#!/usr/bin/env perl

use v5.36.0;

use strict;
use warnings;

use feature 'signatures';

my @numbers_one_to_nine = qw/one two three four five six seven eight nine/;
my @numbers_one_to_nineteen = (@numbers_one_to_nine, qw/ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen/);

my @decenes = (undef, qw/twenty thirty forty fifty sixty seventy eighty ninety/);
sub main {
    my $start_of_range = $ARGV[0];
    my $end_of_range = $ARGV[1];
    if (!defined $end_of_range) {
        $end_of_range = 9_999_999;
    }
    if (!defined $start_of_range) {
        $start_of_range = 0;
    }
    for (my $i = $start_of_range; $i <= $end_of_range; $i++) {
        say convert_number_to_words($i)
    }
}

sub convert_number_to_words($number) {
    my $return = generate_number_without_uppercase_and_end_marks($number);
    $return =~ s/(\w)/\U$1/;
    $return .= '.';
    return $return;
}

sub generate_number_without_uppercase_and_end_marks($number) {
    my $return = '';
    if ($number < 1) {
        $return .= 'zero';
        return $return;
    }
    append_millions_to_return(\$number, \$return);
    append_thousand_hundreds(\$number, \$return);
    append_decene_thousands(\$number, \$return);
    append_hundred(\$number, \$return);
    append_decene(\$number, \$return); 
    return $return;
}

sub append_decene($number_ref, $return_ref) {
    my $number = ${$number_ref};
    my $decene = int ($number / 1);
    return if ($decene < 1);
    ${$return_ref} .= ' and ' if length ${$return_ref};
    ${$return_ref} .= convert_two_chars_number_to_words($decene);
    ${$number_ref} = 0;
}

sub append_decene_thousands($number_ref, $return_ref) {
    my $number = ${$number_ref};
    my $thousand_decene_unit = int ($number / 1_000);
    if (length ${$return_ref} > 0 && $thousand_decene_unit < 1) {
        ${$return_ref} .= ' thousand';
    };
    return if ($thousand_decene_unit < 1);
    ${$return_ref} .= ' and ' if length ${$return_ref};
    ${$return_ref} .= convert_two_chars_number_to_words($thousand_decene_unit) . ' thousand';
    ${$number_ref} = $number % 1_000;
}

sub append_hundred($number_ref, $return_ref) {
    my $number = ${$number_ref};
    my $hundred = int ($number / 100);
    return if ($hundred < 1);
    ${$return_ref} .= ', ' if length ${$return_ref};
    ${$return_ref} .= $numbers_one_to_nine[$hundred-1] . ' ' . 'hundred';
    ${$number_ref} = $number % 100;
}

sub convert_two_chars_number_to_words($number) {
    my $return = '';
    {
        if ($number < 20) {
            $return .= $numbers_one_to_nineteen[$number-1];
            return $return;
        }
        my $decene = int($number / 10);
        $return .= $decenes[$decene-1];
        my $unit = $number % 10;
        if ($unit < 1) {
            return $return;
        }
        $return .= '-';
        $return .= $numbers_one_to_nine[$unit-1];
    }
    return $return;
}

sub append_thousand_hundreds($number_ref, $return_ref) {
    my $number = ${$number_ref};
    my $thousand_hundreds_unit = int ($number / 100_000);
    return if ($thousand_hundreds_unit < 1);
    ${$return_ref} .= ', ' if length ${$return_ref};
    ${$return_ref} .= $numbers_one_to_nine[$thousand_hundreds_unit-1] . ' ' . 'hundred';
    ${$number_ref} = $number % 100_000;
}

sub append_millions_to_return($number_ref, $return_ref) {
    my $number = ${$number_ref};
    my $millions_unit = int ($number / 1_000_000);
    return if ($millions_unit < 1);
    ${$return_ref} .= $numbers_one_to_nine[$millions_unit-1] . ' ' . 'million';
    ${$number_ref} = $number % 1_000_000;
}

main()