#!/usr/bin/perl

use strict;
use warnings;

use Getopt::Long;
use Term::ReadLine;

$| = 1;

my $term = new Term::ReadLine 'yaz-cleanup';
my $OUT = $term->OUT || \*STDOUT;

my $conf = {};

my $count = 0;
my $reccount = 0;
my $oreccount = 0;
my $line = '';
my %trash = ();   # hash for tags to be dumped

# initialization and setup
initialize($conf);

# read in trash tags file if it exists
populate_trash() if ($conf->{trash});

my @record = ();  # current record storage
my %recmeta = (); # metadata about current record
my @context= ();  # last 5 lines of file

my $input = shift || 'incoming.marc.xml';

open MARC, '<:utf8', $input;
open my $NUMARC, '>:utf8', $conf->{output};
print $NUMARC '<?xml version="1.0" encoding="UTF-8"?>',"\n";
print $NUMARC '<collection xmlns="http://www.loc.gov/MARC21/slim">',"\n";

open my $EXMARC, '>:utf8', $conf->{exception};
print $EXMARC '<?xml version="1.0" encoding="UTF-8"?>',"\n";
print $EXMARC '<collection xmlns="http://www.loc.gov/MARC21/slim">',"\n";
open MARC2, '<', $input;
<MARC2>;

# this is the dispatch table which drives command selection in
# edit(), below
my %commands = ( c => \&print_context,
                 C => \&print_linecontext,
                 k => \&kill_line,
                 o => \&show_original,
                 m => \&merge_lines,
                 s => \&substitute,
                 t => \&commit_edit,
                 x => \&dump_record,
                 q => \&quit,
                 '?' => \&help,
                 h   => \&help,
                 help => \&help,
               );

my @spinner = qw(- / | \\);
my $sidx = 0;

while (my $line = getline()) {
    unless ($count % 2000) {
        print "\rWorking... ", $spinner[$sidx];
        $sidx = ($sidx == $#spinner) ? 0 : $sidx + 1;
    }
    update_linecontext();

    next if ($line =~ m|</record>|);

    # catch empty datafield elements
    if ($line =~ m|</datafield>|) {
        if ($record[-2] =~ m/<datafield tag="..." ind1="." ind2=".">/) {
            pop @record; pop @record;
            message("Empty datafield scrubbed");
            next;
        }
    }

    # pad short leaders
    if ($line =~ m|<leader>(.+?)</leader>|) {
        my $leader = $1;
        if (length $leader < 24) {
            $leader .= ' ' x (20 - length($leader));
            $leader .= "4500";
            $line = "<leader>$leader</leader>\n";
            message("Short leader padded");
        }
    }

    # clean misplaced dollarsigns
    if ($line =~ m|<subfield code="\$">c?\d+\.\d{2}|) {
        $line =~ s|"\$">c?(\d+\.\d{2})|"c">\$$1|;
        message("Dollar sign corrected");
    }

    # clean up tags with spaces in them
    $line =~ s/tag="  /tag="00/g;
    $line =~ s/tag=" /tag="0/g;
    $line =~ s/tag="-/tag="0/g;
    $line =~ s/tag="(\d\d) /tag="0$1/g;

    # stow tag data if we're looking at it
    if ($line =~ m/<datafield tag="(.{3})" ind1="(.)" ind2="(.)">/) {
        $recmeta{tag}  = $1;
        $recmeta{ind1} = $2;
        $recmeta{ind2} = $3;
    }

    # automatable subfield maladies
    $line =~ s/code=" ">c/code="c">/;
    $line =~ s/code=" ">\$/code="c"$>/;

    # and stow line back in record
    $record[-1] = $line;

    # naked ampersands
    if ($line =~ /&/ && $line !~ /&\w+?;/)
      { edit("Naked ampersand", $line); next }

    # tags must be numeric
    if ($line =~ /<datafield tag="(.+?)"/) {
        my $match = $1;
        if ($match =~ /\D/) {
            edit("Non-numerics in tag", $line);
            next;
        }
    }

    # subfields can't be non-alphanumeric
    if ($line =~ /<subfield code="(.*?)"/) {
        my $match = $1;
        if ($match =~ /\P{IsAlnum}/ or $match eq '') {
            edit("Junk in subfield code/Null subfield code", $line);
            next;
        }
    }

}
print $NUMARC "</collection>\n";
print $EXMARC "</collection>\n";
print $OUT "\nDone.               \n";

=head2 edit

Handles the Term::ReadLine loop

=cut

sub edit {
    my ($msg, $line_in) = @_;
    return if $trash{$recmeta{tag}};
    message($msg);
    print_context();

    while (1) {
        my $line = $term->readline('marc-cleanup>');
        my @chunks = split /\s+/, $line;

        if (length $chunks[0] == 1)
          { next unless (defined $commands{$chunks[0]}) }

        if (defined $commands{$chunks[0]}) {
            my $term = $commands{$chunks[0]}->($line_in, @chunks[1..$#chunks]);
            last if $term;
        } else {
            if ($context[3] eq " [LINE KILLED]\n") {
                push @record, "$line\n"
            } else {
                $record[-1] = "$line\n";
            }
            $context[3] = "$line\n";
            print_linecontext();
        }
    }
}

=head2 getline

Reads from the incoming MARC file; returns lines into the driver
loop. Batches records for output, and maintains the context listing.

=cut

sub getline {
    my $l = <MARC>;
    $count++;
    if (defined $l) {
        if ($l =~ /<record>/) {
            @record = ($l);
            %recmeta = ();
            $reccount++;
        } elsif ($l =~ m|</record>|) {
            write_record($NUMARC) if $reccount;
        } else {
            push @record, $l;
        }
    }
    return $l;
}

sub write_record {
    my ($FH) = @_;
    $oreccount++ if ($FH eq $NUMARC);
    print $FH '<!-- ', $recmeta{explanation}, " -->\n"
      if(defined $recmeta{explanation});

    # excise unwanted tags
    if (keys %trash or $conf->{autoscrub}) {
        my @trimmed = ();
        my $istrash = 0;
        for my $line (@record) {
            if ($istrash) {
                $istrash = 0 if $line =~ m|</datafield|;
                next;
            }
            if ($line =~ m/<datafield tag="(.{3})"/) {
                my $tag = $1;
                if ($trash{$tag} or ($conf->{autoscrub} and $tag =~ /\D/)) {
                    $istrash = 1;
                    next
                }
            }
            push @trimmed, $line;
        }
        @record = @trimmed;
    }

    # scrub newlines
    unless ($conf->{nocollapse}) {
        s/\n// for (@record);
    }

    # add 903(?) with new record id
    my $renumber = '';
    if ($conf->{'renumber-from'}) {
        $renumber = join('', '<datafield tag="', $conf->{'renumber-tag'},
                         '" ind1=" " ind2=" ">',
                         '<subfield code="', $conf->{'renumber-subfield'}, '">',
                         $conf->{'renumber-from'}, '</subfield></datafield>');
        $renumber .= "\n" if $conf->{nocollapse};
        push @record, $renumber;
        $conf->{'renumber-from'}++;
    }

    print $FH @record;
    print $FH "</record>\n";
}

sub update_linecontext {
    my $line2 = <MARC2>;
    push @context, $line2;
    shift @context if (@context > 5);
}

sub message {
    my ($msg) = @_;
    print $OUT "\r$msg at record $reccount/",$oreccount + 1,"\n";

}

#-----------------------------------------------------------------------------------
# command routines
#-----------------------------------------------------------------------------------

sub substitute {
    my ($line_in, @chunks) = @_;
    my $ofrom = shift @chunks;
    if ($ofrom =~ /^'/ or !@chunks) {
        until ($ofrom =~ /'$/)
          { $ofrom .= join(' ','',shift @chunks) }
        $ofrom =~ s/^'//; $ofrom =~ s/'$//;
    }
    my $to = shift @chunks;
    if ($to =~ /^'/) {
        until ($to =~ /'$/ or !@chunks)
          { $to .= join(' ','',shift @chunks) }
        $to =~ s/^'//; $to =~ s/'$//;
    }

    my $from = '';
    for my $char (split(//,$ofrom)) {
        $char = "\\" . $char if ($char =~ /\W/);
        $from = join('', $from, $char);
    }
    $record[-1] =~ s/$from/$to/;
    $context[3] = $record[-1];
    print_linecontext();
    return 0;
}

sub merge_lines {
    my $last = pop @record;
    $last =~ s/^\s+//;
    $record[-1] =~ s/\n//;
    $record[-1] = join('', $record[-1], $last);
    my @temp = ("\n");
    push @temp, @context[0..1];
    $temp[3] = $record[-1];
    $temp[4] = $context[4];
    @context = @temp;
    print_linecontext();
    return 0;
}

sub kill_line {
    pop @record;
    $context[3] = " [LINE KILLED]\n";
    print_linecontext();
    return 0;
}

sub dump_record {
    my ($line_in, @explanation) = @_;
    $recmeta{explanation} = join(' ', 'Tag', $recmeta{tag}, @explanation);
    my $line = <MARC>; $count++;
    update_linecontext();
    until ($line =~ m|</record>|) {
        push @record, $line;
        $line = <MARC>; $count++;
        update_linecontext();
    }
    push @record, $line;
    write_record($EXMARC);
    return 1;
}

sub commit_edit { return 1 }

sub print_context {
    print "\n Tag:",$recmeta{tag}, " Ind1:'",
      $recmeta{ind1},"' Ind2:'", $recmeta{ind2}, "'";
    print_linecontext();
    return 0;
}

sub print_linecontext {
    print $OUT "\n", join('    |','',@context[0..2]);
    print $OUT '==> |', $context[3];
    print $OUT '    |', $context[4],"\n";
    return 0;
}

sub show_original {
    my ($line_in) = @_;
    print $OUT "\n$line_in\n";
    return 0;
}

sub help {
print $OUT <<HELP;

Type a replacement for the indicated line, or enter a command.

Commands: c  Show record context ('C' for brief context)
          k  Kill indicated line (remove from record)
          m  Merge indicated line with previous line
          o  Show original line
          s  Substitute ARG1 for ARG2 in indicated line
          t  Commit changes and resume stream edit
          x  Write this record to the exception file instead of output
          q  Quit

HELP
return 0;
}

sub quit { exit }

#-----------------------------------------------------------------------------------
# populate_trash
#-----------------------------------------------------------------------------------
# defined a domain-specific language for specifying MARC tags to be dropped from
# records during processing. it is line oriented, and is specified as follows:
#
# each line may specify any number of tags to be included, either singly (\d{1,3})
# or as a range (\d{1,3}\.\.\d{1,3}
#
# if a single number is given, it must be between '000' and '999', inclusive.
#
# ranges obey the previous rule, and also the first number of the range must be less
# than the second number
#
# finally, any single range in a line may be followed by the keyword 'except'. every
# number or range after 'except' is excluded from the range specified. all these
# numbers must actually be within the range.
#
# specifying a tag twice is an error, to help prevent typos

sub populate_trash {
    print $OUT ">>> TRASHTAGS FILE FOUND. LOADING TAGS TO BE STRIPPED FROM OUTPUT\n";
    open TRASH, '<', $conf->{trash}
      or die "Can't open trash tags file!\n";
    while (<TRASH>) {
        my $lastwasrange = 0;
        my %lastrange = ( high => 0, low => 0);
        my $except = 0;

        my @chunks = split /\s+/;
        while (my $chunk = shift @chunks) {

            # single values
            if ($chunk =~ /^\d{1,3}$/) {
                trash_add($chunk, $except);
                $lastwasrange = 0;
                next;
            }

            # ranges
            if ($chunk =~ /^\d{1,3}\.\.\d{1,3}$/) {
                my ($low, $high) = trash_add_range($chunk, $except, \%lastrange);
                $lastwasrange = 1;
                %lastrange = (low => $low, high => $high)
                  unless $except;
                next;
            }

            # 'except'
            if ($chunk eq 'except') {
                die "Keyword 'except' can only follow a range (line $.)\n"
                  unless $lastwasrange;
                die "Keyword 'except' may only occur once per line (line $.)\n"
                  if $except;
                $except = 1;
                next;
            }

            die "Unknown chunk $chunk in .trashtags file (line $.)\n";
        }
    }

    # remove original id sequence tag from trash hash if we know it
    trash_add($conf->{'original-tag'}, 1)
      if ($conf->{'original-tag'} and $trash{$conf->{'original-tag'}});
}

sub trash_add_range {
    my ($chunk, $except, $range) = @_;
    my ($low,$high) = split /\.\./, $chunk;
    die "Ranges must be 'low..high' ($low is greater than $high on line $.)\n"
      if ($low > $high);
    if ($except) {
        die "Exception ranges must be within last addition range (line $.)\n"
          if ($low < $range->{low} or $high > $range->{high});
    }
    for my $tag ($low..$high) {
        trash_add($tag, $except)
    }
    return $low, $high;
}

sub trash_add {
    my ($tag, $except) = @_;
    die "Trash values must be valid tags (000-999)\n"
      unless ($tag >= 0 and $tag <= 999);
    if ($except) {
        delete $trash{$tag};
    } else {
        die "Trash tag '$tag' specified twice (line $.)\n"
          if $trash{$tag};
        $trash{$tag} = 1;
    }
}

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

=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,
                         'autoscrub|a',
                         'exception|x=s',
                         'output|o=s',
                         'nocollapse|n',
                         'renumber-from|rf=i',
                         'original-tag|ot=i',
                         'renumber-tag|rt=i',
                         'renumber-subfield|rt=i',
                         'trash|t=s',
                         'help|h',
                       );
    show_help() unless $rc;
    show_help() if ($c->{help});

    # defaults
    $c->{output} = 'incoming.cleaned.marc.xml' unless defined $c->{output};
    $c->{exception} = 'incoming.exception.marc.xml' unless defined $c->{exception};
    $c->{'renumber-tag'} = 903 unless defined $c->{'renumber-tag'};
    $c->{'renumber-subfield'} = 'a' unless defined $c->{'renumber-subfield'};

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

sub show_help {
    print <<HELP;
Usage is: $0 [OPTIONS] <filelist>
Options
  --output     -o  Cleaned MARCXML output filename (default: incoming.cleaned.marc.xml)
  --exception  -x  Exception (dumped records) MARCXML filename (incoming.exception.marc.xml)
HELP
exit;
}