#!/usr/bin/env perl6

use Test;

is-deeply sort-data('../data.txt'),
          [ 'user@alpha.example.org',
            'rjt@cpan.org',
            'rjt@CPAN.org',
            'Name@example.org',
            'name@example.org',
          ],
          'regular sort';

is-deeply sort-data('../data.txt', True),
          [ 'user@alpha.example.org',
            'rjt@CPAN.org',
            'Name@example.org',
            'name@example.org',
          ],
          'unique sort';

done-testing;

sub sort-data(Str $file, Bool $unique?) {

    my $io := $file.IO;
    die "ERROR: '$file' not found"    unless $io.e;
    die "ERROR: '$file' not readable" unless $io.r;

    my @source = ();
    my %source = ();
    for $io.lines -> Str $line {
        my ($mailbox, $domain) = $line.split("@");
        push @source, [$mailbox, $domain];
        if $unique {
            %source.{$mailbox} = $domain;
        }
    }

    my $sorted = [];
    if $unique {
        for %source.sort({ $^a.value.lc cmp $^b.value.lc || $^a.key cmp $^b.key }) -> $k {
            my $_k = $k.keys;
            my $_v = $k.values;
            $sorted.push: ($_k, $_v).join("@");
        }
    }
    else {
        for @source.sort({ $^a.[0].lc cmp $^b.[0].lc || $^a.[1] cmp $^b.[1] }).reverse -> $k {
            $sorted.push: $k.join("@");
        }
    }

    return $sorted;
}