=head1 LICENSE

Copyright [1999-2015] Wellcome Trust Sanger Institute and the EMBL-European Bioinformatics Institute
Copyright [2016-2020] EMBL-European Bioinformatics Institute

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

=cut


=head1 CONTACT

  Please email comments or questions to the public Ensembl
  developers list at <http://lists.ensembl.org/mailman/listinfo/dev>.

  Questions may also be sent to the Ensembl help desk at
  <http://www.ensembl.org/Help/Contact>.

=cut

=head1 NAME

PairAlign - Dna pairwise alignment module

=head1 SYNOPSIS

#To convert between coordinates:

  my $cdna_coord = $pair->genomic2cDNA($gen_coord);
  my $gen_coord  = $pair->cDNA2genomic($cdna_coord);

=head1 DESCRIPTION

Contains list of sub alignments making up a dna-dna alignment

Creation:

  my $pair = new Bio::EnsEMBL::FeaturePair(
    -start  => $qstart,
    -end    => $qend,
    -strand => $qstrand,
    -hstart => $hstart,
    -hend   => $hend,
    -hend   => $hstrand,
  );

  my $pairaln = new Bio::EnsEMBL::Analysis::PairAlign;
  $pairaln->addFeaturePair($pair);

Any number of pair alignments can be added to the PairAlign object

=cut

package Bio::EnsEMBL::Analysis::PairAlign;

use vars qw(@ISA);
use strict;


sub new {
    my($class,@args) = @_;
    my $self = {};
    bless $self, $class;

    $self->{'_homol'} = [];
    
    return $self; # success - we hope!
}

sub addFeaturePair {
    my ($self,$pair) = @_;

    $self->throw("Not a Bio::EnsEMBL::FeaturePair object") unless ($pair->isa("Bio::EnsEMBL::FeaturePair"));

    push(@{$self->{'_pairs'}},$pair);
    
}


=head2 eachFeaturePair

 Title   : eachFeaturePair 
 Example : my @pairs = $pair->eachFeaturePair
 Returns : Array of Bio::SeqFeature::FeaturePair
 Args    : none
=cut

sub eachFeaturePair {
    my ($self) = @_;

    if (defined($self->{'_pairs'})) {
	return @{$self->{'_pairs'}};
    }
}

sub get_hstrand {
    my ($self) = @_;

    my @features = $self->eachFeaturePair;

    return $features[0]->hstrand;
}

=head2 genomic2cDNA

 Title   : genomic2cDNA
 Usage   : my $cdna_coord = $pair->genomic2cDNA($gen_coord)
 Function: Converts a genomic coordinate to a cdna coordinate
 Returns : int
 Args    : int
=cut

sub genomic2cDNA {
  my ($self,$coord) = @_;
  my @pairs = $self->eachFeaturePair;
  
  @pairs = sort {$a->start <=> $b->start} @pairs;
  
  my $newcoord;
  
  HOMOL: while (my $sf1 = shift(@pairs)) {
    next HOMOL unless ($coord >= $sf1->start && $coord <= $sf1->end);
    
    if ($sf1->strand == 1 && $sf1->hstrand == 1) {
      $newcoord = $sf1->hstart + ($coord - $sf1->start);
      last HOMOL;
    } elsif ($sf1->strand == 1 && $sf1->hstrand == -1) {
      $newcoord = $sf1->hend   - ($coord - $sf1->start);
      last HOMOL;
    } elsif ($sf1->strand == -1 && $sf1->hstrand == 1) {
      $newcoord = $sf1->hstart + ($sf1->end - $coord);
      last HOMOL;
    } elsif ($sf1->strand == -1 && $sf1->hstrand == -1) {
      $newcoord = $sf1->hend   - ($sf1->end - $coord);
      last HOMOL;
    } else {
      $self->throw("ERROR: Wrong strand value in FeaturePair (" . $sf1->strand . "/" . $sf1->hstrand . "\n");
    }
  }    
  
  if (defined($newcoord)) {
    
    return $newcoord;
  } else {
    $self->throw("Couldn't convert $coord");
  }
}

=head2 cDNA2genomic

 Title   : cDNA2genomic
 Usage   : my $gen_coord = $pair->genomic2cDNA($cdna_coord)
 Function: Converts a cdna coordinate to a genomic coordinate
 Example : 
 Returns : int
 Args    : int


=cut

sub cDNA2genomic {
  my ($self,$coord) = @_;
  
  my @pairs = $self->eachFeaturePair;
  
  my $newcoord;
  
  HOMOL: while (my $sf1 = shift(@pairs)) {
    next HOMOL unless ($coord >= $sf1->hstart && $coord <= $sf1->hend);
    
    if ($sf1->strand == 1 && $sf1->hstrand == 1) {
      $newcoord = $sf1->start + ($coord - $sf1->hstart);
      last HOMOL;
    } elsif ($sf1->strand == 1 && $sf1->hstrand == -1) {
      $newcoord = $sf1->start  +($sf1->hend - $coord);
      last HOMOL;
    } elsif ($sf1->strand == -1 && $sf1->hstrand == 1) {
      $newcoord = $sf1->end   - ($coord - $sf1->hstart);
      last HOMOL;
    } elsif ($sf1->strand == -1 && $sf1->hstrand == -1) {
      $newcoord = $sf1->end   - ($sf1->hend - $coord);
      last HOMOL; 
    } else {
      $self->throw("ERROR: Wrong strand value in homol (" . $sf1->strand . "/" . $sf1->hstrand . "\n");
    }
  }
  
  if (defined ($newcoord)) {
    return $newcoord;
  } else {
    $self->throw("Couldn't convert $coord\n");
  }
}

sub find_Pair {
  my ($self,$coord) = @_;
  
  foreach my $p ($self->eachFeaturePair) {
    if ($coord >= $p->hstart && $coord <= $p->hend) {
      return $p;
    }
  }
}

=head2 convert_cDNA_feature

 Title   : convert_cDNA_feature
 Usage   : my @newfeatures = $self->convert_cDNA_feature($f);
 Function: Converts a feature on the cDNA into an array of 
           features on the genomic (for features that span across introns);
 Returns : Array of Bio::EnsEMBL::FeaturePair
 Args    : Bio::EnsEMBL::FeaturePair

=cut

sub convert_cDNA_feature {
  my ($self,$feature) = @_;
    
  my $foundstart = 0;
  my $foundend   = 0;
  
  my @pairs = $self->eachFeaturePair;
  my @newfeatures;
  
  HOMOL: while (my $sf1 = shift(@pairs)) {
    my $skip = 0;
    #print STDERR "Looking at cDNA exon " . $sf1->hstart . "\t" . $sf1->hend . "\t" . $sf1->strand ."\n";
    
    $skip = 1 unless ($feature->start >= $sf1->hstart 
                      && $feature->start <= $sf1->hend);
    
    if($skip){
      #print STDERR "Skipping ".$sf1->hstart . "\t" . $sf1->hend . "\t" . $sf1->strand ."\n";
      next HOMOL;
    }
    if ($feature->end >= $sf1->hstart && $feature->end <= $sf1->hend) {
      $foundend = 1;
    }
    
    my $startcoord = $self->cDNA2genomic($feature->start);
    my $endcoord;
    
    if ($sf1->hstrand == 1) {
      $endcoord   = $sf1->end;
    } else {
      $endcoord   = $sf1->start;
    }
    
    if ($foundend) {
      $endcoord = $self->cDNA2genomic($feature->end);
    }
      
    #print STDERR "Making new genomic feature $startcoord\t$endcoord\n";
    
    my $tmpf = new Bio::EnsEMBL::Feature(-seqname => $feature->seqname,
                                            -start   => $startcoord,
                                            -end     => $endcoord,
                                            -strand  => $feature->strand);
    push(@newfeatures,$tmpf);
    last;
  }
    
  # Now the rest of the pairs until we find the endcoord
  
  while ((my $sf1 = shift(@pairs)) && ($foundend == 0)) {
    
    if ($feature->end >= $sf1->hstart && $feature->end <= $sf1->hend) {
      $foundend = 1;
    }
    
    my $startcoord;
    my $endcoord;
    
    if ($sf1->hstrand == 1) {
      $startcoord = $sf1->start;
      $endcoord   = $sf1->end;
    } else {
      $startcoord = $sf1->end;
      $endcoord   = $sf1->start;
    }
    
    if ($foundend) {
      $endcoord = $self->cDNA2genomic($feature->end);
    }
    
    #	#print STDERR "Making new genomic feature $startcoord\t$endcoord\n";
    
    my $tmpf = new Bio::EnsEMBL::Feature(-seqname => $feature->seqname,
                                         -start   => $startcoord,
                                         -end     => $endcoord,
                                         -strand  => $feature->strand);
    push(@newfeatures,$tmpf);
  }
  #print STDERR "Have ".@newfeatures." features from ".$feature."\n";
  return @newfeatures;
}


sub convert_FeaturePair {
  my ($self,$pair) = @_;

  my $hstrand = $self->get_hstrand;
  
  my $feat = $self->create_Feature($pair->start, $pair->end, $pair->strand,
                                   $pair->slice);
  my @newfeatures = $self->convert_cDNA_feature($feat);
  my @newpairs;
  
  my $hitpairaln  = new Bio::EnsEMBL::Analysis::PairAlign;
  $hitpairaln->addFeaturePair($pair);
  
  foreach my $new (@newfeatures) {
    
    # Now we want to convert these cDNA coords into hit coords
    
    my $hstart1 = $self->genomic2cDNA($new->start);
    my $hend1   = $self->genomic2cDNA($new->end);
    
    my $hstart2 = $hitpairaln->genomic2cDNA($hstart1);
    my $hend2   = $hitpairaln->genomic2cDNA($hend1);
    
    # We can now put the final feature together
    
    my $finalstrand = $hstrand * $pair->strand * $pair->hstrand;
    
    if ($hstart2 > $hend2) {
      my $tmp = $hstart2;
      $hstart2 = $hend2;
      $hend2   = $tmp;
    }
    
    my $finalpair = $self->create_FeaturePair($new->start, $new->end, 
                                              $new->strand,
                                              $hstart2, $hend2, 
                                              $finalstrand, $pair->score);
    
    push(@newpairs,$finalpair);
    
  }
  
  return @newpairs;
}

sub create_FeaturePair {
    my ($self, $start, $end, $strand, $hstart, $hend, 
        $hstrand, $score) = @_;
   
    my $fp = Bio::EnsEMBL::FeaturePair->new(
                                            -start    => $start,
                                            -end      => $end,
                                            -strand   => $strand,
                                            -hstart   => $hstart,
                                            -hend     => $hend,
                                            -hstrand  => $hstrand,
                                            -score    => $score,
                                           );

   
    return $fp;
}

sub create_Feature{
  my ($self, $start, $end, $strand,  $slice) = @_;

  my $feat = new Bio::EnsEMBL::Feature(-start   => $start,
                                       -end     => $end,
                                       -strand  => $strand,
                                       -slice   => $slice,
                                      );
  return $feat;
}

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