+# link up precedence-sorted list into a binary tree
+sub elements_to_tree
+{
+ my($self, $elements)=@_;
+ return undef unless(@$elements);
+ my ($left, $right, $op)=(undef, undef, undef);
+ my $thing=pop @$elements;
+ if($self->is($TYPE_BOOL, $thing))
+ {
+ $right=$self->elements_to_tree($elements);
+ if($thing->{name} ne "NOT")
+ {
+ $left=$self->elements_to_tree($elements);
+ }
+ $thing->left($left);
+ $thing->right($right);
+ }
+ return $thing;
+}
+
+# Dijkstra's shunting-yard algorithm
+sub sort_elements
+{
+ my ($self, @input)=@_;
+ my @opstack=();
+ my @output=();
+# print "INPUT: ", join(', ', map { $_->{name}; } @input), "\n";
+ while(my $thing = shift @input)
+ {
+ if($self->is($TYPE_TAG, $thing))
+ {
+ # Handle tag values by dropping parent
+ if(@input && $self->is($TYPE_TAG, $input[0]))
+ {
+ $thing=shift @input;
+ }
+ push(@output, $thing);
+ }
+ elsif($self->is($TYPE_BOOL, $thing))
+ {
+ while(@opstack &&
+ ($priorities{$thing->{name}} <= $priorities{$opstack[$#opstack]->{name}}))
+ {
+ push(@output, pop(@opstack));
+ }
+ push(@opstack, $thing);
+ }
+ }
+ while(@opstack)
+ {
+ push(@output, pop(@opstack));
+ }
+# print "STACK: ", join(', ', map { $_->{name}; } @output), "\n";
+ return @output;
+}
+
+sub used_tags
+{
+ my($self)=@_;
+ return() unless(defined($self->{tagtree}));
+ return($self->{tagtree}->used_tags());
+}
+
+sub expecting_values
+{
+ my($self)=@_;
+ my $tail=$self->tail();
+ if($self->is($TYPE_TAG, $tail))
+ {
+ return($self->{db}->tag_has_values($tail->id()));
+ }
+}
+
+sub trailing_tag_id
+{
+ my($self)=@_;
+ my $tail=$self->tail();
+ if($self->is($TYPE_TAG, $tail))
+ {
+ return($tail->id());
+ }
+ return undef;
+}
+
+sub trailing_tag_parent
+{
+ my($self)=@_;
+ my $tail=$self->tail();
+ if($self->is($TYPE_TAG, $tail))
+ {
+ return($tail->{parents_id});
+ }
+ return undef;
+}
+
+sub tail
+{
+ my($self)=@_;
+ return($self->{elements}->[$#{$self->{elements}}]);
+}
+
+sub is
+{
+ my($self, $type, $thing)=@_;
+ return 0 unless($thing);
+ return 0 unless($thing->type());
+ return 1 if($type == $thing->type());
+ return 0;
+}
+
+# the one before last
+sub tail_parent
+{
+ my($self)=@_;
+ return($self->{elements}->[($#{$self->{elements}}) - 1]);
+}
+
+######################################################################
+
+sub tags
+{
+ my($self)=@_;
+ if(!$self->{tagtree}) # / or /NOT
+ {
+ my $sql="SELECT DISTINCT name FROM tags WHERE parents_id='';";
+ return($self->{db}->cmd_firstcol($sql));
+ }
+ my $hasvals=$self->expecting_values();
+ my $parent=$self->trailing_tag_parent();
+# print "THASVALS: $hasvals\n";
+# print "TPARENT: ", (defined($parent)? $parent : "NO"), "\n";
+ my @ids=();
+ my $sql="SELECT tags.name FROM ";
+ if($self->in_or())
+ {
+ $sql .= "files_x_tags\n";
+ }
+ else
+ {
+ $sql .= ("(\n" .
+ $self->tags_subselect() .
+ ") AS subselect\n" .
+ "INNER JOIN files_x_tags ON subselect.files_id=files_x_tags.files_id\n");
+ }
+ $sql .= "INNER JOIN tags ON files_x_tags.tags_id=tags.id\n";
+ my @andclauses=();
+ my $id=$self->trailing_tag_id();
+
+ my $parentclause= "tags.parents_id='";
+ if($hasvals)
+ {
+ $parentclause .= $id;
+ }
+ elsif($parent)
+ {
+ $parentclause .= $parent;
+ }
+ $parentclause .= "'";
+ push(@andclauses, $parentclause);
+
+ my @used=$self->used_tags();
+ if(@used)
+ {
+ push(@andclauses, "tags.id NOT IN (" . join(', ', @used) . ")");
+ }
+ if(@andclauses)
+ {
+ $sql .= "WHERE " . join(' AND ', @andclauses) . "\n";
+ }
+
+ $sql .= "GROUP BY tags.name;";
+ print "SQL(TAGS): $sql\n" if($self->{verbose});
+ my @tagnames=$self->{db}->cmd_firstcol($sql);
+ print("SUBNAMES: ", join(', ', @tagnames), "\n") if($self->{verbose});
+ return(@tagnames);
+}
+
+sub artists
+{
+ my($self)=@_;
+ if(!@{$self->{elements}}) # /ALL
+ {
+ my $sql="SELECT DISTINCT name FROM artists WHERE name!='';";
+ return($self->{db}->cmd_firstcol($sql));
+ }
+ my @ids=();
+ my $sql=$self->sql_start("artists.name");
+ $sql .= ("INNER JOIN artists ON files.artists_id=artists.id\n" .
+ "WHERE artists.name != ''\n" .
+ "GROUP BY artists.name;");
+ print "SQL(ARTISTS): $sql\n" if($self->{verbose});
+ my @tagnames=$self->{db}->cmd_firstcol($sql);
+ print("ARTISTS: ", join(', ', @tagnames), "\n") if($self->{verbose});
+ return(@tagnames);
+}
+
+sub albums
+{
+ my($self)=@_;
+ my @ids=();
+ my $tail=$self->tail();
+ if($self->is($TYPE_ARTIST, $tail))
+ {
+ return $self->artist_albums($tail->id());
+ }
+ my $sql=$self->sql_start("albums.name");
+ $sql .= ("INNER JOIN albums ON files.albums_id=albums.id\n" .
+ "WHERE albums.name != ''\n" .
+ "GROUP BY albums.name;");
+ print "SQL(ALBUMS): \n$sql\n" if($self->{verbose});
+ my @names=$self->{db}->cmd_firstcol($sql);
+ print("ALBUMS: ", join(', ', @names), "\n") if($self->{verbose});
+ return(@names);
+}
+
+sub artist_albums
+{
+ my($self, $artist_id)=@_;
+ my $sql=$self->sql_start("albums.name");
+ $sql .= ("INNER JOIN albums ON albums.id=files.albums_id\n" .
+ "INNER JOIN artists ON artists.id=files.artists_id\n" .
+ "WHERE artists.id=? and albums.name <> ''\n" .
+ "GROUP BY albums.name\n");
+ print "ARTIST_ALBUMS SQL: $sql\n" if($self->{verbose});
+ my @albums=$self->{db}->cmd_firstcol($sql, $artist_id);
+ print("ALBUMS: ", join(', ', @albums), "\n") if($self->{verbose});
+ return(@albums);
+}
+
+sub artist_tracks
+{
+ my($self, $artist_id)=@_;
+ my $sql=$self->sql_start("files.name");
+ $sql .= ("INNER JOIN artists ON artists.id=files.artists_id\n" .
+ "INNER JOIN albums ON albums.id=files.albums_id\n" .
+ "WHERE artists.id=? AND albums.name=''\n" .
+ "GROUP BY files.name\n");
+ print "ARTIST_TRACKS SQL: $sql\n" if($self->{verbose});
+ my @names=$self->{db}->cmd_firstcol($sql, $artist_id);
+ print("ARTISTTRACKS: ", join(', ', @names), "\n") if($self->{verbose});
+ return(@names);
+}
+
+sub album_tracks
+{
+ my($self, $artist_id, $album_id)=@_;
+ my $sql=("SELECT files.name FROM files\n" .
+ "INNER JOIN albums ON albums.id=files.albums_id\n" .
+ "INNER JOIN artists ON artists.id=files.artists_id\n" .
+ "WHERE artists.id=? AND albums.id=?\n" .
+ "GROUP BY files.name\n");
+ print "ALBUM_TRACKS SQL($artist_id, $album_id): $sql\n" if($self->{verbose});
+ my @names=$self->{db}->cmd_firstcol($sql, $artist_id, $album_id);
+ print("TRACKS: ", join(', ', @names), "\n") if($self->{verbose});
+ return(@names);
+}
+
+sub tracks
+{
+ my($self)=@_;
+ my $tail=$self->tail();
+ if($self->is($TYPE_ARTIST, $tail))
+ {
+ return $self->artist_tracks($tail->id());
+ }
+ elsif($self->is($TYPE_ALBUM, $tail))
+ {
+ my $artist_id=0;
+ my $artist=$self->tail_parent();
+ if($self->is($TYPE_ARTIST, $artist))
+ {
+ # should always happen
+ $artist_id=$artist->id();
+ }
+ return $self->album_tracks($artist_id, $tail->id());
+ }
+ my $sql=$self->sql_start("files.name");
+ $sql .= "INNER JOIN artists ON files.artists_id=artists.id\n";
+ if($self->{components}->[$#{$self->{components}}] eq $PATH_NOARTIST)
+ {
+ $sql .= "WHERE artists.name =''\n";
+ }
+ $sql .= "GROUP BY files.name;";
+ print "TRACKS SQL($self->{path}): $sql\n" if($self->{verbose});
+ my @names=$self->{db}->cmd_firstcol($sql);
+ print("TRACKS: ", join(', ', @names), "\n") if($self->{verbose});
+ return(@names);
+}
+
+sub filename
+{
+ my($self, $mountpoint)=@_;
+ my $tail=$self->tail();
+ if($self->is($TYPE_FILE, $tail))
+ {
+ my $id=$tail->id();
+ my $sql=("SELECT paths.name, files.name FROM files\n" .
+ "INNER JOIN paths ON files.paths_id=paths.id\n" .
+ "WHERE files.id=?\n" .
+ "GROUP BY paths.name, files.name");
+ print "FILENAME SQL: $sql\n" if($self->{verbose});
+ my ($path, $name)=$self->{db}->cmd_onerow($sql, $id);
+ return($self->{db}->relativise($path, $name, $mountpoint, $self->{path}));
+ }
+ # should never happen
+ return "ERROR";
+}
+
+sub tags_subselect
+{
+ my($self)=@_;
+ my $hasvals=$self->expecting_values();
+ my $tree=$self->{tagtree};
+ my $parent=$self->trailing_tag_parent();
+
+ my $tag=undef;
+ if($hasvals)
+ {
+ $tag=$self->trailing_tag_id();
+# print "Trailing id: $tag\n";
+ }
+ my ($sqlclause, @joins)=(undef, ());
+ ($sqlclause, @joins) = $tree->to_sql($hasvals) if($tree);
+# print "SQL(" . scalar(@joins) ."): $sqlclause\n";
+ my $sql="\tSELECT fxt1.files_id FROM tags t1";
+ my @crosses=();
+ my @inners=();
+# $joinsneeded++ if($tag);
+ for(my $i=0; $i <= $#joins; $i++)
+ {
+ my $cnt=$i+1;
+ my $join=$joins[$i];
+ my $inner=("\t$join JOIN files_x_tags fxt$cnt ON " .
+ "t${cnt}.id=fxt${cnt}.tags_id");
+ if($i > 0)
+ {
+ push(@crosses, "CROSS JOIN tags t$cnt");
+ $inner .= " AND fxt1.files_id=fxt${cnt}.files_id";
+ }
+ push(@inners, $inner);
+ }
+ $sql .= ("\n\t" . join(" ", @crosses)) if(@crosses);
+ $sql .= ("\n" . join("\n", @inners)) if(@inners);
+ $sql .= "\n\tWHERE $sqlclause" if($sqlclause);
+# if($tag)
+# {
+# $sql .= " AND t${joinsneeded}.parents_id='$tag'";
+# }
+ $sql .= "\n\tGROUP BY fxt1.files_id\n";
+ return $sql;
+}
+
+sub sql_start
+{
+ my($self, $tables)=@_;
+ my $sql="SELECT $tables FROM ";
+ if($self->{in_all})
+ {
+ $sql .= "files\n";
+ }
+ else
+ {
+ $sql .= ("(\n" .
+ $self->tags_subselect() .
+ ") AS subselect\n" .
+ "INNER JOIN files ON subselect.files_id=files.id\n");
+ }
+ return $sql;
+}
+
+# we just filter $ALLTRACKS, $NOARTIST and $NOALBUM
+# filtering tags properly requires up to four levels of recursion
+# (tag/tagval/AND/NOT) and is too slow
+sub filter
+{
+ my($self, @dirs)=@_;
+ return(@dirs) unless($ENABLE_FILTER);
+ my $base=$self->{path};
+ my @outdirs=();
+ for my $dir (@dirs)
+ {
+ push(@outdirs, $dir) unless($self->empty("$base/$dir"));
+ }
+ return(@outdirs);
+}
+
+sub empty
+{
+ my($self, $dir)=@_;
+ my $path=ID3FS::Path->new($self->{db}, $dir, $self->{verbose},
+ ($self->{maxtagdepth} - $self->{curtagdepth}));
+ return 1 unless($path->isvalid());
+ my($subdirs,$subfiles)=$path->dirents();
+ return 0 if(@$subfiles || @$subdirs);
+ return 1;
+}
+
+# if path is .../OR/ or .../OR/NOT
+sub in_or
+{
+ my($self)=@_;
+ my $tail=$self->tail();
+ return 0 unless($tail);
+ return 0 unless($tail->type() == $TYPE_BOOL);
+ return 1 if($tail->name() eq "OR");
+ return 0 unless($tail->name() eq "NOT");
+ my $parent=$self->tail_parent();
+ return 0 unless($parent);
+ return 0 unless($parent->type() == $TYPE_BOOL);
+ return 1 if($parent->name() eq "OR");
+ return 0;
+}
+