use 5.38.0;

package Part1;

use List::AllUtils qw/pairmap max sum /;

sub find_numbers($line) {
    my @entries;
    while ( $line =~ /\d+/g ) {
        push @entries => {
            prefix => length $`,
            length => length $&,
            n => 0+$&,
        };
    }
    return @entries;
}

sub near_symbol($numb,$lines) {
        no warnings;
    my $surrounding = join "", map {
        substr $lines->[$_+$numb->{line}],
            max($numb->{prefix}-1,0),
            $numb->{length}+2
    }  -1..1;

    return $surrounding =~ /[^.\d]/;
}

sub numbers_near_symbols($input) {
    my @lines = split "\n", $input;
    unshift @lines, '';

    my @numbers = pairmap { map { +{ %$_, line => $a } } @$b } map { $_ => [find_numbers($lines[$_])] } 1..$#lines;

    @numbers = grep { near_symbol($_,\@lines) } @numbers;
    return @numbers;
}

sub solution_1 ($input) {
    my @numbers = numbers_near_symbols($input);
    return sum map { $_->{n}} @numbers;
}

1;