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

package Text::Tradition::Collation;

use Graph::Easy;
use IPC::Run qw( run binary );
use Text::Tradition::Collation::Reading;
use Moose;

has 'graph' => (
    is => 'ro',
    isa => 'Graph::Easy',
    handles => {
	add_reading => 'add_node',
	del_reading => 'del_node',
	add_path => 'add_edge',
	del_path => 'del_edge',
	reading => 'node',
	path => 'edge',
	readings => 'nodes',
	paths => 'edges',
    },
    default => sub { Graph::Easy->new( undirected => 0 ) },
    );
		

has 'tradition' => (
    is => 'rw',
    isa => 'Text::Tradition',
    );

has 'svg' => (
    is => 'ro',
    isa => 'Str',
    writer => '_save_svg',
    predicate => 'has_svg',
    );

has 'graphviz' => (
    is => 'ro',
    isa => 'Str',
    writer => '_save_graphviz',
    predicate => 'has_graphviz',
    );

has 'graphml' => (
    is => 'ro',
    isa => 'XML::LibXML::Document',
    writer => '_save_graphml',
    predicate => 'has_graphml',
    );

has 'wit_list_separator' => (
			     is => 'rw',
			     isa => 'Str',
			     default => ', ',
			     );

# The collation can be created two ways:
# 1. Collate a set of witnesses (with CollateX I guess) and process
#    the results as in 2.
# 2. Read a pre-prepared collation in one of a variety of formats,
#    and make the graph from that.

# The graph itself will (for now) be immutable, and the positions
# within the graph will also be immutable.  We need to calculate those
# positions upon graph construction.  The equivalences between graph
# nodes will be mutable, entirely determined by the user (or possibly
# by some semantic pre-processing provided by the user.)  So the
# constructor should just make an empty equivalences object.  The
# constructor will also need to make the witness objects, if we didn't
# come through option 1.

sub BUILD {
    my( $self, $args ) = @_;
    $self->graph->use_class('node', 'Text::Tradition::Collation::Reading');

    # Pass through any graph-specific options.
    my $shape = exists( $args->{'shape'} ) ? $args->{'shape'} : 'ellipse';
    $self->graph->set_attribute( 'node', 'shape', $shape );
}

# Wrappers around some methods

sub merge_readings {
    my $self = shift;
    my $first_node = shift;
    my $second_node = shift;
    $first_node->merge_from( $second_node );
    unshift( @_, $first_node, $second_node );
    return $self->graph->merge_nodes( @_ );
}

=head2 Output method(s)

=over

=item B<as_svg>

print $graph->as_svg( $recalculate );

Returns an SVG string that represents the graph.  Uses GraphViz to do
this, because Graph::Easy doesn\'t cope well with long graphs. Unless
$recalculate is passed (and is a true value), the method will return a
cached copy of the SVG after the first call to the method.

=cut

sub as_svg {
    my( $self, $recalc ) = @_;
    return $self->svg if $self->has_svg;
    
    $self->_save_graphviz( $self->graph->as_graphviz() )
	unless( $self->has_graphviz && !$recalc );
    
    my @cmd = qw/dot -Tsvg/;
    my( $svg, $err );
    my $in = $self->graphviz;
    run( \@cmd, \$in, ">", binary(), \$svg );
    $self->{'svg'} = $svg;
    return $svg;
}

=item B<as_graphml>

print $graph->as_graphml( $recalculate )

Returns a GraphML representation of the collation graph, with
transposition information and position information. Unless
$recalculate is passed (and is a true value), the method will return a
cached copy of the SVG after the first call to the method.

=cut

sub as_graphml {
    my( $self, $recalc ) = @_;
    return $self->graphml if $self->has_graphml;

    # Some namespaces
    my $graphml_ns = 'http://graphml.graphdrawing.org/xmlns';
    my $xsi_ns = 'http://www.w3.org/2001/XMLSchema-instance';
    my $graphml_schema = 'http://graphml.graphdrawing.org/xmlns ' .
	'http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd';

    # Create the document and root node
    my $graphml = XML::LibXML->createDocument( "1.0", "UTF-8" );
    my $root = $graphml->createElementNS( $graphml_ns, 'graphml' );
    $graphml->setDocumentElement( $root );
    $root->setNamespace( $xsi_ns, 'xsi', 0 );
    $root->setAttributeNS( $xsi_ns, 'schemaLocation', $graphml_schema );

    # Add the data keys for nodes
    my @node_data = ( 'name', 'token', 'identical', 'position' );
    foreach my $ndi ( 0 .. $#node_data ) {
	my $key = $root->addNewChild( $graphml_ns, 'key' );
	$key->setAttribute( 'attr.name', $node_data[$ndi] );
	$key->setAttribute( 'attr.type', 'string' );
	$key->setAttribute( 'for', 'node' );
	$key->setAttribute( 'id', 'd'.$ndi );
    }

    # Add the data keys for edges
    my %wit_hash;
    my $wit_ctr = 0;
    foreach my $wit ( $self->getWitnessList ) {
	my $wit_key = 'w' . $wit_ctr++;
	$wit_hash{$wit} = $wit_key;
	my $key = $root->addNewChild( $graphml_ns, 'key' );
	$key->setAttribute( 'attr.name', $wit );
	$key->setAttribute( 'attr.type', 'string' );
	$key->setAttribute( 'for', 'edge' );
	$key->setAttribute( 'id', $wit_key );
    }

    # Add the graph, its nodes, and its edges
    my $graph = $root->addNewChild( $graphml_ns, 'graph' );
    $graph->setAttribute( 'edgedefault', 'directed' );
    $graph->setAttribute( 'id', 'g0' ); # TODO make this meaningful
    $graph->setAttribute( 'parse.edgeids', 'canonical' );
    $graph->setAttribute( 'parse.edges', $self->edges() );
    $graph->setAttribute( 'parse.nodeids', 'canonical' );
    $graph->setAttribute( 'parse.nodes', $self->nodes() );
    $graph->setAttribute( 'parse.order', 'nodesfirst' );

    my $node_ctr = 0;
    my %node_hash;
    foreach my $n ( $self->readings ) {
	my %this_node_data = ();
	foreach my $ndi ( 0 .. $#node_data ) {
	    my $value;
	    $this_node_data{'d'.$ndi} = $n->name if $node_data[$ndi] eq 'name';
	    $this_node_data{'d'.$ndi} = $n->label 
		if $node_data[$ndi] eq 'token';
	    $this_node_data{'d'.$ndi} = $n->primary->name if $n->has_primary;
	    $this_node_data{'d'.$ndi} = 
		$self->{'positions'}->node_position( $n )
		if $node_data[$ndi] eq 'position';
	}
	my $node_el = $graph->addNewChild( $graphml_ns, 'node' );
	my $node_xmlid = 'n' . $node_ctr++;
	$node_hash{ $n->name } = $node_xmlid;
	$node_el->setAttribute( 'id', $node_xmlid );
	    
	foreach my $dk ( keys %this_node_data ) {
	    my $d_el = $node_el->addNewChild( $graphml_ns, 'data' );
	    $d_el->setAttribute( 'key', $dk );
	    $d_el->appendTextChild( $this_node_data{$dk} );
	}
    }

    foreach my $e ( $self->edges() ) {
	my( $name, $from, $to ) = ( $e->name,
				    $node_hash{ $e->from()->name() },
				    $node_hash{ $e->to()->name() } );
	my $edge_el = $graph->addNewChild( $graphml_ns, 'edge' );
	$edge_el->setAttribute( 'source', $from );
	$edge_el->setAttribute( 'target', $to );
	$edge_el->setAttribute( 'id', $name );
	# TODO Got to add the witnesses
    }

    # Return the thing
    $self->_save_graphml( $graphml );
    return $graphml;
}

=back

=item B<start>

my $beginning = $collation->start();

Returns the beginning of the collation, a meta-reading with label '#START#'.

=cut

sub start {
    # Return the beginning reading of the graph.
    my $self = shift;
    my( $new_start ) = @_;
    if( $new_start ) {
	$self->del_reading( '#START#' );
	$self->graph->rename_node( $new_start, '#START#' );
    }
    return $self->reading('#START#');
}

=item B<next_reading>

my $next_reading = $graph->next_reading( $reading, $witpath );

Returns the reading that follows the given reading along the given witness
path.  TODO These are badly named.

=cut

sub next_reading {
    # Return the successor via the corresponding edge.
    my $self = shift;
    return $self->_find_linked_reading( 'next', @_ );
}

=item B<prior_reading>

my $prior_reading = $graph->prior_reading( $reading, $witpath );

Returns the reading that precedes the given reading along the given witness
path.  TODO These are badly named.

=cut

sub prior_reading {
    # Return the predecessor via the corresponding edge.
    my $self = shift;
    return $self->_find_linked_reading( 'prior', @_ );
}

sub _find_linked_reading {
    my( $self, $direction, $node, $edge ) = @_;
    $edge = 'base text' unless $edge;
    my @linked_edges = $direction eq 'next' 
	? $node->outgoing() : $node->incoming();
    return undef unless scalar( @linked_edges );
    
    # We have to find the linked edge that contains all of the
    # witnesses supplied in $edge.
    my @edge_wits = $self->witnesses_of_label( $edge );
    foreach my $le ( @linked_edges ) {
	my @le_wits = $self->witnesses_of_label( $le->name );
	if( _is_within( \@edge_wits, \@le_wits ) ) {
	    # This is the right edge.
	    return $direction eq 'next' ? $le->to() : $le->from();
	}
    }
    warn "Could not find $direction node from " . $node->label 
	. " along edge $edge";
    return undef;
}

# Some set logic.
sub _is_within {
    my( $set1, $set2 ) = @_;
    my $ret = 1;
    foreach my $el ( @$set1 ) {
	$ret = 0 unless grep { /^\Q$el\E$/ } @$set2;
    }
    return $ret;
}

# Walk the paths for each witness in the graph, and return the nodes
# that the graph has in common.

sub walk_witness_paths {
    my( $self, $end ) = @_;
    # For each witness, walk the path through the graph.
    # Then we need to find the common nodes.  
    # TODO This method is going to fall down if we have a very gappy 
    # text in the collation.
    my $paths = {};
    my @common_nodes;
    foreach my $wit ( @{$self->tradition->witnesses} ) {
	my $curr_reading = $self->start;
	my @wit_path = ( $curr_reading );
	my %seen_readings;
	# TODO Detect loops at some point
	while( $curr_reading->name ne $end->name ) {
	    if( $seen_readings{$curr_reading->name} ) {
		warn "Detected loop walking path for witness " . $wit->sigil
		    . " at reading " . $curr_reading->name;
		last;
	    }
	    my $next_reading = $self->next_reading( $curr_reading, 
						    $wit->sigil );
	    push( @wit_path, $next_reading );
	    $seen_readings{$curr_reading->name} = 1;
	    $curr_reading = $next_reading;
	}
	$wit->path( \@wit_path );
	if( @common_nodes ) {
	    my @cn;
	    foreach my $n ( @wit_path ) {
		push( @cn, $n ) if grep { $_ eq $n } @common_nodes;
	    }
	    @common_nodes = ();
	    push( @common_nodes, @cn );
	} else {
	    push( @common_nodes, @wit_path );
	}
    }

    # Mark all the nodes as either common or not.
    foreach my $cn ( @common_nodes ) {
	print STDERR "Setting " . $cn->name . " as common node\n";
	$cn->make_common;
    }
    foreach my $n ( $self->readings() ) {
	$n->make_variant unless $n->is_common;
    }
}

sub common_readings {
    my $self = shift;
    my @common = grep { $_->is_common } $self->readings();
    return @common;
}

# Calculate the relative positions of nodes in the graph, if they
# were not given to us.
sub calculate_positions {
    my $self = shift;

    # We have to calculate the position identifiers for each word,
    # keyed on the common nodes.  This will be 'fun'.  The end result
    # is a hash per witness, whose key is the word node and whose
    # value is its position in the text.  Common nodes are always N,1
    # so have identical positions in each text.
    my @common = $self->common_readings();

    my $node_pos = {};
    foreach my $wit ( @{$self->tradition->witnesses} ) {
	# First we walk each path, making a matrix for each witness that
	# corresponds to its eventual position identifier.  Common nodes
	# always start a new row, and are thus always in the first column.

	my $wit_matrix = [];
	my $cn = 0;  # We should hit the common readings in order.
	my $row = [];
	foreach my $wn ( @{$wit->path} ) {
	    if( $wn eq $common[$cn] ) {
		# Set up to look for the next common node, and
		# start a new row of words.
		$cn++;
		push( @$wit_matrix, $row ) if scalar( @$row );
		$row = [];
	    }
	    push( @$row, $wn );
	}
	push( @$wit_matrix, $row );  # Push the last row onto the matrix

	# Now we have a matrix per witness, so that each row in the
	# matrix begins with a common node, and continues with all the
	# variant words that appear in the witness.  We turn this into
	# real positions in row,cell format.  But we need some
	# trickery in order to make sure that each node gets assigned
	# to only one position.

	foreach my $li ( 1..scalar(@$wit_matrix) ) {
	    foreach my $di ( 1..scalar(@{$wit_matrix->[$li-1]}) ) {
		my $reading = $wit_matrix->[$li-1]->[$di-1];
		my $position = "$li,$di";
		# If we have seen this node before, we need to compare
		# its position with what went before.
		unless( $reading->has_position &&
			_cmp_position( $position, $reading->position ) < 1 ) {
		    # The new position ID replaces the old one.
		    $reading->position( $position );
		} # otherwise, the old position needs to stay.
	    }
	}
    }
}

sub _cmp_position {
    my( $a, $b ) = @_;
    my @pos_a = split(/,/, $a );
    my @pos_b = split(/,/, $b );

    my $big_cmp = $pos_a[0] <=> $pos_b[0];
    return $big_cmp if $big_cmp;
    # else 
    return $pos_a[1] <=> $pos_b[1];
}
 
# Return the string that joins together a list of witnesses for
# display on a single path.
sub path_label {
    my $self = shift;
    return join( $self->wit_list_separator, @_ );
}

sub witnesses_of_label {
    my $self = shift;
    my $regex = $self->wit_list_separator;
    return split( /^\Q$regex\E$/, @_ );
}    

no Moose;
__PACKAGE__->meta->make_immutable;
Commit	Line	Data
dd3b58b0	1	package Text::Tradition::Collation;
d047cd52	2
d047cd52	3	use Graph::Easy;
8e1394aa	4	use IPC::Run qw( run binary );
8e1394aa	5	use Text::Tradition::Collation::Reading;
dd3b58b0	6	use Moose;
	7
	8	has 'graph' => (
d047cd52	9	is => 'ro',
	10	isa => 'Graph::Easy',
	11	handles => {
8e1394aa	12	add_reading => 'add_node',
	13	del_reading => 'del_node',
	14	add_path => 'add_edge',
	15	del_path => 'del_edge',
	16	reading => 'node',
	17	path => 'edge',
	18	readings => 'nodes',
	19	paths => 'edges',
d047cd52	20	},
	21	default => sub { Graph::Easy->new( undirected => 0 ) },
	22	);
784877d9	23
dd3b58b0	24
dd3b58b0	25	has 'tradition' => (
8e1394aa	26	is => 'rw',
d047cd52	27	isa => 'Text::Tradition',
d047cd52	28	);
dd3b58b0	29
8e1394aa	30	has 'svg' => (
	31	is => 'ro',
	32	isa => 'Str',
	33	writer => '_save_svg',
	34	predicate => 'has_svg',
	35	);
	36
	37	has 'graphviz' => (
	38	is => 'ro',
	39	isa => 'Str',
	40	writer => '_save_graphviz',
	41	predicate => 'has_graphviz',
	42	);
	43
	44	has 'graphml' => (
	45	is => 'ro',
	46	isa => 'XML::LibXML::Document',
	47	writer => '_save_graphml',
	48	predicate => 'has_graphml',
	49	);
	50
4a8828f0	51	has 'wit_list_separator' => (
	52	is => 'rw',
	53	isa => 'Str',
	54	default => ', ',
	55	);
	56
dd3b58b0	57	# The collation can be created two ways:
	58	# 1. Collate a set of witnesses (with CollateX I guess) and process
	59	# the results as in 2.
	60	# 2. Read a pre-prepared collation in one of a variety of formats,
	61	# and make the graph from that.
	62
	63	# The graph itself will (for now) be immutable, and the positions
	64	# within the graph will also be immutable. We need to calculate those
	65	# positions upon graph construction. The equivalences between graph
	66	# nodes will be mutable, entirely determined by the user (or possibly
	67	# by some semantic pre-processing provided by the user.) So the
	68	# constructor should just make an empty equivalences object. The
	69	# constructor will also need to make the witness objects, if we didn't
	70	# come through option 1.
	71
d047cd52	72	sub BUILD {
d047cd52	73	my( $self, $args ) = @_;
8e1394aa	74	$self->graph->use_class('node', 'Text::Tradition::Collation::Reading');
d047cd52	75
4a8828f0	76	# Pass through any graph-specific options.
	77	my $shape = exists( $args->{'shape'} ) ? $args->{'shape'} : 'ellipse';
	78	$self->graph->set_attribute( 'node', 'shape', $shape );
d047cd52	79	}
784877d9	80
	81	# Wrappers around some methods
	82
	83	sub merge_readings {
	84	my $self = shift;
	85	my $first_node = shift;
	86	my $second_node = shift;
	87	$first_node->merge_from( $second_node );
	88	unshift( @_, $first_node, $second_node );
	89	return $self->graph->merge_nodes( @_ );
	90	}
	91
8e1394aa	92	=head2 Output method(s)
	93
	94	=over
	95
	96	=item B<as_svg>
	97
	98	print $graph->as_svg( $recalculate );
	99
	100	Returns an SVG string that represents the graph. Uses GraphViz to do
4a8828f0	101	this, because Graph::Easy doesn\'t cope well with long graphs. Unless
8e1394aa	102	$recalculate is passed (and is a true value), the method will return a
	103	cached copy of the SVG after the first call to the method.
	104
	105	=cut
	106
	107	sub as_svg {
	108	my( $self, $recalc ) = @_;
	109	return $self->svg if $self->has_svg;
	110
	111	$self->_save_graphviz( $self->graph->as_graphviz() )
	112	unless( $self->has_graphviz && !$recalc );
	113
	114	my @cmd = qw/dot -Tsvg/;
	115	my( $svg, $err );
	116	my $in = $self->graphviz;
	117	run( \@cmd, \$in, ">", binary(), \$svg );
	118	$self->{'svg'} = $svg;
	119	return $svg;
	120	}
	121
	122	=item B<as_graphml>
	123
	124	print $graph->as_graphml( $recalculate )
	125
	126	Returns a GraphML representation of the collation graph, with
	127	transposition information and position information. Unless
	128	$recalculate is passed (and is a true value), the method will return a
	129	cached copy of the SVG after the first call to the method.
	130
	131	=cut
	132
	133	sub as_graphml {
	134	my( $self, $recalc ) = @_;
	135	return $self->graphml if $self->has_graphml;
	136
	137	# Some namespaces
	138	my $graphml_ns = 'http://graphml.graphdrawing.org/xmlns';
	139	my $xsi_ns = 'http://www.w3.org/2001/XMLSchema-instance';
	140	my $graphml_schema = 'http://graphml.graphdrawing.org/xmlns ' .
	141	'http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd';
	142
	143	# Create the document and root node
	144	my $graphml = XML::LibXML->createDocument( "1.0", "UTF-8" );
	145	my $root = $graphml->createElementNS( $graphml_ns, 'graphml' );
	146	$graphml->setDocumentElement( $root );
	147	$root->setNamespace( $xsi_ns, 'xsi', 0 );
	148	$root->setAttributeNS( $xsi_ns, 'schemaLocation', $graphml_schema );
	149
	150	# Add the data keys for nodes
	151	my @node_data = ( 'name', 'token', 'identical', 'position' );
	152	foreach my $ndi ( 0 .. $#node_data ) {
	153	my $key = $root->addNewChild( $graphml_ns, 'key' );
	154	$key->setAttribute( 'attr.name', $node_data[$ndi] );
	155	$key->setAttribute( 'attr.type', 'string' );
	156	$key->setAttribute( 'for', 'node' );
	157	$key->setAttribute( 'id', 'd'.$ndi );
	158	}
	159
	160	# Add the data keys for edges
	161	my %wit_hash;
	162	my $wit_ctr = 0;
	163	foreach my $wit ( $self->getWitnessList ) {
	164	my $wit_key = 'w' . $wit_ctr++;
	165	$wit_hash{$wit} = $wit_key;
166	my $key = $root->addNewChild( $graphml_ns, 'key' );
167	$key->setAttribute( 'attr.name', $wit );
168	$key->setAttribute( 'attr.type', 'string' );
169	$key->setAttribute( 'for', 'edge' );
170	$key->setAttribute( 'id', $wit_key );
171	}
172
173	# Add the graph, its nodes, and its edges
174	my $graph = $root->addNewChild( $graphml_ns, 'graph' );
175	$graph->setAttribute( 'edgedefault', 'directed' );
176	$graph->setAttribute( 'id', 'g0' ); # TODO make this meaningful
177	$graph->setAttribute( 'parse.edgeids', 'canonical' );
178	$graph->setAttribute( 'parse.edges', $self->edges() );
179	$graph->setAttribute( 'parse.nodeids', 'canonical' );
180	$graph->setAttribute( 'parse.nodes', $self->nodes() );
181	$graph->setAttribute( 'parse.order', 'nodesfirst' );
182
183	my $node_ctr = 0;
184	my %node_hash;
185	foreach my $n ( $self->readings ) {
186	my %this_node_data = ();
187	foreach my $ndi ( 0 .. $#node_data ) {
188	my $value;
189	$this_node_data{'d'.$ndi} = $n->name if $node_data[$ndi] eq 'name';
190	$this_node_data{'d'.$ndi} = $n->label
191	if $node_data[$ndi] eq 'token';
192	$this_node_data{'d'.$ndi} = $n->primary->name if $n->has_primary;
193	$this_node_data{'d'.$ndi} =
194	$self->{'positions'}->node_position( $n )
195	if $node_data[$ndi] eq 'position';
196	}
197	my $node_el = $graph->addNewChild( $graphml_ns, 'node' );
198	my $node_xmlid = 'n' . $node_ctr++;
199	$node_hash{ $n->name } = $node_xmlid;
200	$node_el->setAttribute( 'id', $node_xmlid );
201
202	foreach my $dk ( keys %this_node_data ) {
203	my $d_el = $node_el->addNewChild( $graphml_ns, 'data' );
204	$d_el->setAttribute( 'key', $dk );
205	$d_el->appendTextChild( $this_node_data{$dk} );
206	}
207	}
208
209	foreach my $e ( $self->edges() ) {
210	my( $name, $from, $to ) = ( $e->name,
211	$node_hash{ $e->from()->name() },
212	$node_hash{ $e->to()->name() } );
213	my $edge_el = $graph->addNewChild( $graphml_ns, 'edge' );
214	$edge_el->setAttribute( 'source', $from );
215	$edge_el->setAttribute( 'target', $to );
216	$edge_el->setAttribute( 'id', $name );
217	# TODO Got to add the witnesses
218	}
219
220	# Return the thing
221	$self->_save_graphml( $graphml );
222	return $graphml;
223	}
224
225	=back
226
227	=item B<start>
228
229	my $beginning = $collation->start();
230
231	Returns the beginning of the collation, a meta-reading with label '#START#'.
232
233	=cut
234
235	sub start {
4a8828f0	236	# Return the beginning reading of the graph.
8e1394aa	237	my $self = shift;
	238	my( $new_start ) = @_;
	239	if( $new_start ) {
	240	$self->del_reading( '#START#' );
	241	$self->graph->rename_node( $new_start, '#START#' );
	242	}
	243	return $self->reading('#START#');
	244	}
	245
4a8828f0	246	=item B<next_reading>
8e1394aa	247
4a8828f0	248	my $next_reading = $graph->next_reading( $reading, $witpath );
8e1394aa	249
4a8828f0	250	Returns the reading that follows the given reading along the given witness
8e1394aa	251	path. TODO These are badly named.
	252
	253	=cut
	254
4a8828f0	255	sub next_reading {
8e1394aa	256	# Return the successor via the corresponding edge.
8e1394aa	257	my $self = shift;
4a8828f0	258	return $self->_find_linked_reading( 'next', @_ );
8e1394aa	259	}
8e1394aa	260
4a8828f0	261	=item B<prior_reading>
8e1394aa	262
4a8828f0	263	my $prior_reading = $graph->prior_reading( $reading, $witpath );
8e1394aa	264
4a8828f0	265	Returns the reading that precedes the given reading along the given witness
8e1394aa	266	path. TODO These are badly named.
	267
	268	=cut
	269
4a8828f0	270	sub prior_reading {
8e1394aa	271	# Return the predecessor via the corresponding edge.
8e1394aa	272	my $self = shift;
4a8828f0	273	return $self->_find_linked_reading( 'prior', @_ );
8e1394aa	274	}
8e1394aa	275
4a8828f0	276	sub _find_linked_reading {
8e1394aa	277	my( $self, $direction, $node, $edge ) = @_;
	278	$edge = 'base text' unless $edge;
	279	my @linked_edges = $direction eq 'next'
	280	? $node->outgoing() : $node->incoming();
	281	return undef unless scalar( @linked_edges );
	282
	283	# We have to find the linked edge that contains all of the
	284	# witnesses supplied in $edge.
4a8828f0	285	my @edge_wits = $self->witnesses_of_label( $edge );
8e1394aa	286	foreach my $le ( @linked_edges ) {
4a8828f0	287	my @le_wits = $self->witnesses_of_label( $le->name );
8e1394aa	288	if( _is_within( \@edge_wits, \@le_wits ) ) {
	289	# This is the right edge.
	290	return $direction eq 'next' ? $le->to() : $le->from();
	291	}
	292	}
	293	warn "Could not find $direction node from " . $node->label
	294	. " along edge $edge";
	295	return undef;
	296	}
	297
4a8828f0	298	# Some set logic.
	299	sub _is_within {
	300	my( $set1, $set2 ) = @_;
	301	my $ret = 1;
	302	foreach my $el ( @$set1 ) {
	303	$ret = 0 unless grep { /^\Q$el\E$/ } @$set2;
	304	}
	305	return $ret;
	306	}
	307
	308	# Walk the paths for each witness in the graph, and return the nodes
	309	# that the graph has in common.
	310
	311	sub walk_witness_paths {
	312	my( $self, $end ) = @_;
	313	# For each witness, walk the path through the graph.
	314	# Then we need to find the common nodes.
	315	# TODO This method is going to fall down if we have a very gappy
	316	# text in the collation.
	317	my $paths = {};
	318	my @common_nodes;
	319	foreach my $wit ( @{$self->tradition->witnesses} ) {
	320	my $curr_reading = $self->start;
	321	my @wit_path = ( $curr_reading );
	322	my %seen_readings;
	323	# TODO Detect loops at some point
	324	while( $curr_reading->name ne $end->name ) {
	325	if( $seen_readings{$curr_reading->name} ) {
	326	warn "Detected loop walking path for witness " . $wit->sigil
	327	. " at reading " . $curr_reading->name;
	328	last;
	329	}
	330	my $next_reading = $self->next_reading( $curr_reading,
	331	$wit->sigil );
	332	push( @wit_path, $next_reading );
	333	$seen_readings{$curr_reading->name} = 1;
	334	$curr_reading = $next_reading;
	335	}
	336	$wit->path( \@wit_path );
	337	if( @common_nodes ) {
	338	my @cn;
	339	foreach my $n ( @wit_path ) {
	340	push( @cn, $n ) if grep { $_ eq $n } @common_nodes;
	341	}
	342	@common_nodes = ();
	343	push( @common_nodes, @cn );
	344	} else {
	345	push( @common_nodes, @wit_path );
	346	}
	347	}
	348
	349	# Mark all the nodes as either common or not.
	350	foreach my $cn ( @common_nodes ) {
	351	print STDERR "Setting " . $cn->name . " as common node\n";
	352	$cn->make_common;
	353	}
	354	foreach my $n ( $self->readings() ) {
	355	$n->make_variant unless $n->is_common;
	356	}
	357	}
	358
	359	sub common_readings {
	360	my $self = shift;
	361	my @common = grep { $_->is_common } $self->readings();
362	return @common;
363	}
364
365	# Calculate the relative positions of nodes in the graph, if they
366	# were not given to us.
367	sub calculate_positions {
368	my $self = shift;
369
370	# We have to calculate the position identifiers for each word,
371	# keyed on the common nodes. This will be 'fun'. The end result
372	# is a hash per witness, whose key is the word node and whose
373	# value is its position in the text. Common nodes are always N,1
374	# so have identical positions in each text.
375	my @common = $self->common_readings();
376
377	my $node_pos = {};
378	foreach my $wit ( @{$self->tradition->witnesses} ) {
379	# First we walk each path, making a matrix for each witness that
380	# corresponds to its eventual position identifier. Common nodes
381	# always start a new row, and are thus always in the first column.
382
383	my $wit_matrix = [];
384	my $cn = 0; # We should hit the common readings in order.
385	my $row = [];
386	foreach my $wn ( @{$wit->path} ) {
387	if( $wn eq $common[$cn] ) {
388	# Set up to look for the next common node, and
389	# start a new row of words.
390	$cn++;
391	push( @$wit_matrix, $row ) if scalar( @$row );
392	$row = [];
393	}
394	push( @$row, $wn );
395	}
396	push( @$wit_matrix, $row ); # Push the last row onto the matrix
397
398	# Now we have a matrix per witness, so that each row in the
399	# matrix begins with a common node, and continues with all the
400	# variant words that appear in the witness. We turn this into
401	# real positions in row,cell format. But we need some
402	# trickery in order to make sure that each node gets assigned
403	# to only one position.
404
405	foreach my $li ( 1..scalar(@$wit_matrix) ) {
406	foreach my $di ( 1..scalar(@{$wit_matrix->[$li-1]}) ) {
407	my $reading = $wit_matrix->[$li-1]->[$di-1];
408	my $position = "$li,$di";
409	# If we have seen this node before, we need to compare
410	# its position with what went before.
411	unless( $reading->has_position &&
412	_cmp_position( $position, $reading->position ) < 1 ) {
413	# The new position ID replaces the old one.
414	$reading->position( $position );
415	} # otherwise, the old position needs to stay.
416	}
417	}
418	}
419	}
420
421	sub _cmp_position {
422	my( $a, $b ) = @_;
423	my @pos_a = split(/,/, $a );
424	my @pos_b = split(/,/, $b );
8e1394aa	425
4a8828f0	426	my $big_cmp = $pos_a[0] <=> $pos_b[0];
	427	return $big_cmp if $big_cmp;
	428	# else
	429	return $pos_a[1] <=> $pos_b[1];
8e1394aa	430	}
4a8828f0	431
	432	# Return the string that joins together a list of witnesses for
	433	# display on a single path.
	434	sub path_label {
	435	my $self = shift;
	436	return join( $self->wit_list_separator, @_ );
	437	}
	438
	439	sub witnesses_of_label {
	440	my $self = shift;
	441	my $regex = $self->wit_list_separator;
	442	return split( /^\Q$regex\E$/, @_ );
	443	}
8e1394aa	444
dd3b58b0	445	no Moose;
dd3b58b0	446	__PACKAGE__->meta->make_immutable;