[scpubgit/stemmatology.git] / lib / Text / Tradition / Collation / RelationshipStore.pm

package Text::Tradition::Collation::RelationshipStore;

use strict;
use warnings;
use Text::Tradition::Error;
use Text::Tradition::Collation::Relationship;
use TryCatch;

use Moose;

=head1 NAME

Text::Tradition::Collation::RelationshipStore - Keeps track of the relationships
between readings in a given collation
    
=head1 DESCRIPTION

Text::Tradition is a library for representation and analysis of collated
texts, particularly medieval ones.  The RelationshipStore is an internal object
of the collation, to keep track of the defined relationships (both specific and
general) between readings.

=begin testing

use Text::Tradition;
use TryCatch;

use_ok( 'Text::Tradition::Collation::RelationshipStore' );

# Add some relationships, and delete them

my $cxfile = 't/data/Collatex-16.xml';
my $t = Text::Tradition->new( 
    'name'  => 'inline', 
    'input' => 'CollateX',
    'file'  => $cxfile,
    );
my $c = $t->collation;

my @v1 = $c->add_relationship( 'n21', 'n22', { 'type' => 'meaning' } );
is( scalar @v1, 1, "Added a single relationship" );
is( $v1[0]->[0], 'n21', "Got correct node 1" );
is( $v1[0]->[1], 'n22', "Got correct node 2" );
my @v2 = $c->add_relationship( 'n9', 'n23', 
	{ 'type' => 'spelling', 'scope' => 'global' } );
is( scalar @v2, 2, "Added a global relationship with two instances" );
@v1 = $c->del_relationship( 'n22', 'n21' );
is( scalar @v1, 1, "Deleted first relationship" );
@v2 = $c->del_relationship( 'n8', 'n13' );
is( scalar @v2, 2, "Deleted second global relationship" );
try {
	my @v3 = $c->del_relationship( 'n1', 'n2' );
	ok( 0, "Should have errored on non-existent relationship" );
} catch( Text::Tradition::Error $e ) {
	like( $e->message, qr/No relationship defined/, "Attempt to delete non-existent relationship errored" );
}

=end testing

=head1 METHODS

=head2 new( collation => $collation );

Creates a new relationship store for the given collation.

=cut

has 'collation' => (
	is => 'ro',
	isa => 'Text::Tradition::Collation',
	required => 1,
	weak_ref => 1,
	);

has 'scopedrels' => (
	is => 'ro',
	isa => 'HashRef[HashRef[Text::Tradition::Collation::Relationship]]',
	default => sub { {} },
	);

has 'graph' => (
	is => 'ro',
	isa => 'Graph',
	default => sub { Graph->new( undirected => 1 ) },
    handles => {
    	relationships => 'edges',
    	add_reading => 'add_vertex',
    	delete_reading => 'delete_vertex',
    },
	);
	
=head2 get_relationship

Return the relationship object, if any, that exists between two readings.

=cut

sub get_relationship {
	my $self = shift;
	my @vector;
	if( @_ == 1 && ref( $_[0] ) eq 'ARRAY' ) {
		# Dereference the edge arrayref that was passed.
		my $edge = shift;
		@vector = @$edge;
	} else {
		@vector = @_;
	}
	my $relationship;
	if( $self->graph->has_edge_attribute( @vector, 'object' ) ) {
		$relationship = $self->graph->get_edge_attribute( @vector, 'object' );
	} 
	return $relationship;
}

sub _set_relationship {
	my( $self, $relationship, @vector ) = @_;
	$self->graph->add_edge( @vector );
	$self->graph->set_edge_attribute( @vector, 'object', $relationship );
}

=head2 create

Create a new relationship with the given options and return it.
Warn and return undef if the relationship cannot be created.

=cut

sub create {
	my( $self, $options ) = @_;
	# Check to see if a relationship exists between the two given readings
	my $source = delete $options->{'orig_a'};
	my $target = delete $options->{'orig_b'};
	my $rel = $self->get_relationship( $source, $target );
	if( $rel ) {
		if( $rel->type eq 'collated' ) {
			# Always replace a 'collated' relationship with a more descriptive
			# one, if asked.
			$self->del_relationship( $source, $target );
		} elsif( $rel->type ne $options->{'type'} ) {
			throw( "Another relationship of type " . $rel->type 
				. " already exists between $source and $target" );
		} else {
			return $rel;
		}
	}
	
	# Check to see if a nonlocal relationship is defined for the two readings
	$rel = $self->scoped_relationship( $options->{'reading_a'}, 
		$options->{'reading_b'} );
	if( $rel && $rel->type eq $options->{'type'} ) {
		return $rel;
	} elsif( $rel ) {
		throw( sprintf( "Relationship of type %s with scope %s already defined for readings %s and %s", $rel->type, $rel->scope, $options->{'reading_a'}, $options->{'reading_b'} ) );
	} else {
		$rel = Text::Tradition::Collation::Relationship->new( $options );
		$self->add_scoped_relationship( $rel ) if $rel->nonlocal;
		return $rel;
	}
}

=head2 add_scoped_relationship( $rel )

Keep track of relationships defined between specific readings that are scoped
non-locally.  Key on whichever reading occurs first alphabetically.

=cut

sub add_scoped_relationship {
	my( $self, $rel ) = @_;
	my $r = $self->scoped_relationship( $rel->reading_a, $rel->reading_b );
	if( $r ) {
		warn sprintf( "Scoped relationship of type %s already exists between %s and %s",
			$r->type, $rel->reading_a, $rel->reading_b );
		return;
	}
	$self->scopedrels->{$rel->reading_a}->{$rel->reading_b} = $rel;
}

=head2 scoped_relationship( $reading_a, $reading_b )

Returns the general (document-level or global) relationship that has been defined 
between the two reading strings. Returns undef if there is no general relationship.

=cut

sub scoped_relationship {
	my( $self, $rdga, $rdgb ) = @_;
	my( $first, $second ) = sort( $rdga, $rdgb );
	if( exists $self->scopedrels->{$first}->{$second} ) {
		return $self->scopedrels->{$first}->{$second};
	} else {
		return undef;
	}
}

=head2 add_relationship( $self, $source, $sourcetext, $target, $targettext, $opts )

Adds the relationship specified in $opts (see Text::Tradition::Collation::Relationship 
for the possible options) between the readings given in $source and $target.  Sets
up a scoped relationship between $sourcetext and $targettext if the relationship is
scoped non-locally.

Returns a status boolean and a list of all reading pairs connected by the call to
add_relationship.

=cut

sub add_relationship {
	my( $self, $source, $source_rdg, $target, $target_rdg, $options ) = @_;

	my $relationship;
	my $thispaironly;
	if( ref( $options ) eq 'Text::Tradition::Collation::Relationship' ) {
		$relationship = $options;
		$thispaironly = 1;  # If existing rel, set only where asked.
	} else {
		# Check the options
		$options->{'scope'} = 'local' unless $options->{'scope'};
		
		my( $is_valid, $reason ) = 
			$self->relationship_valid( $source, $target, $options->{'type'} );
		unless( $is_valid ) {
			throw( "Invalid relationship: $reason" );
		}
		
		# Try to create the relationship object.
		$options->{'reading_a'} = $source_rdg->text;
		$options->{'reading_b'} = $target_rdg->text;
		$options->{'orig_a'} = $source;
		$options->{'orig_b'} = $target;
		$relationship = $self->create( $options );  # Will throw on error
    }


	# Find all the pairs for which we need to set the relationship.
	my @vectors = ( [ $source, $target ] );	
    if( $relationship->colocated && $relationship->nonlocal && !$thispaironly ) {
    	# Is there a relationship with this a & b already?
    	my $otherrel = $self->scoped_relationship( $relationship->reading_a, 
    		$relationship->reading_b );
    	if( $otherrel && $otherrel->type eq $relationship->type 
    		&& $otherrel->scope eq $relationship->scope ) {
    		warn "Applying existing scoped relationship";
    		$relationship = $otherrel;
    	}
    	my $c = $self->collation;
    	# Set the same relationship everywhere we can, throughout the graph.
    	my @identical_readings = grep { $_->text eq $relationship->reading_a }
    		$c->readings;
    	foreach my $ir ( @identical_readings ) {
    		next if $ir->id eq $source;
    		# Check to see if there is a target reading with the same text at
    		# the same rank.
    		my @itarget = grep 
    			{ $_->rank == $ir->rank && $_->text eq $relationship->reading_b }
    			$c->readings;
    		if( @itarget ) {
    			# We found a hit.
    			warn "More than one reading with text " . $target_rdg->text
    				. " at rank " . $ir->rank . "!" if @itarget > 1;
    			push( @vectors, [ $ir->id, $itarget[0]->id ] );
    		}
    	}	
    }
    
    # Now set the relationship(s).
    my @pairs_set;
    foreach my $v ( @vectors ) {
		my $rel = $self->get_relationship( @$v );
    	if( $rel && $rel ne $relationship ) {
    		if( $rel->nonlocal ) {
    			$DB::single = 1;
    			throw( "Found conflicting relationship at @$v" );
    		} else {
    			warn "Not overriding local relationship set at @$v";
    		}
    		next;
    	}
    	$self->_set_relationship( $relationship, @$v );
    	push( @pairs_set, $v );
    }
    
    return @pairs_set;
}

=head2 del_relationship( $source, $target )

Removes the relationship between the given readings. If the relationship is
non-local, removes the relationship everywhere in the graph.

=cut

sub del_relationship {
	my( $self, $source, $target ) = @_;
	my $rel = $self->get_relationship( $source, $target );
	throw( "No relationship defined between $source and $target" ) unless $rel;
	my @vectors = ( [ $source, $target ] );
	$self->_remove_relationship( $source, $target );
	if( $rel->nonlocal ) {
		# Remove the relationship wherever it occurs.
		my @rel_edges = grep { $self->get_relationship( @$_ ) == $rel }
			$self->relationships;
		foreach my $re ( @rel_edges ) {
			$self->_remove_relationship( @$re );
			push( @vectors, $re );
		}
	}
	return @vectors;
}

sub _remove_relationship {
	my( $self, @vector ) = @_;
	$self->graph->delete_edge( @vector );
}
	
=head2 relationship_valid( $source, $target, $type )

Checks whether a relationship of type $type may exist between the readings given
in $source and $target.  Returns a tuple of ( status, message ) where status is
a yes/no boolean and, if the answer is no, message gives the reason why.

=cut

sub relationship_valid {
    my( $self, $source, $target, $rel ) = @_;
    my $c = $self->collation;
    if ( $rel eq 'transposition' || $rel eq 'repetition' ) {
		# Check that the two readings do (for a repetition) or do not (for
		# a transposition) appear in the same witness.
		# TODO this might be called before witness paths are set...
		my %seen_wits;
		map { $seen_wits{$_} = 1 } $c->reading_witnesses( $source );
		foreach my $w ( $c->reading_witnesses( $target ) ) {
			if( $seen_wits{$w} ) {
				return ( 0, "Readings both occur in witness $w" ) 
					if $rel eq 'transposition';
				return ( 1, "ok" ) if $rel eq 'repetition';
		}
		return $rel eq 'transposition' ? ( 1, "ok" )
			: ( 0, "Readings occur only in distinct witnesses" );
		}
	} else {
		# Check that linking the source and target in a relationship won't lead
		# to a path loop for any witness.  If they have the same rank then fine.
		return( 1, "ok" ) 
			if $c->reading( $source )->has_rank
				&& $c->reading( $target )->has_rank
				&& $c->reading( $source )->rank == $c->reading( $target )->rank;
		
		# Otherwise, first make a lookup table of all the
		# readings related to either the source or the target.
		my @proposed_related = ( $source, $target );
		push( @proposed_related, $self->related_readings( $source, 'colocated' ) );
		push( @proposed_related, $self->related_readings( $target, 'colocated' ) );
		my %pr_ids;
		map { $pr_ids{ $_ } = 1 } @proposed_related;
	
		# The cumulative predecessors and successors of the proposed-related readings
		# should not overlap.
		my %all_pred;
		my %all_succ;
		foreach my $pr ( keys %pr_ids ) {
			map { $all_pred{$_} = 1 } $c->sequence->all_predecessors( $pr );
			map { $all_succ{$_} = 1 } $c->sequence->all_successors( $pr );
		}
		foreach my $k ( keys %all_pred ) {
			return( 0, "Relationship would create witness loop" )
				if exists $all_succ{$k};
		}
		foreach my $k ( keys %pr_ids ) {
			return( 0, "Relationship would create witness loop" )
				if exists $all_pred{$k} || exists $all_succ{$k};
		}
		return ( 1, "ok" );
	}
}

=head2 related_readings( $reading, $filter )

Returns a list of readings that are connected via relationship links to $reading.
If $filter is set to a subroutine ref, returns only those related readings where
$filter( $relationship ) returns a true value.

=cut

sub related_readings {
	my( $self, $reading, $filter ) = @_;
	my $return_object;
	if( ref( $reading ) eq 'Text::Tradition::Collation::Reading' ) {
		$reading = $reading->id;
		$return_object = 1;
	}
	my @answer;
	if( $filter ) {
		# Backwards compat
		if( $filter eq 'colocated' ) {
			$filter = sub { $_[0]->colocated };
		}
		my %found = ( $reading => 1 );
		my $check = [ $reading ];
		my $iter = 0;
		while( @$check ) {
			my $more = [];
			foreach my $r ( @$check ) {
				foreach my $nr ( $self->graph->neighbors( $r ) ) {
					if( &$filter( $self->get_relationship( $r, $nr ) ) ) {
						push( @$more, $nr ) unless exists $found{$nr};
						$found{$nr} = 1;
					}
				}
			}
			$check = $more;
		}
		delete $found{$reading};
		@answer = keys %found;
	} else {
		@answer = $self->graph->all_reachable( $reading );
	}
	if( $return_object ) {
		my $c = $self->collation;
		return map { $c->reading( $_ ) } @answer;
	} else {
		return @answer;
	}
}

=head2 merge_readings( $kept, $deleted );

Makes a best-effort merge of the relationship links between the given readings, and
stops tracking the to-be-deleted reading.

=cut

sub merge_readings {
	my( $self, $kept, $deleted, $combined ) = @_;
	foreach my $edge ( $self->graph->edges_at( $deleted ) ) {
		# Get the pair of kept / rel
		my @vector = ( $kept );
		push( @vector, $edge->[0] eq $deleted ? $edge->[1] : $edge->[0] );
		next if $vector[0] eq $vector[1]; # Don't add a self loop
		
		# If kept changes its text, drop the relationship.
		next if $combined;
			
		# If kept / rel already has a relationship, warn and keep the old
		my $rel = $self->get_relationship( @vector );
		if( $rel ) {
			warn sprintf( "Readings %s and %s have existing relationship; dropping link with %s", @vector, $deleted );
			next;
		}
		
		# Otherwise, adopt the relationship that would be deleted.
		$rel = $self->get_relationship( @$edge );
		$self->_set_relationship( $rel, @vector );
	}
	$self->delete_reading( $deleted );
}

sub _as_graphml { 
	my( $self, $graphml_ns, $xmlroot, $node_hash, $nodeid_key, $edge_keys ) = @_;
	
    my $rgraph = $xmlroot->addNewChild( $graphml_ns, 'graph' );
	$rgraph->setAttribute( 'edgedefault', 'directed' );
    $rgraph->setAttribute( 'id', 'relationships', );
    $rgraph->setAttribute( 'parse.edgeids', 'canonical' );
    $rgraph->setAttribute( 'parse.edges', scalar($self->graph->edges) );
    $rgraph->setAttribute( 'parse.nodeids', 'canonical' );
    $rgraph->setAttribute( 'parse.nodes', scalar($self->graph->vertices) );
    $rgraph->setAttribute( 'parse.order', 'nodesfirst' );
    
    # Add the vertices according to their XML IDs
    my %rdg_lookup = ( reverse %$node_hash );
    foreach my $n ( sort _by_xmlid keys( %rdg_lookup ) ) {
    	my $n_el = $rgraph->addNewChild( $graphml_ns, 'node' );
    	$n_el->setAttribute( 'id', $n );
    	_add_graphml_data( $n_el, $nodeid_key, $rdg_lookup{$n} );
    }
    
    # Add the relationship edges, with their object information
    my $edge_ctr = 0;
    foreach my $e ( sort { $a->[0] cmp $b->[0] } $self->graph->edges ) {
    	# Add an edge and fill in its relationship info.
		my $edge_el = $rgraph->addNewChild( $graphml_ns, 'edge' );
		$edge_el->setAttribute( 'source', $node_hash->{$e->[0]} );
		$edge_el->setAttribute( 'target', $node_hash->{$e->[1]} );
		$edge_el->setAttribute( 'id', 'e'.$edge_ctr++ );

		my $rel_obj = $self->get_relationship( @$e );
		_add_graphml_data( $edge_el, $edge_keys->{'relationship'}, $rel_obj->type );
		_add_graphml_data( $edge_el, $edge_keys->{'scope'}, $rel_obj->scope );
		_add_graphml_data( $edge_el, $edge_keys->{'annotation'}, $rel_obj->annotation );
		_add_graphml_data( $edge_el, $edge_keys->{'non_correctable'}, 
			$rel_obj->non_correctable ) if $rel_obj->noncorr_set;
		_add_graphml_data( $edge_el, $edge_keys->{'non_independent'}, 
			$rel_obj->non_independent ) if $rel_obj->nonind_set;
	}
}

sub _by_xmlid {
	my $tmp_a = $a;
	my $tmp_b = $b;
	$tmp_a =~ s/\D//g;
	$tmp_b =~ s/\D//g;
	return $tmp_a <=> $tmp_b;
}

sub _add_graphml_data {
    my( $el, $key, $value ) = @_;
    return unless defined $value;
    my $data_el = $el->addNewChild( $el->namespaceURI, 'data' );
    $data_el->setAttribute( 'key', $key );
    $data_el->appendText( $value );
}

sub throw {
	Text::Tradition::Error->throw( 
		'ident' => 'Relationship error',
		'message' => $_[0],
		);
}

no Moose;
__PACKAGE__->meta->make_immutable;

1;
Commit	Line	Data
22222af9	1	package Text::Tradition::Collation::RelationshipStore;
	2
	3	use strict;
	4	use warnings;
63778331	5	use Text::Tradition::Error;
22222af9	6	use Text::Tradition::Collation::Relationship;
a1615ee4	7	use TryCatch;
22222af9	8
	9	use Moose;
	10
	11	=head1 NAME
	12
2626f709	13	Text::Tradition::Collation::RelationshipStore - Keeps track of the relationships
2626f709	14	between readings in a given collation
22222af9	15
	16	=head1 DESCRIPTION
	17
	18	Text::Tradition is a library for representation and analysis of collated
	19	texts, particularly medieval ones. The RelationshipStore is an internal object
	20	of the collation, to keep track of the defined relationships (both specific and
	21	general) between readings.
	22
3ae5e2ad	23	=begin testing
	24
	25	use Text::Tradition;
ee801e17	26	use TryCatch;
3ae5e2ad	27
	28	use_ok( 'Text::Tradition::Collation::RelationshipStore' );
	29
ee801e17	30	# Add some relationships, and delete them
	31
	32	my $cxfile = 't/data/Collatex-16.xml';
	33	my $t = Text::Tradition->new(
	34	'name' => 'inline',
	35	'input' => 'CollateX',
	36	'file' => $cxfile,
	37	);
	38	my $c = $t->collation;
	39
	40	my @v1 = $c->add_relationship( 'n21', 'n22', { 'type' => 'meaning' } );
	41	is( scalar @v1, 1, "Added a single relationship" );
	42	is( $v1[0]->[0], 'n21', "Got correct node 1" );
	43	is( $v1[0]->[1], 'n22', "Got correct node 2" );
	44	my @v2 = $c->add_relationship( 'n9', 'n23',
	45	{ 'type' => 'spelling', 'scope' => 'global' } );
	46	is( scalar @v2, 2, "Added a global relationship with two instances" );
	47	@v1 = $c->del_relationship( 'n22', 'n21' );
	48	is( scalar @v1, 1, "Deleted first relationship" );
	49	@v2 = $c->del_relationship( 'n8', 'n13' );
	50	is( scalar @v2, 2, "Deleted second global relationship" );
	51	try {
	52	my @v3 = $c->del_relationship( 'n1', 'n2' );
	53	ok( 0, "Should have errored on non-existent relationship" );
	54	} catch( Text::Tradition::Error $e ) {
	55	like( $e->message, qr/No relationship defined/, "Attempt to delete non-existent relationship errored" );
	56	}
	57
3ae5e2ad	58	=end testing
3ae5e2ad	59
22222af9	60	=head1 METHODS
	61
	62	=head2 new( collation => $collation );
	63
	64	Creates a new relationship store for the given collation.
	65
	66	=cut
	67
	68	has 'collation' => (
	69	is => 'ro',
	70	isa => 'Text::Tradition::Collation',
	71	required => 1,
	72	weak_ref => 1,
	73	);
	74
	75	has 'scopedrels' => (
	76	is => 'ro',
	77	isa => 'HashRef[HashRef[Text::Tradition::Collation::Relationship]]',
	78	default => sub { {} },
	79	);
	80
	81	has 'graph' => (
	82	is => 'ro',
	83	isa => 'Graph',
	84	default => sub { Graph->new( undirected => 1 ) },
	85	handles => {
	86	relationships => 'edges',
	87	add_reading => 'add_vertex',
	88	delete_reading => 'delete_vertex',
	89	},
	90	);
	91
3ae5e2ad	92	=head2 get_relationship
	93
	94	Return the relationship object, if any, that exists between two readings.
	95
	96	=cut
	97
	98	sub get_relationship {
4633f9e4	99	my $self = shift;
	100	my @vector;
	101	if( @_ == 1 && ref( $_[0] ) eq 'ARRAY' ) {
	102	# Dereference the edge arrayref that was passed.
	103	my $edge = shift;
	104	@vector = @$edge;
	105	} else {
	106	@vector = @_;
	107	}
3ae5e2ad	108	my $relationship;
	109	if( $self->graph->has_edge_attribute( @vector, 'object' ) ) {
	110	$relationship = $self->graph->get_edge_attribute( @vector, 'object' );
ca6e6095	111	}
3ae5e2ad	112	return $relationship;
	113	}
	114
	115	sub _set_relationship {
	116	my( $self, $relationship, @vector ) = @_;
	117	$self->graph->add_edge( @vector );
	118	$self->graph->set_edge_attribute( @vector, 'object', $relationship );
	119	}
a1615ee4	120
22222af9	121	=head2 create
	122
	123	Create a new relationship with the given options and return it.
	124	Warn and return undef if the relationship cannot be created.
	125
	126	=cut
	127
	128	sub create {
	129	my( $self, $options ) = @_;
	130	# Check to see if a relationship exists between the two given readings
	131	my $source = delete $options->{'orig_a'};
	132	my $target = delete $options->{'orig_b'};
3ae5e2ad	133	my $rel = $self->get_relationship( $source, $target );
3ae5e2ad	134	if( $rel ) {
3d14b48e	135	if( $rel->type eq 'collated' ) {
	136	# Always replace a 'collated' relationship with a more descriptive
	137	# one, if asked.
	138	$self->del_relationship( $source, $target );
	139	} elsif( $rel->type ne $options->{'type'} ) {
63778331	140	throw( "Another relationship of type " . $rel->type
63778331	141	. " already exists between $source and $target" );
22222af9	142	} else {
	143	return $rel;
	144	}
	145	}
	146
	147	# Check to see if a nonlocal relationship is defined for the two readings
	148	$rel = $self->scoped_relationship( $options->{'reading_a'},
	149	$options->{'reading_b'} );
	150	if( $rel && $rel->type eq $options->{'type'} ) {
	151	return $rel;
	152	} elsif( $rel ) {
63778331	153	throw( sprintf( "Relationship of type %s with scope %s already defined for readings %s and %s", $rel->type, $rel->scope, $options->{'reading_a'}, $options->{'reading_b'} ) );
22222af9	154	} else {
	155	$rel = Text::Tradition::Collation::Relationship->new( $options );
	156	$self->add_scoped_relationship( $rel ) if $rel->nonlocal;
	157	return $rel;
	158	}
	159	}
	160
	161	=head2 add_scoped_relationship( $rel )
	162
	163	Keep track of relationships defined between specific readings that are scoped
	164	non-locally. Key on whichever reading occurs first alphabetically.
	165
	166	=cut
	167
	168	sub add_scoped_relationship {
	169	my( $self, $rel ) = @_;
	170	my $r = $self->scoped_relationship( $rel->reading_a, $rel->reading_b );
	171	if( $r ) {
	172	warn sprintf( "Scoped relationship of type %s already exists between %s and %s",
	173	$r->type, $rel->reading_a, $rel->reading_b );
	174	return;
	175	}
	176	$self->scopedrels->{$rel->reading_a}->{$rel->reading_b} = $rel;
	177	}
	178
	179	=head2 scoped_relationship( $reading_a, $reading_b )
	180
	181	Returns the general (document-level or global) relationship that has been defined
	182	between the two reading strings. Returns undef if there is no general relationship.
	183
	184	=cut
	185
	186	sub scoped_relationship {
	187	my( $self, $rdga, $rdgb ) = @_;
	188	my( $first, $second ) = sort( $rdga, $rdgb );
	189	if( exists $self->scopedrels->{$first}->{$second} ) {
	190	return $self->scopedrels->{$first}->{$second};
	191	} else {
	192	return undef;
	193	}
	194	}
	195
	196	=head2 add_relationship( $self, $source, $sourcetext, $target, $targettext, $opts )
	197
	198	Adds the relationship specified in $opts (see Text::Tradition::Collation::Relationship
	199	for the possible options) between the readings given in $source and $target. Sets
	200	up a scoped relationship between $sourcetext and $targettext if the relationship is
	201	scoped non-locally.
	202
	203	Returns a status boolean and a list of all reading pairs connected by the call to
	204	add_relationship.
	205
	206	=cut
	207
	208	sub add_relationship {
	209	my( $self, $source, $source_rdg, $target, $target_rdg, $options ) = @_;
	210
ca6e6095	211	my $relationship;
	212	my $thispaironly;
	213	if( ref( $options ) eq 'Text::Tradition::Collation::Relationship' ) {
	214	$relationship = $options;
	215	$thispaironly = 1; # If existing rel, set only where asked.
	216	} else {
	217	# Check the options
	218	$options->{'scope'} = 'local' unless $options->{'scope'};
	219
	220	my( $is_valid, $reason ) =
	221	$self->relationship_valid( $source, $target, $options->{'type'} );
	222	unless( $is_valid ) {
	223	throw( "Invalid relationship: $reason" );
	224	}
	225
	226	# Try to create the relationship object.
	227	$options->{'reading_a'} = $source_rdg->text;
	228	$options->{'reading_b'} = $target_rdg->text;
	229	$options->{'orig_a'} = $source;
	230	$options->{'orig_b'} = $target;
	231	$relationship = $self->create( $options ); # Will throw on error
22222af9	232	}
ca6e6095	233
22222af9	234
	235	# Find all the pairs for which we need to set the relationship.
	236	my @vectors = ( [ $source, $target ] );
ca6e6095	237	if( $relationship->colocated && $relationship->nonlocal && !$thispaironly ) {
	238	# Is there a relationship with this a & b already?
	239	my $otherrel = $self->scoped_relationship( $relationship->reading_a,
	240	$relationship->reading_b );
	241	if( $otherrel && $otherrel->type eq $relationship->type
	242	&& $otherrel->scope eq $relationship->scope ) {
	243	warn "Applying existing scoped relationship";
	244	$relationship = $otherrel;
	245	}
22222af9	246	my $c = $self->collation;
	247	# Set the same relationship everywhere we can, throughout the graph.
	248	my @identical_readings = grep { $_->text eq $relationship->reading_a }
	249	$c->readings;
	250	foreach my $ir ( @identical_readings ) {
cf6c01be	251	next if $ir->id eq $source;
22222af9	252	# Check to see if there is a target reading with the same text at
	253	# the same rank.
	254	my @itarget = grep
	255	{ $_->rank == $ir->rank && $_->text eq $relationship->reading_b }
	256	$c->readings;
	257	if( @itarget ) {
	258	# We found a hit.
	259	warn "More than one reading with text " . $target_rdg->text
	260	. " at rank " . $ir->rank . "!" if @itarget > 1;
cf6c01be	261	push( @vectors, [ $ir->id, $itarget[0]->id ] );
22222af9	262	}
	263	}
	264	}
	265
	266	# Now set the relationship(s).
	267	my @pairs_set;
	268	foreach my $v ( @vectors ) {
3ae5e2ad	269	my $rel = $self->get_relationship( @$v );
ca6e6095	270	if( $rel && $rel ne $relationship ) {
63778331	271	if( $rel->nonlocal ) {
ca6e6095	272	$DB::single = 1;
63778331	273	throw( "Found conflicting relationship at @$v" );
	274	} else {
	275	warn "Not overriding local relationship set at @$v";
	276	}
3ae5e2ad	277	next;
22222af9	278	}
3ae5e2ad	279	$self->_set_relationship( $relationship, @$v );
22222af9	280	push( @pairs_set, $v );
	281	}
	282
63778331	283	return @pairs_set;
22222af9	284	}
22222af9	285
ee801e17	286	=head2 del_relationship( $source, $target )
	287
	288	Removes the relationship between the given readings. If the relationship is
	289	non-local, removes the relationship everywhere in the graph.
	290
	291	=cut
	292
	293	sub del_relationship {
	294	my( $self, $source, $target ) = @_;
	295	my $rel = $self->get_relationship( $source, $target );
	296	throw( "No relationship defined between $source and $target" ) unless $rel;
	297	my @vectors = ( [ $source, $target ] );
	298	$self->_remove_relationship( $source, $target );
	299	if( $rel->nonlocal ) {
	300	# Remove the relationship wherever it occurs.
	301	my @rel_edges = grep { $self->get_relationship( @$_ ) == $rel }
	302	$self->relationships;
	303	foreach my $re ( @rel_edges ) {
	304	$self->_remove_relationship( @$re );
	305	push( @vectors, $re );
	306	}
	307	}
	308	return @vectors;
	309	}
	310
ca6e6095	311	sub _remove_relationship {
	312	my( $self, @vector ) = @_;
	313	$self->graph->delete_edge( @vector );
	314	}
	315
22222af9	316	=head2 relationship_valid( $source, $target, $type )
	317
	318	Checks whether a relationship of type $type may exist between the readings given
	319	in $source and $target. Returns a tuple of ( status, message ) where status is
	320	a yes/no boolean and, if the answer is no, message gives the reason why.
	321
	322	=cut
	323
	324	sub relationship_valid {
	325	my( $self, $source, $target, $rel ) = @_;
	326	my $c = $self->collation;
	327	if ( $rel eq 'transposition' \|\| $rel eq 'repetition' ) {
	328	# Check that the two readings do (for a repetition) or do not (for
	329	# a transposition) appear in the same witness.
32e95735	330	# TODO this might be called before witness paths are set...
22222af9	331	my %seen_wits;
	332	map { $seen_wits{$_} = 1 } $c->reading_witnesses( $source );
	333	foreach my $w ( $c->reading_witnesses( $target ) ) {
	334	if( $seen_wits{$w} ) {
	335	return ( 0, "Readings both occur in witness $w" )
	336	if $rel eq 'transposition';
	337	return ( 1, "ok" ) if $rel eq 'repetition';
	338	}
	339	return $rel eq 'transposition' ? ( 1, "ok" )
	340	: ( 0, "Readings occur only in distinct witnesses" );
	341	}
	342	} else {
	343	# Check that linking the source and target in a relationship won't lead
a1615ee4	344	# to a path loop for any witness. If they have the same rank then fine.
a1615ee4	345	return( 1, "ok" )
84d4ca78	346	if $c->reading( $source )->has_rank
	347	&& $c->reading( $target )->has_rank
	348	&& $c->reading( $source )->rank == $c->reading( $target )->rank;
a1615ee4	349
a1615ee4	350	# Otherwise, first make a lookup table of all the
22222af9	351	# readings related to either the source or the target.
	352	my @proposed_related = ( $source, $target );
	353	push( @proposed_related, $self->related_readings( $source, 'colocated' ) );
	354	push( @proposed_related, $self->related_readings( $target, 'colocated' ) );
	355	my %pr_ids;
	356	map { $pr_ids{ $_ } = 1 } @proposed_related;
	357
a1615ee4	358	# The cumulative predecessors and successors of the proposed-related readings
	359	# should not overlap.
	360	my %all_pred;
	361	my %all_succ;
22222af9	362	foreach my $pr ( keys %pr_ids ) {
a1615ee4	363	map { $all_pred{$_} = 1 } $c->sequence->all_predecessors( $pr );
	364	map { $all_succ{$_} = 1 } $c->sequence->all_successors( $pr );
	365	}
	366	foreach my $k ( keys %all_pred ) {
	367	return( 0, "Relationship would create witness loop" )
	368	if exists $all_succ{$k};
	369	}
	370	foreach my $k ( keys %pr_ids ) {
	371	return( 0, "Relationship would create witness loop" )
	372	if exists $all_pred{$k} \|\| exists $all_succ{$k};
	373	}
22222af9	374	return ( 1, "ok" );
	375	}
	376	}
	377
7f52eac8	378	=head2 related_readings( $reading, $filter )
22222af9	379
22222af9	380	Returns a list of readings that are connected via relationship links to $reading.
7f52eac8	381	If $filter is set to a subroutine ref, returns only those related readings where
7f52eac8	382	$filter( $relationship ) returns a true value.
22222af9	383
	384	=cut
	385
	386	sub related_readings {
7f52eac8	387	my( $self, $reading, $filter ) = @_;
22222af9	388	my $return_object;
	389	if( ref( $reading ) eq 'Text::Tradition::Collation::Reading' ) {
	390	$reading = $reading->id;
	391	$return_object = 1;
	392	}
c84275ff	393	my @answer;
7f52eac8	394	if( $filter ) {
	395	# Backwards compat
	396	if( $filter eq 'colocated' ) {
	397	$filter = sub { $_[0]->colocated };
	398	}
c84275ff	399	my %found = ( $reading => 1 );
	400	my $check = [ $reading ];
	401	my $iter = 0;
	402	while( @$check ) {
c84275ff	403	my $more = [];
	404	foreach my $r ( @$check ) {
	405	foreach my $nr ( $self->graph->neighbors( $r ) ) {
7f52eac8	406	if( &$filter( $self->get_relationship( $r, $nr ) ) ) {
c84275ff	407	push( @$more, $nr ) unless exists $found{$nr};
	408	$found{$nr} = 1;
	409	}
	410	}
	411	}
	412	$check = $more;
22222af9	413	}
7f52eac8	414	delete $found{$reading};
c84275ff	415	@answer = keys %found;
	416	} else {
	417	@answer = $self->graph->all_reachable( $reading );
22222af9	418	}
	419	if( $return_object ) {
	420	my $c = $self->collation;
c84275ff	421	return map { $c->reading( $_ ) } @answer;
22222af9	422	} else {
c84275ff	423	return @answer;
22222af9	424	}
	425	}
	426
	427	=head2 merge_readings( $kept, $deleted );
	428
	429	Makes a best-effort merge of the relationship links between the given readings, and
	430	stops tracking the to-be-deleted reading.
	431
	432	=cut
	433
	434	sub merge_readings {
	435	my( $self, $kept, $deleted, $combined ) = @_;
	436	foreach my $edge ( $self->graph->edges_at( $deleted ) ) {
	437	# Get the pair of kept / rel
	438	my @vector = ( $kept );
	439	push( @vector, $edge->[0] eq $deleted ? $edge->[1] : $edge->[0] );
	440	next if $vector[0] eq $vector[1]; # Don't add a self loop
	441
	442	# If kept changes its text, drop the relationship.
	443	next if $combined;
	444
	445	# If kept / rel already has a relationship, warn and keep the old
3ae5e2ad	446	my $rel = $self->get_relationship( @vector );
3ae5e2ad	447	if( $rel ) {
22222af9	448	warn sprintf( "Readings %s and %s have existing relationship; dropping link with %s", @vector, $deleted );
	449	next;
	450	}
	451
	452	# Otherwise, adopt the relationship that would be deleted.
3ae5e2ad	453	$rel = $self->get_relationship( @$edge );
3ae5e2ad	454	$self->_set_relationship( $rel, @vector );
22222af9	455	}
	456	$self->delete_reading( $deleted );
	457	}
	458
027d819c	459	sub _as_graphml {
2626f709	460	my( $self, $graphml_ns, $xmlroot, $node_hash, $nodeid_key, $edge_keys ) = @_;
c84275ff	461
	462	my $rgraph = $xmlroot->addNewChild( $graphml_ns, 'graph' );
	463	$rgraph->setAttribute( 'edgedefault', 'directed' );
	464	$rgraph->setAttribute( 'id', 'relationships', );
	465	$rgraph->setAttribute( 'parse.edgeids', 'canonical' );
	466	$rgraph->setAttribute( 'parse.edges', scalar($self->graph->edges) );
	467	$rgraph->setAttribute( 'parse.nodeids', 'canonical' );
	468	$rgraph->setAttribute( 'parse.nodes', scalar($self->graph->vertices) );
	469	$rgraph->setAttribute( 'parse.order', 'nodesfirst' );
	470
	471	# Add the vertices according to their XML IDs
2626f709	472	my %rdg_lookup = ( reverse %$node_hash );
2626f709	473	foreach my $n ( sort _by_xmlid keys( %rdg_lookup ) ) {
c84275ff	474	my $n_el = $rgraph->addNewChild( $graphml_ns, 'node' );
c84275ff	475	$n_el->setAttribute( 'id', $n );
2626f709	476	_add_graphml_data( $n_el, $nodeid_key, $rdg_lookup{$n} );
c84275ff	477	}
	478
	479	# Add the relationship edges, with their object information
	480	my $edge_ctr = 0;
	481	foreach my $e ( sort { $a->[0] cmp $b->[0] } $self->graph->edges ) {
	482	# Add an edge and fill in its relationship info.
	483	my $edge_el = $rgraph->addNewChild( $graphml_ns, 'edge' );
	484	$edge_el->setAttribute( 'source', $node_hash->{$e->[0]} );
	485	$edge_el->setAttribute( 'target', $node_hash->{$e->[1]} );
	486	$edge_el->setAttribute( 'id', 'e'.$edge_ctr++ );
	487
3ae5e2ad	488	my $rel_obj = $self->get_relationship( @$e );
c84275ff	489	_add_graphml_data( $edge_el, $edge_keys->{'relationship'}, $rel_obj->type );
c84275ff	490	_add_graphml_data( $edge_el, $edge_keys->{'scope'}, $rel_obj->scope );
3d14b48e	491	_add_graphml_data( $edge_el, $edge_keys->{'annotation'}, $rel_obj->annotation );
c84275ff	492	_add_graphml_data( $edge_el, $edge_keys->{'non_correctable'},
	493	$rel_obj->non_correctable ) if $rel_obj->noncorr_set;
	494	_add_graphml_data( $edge_el, $edge_keys->{'non_independent'},
	495	$rel_obj->non_independent ) if $rel_obj->nonind_set;
	496	}
	497	}
	498
	499	sub _by_xmlid {
2626f709	500	my $tmp_a = $a;
	501	my $tmp_b = $b;
	502	$tmp_a =~ s/\D//g;
	503	$tmp_b =~ s/\D//g;
	504	return $tmp_a <=> $tmp_b;
c84275ff	505	}
	506
	507	sub _add_graphml_data {
	508	my( $el, $key, $value ) = @_;
	509	return unless defined $value;
	510	my $data_el = $el->addNewChild( $el->namespaceURI, 'data' );
	511	$data_el->setAttribute( 'key', $key );
	512	$data_el->appendText( $value );
83d5ac3a	513	}
83d5ac3a	514
63778331	515	sub throw {
	516	Text::Tradition::Error->throw(
	517	'ident' => 'Relationship error',
	518	'message' => $_[0],
	519	);
	520	}
	521
22222af9	522	no Moose;
	523	__PACKAGE__->meta->make_immutable;
	524
	525	1;