#!/usr/bin/perl

use strict;
use warnings;

my $csv_file="@ARGV";
my %struct_hash;

##### functions


sub read_csv {
	my @csv;
	open my $fh, "$csv_file" or die "bad file: \"$csv_file\" - can't open\n";
	push(@csv, "$_") while(<$fh>);
	close $fh;
	return @csv;
};

sub build_struct_hash {
	my %struct_hash;
	foreach(read_csv()) {
		my($pos_xy, $pos_str) = split(/;/, "$_");
		$pos_xy =~ s/\D//g;
		$pos_str =~ s/\r//g; chomp($pos_str);
		$struct_hash{$pos_xy} = {};
		$struct_hash{$pos_xy}->{'str'} = $pos_str;
	};
	return %struct_hash;
};

sub get_parent_id {
	my $len = $_[0] - sqrt(4*$_[0]+1)-1;
#	my $len_tmp = length($_[0]);
#	my $plen = 2;
#	my $incr = 2;
#	my $len;
#	$len = 2 if length($_[0]) == 2;
#	while($plen < $len_tmp) {
#		$len = $plen;
#		$plen = $plen + (2*$incr);
#		$incr++;
#	};
	return substr($_[0], 0, $len);
};


########### main body:

%struct_hash = build_struct_hash();

########## user body:


## example
# for work with all keys we need to do it like this:
foreach(sort {$a <=> $b} keys(%struct_hash)) {

	## id in current loop
	my $foo = "$_";

	## current loop's parent id
	my $bar = get_parent_id("$_");

	## current loop id's key
	my $baz = "$struct_hash{$foo}->{'str'}";

	## current loop id's parent key
	my $heh = "$struct_hash{$bar}->{'str'}";

	## example of output format
	print "$baz|$foo;$heh|$bar\n";

};

exit;