#!/usr/bin/perl

use strict;
use warnings;
use File::Basename;

# gcq@20211019
# Count (TG)mTn For CFTR (hg19 chr7:117188660-117188680)
# REF: (TG)11T7
# left seq TCATCTTTTATTTTTGA
# right seq AACAGGGATTTGGGGA
#
# To Be DONE:
# Ajust For sequencing errors, ex. STR error
# Ajust For STR Length/Counts, ex. more repeats ,less count

my $Rlseq="TTTTGA";
my $Rrseq="AACAGG";

my $tot=0;
my (%dat);
my $bam=shift;
my $sample=basename($bam,".bam");
my $chrID;
open my $fhead, "samtools view -H $bam |" or die "Cannot open pipe:$!\n";
while(<$fhead>){
    if(/LN:159138663/){
        my $chr=$1 if /SN:([a-z]*7)\s+/;
        $chrID=$chr.":117188660-117188670";
    }
    if(/LN:159345973/){
        my $chr=$1 if /SN:([a-z]*7)\s+/; 
        $chrID=$chr.":117548606-117548617"
    }
}
close($fhead);

exit unless $chrID;
open my $fh, "samtools view $bam $chrID |"   or die "Cannot open pipe:$!\n";
while(<$fh>){
    chomp;
    my ($id, $flag, $mapq, $seq)=(split /\t/)[0, 1, 4, 9];
    next if $flag & 1024 or $flag & 2048;
    next if $flag & 256;
    next unless $seq=~/([ATCG]{6})((?:TG){6,}T{3,})([ATCG]{6})/;       
    my ($lseq,$strseq,$rseq)=$seq=~/([ATCG]{6})((?:TG){6,}T{3,})([ATCG]{6})/;
    next if $lseq =~/TG$/;
    next if $rseq =~/^T/;       
    
    my $ldist=distance($lseq, $Rlseq);
    my $rdist=distance($rseq, $Rrseq);
   # next if $rdist>1 or $ldist>1;
    next if $rdist + $ldist> 2;
    $tot++;
    $dat{$strseq}++;
}
print join("\t","Sample","GT","Depth","GT1","VAF1","GT2","VAF2"),"\n";
print $sample,"\t";
my $gts='';
for my $seq(sort { $dat{$b} <=> $dat{$a}} keys %dat){
	my ($tgseq)=$seq=~/^((?:TG)+)/;
	my ($tseq)=$seq=~/(T+)$/;
	my $tg_len=length($tgseq)/2;
	my $t_len=length($tseq);
	next if $dat{$seq}<$tot/20;
    my $gts_info=join("\t","(TG)$tg_len(T)$t_len",sprintf("%.2f",$dat{$seq}/$tot));
    $gts=$gts? $gts."\t".$gts_info:$gts_info;
}
my $gt=get_GT($gts);
print join("\t",$gt,$tot,$gts),"\n";

sub distance{ 
    my ($s1,$s2) = @_;
    my ($len1,$len2) = (length $s1,length $s2);
    return $len2 if ($len1 == 0);
    return $len1 if ($len2 == 0);
 
    my %mat;
    for (my $i = 0; $i <= $len1; ++$i){
        for (my $j = 0; $j <= $len2; ++$j){
            $mat{$i}{$j} = 0;
            $mat{0}{$j} = $j;
        }
        $mat{$i}{0} = $i;
    }
    my @ar1 = split(//,$s1);
    my @ar2 = split(//,$s2);
 
    for (my $i = 1; $i <= $len1; ++$i){
        for (my $j = 1; $j <= $len2; ++$j){
            my $cost = ($ar1[$i-1] eq $ar2[$j-1]) ? 0 : 1;
            $mat{$i}{$j} = min($mat{$i-1}{$j} + 1,$mat{$i}{$j-1} + 1,$mat{$i-1}{$j-1} + $cost);
        }
    }
    return $mat{$len1}{$len2};
}

sub min {
	my @out = sort {$a <=> $b} @_;
	return($out[0]);
}

sub get_GT{
    my $GTs=shift;
    my $gt='';

    my @cont=split /\t/,$GTs;
    if($cont[1]>0.8 or $#cont<=1){
       return $cont[0].'/'.$cont[0];
    }elsif($cont[1]/$cont[3] > 3){
       return $cont[0].'/'.$cont[0];
    }else{
       $gt=$cont[0].'/'.$cont[2];
    }
    return  join("/", sort(split /\//,$gt));
}