use warnings;
use strict;

use 5.30.0;
use MCE::Loop;

MCE::Loop::init(
    max_workers => 4,
    init_relay  => 1,  # enables MCE::Relay feature
);

mce_loop_f {
    my ( $mce, $chunk_ref, $chunk_id ) = @_;
    my $output = '';

    for my $line ( @{ $chunk_ref } ) {
        # Skip lines ending with an empty field
        next if substr($line, -2) eq "\t\n";

        # Remove "\n";
        chomp $line;

        # Split matching lines into fields on "\t", creating @fields
        my @fields = split /\t/, $line;

        # Copy only the desired fields from @fields to create a new
        # line in TSV format
        # This can be done in one simple step in Perl, using
        # array slices and the join() function
        my $new_line = join "\t", @fields[ 2, 3, 12..18, 25..28, 31 ];

        # Append to buffer with newline char
        $output .= $new_line . "\n";;
    }

    # The MCE relay takes a code block and runs serially
    # including orderly, one worker at a time. Orderly is
    # driven by the chunk_id value behind the scene.
    # Thus, must call MCE::relay per each chunk.
    MCE::relay {
        print $output;
        STDOUT->flush;
    };

} \*STDIN;

# This signals the workers to exit.
# If omitted, called automatically when the script terminates.
MCE::Loop::finish;