# $Id: maf.pm,v 1.4 2003/11/15 13:05:58 heikki Exp $
#
# BioPerl module for Bio::AlignIO::maf
#
# Copyright Allen Day
#

=head1 NAME

Bio::AlignIO::maf - Multipla Alignment Format sequence input stream

=head1 SYNOPSIS

 Do not use this module directly.  Use it via the Bio::AlignIO class.

 use Bio::AlignIO;

 my $alignio = Bio::AlignIO->new(-fh => \*STDIN, -format => 'maf');

 while(my $aln = $alignio->next_aln()){
   my $match_line = $aln->match_line;

   print $aln, "\n";

   print $aln->length, "\n";
   print $aln->no_residues, "\n";
   print $aln->is_flush, "\n";
   print $aln->no_sequences, "\n";

   $aln->splice_by_seq_pos(1);

   print $aln->consensus_string(60), "\n";
   print $aln->get_seq_by_pos(1)->seq, "\n";
   print $aln->match_line(), "\n";

   print "\n";
 }

=head1 DESCRIPTION

This class constructs Bio::SimpleAlign objects from an MAF-format
multiple alignment file.

Writing in MAF format is currently unimplemented.

Spec of MAF format is here:
  http://hgwdev-sugnet.cse.ucsc.edu/cgi-bin/hgGateway?org=human

=head1 FEEDBACK

=head2 Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track
 the bugs and their resolution.
 Bug reports can be submitted via email or the web:

  bioperl-bugs@bio.perl.org
  http://bugzilla.bioperl.org/

=head1 AUTHORS - Allen Day

Email: allenday@ucla.edu

=head1 APPENDIX

The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _

=cut

# Let the code begin...

package Bio::AlignIO::maf;
use vars qw(@ISA $seen_header);
use strict;

use Bio::SimpleAlign;
use Bio::AlignIO;

$seen_header = 0;

@ISA = qw(Bio::AlignIO);

=head2 new

 Title   : new
 Usage   : my $alignio = new Bio::AlignIO(-format => 'maf'
					  -file   => '>file',
					  -idlength => 10,
					  -idlinebreak => 1);
 Function: Initialize a new L<Bio::AlignIO::maf> reader
 Returns : L<Bio::AlignIO> object
 Args    :

=cut

sub _initialize {
  my($self,@args) = @_;
  $self->SUPER::_initialize(@args);

  1;
}

=head2 next_aln

 Title   : next_aln
 Usage   : $aln = $stream->next_aln()
 Function: returns the next alignment in the stream.
           Throws an exception if trying to read in PHYLIP
           sequential format.
 Returns : L<Bio::SimpleAlign> object
 Args    : 

=cut

sub next_aln {
  my $self = shift;

  if(!$seen_header){
	my $line = $self->_readline;
	$self->throw("This doesn't look like a MAF file.  First line should start with ##maf, but it was: ".$line)
	  unless $line =~ /^##maf/;
	$seen_header = 1;
  }

  my $aln =  Bio::SimpleAlign->new(-source => 'maf');

  my($aline, @slines);
  while(my $line = $self->_readline()){
	$aline = $line if $line =~ /^a/;
	push @slines, $line if $line =~ /^s /;
	last if $line !~ /\S/;

  }

  return undef unless $aline;

  my($kvs) = $aline =~ /^a\s+(.+)$/;
  my @kvs  = split /\s+/, $kvs if $kvs;
  my %kv;
  foreach my $kv (@kvs){
    my($k,$v) = $kv =~ /(.+)=(.+)/;
    $kv{$k} = $v;
  }

  $aln->score($kv{score});

  foreach my $sline (@slines){
	my($s,$src,$start,$size,$strand,$srcsize,$text) =
	  split /\s+/, $sline;

	my $seq = new Bio::LocatableSeq('-seq'   => $text,
									'-id'    => $src,
									'-start' => $start,
									'-end'   => $start + $size,
								   );
	$aln->add_seq($seq);
  }

  return $aln;
}

sub write_aln {
  shift->throw_not_implemented
}

1;