#!/usr/bin/perl -w
#
# Copyright 2002,2005 Greg Kroah-Hartman <greg@kroah.com>
# Copyright 2005 Ryan Anderson <ryan@michonline.com>
#
# GPL v2 (See COPYING)
#
# Ported to support git "mbox" format files by Ryan Anderson <ryan@michonline.com>
#
# Sends a collection of emails to the given email addresses, disturbingly fast.
#
# Supports two formats:
# 1. mbox format files (ignoring most headers and MIME formatting - this is designed for sending patches)
# 2. The original format support by Greg's script:
#    first line of the message is who to CC,
#    and second line is the subject of the message.
#

use strict;
use warnings;
use Term::ReadLine;
use Getopt::Long;
use Data::Dumper;
use Term::ANSIColor;
use Git;

$SIG{INT} = sub { print color("reset"), "\n"; exit };

package FakeTerm;
sub new {
        my ($class, $reason) = @_;
        return bless \$reason, shift;
}
sub readline {
        my $self = shift;
        die "Cannot use readline on FakeTerm: $$self";
}
package main;


sub usage {
        print <<EOT;
git-send-email [options] <file | directory>...
Options:
   --from         Specify the "From:" line of the email to be sent.

   --to           Specify the primary "To:" line of the email.

   --cc           Specify an initial "Cc:" list for the entire series
                  of emails.

   --cc-cmd       Specify a command to execute per file which adds
                  per file specific cc address entries

   --bcc          Specify a list of email addresses that should be Bcc:
                  on all the emails.

   --compose      Use \$GIT_EDITOR, core.editor, \$EDITOR, or \$VISUAL to edit
                  an introductory message for the patch series.

   --subject      Specify the initial "Subject:" line.
                  Only necessary if --compose is also set.  If --compose
                  is not set, this will be prompted for.

   --in-reply-to  Specify the first "In-Reply-To:" header line.
                  Only used if --compose is also set.  If --compose is not
                  set, this will be prompted for.

   --chain-reply-to If set, the replies will all be to the previous
                  email sent, rather than to the first email sent.
                  Defaults to on.

   --signed-off-cc Automatically add email addresses that appear in
                 Signed-off-by: or Cc: lines to the cc: list. Defaults to on.

   --identity     The configuration identity, a subsection to prioritise over
                  the default section.

   --smtp-server  If set, specifies the outgoing SMTP server to use.
                  Defaults to localhost.  Port number can be specified here with
                  hostname:port format or by using --smtp-server-port option.

   --smtp-server-port Specify a port on the outgoing SMTP server to connect to.

   --smtp-user    The username for SMTP-AUTH.

   --smtp-pass    The password for SMTP-AUTH.

   --smtp-ssl     If set, connects to the SMTP server using SSL.

   --suppress-from Suppress sending emails to yourself if your address
                  appears in a From: line. Defaults to off.

   --thread       Specify that the "In-Reply-To:" header should be set on all
                  emails. Defaults to on.

   --quiet        Make git-send-email less verbose.  One line per email
                  should be all that is output.

   --dry-run      Do everything except actually send the emails.

   --envelope-sender    Specify the envelope sender used to send the emails.

EOT
        exit(1);
}

# most mail servers generate the Date: header, but not all...
sub format_2822_time {
        my ($time) = @_;
        my @localtm = localtime($time);
        my @gmttm = gmtime($time);
        my $localmin = $localtm[1] + $localtm[2] * 60;
        my $gmtmin = $gmttm[1] + $gmttm[2] * 60;
        if ($localtm[0] != $gmttm[0]) {
                die "local zone differs from GMT by a non-minute interval\n";
        }
        if ((($gmttm[6] + 1) % 7) == $localtm[6]) {
                $localmin += 1440;
        } elsif ((($gmttm[6] - 1) % 7) == $localtm[6]) {
                $localmin -= 1440;
        } elsif ($gmttm[6] != $localtm[6]) {
                die "local time offset greater than or equal to 24 hours\n";
        }
        my $offset = $localmin - $gmtmin;
        my $offhour = $offset / 60;
        my $offmin = abs($offset % 60);
        if (abs($offhour) >= 24) {
                die ("local time offset greater than or equal to 24 hours\n");
        }

        return sprintf("%s, %2d %s %d %02d:%02d:%02d %s%02d%02d",
                       qw(Sun Mon Tue Wed Thu Fri Sat)[$localtm[6]],
                       $localtm[3],
                       qw(Jan Feb Mar Apr May Jun
                          Jul Aug Sep Oct Nov Dec)[$localtm[4]],
                       $localtm[5]+1900,
                       $localtm[2],
                       $localtm[1],
                       $localtm[0],
                       ($offset >= 0) ? '+' : '-',
                       abs($offhour),
                       $offmin,
                       );
}

my $have_email_valid = eval { require Email::Valid; 1 };
my $smtp;

sub unique_email_list(@);
sub cleanup_compose_files();

# Constants (essentially)
my $compose_filename = ".msg.$$";

# Variables we fill in automatically, or via prompting:
my (@to,@cc,@initial_cc,@bcclist,@xh,
        $initial_reply_to,$initial_subject,@files,$author,$sender,$compose,$time);

my $envelope_sender;

# Example reply to:
#$initial_reply_to = ''; #<20050203173208.GA23964@foobar.com>';

my $repo = Git->repository();
my $term = eval {
        new Term::ReadLine 'git-send-email';
};
if ($@) {
        $term = new FakeTerm "$@: going non-interactive";
}

# Behavior modification variables
my ($quiet, $dry_run) = (0, 0);

# Variables with corresponding config settings
my ($thread, $chain_reply_to, $suppress_from, $signed_off_cc, $cc_cmd);
my ($smtp_server, $smtp_server_port, $smtp_authuser, $smtp_authpass, $smtp_ssl);
my ($identity, $aliasfiletype, @alias_files, @smtp_host_parts);

my %config_bool_settings = (
    "thread" => [\$thread, 1],
    "chainreplyto" => [\$chain_reply_to, 1],
    "suppressfrom" => [\$suppress_from, 0],
    "signedoffcc" => [\$signed_off_cc, 1],
    "smtpssl" => [\$smtp_ssl, 0],
);

my %config_settings = (
    "smtpserver" => \$smtp_server,
    "smtpserverport" => \$smtp_server_port,
    "smtpuser" => \$smtp_authuser,
    "smtppass" => \$smtp_authpass,
    "cccmd" => \$cc_cmd,
    "aliasfiletype" => \$aliasfiletype,
    "bcc" => \@bcclist,
    "aliasesfile" => \@alias_files,
);

# Begin by accumulating all the variables (defined above), that we will end up
# needing, first, from the command line:

my $rc = GetOptions("sender|from=s" => \$sender,
                    "in-reply-to=s" => \$initial_reply_to,
                    "subject=s" => \$initial_subject,
                    "to=s" => \@to,
                    "cc=s" => \@initial_cc,
                    "bcc=s" => \@bcclist,
                    "chain-reply-to!" => \$chain_reply_to,
                    "smtp-server=s" => \$smtp_server,
                    "smtp-server-port=s" => \$smtp_server_port,
                    "smtp-user=s" => \$smtp_authuser,
                    "smtp-pass=s" => \$smtp_authpass,
                    "smtp-ssl!" => \$smtp_ssl,
                    "identity=s" => \$identity,
                    "compose" => \$compose,
                    "quiet" => \$quiet,
                    "cc-cmd=s" => \$cc_cmd,
                    "suppress-from!" => \$suppress_from,
                    "signed-off-cc|signed-off-by-cc!" => \$signed_off_cc,
                    "dry-run" => \$dry_run,
                    "envelope-sender=s" => \$envelope_sender,
                    "thread!" => \$thread,
         );

unless ($rc) {
    usage();
}

# Now, let's fill any that aren't set in with defaults:

sub read_config {
        my ($prefix) = @_;

        foreach my $setting (keys %config_bool_settings) {
                my $target = $config_bool_settings{$setting}->[0];
                $$target = $repo->config_bool("$prefix.$setting") unless (defined $$target);
        }

        foreach my $setting (keys %config_settings) {
                my $target = $config_settings{$setting};
                if (ref($target) eq "ARRAY") {
                        unless (@$target) {
                                my @values = $repo->config("$prefix.$setting");
                                @$target = @values if (@values && defined $values[0]);
                        }
                }
                else {
                        $$target = $repo->config("$prefix.$setting") unless (defined $$target);
                }
        }
}

# read configuration from [sendemail "$identity"], fall back on [sendemail]
$identity = $repo->config("sendemail.identity") unless (defined $identity);
read_config("sendemail.$identity") if (defined $identity);
read_config("sendemail");

# fall back on builtin bool defaults
foreach my $setting (values %config_bool_settings) {
        ${$setting->[0]} = $setting->[1] unless (defined (${$setting->[0]}));
}

my ($repoauthor) = $repo->ident_person('author');
my ($repocommitter) = $repo->ident_person('committer');

# Verify the user input

foreach my $entry (@to) {
        die "Comma in --to entry: $entry'\n" unless $entry !~ m/,/;
}

foreach my $entry (@initial_cc) {
        die "Comma in --cc entry: $entry'\n" unless $entry !~ m/,/;
}

foreach my $entry (@bcclist) {
        die "Comma in --bcclist entry: $entry'\n" unless $entry !~ m/,/;
}

my %aliases;
my %parse_alias = (
        # multiline formats can be supported in the future
        mutt => sub { my $fh = shift; while (<$fh>) {
                if (/^\s*alias\s+(\S+)\s+(.*)$/) {
                        my ($alias, $addr) = ($1, $2);
                        $addr =~ s/#.*$//; # mutt allows # comments
                         # commas delimit multiple addresses
                        $aliases{$alias} = [ split(/\s*,\s*/, $addr) ];
                }}},
        mailrc => sub { my $fh = shift; while (<$fh>) {
                if (/^alias\s+(\S+)\s+(.*)$/) {
                        # spaces delimit multiple addresses
                        $aliases{$1} = [ split(/\s+/, $2) ];
                }}},
        pine => sub { my $fh = shift; while (<$fh>) {
                if (/^(\S+)\t.*\t(.*)$/) {
                        $aliases{$1} = [ split(/\s*,\s*/, $2) ];
                }}},
        gnus => sub { my $fh = shift; while (<$fh>) {
                if (/\(define-mail-alias\s+"(\S+?)"\s+"(\S+?)"\)/) {
                        $aliases{$1} = [ $2 ];
                }}}
);

if (@alias_files and $aliasfiletype and defined $parse_alias{$aliasfiletype}) {
        foreach my $file (@alias_files) {
                open my $fh, '<', $file or die "opening $file: $!\n";
                $parse_alias{$aliasfiletype}->($fh);
                close $fh;
        }
}

($sender) = expand_aliases($sender) if defined $sender;

my $prompting = 0;
if (!defined $sender) {
        $sender = $repoauthor || $repocommitter;
        do {
                $_ = $term->readline("Who should the emails appear to be from? [$sender] ");
        } while (!defined $_);

        $sender = $_ if ($_);
        print "Emails will be sent from: ", $sender, "\n";
        $prompting++;
}

if (!@to) {
        do {
                $_ = $term->readline("Who should the emails be sent to? ",
                                "");
        } while (!defined $_);
        my $to = $_;
        push @to, split /,/, $to;
        $prompting++;
}

sub expand_aliases {
        my @cur = @_;
        my @last;
        do {
                @last = @cur;
                @cur = map { $aliases{$_} ? @{$aliases{$_}} : $_ } @last;
        } while (join(',',@cur) ne join(',',@last));
        return @cur;
}

@to = expand_aliases(@to);
@to = (map { sanitize_address($_) } @to);
@initial_cc = expand_aliases(@initial_cc);
@bcclist = expand_aliases(@bcclist);

if (!defined $initial_subject && $compose) {
        do {
                $_ = $term->readline("What subject should the emails start with? ",
                        $initial_subject);
        } while (!defined $_);
        $initial_subject = $_;
        $prompting++;
}

if ($thread && !defined $initial_reply_to && $prompting) {
        do {
                $_= $term->readline("Message-ID to be used as In-Reply-To for the first email? ",
                        $initial_reply_to);
        } while (!defined $_);

        $initial_reply_to = $_;
        $initial_reply_to =~ s/^\s+<?/</;
        $initial_reply_to =~ s/>?\s+$/>/;
}

if (!defined $smtp_server) {
        foreach (qw( /usr/sbin/sendmail /usr/lib/sendmail )) {
                if (-x $_) {
                        $smtp_server = $_;
                        last;
                }
        }
        $smtp_server ||= 'localhost'; # could be 127.0.0.1, too... *shrug*
}

if ($compose) {
        # Note that this does not need to be secure, but we will make a small
        # effort to have it be unique
        open(C,">",$compose_filename)
                or die "Failed to open for writing $compose_filename: $!";
        print C "From $sender # This line is ignored.\n";
        printf C "Subject: %s\n\n", $initial_subject;
        printf C <<EOT;
GIT: Please enter your email below.
GIT: Lines beginning in "GIT: " will be removed.
GIT: Consider including an overall diffstat or table of contents
GIT: for the patch you are writing.

EOT
        close(C);

        my $editor = $ENV{GIT_EDITOR} || $repo->config("core.editor") || $ENV{VISUAL} || $ENV{EDITOR} || "vi";
        system($editor, $compose_filename);

        open(C2,">",$compose_filename . ".final")
                or die "Failed to open $compose_filename.final : " . $!;

        open(C,"<",$compose_filename)
                or die "Failed to open $compose_filename : " . $!;

        while(<C>) {
                next if m/^GIT: /;
                print C2 $_;
        }
        close(C);
        close(C2);

        do {
                $_ = $term->readline("Send this email? (y|n) ");
        } while (!defined $_);

        if (uc substr($_,0,1) ne 'Y') {
                cleanup_compose_files();
                exit(0);
        }

        @files = ($compose_filename . ".final");
}


# Now that all the defaults are set, process the rest of the command line
# arguments and collect up the files that need to be processed.
for my $f (@ARGV) {
        if (-d $f) {
                opendir(DH,$f)
                        or die "Failed to opendir $f: $!";

                push @files, grep { -f $_ } map { +$f . "/" . $_ }
                                sort readdir(DH);

        } elsif (-f $f) {
                push @files, $f;

        } else {
                print STDERR "Skipping $f - not found.\n";
        }
}

if (@files) {
        unless ($quiet) {
                print $_,"\n" for (@files);
        }
} else {
        print STDERR "\nNo patch files specified!\n\n";
        usage();
}

# Variables we set as part of the loop over files
our ($message_id, %mail, $subject, $reply_to, $references, $message);

sub extract_valid_address {
        my $address = shift;
        my $local_part_regexp = '[^<>"\s@]+';
        my $domain_regexp = '[^.<>"\s@]+(?:\.[^.<>"\s@]+)+';

        # check for a local address:
        return $address if ($address =~ /^($local_part_regexp)$/);

        $address =~ s/^\s*<(.*)>\s*$/$1/;
        if ($have_email_valid) {
                return scalar Email::Valid->address($address);
        } else {
                # less robust/correct than the monster regexp in Email::Valid,
                # but still does a 99% job, and one less dependency
                $address =~ /($local_part_regexp\@$domain_regexp)/;
                return $1;
        }
}

# Usually don't need to change anything below here.

# we make a "fake" message id by taking the current number
# of seconds since the beginning of Unix time and tacking on
# a random number to the end, in case we are called quicker than
# 1 second since the last time we were called.

# We'll setup a template for the message id, using the "from" address:

my ($message_id_stamp, $message_id_serial);
sub make_message_id
{
        my $uniq;
        if (!defined $message_id_stamp) {
                $message_id_stamp = sprintf("%s-%s", time, $$);
                $message_id_serial = 0;
        }
        $message_id_serial++;
        $uniq = "$message_id_stamp-$message_id_serial";

        my $du_part;
        for ($sender, $repocommitter, $repoauthor) {
                $du_part = extract_valid_address(sanitize_address($_));
                last if (defined $du_part and $du_part ne '');
        }
        if (not defined $du_part or $du_part eq '') {
                use Sys::Hostname qw();
                $du_part = 'user@' . Sys::Hostname::hostname();
        }
        my $message_id_template = "<%s-git-send-email-%s>";
        $message_id = sprintf($message_id_template, $uniq, $du_part);
        #print "new message id = $message_id\n"; # Was useful for debugging
}



$time = time - scalar $#files;

sub unquote_rfc2047 {
        local ($_) = @_;
        if (s/=\?utf-8\?q\?(.*)\?=/$1/g) {
                s/_/ /g;
                s/=([0-9A-F]{2})/chr(hex($1))/eg;
        }
        return "$_";
}

# use the simplest quoting being able to handle the recipient
sub sanitize_address
{
        my ($recipient) = @_;
        my ($recipient_name, $recipient_addr) = ($recipient =~ /^(.*?)\s*(<.*)/);

        if (not $recipient_name) {
                return "$recipient";
        }

        # if recipient_name is already quoted, do nothing
        if ($recipient_name =~ /^(".*"|=\?utf-8\?q\?.*\?=)$/) {
                return $recipient;
        }

        # rfc2047 is needed if a non-ascii char is included
        if ($recipient_name =~ /[^[:ascii:]]/) {
                $recipient_name =~ s/([^-a-zA-Z0-9!*+\/])/sprintf("=%02X", ord($1))/eg;
                $recipient_name =~ s/(.*)/=\?utf-8\?q\?$1\?=/;
        }

        # double quotes are needed if specials or CTLs are included
        elsif ($recipient_name =~ /[][()<>@,;:\\".\000-\037\177]/) {
                $recipient_name =~ s/(["\\\r])/\\$1/;
                $recipient_name = "\"$recipient_name\"";
        }

        return "$recipient_name $recipient_addr";

}

sub send_message
{
        my @recipients = unique_email_list(@to);
        @cc = (map { sanitize_address($_) } @cc);
        my $to = join (",\n\t", @recipients);
        @recipients = unique_email_list(@recipients,@cc,@bcclist);
        @recipients = (map { extract_valid_address($_) } @recipients);
        my $date = format_2822_time($time++);
        my $gitversion = '@@GIT_VERSION@@';
        if ($gitversion =~ m/..GIT_VERSION../) {
            $gitversion = Git::version();
        }

        my $cc = join(", ", unique_email_list(@cc));
        my $ccline = "";
        if ($cc ne '') {
                $ccline = "\nCc: $cc";
        }
        my $sanitized_sender = sanitize_address($sender);
        make_message_id();

        my $header = "From: $sanitized_sender
To: $to${ccline}
Subject: $subject
Date: $date
Message-Id: $message_id
X-Mailer: git-send-email $gitversion
";
        if ($thread && $reply_to) {

                $header .= "In-Reply-To: $reply_to\n";
                $header .= "References: $references\n";
        }
        if (@xh) {
                $header .= join("\n", @xh) . "\n";
        }

        my @sendmail_parameters = ('-i', @recipients);
        my $raw_from = $sanitized_sender;
        $raw_from = $envelope_sender if (defined $envelope_sender);
        $raw_from = extract_valid_address($raw_from);
        unshift (@sendmail_parameters,
                        '-f', $raw_from) if(defined $envelope_sender);

        if ($dry_run) {
                # We don't want to send the email.
        } elsif ($smtp_server =~ m#^/#) {
                my $pid = open my $sm, '|-';
                defined $pid or die $!;
                if (!$pid) {
                        exec($smtp_server, @sendmail_parameters) or die $!;
                }
                print $sm "$header\n$message";
                close $sm or die $?;
        } else {

                if (!defined $smtp_server) {
                        die "The required SMTP server is not properly defined."
                }

                if ($smtp_ssl) {
                        $smtp_server_port ||= 465; # ssmtp
                        require Net::SMTP::SSL;
                        $smtp ||= Net::SMTP::SSL->new($smtp_server, Port => $smtp_server_port);
                }
                else {
                        require Net::SMTP;
                        $smtp ||= Net::SMTP->new((defined $smtp_server_port)
                                                 ? "$smtp_server:$smtp_server_port"
                                                 : $smtp_server);
                }

                if (!$smtp) {
                        die "Unable to initialize SMTP properly.  Is there something wrong with your config?";
                }

                if ((defined $smtp_authuser) && (defined $smtp_authpass)) {
                        $smtp->auth( $smtp_authuser, $smtp_authpass ) or die $smtp->message;
                }
                $smtp->mail( $raw_from ) or die $smtp->message;
                $smtp->to( @recipients ) or die $smtp->message;
                $smtp->data or die $smtp->message;
                $smtp->datasend("$header\n$message") or die $smtp->message;
                $smtp->dataend() or die $smtp->message;
                $smtp->ok or die "Failed to send $subject\n".$smtp->message;
        }
        if ($quiet) {
                printf (($dry_run ? "Dry-" : "")."Sent %s\n", $subject);
        } else {
                print (($dry_run ? "Dry-" : "")."OK. Log says:\nDate: $date\n");
                if ($smtp_server !~ m#^/#) {
                        print "Server: $smtp_server\n";
                        print "MAIL FROM:<$raw_from>\n";
                        print "RCPT TO:".join(',',(map { "<$_>" } @recipients))."\n";
                } else {
                        print "Sendmail: $smtp_server ".join(' ',@sendmail_parameters)."\n";
                }
                print "From: $sanitized_sender\nSubject: $subject\nCc: $cc\nTo: $to\n\n";
                if ($smtp) {
                        print "Result: ", $smtp->code, ' ',
                                ($smtp->message =~ /\n([^\n]+\n)$/s), "\n";
                } else {
                        print "Result: OK\n";
                }
        }
}

$reply_to = $initial_reply_to;
$references = $initial_reply_to || '';
$subject = $initial_subject;

foreach my $t (@files) {
        open(F,"<",$t) or die "can't open file $t";

        my $author = undef;
        @cc = @initial_cc;
        @xh = ();
        my $input_format = undef;
        my $header_done = 0;
        $message = "";
        while(<F>) {
                if (!$header_done) {
                        if (/^From /) {
                                $input_format = 'mbox';
                                next;
                        }
                        chomp;
                        if (!defined $input_format && /^[-A-Za-z]+:\s/) {
                                $input_format = 'mbox';
                        }

                        if (defined $input_format && $input_format eq 'mbox') {
                                if (/^Subject:\s+(.*)$/) {
                                        $subject = $1;

                                } elsif (/^(Cc|From):\s+(.*)$/) {
                                        if (unquote_rfc2047($2) eq $sender) {
                                                next if ($suppress_from);
                                        }
                                        elsif ($1 eq 'From') {
                                                $author = unquote_rfc2047($2);
                                        }
                                        printf("(mbox) Adding cc: %s from line '%s'\n",
                                                $2, $_) unless $quiet;
                                        push @cc, $2;
                                }
                                elsif (!/^Date:\s/ && /^[-A-Za-z]+:\s+\S/) {
                                        push @xh, $_;
                                }

                        } else {
                                # In the traditional
                                # "send lots of email" format,
                                # line 1 = cc
                                # line 2 = subject
                                # So let's support that, too.
                                $input_format = 'lots';
                                if (@cc == 0) {
                                        printf("(non-mbox) Adding cc: %s from line '%s'\n",
                                                $_, $_) unless $quiet;

                                        push @cc, $_;

                                } elsif (!defined $subject) {
                                        $subject = $_;
                                }
                        }

                        # A whitespace line will terminate the headers
                        if (m/^\s*$/) {
                                $header_done = 1;
                        }
                } else {
                        $message .=  $_;
                        if (/^(Signed-off-by|Cc): (.*)$/i && $signed_off_cc) {
                                my $c = $2;
                                chomp $c;
                                push @cc, $c;
                                printf("(sob) Adding cc: %s from line '%s'\n",
                                        $c, $_) unless $quiet;
                        }
                }
        }
        close F;

        if (defined $cc_cmd) {
                open(F, "$cc_cmd $t |")
                        or die "(cc-cmd) Could not execute '$cc_cmd'";
                while(<F>) {
                        my $c = $_;
                        $c =~ s/^\s*//g;
                        $c =~ s/\n$//g;
                        push @cc, $c;
                        printf("(cc-cmd) Adding cc: %s from: '%s'\n",
                                $c, $cc_cmd) unless $quiet;
                }
                close F
                        or die "(cc-cmd) failed to close pipe to '$cc_cmd'";
        }

        if (defined $author) {
                $message = "From: $author\n\n$message";
        }

        send_message();

        # set up for the next message
        if ($chain_reply_to || !defined $reply_to || length($reply_to) == 0) {
                $reply_to = $message_id;
                if (length $references > 0) {
                        $references .= "\n $message_id";
                } else {
                        $references = "$message_id";
                }
        }
}

if ($compose) {
        cleanup_compose_files();
}

sub cleanup_compose_files() {
        unlink($compose_filename, $compose_filename . ".final");

}

$smtp->quit if $smtp;

sub unique_email_list(@) {
        my %seen;
        my @emails;

        foreach my $entry (@_) {
                if (my $clean = extract_valid_address($entry)) {
                        $seen{$clean} ||= 0;
                        next if $seen{$clean}++;
                        push @emails, $entry;
                } else {
                        print STDERR "W: unable to extract a valid address",
                                        " from: $entry\n";
                }
        }
        return @emails;
}