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

use XML::Twig;
use YAML::Tiny;
use Getopt::Long;


my $conf = initialize();
my $marcxml = shift;

open HOLDINGS, '>', $conf->{output};
open X, '>', $conf->{pubnotesfile};
open Z, '>', $conf->{privnotesfile};
my $holdings = {};
my %sample = ( x => {}, z => {} ); # hash of all subfields in all 852s
my $copyid = 0;


$| = 1;
my $count = 0;
my $total = `grep -c '<record' $marcxml`;
my $percent = 0;
my $prevper = -1;

my $yaml = YAML::Tiny->new;
my $t = XML::Twig->new( twig_handlers => { record => \&record } );
$t->parsefile($marcxml);
$yaml->[0] = \%sample;
$yaml->write('holdings.sample');
print "\n\n";

sub record {
    my($t, $r)= @_;
    $holdings = { copies => [] };

    my @dfields = $r->children('datafield');
    for my $d (@dfields) 
      { process_datafields($d) }

    for my $copy (@{$holdings->{copies}})
      { print_reports($copy) }
    $r->purge;

    $count++;
    $percent = int(($count / $total) * 100);
    print "\r$percent% done ($count)" if ($percent != $prevper);
    $prevper = $percent;
}

sub process_datafields {
    my ($d) = @_;
    # get 903
    if ($d->{'att'}->{'tag'} == 903) {
        my $s = $d->first_child('subfield');
        $holdings->{id} = $s->text;;
    }

    # and holdings data
    if ($d->{'att'}->{'tag'} == $conf->{tag}) {
        push @{$holdings->{copies}}, { x =>[], z => [] };
        $holdings->{copies}[-1]{copyid} = $copyid;
        my @subs = $d->children('subfield');
        for my $s (@subs)
          { process_subs($s) }
        $copyid++;
    }
}

sub process_subs {
    my ($s) = @_;
    my $copy = $holdings->{copies}[-1];

    my $code = $s->{'att'}->{'code'};
    my $value = $s->text;

    if ($code eq $conf->{pubnotes} or $code eq $conf->{privnotes}) {
        push @{$copy->{$code}}, $value;
        my ($k,$v) = split /:/, $value;
        $sample{$code}{$k} = $v;
    } else {
        $copy->{$code} = $value;
        $sample{$code} = $value;
    }
}

sub print_reports {
    return unless defined $holdings->{id};
    my ($copy) = @_;
    my $note = 0;
    for (@{$copy->{x}}) {
        print X join("\t", $holdings->{id}, $copy->{copyid}, $note, $_), "\n";
        $note++;
    }
    $note = 0;
    for (@{$copy->{z}}) {
        print Z join("\t", $holdings->{id}, $copy->{copyid}, $note, $_), "\n";
        $note++;
    }
    my @fields = ();
    for ( @{$conf->{fields}} )
      { $copy->{$_} = '' unless defined $copy->{$_}; push @fields, $copy->{$_} }
    print HOLDINGS join("\t", $holdings->{id}, $copy->{copyid}, @fields), "\n";
}


#------------------------------------------------


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

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

    my $rc = GetOptions( $c,
                         'fields|f=s',
                         'output|o=s',
                         'prefix|p=s',
                         'pubnotes|pub=i',
                         'pubnotesfile=s',
                         'privnotes|priv=s',
                         'privnotesfile=s',
                         'tag|t=i',
                         'help|h',
                       );
    show_help() unless $rc;
    show_help() if ($c->{help});

    # set defaults
    $c->{prefix} = (defined $c->{prefix}) ? ($c->{prefix} . '.') : '';
    $c->{tag} = $c->{tag} || '852';
    $c->{output} =
      $c->{output} || join('', $c->{prefix}, "holdings.pg");
    $c->{pubnotes} = $c->{pubnotes} || 'x';
    $c->{pubnotesfile} =
      $c->{pubnotesfile} || join('', $c->{prefix}, "holdings.pubnote.pg");
    $c->{privnotes} = $c->{privnotes} || 'z';
    $c->{privnotesfile} =
      $c->{privnotesfile} || join('', $c->{prefix}, "holdings.privnote.pg");

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

    # explode and validate fields string
    process_fields($c);
    return $c;
}

sub process_fields {
    my ($c) = @_;
    my @holdings_fields = split /,/, $c->{fields};
    for (@holdings_fields) { 
        die "Field names must be alphanumeric!\n" if /\W/;
        die "Field names must be single characters!\n"
          if /\w{2,}/;
    }
    $c->{fields} = \@holdings_fields;
}

sub show_help {
    print <<HELP;
Usage is: extract_holdings MARCXML_FILE HOLDINGS_TAG
HELP
    exit;
}