#!/bin/perl
use Getopt::Std;
use utf8::all;
use v5.36;
my %options;
getopts("a",\%options);
my $togrep = shift;
$togrep = qr/$togrep/;
my $lastfile = "";
local $/ = "";
sub printfound($found, $file, $lastfile){
	print "#" x 10, "\n#$file\n" , "#" x 10, "\n" if $file ne $lastfile;
	my ($postmatch, @string);
	while ($found =~ /(?s)(.*?)(?-s)($togrep)/gp){
		my $prematch = $1;
		my $match = $2;
		$postmatch = ${^POSTMATCH};
		$match =~ s/^/\e[1;31m/mg;
		$match =~ s/$/\e[0m/mg;
		push @string, $prematch, $match;
	}
	push @string, $postmatch;
	print join '', @string;
	return $file
}
while (<>) {
	if ($options{a}){
		$lastfile = printfound $_, $ARGV, $lastfile if /$togrep/i;
	}else{
		$lastfile = printfound $_, $ARGV, $lastfile if /\A.*$togrep/i;
	}
}
if ($!) {
    die "unexpected error while reading from: $!";
}