package WebPAC::Normalize::MARC;
use Exporter 'import';
@EXPORT = qw/
	marc_template
/;

use strict;
use warnings;

use Data::Dump qw/dump/;
use Carp qw/confess/;

use WebPAC::Normalize;

my $debug = 1;

=head1 NAME

WebPAC::Normalize::MARC - create MARC/ISO2709 records

=cut

=head1 FUNCTIONS

=head2 marc_template

	marc_template(
		from => 225, to => 440,
		subfields_rename => [
			'a' => 'a',
			'x' => 'x',
			'v' => 'v',
			'h' => 'n',
			'i' => 'p',
			'w' => 'v',
		],
		isis_template => [
			'a ; |v. |i',
			'a. |i ; |w',
		],
		marc_template => [
			'a, |x ; |v. |n, |p ; |v',
			'a ; |v. |p ; |v',
		],
	);

Returns number of records produced.

=cut

sub marc_template {
	my $args = {@_};
	warn "## marc_template(",dump($args),")",$/ if $debug;

	foreach ( qw/subfields_rename isis_template marc_template/ ) {
#		warn "ref($_) = ",ref($args->{$_})  if $debug;
		die "$_ not ARRAY" if defined($args->{$_}) && ref($args->{$_}) ne 'ARRAY';
	}

	die "marc_template needs isis_template or marc_template"
		if ! defined $args->{isis_template} && ! defined $args->{marc_template};

	my $rec = WebPAC::Normalize::_get_rec() || die "_get_rec?";
	my $r = $rec->{ $args->{from} } || return;
	die "record field ", $args->{from}, " isn't array ",dump( $rec ) unless (ref($r) eq 'ARRAY');

	my @subfields_rename = @{ $args->{subfields_rename} };
#	warn "### subfields_rename [$#subfields_rename] = ",dump( @subfields_rename )  if $debug;

	confess "need mapping in pairs for subfields_rename"
		if $#subfields_rename % 2 != 1;
	
	my ( $subfields_rename, $from_subfields );
	our $to_subfields = {};
	while ( my ( $from, $to ) = splice(@subfields_rename, 0, 2) ) {
		my ( $f, $t ) = (
			$from_subfields->{ $from }++,
			$to_subfields->{ $to }++
		);
		$subfields_rename->{ $from }->[ $f ] = [ $to => $t ];
	}
	warn "### subfields_rename = ",dump( $subfields_rename ),$/ if $debug;
	warn "### from_subfields = ", dump( $from_subfields ),$/ if $debug;
	warn "### to_subfields = ", dump( $to_subfields ),$/ if $debug;

	our $_template;

	$_template->{isis}->{fields_re} = join('|', keys %$from_subfields );
	$_template->{marc}->{fields_re} = join('|', keys %$to_subfields );

	my @marc_out;

	sub _parse_template {
		my ( $name, $templates ) = @_;

		my $fields_re = $_template->{$name}->{fields_re} || die "can't find $name in ",dump( $_template->{$name}->{fields_re} );

		foreach my $template ( @{ $templates } ) {
			our $count = {};
			our @order = ();
			sub my_count {
				my $sf = shift;
				my $nr = $count->{$sf}++;
				push @order, [ $sf, $nr ];
				return $sf . $nr;
			}
			my $pos_template = $template;
			$pos_template =~ s/($fields_re)/my_count($1)/ge;
			my $count_key = dump( $count );
			warn "### template: |$template| -> |$pos_template| count = $count_key order = ",dump( @order ),$/ if $debug;
			$_template->{$name}->{pos}->{ $count_key } = $pos_template;
			$_template->{$name}->{order}->{ $pos_template } = [ @order ];
		}
		warn "### from ",dump( $templates ), " using $fields_re created ", dump( $_template ),$/ if $debug;
	}

	_parse_template( 'marc', $args->{marc_template} );
	_parse_template( 'isis', $args->{isis_template} );
	warn "### _template = ",dump( $_template ),$/ if $debug;

	my $m;

	foreach my $r ( @{ $rec->{ $args->{from} } } ) {

		my $i1 = $r->{i1} || ' ';
		my $i2 = $r->{i2} || ' ';
		$m = [ $args->{to}, $i1, $i2 ];

		warn "### r = ",dump( $r ),$/ if $debug;

		my ( $from_mapping, $to_mapping, $from_count, $to_count );
		foreach my $from_sf ( keys %{$r} ) {
			# skip everything which isn't one char subfield (e.g. 'subfields')
			next unless $from_sf =~ m/^\w$/;
			my $from_nr = $from_count->{$from_sf}++;
			my $rename_to = $subfields_rename->{ $from_sf } ||
				die "can't find subfield rename for $from_sf/$from_nr in ", dump( $subfields_rename );
			my ( $to_sf, $to_nr ) = @{ $rename_to->[$from_nr] };
			$to_mapping->{ $to_sf }->[ $to_nr ] = [ $from_sf => $from_nr ];

			my $to_nr2 = $to_count->{ $to_sf }++;
			$from_mapping->{ $from_sf }->[ $from_nr ] = [ $to_sf => $to_nr2 ];

			warn "### from $from_sf/$from_nr -> $to_sf/$to_nr\tto $from_sf/$from_nr -> $to_sf/$to_nr2\n" if $debug;
		}

		warn "### from_mapping = ",dump( $from_mapping ), "\n### to_mapping = ",dump( $to_mapping ),$/ if $debug;

		my $count_key = {
			from => dump( $from_count ),
			to   => dump( $to_count),
		};

		warn "### count_key = ",dump( $count_key ),$/ if $debug;

		my $processed_templates = 0;

		# this defines order of traversal
		foreach ( qw/isis:from marc:to/ ) {
			my ($name,$count_name) = split(/:/);

			my $ckey = $count_key->{$count_name} || die "can't find count_key $count_name in ",dump( $count_key );

			my $template = $_template->{$name}->{pos}->{ $ckey } || next;
			$processed_templates++;

			warn "### traverse $name $count_name selected template: |$template|\n",$/ if $debug;

			our $fill_in = {};

			my @templates = split(/\|/, $template );
			@templates = ( $template );

			foreach my $sf ( @templates ) {
				sub fill_in {
					my ( $name, $r, $sf, $nr ) = @_;
					my ( $from_sf, $from_nr );
					if ( $name eq 'marc' ) {
						die "no $sf/$nr in to_mapping: ",dump( $to_mapping ), " form record ",dump( $r ) unless defined $to_mapping->{$sf}->[$nr];
						( $from_sf, $from_nr ) = @{ $to_mapping->{$sf}->[$nr] };
					} else {
						( $from_sf, $from_nr ) = ( $sf, $nr );
					}
					my $v = $r->{ $from_sf }; # || die "no $from_sf/$from_nr";
					warn "#### fill_in( $sf, $nr ) = $from_sf/$from_nr >>>> ",dump( $v ),$/ if $debug;
					if ( ref( $v ) eq 'ARRAY' ) {
						$fill_in->{$sf}->[$nr] = $v->[$from_nr];
						return $v->[$from_nr];
					} elsif ( $from_nr == 0 ) {
						$fill_in->{$sf}->[$nr] = $v;
						return $v;
					} else {
						die "requested subfield $from_sf/$from_nr but it's ",dump( $v );
					}
				}
				my $fields_re = $_template->{$name}->{fields_re} || die "can't find $name in ",dump( $_template->{$name}->{fields_re} );
				warn "#### $sf <<<< $fields_re\n",$/ if $debug;
				$sf =~ s/($fields_re)(\d+)/fill_in($name,$r,$1,$2)/ge;
				warn "#### >>>> $sf with fill_in = ",dump( $fill_in ),$/ if $debug;
			}

			warn "## template: |$template|\n## _template->$name = ",dump( $_template->{$name} ),$/ if $debug;

			foreach my $sf ( @{ $_template->{$name}->{order}->{$template} } ) {
				my ( $sf, $nr ) = @$sf;
				my $v = $fill_in->{$sf}->[$nr] || die "can't find fill_in $sf/$nr";
				if ( $name eq 'isis') {
					( $sf, $nr ) = @{ $from_mapping->{$sf}->[$nr] };
				}
				warn "++ $sf/$nr |$v|\n" if $debug;
				push @$m, ( $sf, $v );
			}

			warn "#### >>>> created MARC record: ", dump( $m ),$/ if $debug;

			push @marc_out, $m;

			last;
		}
	
		die "I don't have template for fields ",dump( $count_key ), "\n## available templates\n", dump( $_template ) unless $processed_templates;
		warn ">>> $processed_templates templates applied to data\n",$/ if $debug;
	}


	my $recs = 0;

	foreach my $marc ( @marc_out ) {
		warn "+++ ",dump( $marc ),$/ if $debug;
		WebPAC::Normalize::_marc_push( $marc );
		$recs++;
	}

	warn "### marc_template produced $recs MARC records: ",dump( @marc_out ),$/ if $debug;

	return $recs;
}

1;
