lib/WebPAC/Input.pm

package WebPAC::Input;

use warnings;
use strict;

use lib 'lib';

use WebPAC::Common;
use base qw/WebPAC::Common/;
use Data::Dump qw/dump/;
use Encode qw/decode from_to/;
use YAML;

=head1 NAME

WebPAC::Input - read different file formats into WebPAC

=cut

our $VERSION = '0.19';

=head1 SYNOPSIS

This module implements input as database which have fixed and known
I<size> while indexing and single unique numeric identifier for database
position ranging from 1 to I<size>.

Simply, something that is indexed by unmber from 1 .. I<size>.

Examples of such databases are CDS/ISIS files, MARC files, lines in
text file, and so on.

Specific file formats are implemented using low-level interface modules,
located in C<WebPAC::Input::*> namespace which export C<open_db>,
C<fetch_rec> and optional C<init> functions.

Perhaps a little code snippet.

        use WebPAC::Input;

        my $db = WebPAC::Input->new(
                module => 'WebPAC::Input::ISIS',
        );

        $db->open( path => '/path/to/database' );
        print "database size: ",$db->size,"\n";
        while (my $rec = $db->fetch) {
                # do something with $rec
        }


=head1 FUNCTIONS

=head2 new

Create new input database object.

  my $db = new WebPAC::Input(
        module => 'WebPAC::Input::MARC',
        recode => 'char pairs',
        no_progress_bar => 1,
        input_config => {
                mapping => [ 'foo', 'bar', 'baz' ],
        },
  );

C<module> is low-level file format module. See L<WebPAC::Input::ISIS> and
L<WebPAC::Input::MARC>.

C<recode> is optional string constisting of character or words pairs that
should be replaced in input stream.

C<no_progress_bar> disables progress bar output on C<STDOUT>

This function will also call low-level C<init> if it exists with same
parametars.

=cut

sub new {
        my $class = shift;
        my $self = {@_};
        bless($self, $class);

        my $log = $self->_get_logger;

        $log->logconfess("code_page argument is not suppored any more.") if $self->{code_page};
        $log->logconfess("encoding argument is not suppored any more.") if $self->{encoding};
        $log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_ref") if $self->{lookup};
        $log->logconfess("low_mem argument is not suppored any more. rewrite it to load_row and save_row") if $self->{low_mem};

        $log->logconfess("specify low-level file format module") unless ($self->{module});
        my $module_path = $self->{module};
        $module_path =~ s#::#/#g;
        $module_path .= '.pm';
        $log->debug("require low-level module $self->{module} from $module_path");

        require $module_path;

        $self ? return $self : return undef;
}

=head2 open

This function will read whole database in memory and produce lookups.

 my $store;     # simple in-memory hash

 $input->open(
        path => '/path/to/database/file',
        input_encoding => 'cp852',
        strict_encoding => 0,
        limit => 500,
        offset => 6000,
        stats => 1,
        lookup_coderef => sub {
                my $rec = shift;
                # store lookups
        },
        modify_records => {
                900 => { '^a' => { ' : ' => '^b' } },
                901 => { '*' => { '^b' => ' ; ' } },
        },
        modify_file => 'conf/modify/mapping.map',
        save_row => sub {
                my $a = shift;
                $store->{ $a->{id} } = $a->{row};
        },
        load_row => sub {
                my $a = shift;
                return defined($store->{ $a->{id} }) &&
                        $store->{ $a->{id} };
        },

 );

By default, C<input_encoding> is assumed to be C<cp852>.

C<offset> is optional parametar to position at some offset before reading from database.

C<limit> is optional parametar to read just C<limit> records from database

C<stats> create optional report about usage of fields and subfields

C<lookup_coderef> is closure to called to save data into lookups

C<modify_records> specify mapping from subfields to delimiters or from
delimiters to subfields, as well as oprations on fields (if subfield is
defined as C<*>.

C<modify_file> is alternative for C<modify_records> above which preserves order and offers
(hopefully) simplier sintax than YAML or perl (see L</modify_file_regex>). This option
overrides C<modify_records> if both exists for same input.

C<save_row> and C<load_row> are low-level implementation of store engine. Calling convention
is documented in example above.

C<strict_encoding> should really default to 1, but it doesn't for now.

Returns size of database, regardless of C<offset> and C<limit>
parametars, see also C<size>.

=cut

sub open {
        my $self = shift;
        my $arg = {@_};

        my $log = $self->_get_logger();
        $log->debug( "arguments: ",dump( $arg ));

        $log->logconfess("encoding argument is not suppored any more.") if $self->{encoding};
        $log->logconfess("code_page argument is not suppored any more.") if $self->{code_page};
        $log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_coderef") if ($arg->{lookup});
        $log->logconfess("lookup_coderef must be CODE, not ",ref($arg->{lookup_coderef}))
                if ($arg->{lookup_coderef} && ref($arg->{lookup_coderef}) ne 'CODE');

        $log->debug( $arg->{lookup_coderef} ? '' : 'not ', "using lookup_coderef");

        $log->logcroak("need path") if (! $arg->{'path'});
        my $input_encoding = $arg->{'input_encoding'} || $self->{'input_encoding'} || 'cp852';

        # store data in object
        foreach my $v (qw/path offset limit/) {
                $self->{$v} = $arg->{$v} if ($arg->{$v});
        }

        if ($arg->{load_row} || $arg->{save_row}) {
                $log->logconfess("save_row and load_row must be defined in pair and be CODE") unless (
                        ref($arg->{load_row}) eq 'CODE' &&
                        ref($arg->{save_row}) eq 'CODE'
                );
                $self->{load_row} = $arg->{load_row};
                $self->{save_row} = $arg->{save_row};
                $log->debug("using load_row and save_row instead of in-memory hash");
        }

        my $filter_ref;
        my $recode_regex;
        my $recode_map;

        if ($self->{recode}) {
                my @r = split(/\s/, $self->{recode});
                if ($#r % 2 != 1) {
                        $log->logwarn("recode needs even number of elements (some number of valid pairs)");
                } else {
                        while (@r) {
                                my $from = shift @r;
                                my $to = shift @r;
                                $recode_map->{$from} = $to;
                        }

                        $recode_regex = join '|' => keys %{ $recode_map };

                        $log->debug("using recode regex: $recode_regex");
                }

        }

        my $rec_regex;
        if (my $p = $arg->{modify_file}) {
                $log->debug("using modify_file $p");
                $rec_regex = $self->modify_file_regexps( $p );
        } elsif (my $h = $arg->{modify_records}) {
                $log->debug("using modify_records ", sub { dump( $h ) });
                $rec_regex = $self->modify_record_regexps(%{ $h });
        }
        $log->debug("rec_regex: ", sub { dump($rec_regex) }) if ($rec_regex);

        my $class = $self->{module} || $log->logconfess("can't get low-level module name!");

        my $ll_db = $class->new(
                path => $arg->{path},
                input_config => $arg->{input_config} || $self->{input_config},
#               filter => sub {
#                       my ($l,$f_nr) = @_;
#                       return unless defined($l);
#                       $l = decode($input_encoding, $l);
#                       $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map);
#                       return $l;
#               },
                %{ $arg },
        );

        unless (defined($ll_db)) {
                $log->logwarn("can't open database $arg->{path}, skipping...");
                return;
        }

        my $size = $ll_db->size;

        unless ($size) {
                $log->logwarn("no records in database $arg->{path}, skipping...");
                return;
        }

        my $from_rec = 1;
        my $to_rec = $size;

        if (my $s = $self->{offset}) {
                $log->debug("skipping to MFN $s");
                $from_rec = $s;
        } else {
                $self->{offset} = $from_rec;
        }

        if ($self->{limit}) {
                $log->debug("limiting to ",$self->{limit}," records");
                $to_rec = $from_rec + $self->{limit} - 1;
                $to_rec = $size if ($to_rec > $size);
        }

        # store size for later
        $self->{size} = ($to_rec - $from_rec) ? ($to_rec - $from_rec + 1) : 0;

        my $strict_encoding = $arg->{strict_encoding} || $self->{strict_encoding}; ## FIXME should be 1 really

        $log->info("processing $self->{size}/$size records [$from_rec-$to_rec]",
                " encoding $input_encoding ", $strict_encoding ? ' [strict]' : '',
                $self->{stats} ? ' [stats]' : '',
        );

        # read database
        for (my $pos = $from_rec; $pos <= $to_rec; $pos++) {

                $log->debug("position: $pos\n");

                my $rec = $ll_db->fetch_rec($pos, sub {
                                my ($l,$f_nr,$debug) = @_;
#                               return unless defined($l);
#                               return $l unless ($rec_regex && $f_nr);

                                return unless ( defined($l) && defined($f_nr) );

                                warn "-=> $f_nr ## |$l|\n" if ($debug);
                                $log->debug("-=> $f_nr ## $l");

                                # codepage conversion and recode_regex
                                $l = decode($input_encoding, $l, 1);
                                $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map);

                                # apply regexps
                                if ($rec_regex && defined($rec_regex->{$f_nr})) {
                                        $log->logconfess("regexps->{$f_nr} must be ARRAY") if (ref($rec_regex->{$f_nr}) ne 'ARRAY');
                                        my $c = 0;
                                        foreach my $r (@{ $rec_regex->{$f_nr} }) {
                                                my $old_l = $l;
                                                $log->logconfess("expected regex in ", dump( $r )) unless defined($r->{regex});
                                                eval '$l =~ ' . $r->{regex};
                                                if ($old_l ne $l) {
                                                        my $d = "|$old_l| -> |$l| "; # . $r->{regex};
                                                        $d .= ' +' . $r->{line} . ' ' . $r->{file} if defined($r->{line});
                                                        $d .= ' ' . $r->{debug} if defined($r->{debug});
                                                        $log->debug("MODIFY $d");
                                                        warn "*** $d\n" if ($debug);

                                                }
                                                $log->error("error applying regex: ",dump($r), $@) if $@;
                                        }
                                }

                                $log->debug("<=- $f_nr ## |$l|");
                                warn "<=- $f_nr ## $l\n" if ($debug);
                                return $l;
                });

                $log->debug(sub { dump($rec) });

                if (! $rec) {
                        $log->warn("record $pos empty? skipping...");
                        next;
                }

                # store
                if ($self->{save_row}) {
                        $self->{save_row}->({
                                id => $pos,
                                row => $rec,
                        });
                } else {
                        $self->{data}->{$pos} = $rec;
                }

                # create lookup
                $arg->{'lookup_coderef'}->( $rec ) if ($rec && $arg->{'lookup_coderef'});

                # update counters for statistics
                if ($self->{stats}) {

                        # fetch clean record with regexpes applied for statistics
                        my $rec = $ll_db->fetch_rec($pos);

                        foreach my $fld (keys %{ $rec }) {
                                $self->{_stats}->{fld}->{ $fld }++;

                                #$log->logdie("invalid record fild $fld, not ARRAY")
                                next unless (ref($rec->{ $fld }) eq 'ARRAY');
        
                                foreach my $row (@{ $rec->{$fld} }) {

                                        if (ref($row) eq 'HASH') {

                                                foreach my $sf (keys %{ $row }) {
                                                        next if ($sf eq 'subfields');
                                                        $self->{_stats}->{sf}->{ $fld }->{ $sf }->{count}++;
                                                        $self->{_stats}->{sf}->{ $fld }->{ $sf }->{repeatable}++
                                                                        if (ref($row->{$sf}) eq 'ARRAY');
                                                }

                                        } else {
                                                $self->{_stats}->{repeatable}->{ $fld }++;
                                        }
                                }
                        }
                }

                $self->progress_bar($pos,$to_rec) unless ($self->{no_progress_bar});

        }

        $self->{pos} = -1;
        $self->{last_pcnt} = 0;

        # store max mfn and return it.
        $self->{max_pos} = $to_rec;
        $log->debug("max_pos: $to_rec");

        # save for dump
        $self->{ll_db} = $ll_db;

        return $size;
}

=head2 fetch

Fetch next record from database. It will also displays progress bar.

 my $rec = $isis->fetch;

Record from this function should probably go to C<data_structure> for
normalisation.

=cut

sub fetch {
        my $self = shift;

        my $log = $self->_get_logger();

        $log->logconfess("it seems that you didn't load database!") unless ($self->{pos});

        if ($self->{pos} == -1) {
                $self->{pos} = $self->{offset};
        } else {
                $self->{pos}++;
        }

        my $mfn = $self->{pos};

        if ($mfn > $self->{max_pos}) {
                $self->{pos} = $self->{max_pos};
                $log->debug("at EOF");
                return;
        }

        $self->progress_bar($mfn,$self->{max_pos}) unless ($self->{no_progress_bar});

        my $rec;

        if ($self->{load_row}) {
                $rec = $self->{load_row}->({ id => $mfn });
        } else {
                $rec = $self->{data}->{$mfn};
        }

        $rec ||= 0E0;
}

=head2 pos

Returns current record number (MFN).

 print $isis->pos;

First record in database has position 1.

=cut

sub pos {
        my $self = shift;
        return $self->{pos};
}


=head2 size

Returns number of records in database

 print $isis->size;

Result from this function can be used to loop through all records

 foreach my $mfn ( 1 ... $isis->size ) { ... }

because it takes into account C<offset> and C<limit>.

=cut

sub size {
        my $self = shift;
        return $self->{size};
}

=head2 seek

Seek to specified MFN in file.

 $isis->seek(42);

First record in database has position 1.

=cut

sub seek {
        my $self = shift;
        my $pos = shift;

        my $log = $self->_get_logger();

        $log->logconfess("called without pos") unless defined($pos);

        if ($pos < 1) {
                $log->warn("seek before first record");
                $pos = 1;
        } elsif ($pos > $self->{max_pos}) {
                $log->warn("seek beyond last record");
                $pos = $self->{max_pos};
        }

        return $self->{pos} = (($pos - 1) || -1);
}

=head2 stats

Dump statistics about field and subfield usage

  print $input->stats;

=cut

sub stats {
        my $self = shift;

        my $log = $self->_get_logger();

        my $s = $self->{_stats};
        if (! $s) {
                $log->warn("called stats, but there is no statistics collected");
                return;
        }

        my $max_fld = 0;

        my $out = join("\n",
                map {
                        my $f = $_;
                        die "no field in ", dump( $s->{fld} ) unless defined( $f );
                        my $v = $s->{fld}->{$f} || die "no s->{fld}->{$f}";
                        $max_fld = $v if ($v > $max_fld);

                        my $o = sprintf("%4s %d ~", $f, $v);

                        if (defined($s->{sf}->{$f})) {
                                my @subfields = keys %{ $s->{sf}->{$f} };
                                map {
                                        $o .= sprintf(" %s:%d%s", $_, 
                                                $s->{sf}->{$f}->{$_}->{count},
                                                $s->{sf}->{$f}->{$_}->{repeatable} ? '*' : '',
                                        );
                                } (
                                        # first indicators and other special subfields
                                        sort( grep { length($_)  > 1 } @subfields ),
                                        # then subfileds (single char)
                                        sort( grep { length($_) == 1 } @subfields ),
                                );
                        }

                        if (my $v_r = $s->{repeatable}->{$f}) {
                                $o .= " ($v_r)" if ($v_r != $v);
                        }

                        $o;
                } sort { 
                        if ( $a =~ m/^\d+$/ && $b =~ m/^\d+$/ ) {
                                $a <=> $b
                        } else {
                                $a cmp $b
                        }
                } keys %{ $s->{fld} }
        );

        $log->debug( sub { dump($s) } );

        my $path = 'var/stats.yml';
        YAML::DumpFile( $path, $s );
        $log->info( 'created ', $path, ' with ', -s $path, ' bytes' );

        return $out;
}

=head2 dump_ascii

Display humanly readable dump of record

=cut

sub dump_ascii {
        my $self = shift;

        return unless $self->{ll_db};

        if ($self->{ll_db}->can('dump_ascii')) {
                return $self->{ll_db}->dump_ascii( $self->{pos} );
        } else {
                return dump( $self->{ll_db}->fetch_rec( $self->{pos} ) );
        }
}

=head2 _get_regex

Helper function called which create regexps to be execute on code.

  _get_regex( 900, 'regex:[0-9]+' ,'numbers' );
  _get_regex( 900, '^b', ' : ^b' );

It supports perl regexps with C<regex:> prefix to from value and has
additional logic to skip empty subfields.

=cut

sub _get_regex {
        my ($sf,$from,$to) = @_;

        # protect /
        $from =~ s!/!\\/!gs;
        $to =~ s!/!\\/!gs;

        if ($from =~ m/^regex:(.+)$/) {
                $from = $1;
        } else {
                $from = '\Q' . $from . '\E';
        }
        if ($sf =~ /^\^/) {
                my $need_subfield_data = '*';   # no
                # if from is also subfield, require some data in between
                # to correctly skip empty subfields
                $need_subfield_data = '+' if ($from =~ m/^\\Q\^/);
                return
                        's/\Q'. $sf .'\E([^\^]' . $need_subfield_data . '?)'. $from .'([^\^]*?)/'. $sf .'$1'. $to .'$2/';
        } else {
                return
                        's/'. $from .'/'. $to .'/g';
        }
}


=head2 modify_record_regexps

Generate hash with regexpes to be applied using L<filter>.

  my $regexpes = $input->modify_record_regexps(
                900 => { '^a' => { ' : ' => '^b' } },
                901 => { '*' => { '^b' => ' ; ' } },
  );

=cut

sub modify_record_regexps {
        my $self = shift;
        my $modify_record = {@_};

        my $regexpes;

        my $log = $self->_get_logger();

        foreach my $f (keys %$modify_record) {
                $log->debug("field: $f");

                foreach my $sf (keys %{ $modify_record->{$f} }) {
                        $log->debug("subfield: $sf");

                        foreach my $from (keys %{ $modify_record->{$f}->{$sf} }) {
                                my $to = $modify_record->{$f}->{$sf}->{$from};
                                #die "no field?" unless defined($to);
                                my $d = "|$from| -> |$to|";
                                $log->debug("transform: $d");

                                my $regex = _get_regex($sf,$from,$to);
                                push @{ $regexpes->{$f} }, { regex => $regex, debug => $d };
                                $log->debug("regex: $regex");
                        }
                }
        }

        return $regexpes;
}

=head2 modify_file_regexps

Generate hash with regexpes to be applied using L<filter> from
pseudo hash/yaml format for regex mappings.

It should be obvious:

        200
          '^a'
            ' : ' => '^e'
            ' = ' => '^d'

In field I<200> find C<'^a'> and then C<' : '>, and replace it with C<'^e'>.
In field I<200> find C<'^a'> and then C<' = '>, and replace it with C<'^d'>.

  my $regexpes = $input->modify_file_regexps( 'conf/modify/common.pl' );

On undef path it will just return.

=cut

sub modify_file_regexps {
        my $self = shift;

        my $modify_path = shift || return;

        my $log = $self->_get_logger();

        my $regexpes;

        CORE::open(my $fh, $modify_path) || $log->logdie("can't open modify file $modify_path: $!");

        my ($f,$sf);

        while(<$fh>) {
                chomp;
                next if (/^#/ || /^\s*$/);

                if (/^\s*(\d+)\s*$/) {
                        $f = $1;
                        $log->debug("field: $f");
                        next;
                } elsif (/^\s*'([^']*)'\s*$/) {
                        $sf = $1;
                        $log->die("can't define subfiled before field in: $_") unless ($f);
                        $log->debug("subfield: $sf");
                } elsif (/^\s*'([^']*)'\s*=>\s*'([^']*)'\s*$/) {
                        my ($from,$to) = ($1, $2);

                        $log->debug("transform: |$from| -> |$to|");

                        my $regex = _get_regex($sf,$from,$to);
                        push @{ $regexpes->{$f} }, {
                                regex => $regex,
                                file => $modify_path,
                                line => $.,
                        };
                        $log->debug("regex: $regex");
                } else {
                        die "can't parse: $_";
                }
        }

        return $regexpes;
}

=head1 AUTHOR

Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>

=head1 COPYRIGHT & LICENSE

Copyright 2005-2006 Dobrica Pavlinusic, All Rights Reserved.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=cut

1; # End of WebPAC::Input