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

use XML::Twig;
use YAML::Tiny;
use Getopt::Long;
use Equinox::Migration::SubfieldMapper;

$| = 1;

my $c = initialize();
my $marcxml = shift;
my $copyid = 0;
my $holdings;

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);
write_sample_fieds();

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

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

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

sub process_datafields {
    my ($d) = @_;
    my $tag = $d->{'att'}->{'tag'};

    if ($tag == 903) {
        my $s = $d->first_child('subfield');
        $holdings->{id} = $s->text;;
    } elsif ($c->{map}->has($tag)) {
        push @{$holdings->{copies}}, { tag => $tag };
        my @subs = $d->children('subfield');
        for my $sub (@subs)
          { process_subs($tag,$sub) }
    }
}

sub process_subs {
    my ($tag, $sub) = @_;
    my $code = $sub->{'att'}->{'code'};

    unless ($c->{map}->has($tag, $code)) {
        # this is a subfield code we don't have mapped. report on it if this is a sample tag
        push @{$c->{sample}{$tag}}, $code if defined $c->{sample}{tag};
        return;
    }

    my $copy = $holdings->{copies}[-1];
    my $field = $c->{map}->field($tag, $code);
    if ($c->{map}->mod($field) eq 'multi') {
        my $name = $tag . $code;
        push @{$copy->{multi}{$name}}, $sub->text;
    } else {
        $copy->{uni}{$code} = $sub->text;
    }
}


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

sub write_data_out {
    my $i = 0;

    for my $copy (@{$holdings->{copies}}) {
        print HOLDINGS $holdings->{id}, "\t$i\t", $copy->{tag};
        for ( sort keys %{ $c->{map}{fields} } ) {
            if (defined $copy->{uni}{$_->{sub}}) {
                print HOLDINGS "\t", $copy->{uni}{$_->{sub}};
            } else {
                print HOLDINGS "\t";
            }
        }
        print HOLDINGS "\n";

        for my $m (sort keys %{$copy->{multi}}) {
            my $fh = $c->{files}{multi}{$m};
            print $fh join("\t", $holdings->{id}, $i, @{$copy->{multi}{$m}}), "\n";
        }
        $i++;
    }
}

sub write_sample_fields {
}

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


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

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

    my $rc = GetOptions( $c,
                         'sample|s=s',
                         'map|m=s',
                         'ils=s',
                         'prefix|p=s',
                         'help|h',
                       );
    show_help() unless $rc;
    show_help() if ($c->{help});

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

    # generate subfield map
    $c->{map} = Equinox::Migration::SubfieldMapper->new( file => $c->{map} );

    # explode sample tags string
    if (defined $c->{sample}) {
        my $sample = $c->{sample};
        $c->{sample} = {};
        for (split /,/, $c->{sample}) {
            $c->{sample}{$_} = [];
        }
    }

    # open required files
    open HOLDINGS, '>', ($c->{prefix} . ".holdings.pg");
    for my $f (keys %{$c->{map}{fields}}) {
        if ($c->{map}->mod($f)) {
          open my $mfh, '>', join('.', $c->{prefix}, "holdings",
                                  $c->{map}{fields}{$f}{tag},
                                  $c->{map}{fields}{$f}{sub}, "pg");
          $c->{files}{multi}{ ($c->{map}{fields}{$f}{tag} . $c->{map}{fields}{$f}{sub}) }
            = $mfh;
      }
    }

    # print file headers
    print HOLDINGS "BEGIN;\n";
    print HOLDINGS "CREATE TABLE ", $c->{prefix}, ".asset_copy_", $c->{ils};
    print HOLDINGS $c->{library} if (defined $c->{library});
    print HOLDINGS " (";
    for ( sort keys %{ $c->{map}{fields} } ) {
        print HOLDINGS "l_", $_, " TEXT, ";
    }
    print HOLDINGS ") INHERITS FROM (", $c->{prefix}, ".asset_copy);\n";
    print HOLDINGS "COPY ", $c->{prefix}, ".asset_copy_", $c->{ils};
    print HOLDINGS $c->{library} if (defined $c->{library});
    print HOLDINGS " (";
    for ( sort keys %{ $c->{map}{fields} } ) {
        print HOLDINGS "l_", $_, ", ";
    }
    print HOLDINGS ") FROM STDIN;\n";


    return $c;
}

sub show_help {
    print <<HELP;
Usage is: ...
HELP
    exit;
}