->{output} or die "Can't open output file: $!\n";
while (<MI>) {
    m/tag="$conf->{tag}",+?<subfield code="$conf->{subfield}">(\d+)</;
    print MO unless $exclude{$1};
}


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

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

    my $rc = GetOptions( $c,
                         'lowerbound|l=i',
                         'input|i=s',
                         'output|o=s',
                         'tag|t=i',
                         'subfield|s=s',
                         'help|h',
                       );
    show_help() unless $rc;
    show_help() if ($c->{help});

    $conf->{tag} = $conf->{tag} || 903;
    $conf->{subfield} = $conf->{subfield} || 'a';

    my @keys = keys %{$c};
    show_help() unless (@ARGV and @keys);
    for my $key ('output', 'lowerbound', 'input')
      { push @missing, $key unless $c->{$key} }
    if (@missing) {
        print "Required option: ", join(', ', @missing), " missing!\n";
        show_help();
    }
}

sub show_help {
    print <<HELP;
Usage is: extract_loadset -l BOUND -i INPUTXML -o OUTPUTXML MATCHSET

  --lowerbound  -l  Lowest record ID which will be included in the loadset
  --input       -i  MARCXML input file
  --output      -o  MARCXML output file
  --tag         -t  MARC tag to use as identifier (default: 903)
  --subfield    -s  Subfield of --tag argument (default: 'a')
HELP
exit;
}