format-duration.p6

#!/usr/bin/env perl6

sub format-duration(Int $milliseconds where * >= 0) returns Str {
  my ($ms, $s, $m, $h, $d) = $milliseconds.polymod(1000, 60, 60, 24);
  my $ms-hundreds = ($ms / 100).round;

  if $d {
    "{$d}d {$h}h {$m}m {$s}s"
  } elsif $h {
    "{$h}h {$m}m {$s}s"
  } elsif $m {
    "{$m}m {$s}s"
  } else {
    "{$s}.{$ms-hundreds}s"
  }
}

sub MAIN(Int $milliseconds where * >= 0) {
  say format-duration($milliseconds);
}