#!/usr/bin/perl
use 5.28.0;
my $lineCounter = 1;
my %startPoints;
my %startPoints_plusStrand;
my %startPoints_minusStrand;
my ($chr, $start, $end, $strand);

open (my $OUT_FH,  ">", "results.bed" ) or die "Cannot open file.\n $!";

# Count frequency of start sited in the column-2.
while(<DATA>){
	next if /^#/; #ignore comments in the input file 
	chomp (my $line = $_);
    ($chr, $start, $end, $strand) = (split /\t/, $line)[0,1,2,5];
	my $startPoint;
	if($strand eq '+'){
			$startPoint = $start;
			$startPoints_plusStrand{$startPoint}++;
	} elsif ($strand eq '-') {
			$startPoint = $end;
			$startPoints_minusStrand{$startPoint}++;
	} else {
			die "Goofy BED Data on line $lineCounter:\n$_";
	}
}

say $OUT_FH "#Plus Strand BedGraph:";
for my $key (sort {$a <=> $b} keys %startPoints_plusStrand) {
        say $OUT_FH $key+1, "\t","+","$startPoints_plusStrand{$key}";
}
__DATA__
#chromosome	start	end	position	col-5	strand
chr7	127471196	127472363	Pos1	0	+
chr7	127471196	127472363	Pos1	0	+
chr7	127471196	127472363	Pos1	0	+
chr7	127471196	127472363	Pos1	0	+
chr7	127471196	127472363	Pos1	0	+
chr7	127472363	127473530	Pos2	0	+
chr7	127473530	127474697	Pos3	0	-
chr7	127474697	127475864	Pos4	0	-
#chr8	40000	40500	Pos5	0	+
#chr8	40000	40600	Pos5	0	+
#chr8	40000	40650	Pos5	0	+
#chr8	41000	41200	Pos6	0	-

##</code><code>##

chr7	127471196	127472363	Pos1	0	+
chr8	40000	40500	Pos5	0	+