#!/usr/bin/perl
use warnings;
use strict;
use Email::Stuffer;
use Email::Sender::Transport::SMTP::Persistent;
use File::Basename;
use Encode;
use Encode::Locale;
use File::Slurp;
use threads;
use Thread::Queue;
use Getopt::Long;
use Pod::Usage;
use Encode::MIME::Header;
use Time::HiRes qw(gettimeofday tv_interval);
use Data::Dumper;

use open ':encoding(locale)';
@ARGV = map { decode(locale => $_, 1) } @ARGV;

# ####
# configurable settings
# ####

my $transport = Email::Sender::Transport::SMTP::Persistent->new({
	host => 'localhost',
	port => 25,
	#debug => 1,
});
my $thread_count = 64;

# ####
# end config
# ####

my %opts = ();

Getopt::Long::Configure ("bundling");
pod2usage(-verbose => 0) if (@ARGV== 0);
GetOptions(\%opts, "help|h", "to=s", "from=s", "subject=s", "content-html=s", "content-txt=s", "debug") or pod2usage(2);
pod2usage(0) if $opts{help};

sub trim {
	my $string = shift;
	$string =~ s/^\s+//;
	$string =~ s/\s+$//;
	return $string;
}

my $subject = $opts{subject};
my $from = $opts{from};
my @addrlist;
my $content_html;
my $content_txt;

if ($opts{to} =~ m/.+\@.+\..+/) {
	push @addrlist, $opts{to};
} else {
	if (-r $opts{to}) {
		open LIST, "<", $opts{to} or die;
		for (<LIST>) {
			my $to = trim($_);
			next if ($to eq "");
			push @addrlist, $to;
		}
		close LIST;
	} else {
		print STDERR "Error: can't read recipient file: $!\n";
	}
}

if (0+@addrlist < $thread_count) {
	$thread_count = 0+@addrlist;
}

die "Error: subject not set\n" unless ($opts{subject});
die "Error: from not set\n" unless ($opts{from});
die "Error: content-txt not set\n" unless ($opts{"content-txt"});
die "Error: can't read content-txt: $!\n" unless (-r $opts{"content-txt"});
die "Error: can't read content-html: $!\n" if ($opts{"content-html"} and not -r $opts{"content-html"});

if ($opts{"content-html"}) {
	$content_html = read_file($opts{"content-html"}, binmode => ':utf8');
}
$content_txt = read_file($opts{"content-txt"}, binmode => ':utf8');

print "Building email ... " if $opts{debug};

# create mail
# To will be filled when sending
my $msg = Email::Stuffer->new();
$msg->from($from);
$msg->subject(trim($subject));
$msg->text_body($content_txt);
$msg->html_body($content_html);
$msg->header("Precedence", "bulk");
#$msg->header("List-Unsubscribe", "<mailto:$from>");
$msg->transport($transport);

print "done\n" if $opts{debug};

my $q = Thread::Queue->new();

print "creating worker threads\n" if $opts{debug};
for (my $i = 0; $i < $thread_count; $i++) {
	my $thr = threads->new(sub {
			while (my $to = $q->dequeue()) {
				$msg->to($to);
				$msg->send();
				print "sent mail in thread".threads->self->tid()."\n" if $opts{debug};
			}
			$transport->disconnect;
		});
}

print "Sending\n";

my $send_time = [gettimeofday];

for (@addrlist) {
	$q->enqueue($_);
}

$q->end();

# wait for everyone before exiting
foreach my $thr (threads->list) {
	if ($thr->tid && !threads::equal($thr, threads->self)) {
		print "waiting for thread ".$thr->tid()." to finish\n" if $opts{debug};
		$thr->join;
	}
}

print "done after ".tv_interval($send_time)." seconds\n";

__END__

=head1 NAME

mailer.pl - send lots of mails

=head1 SYNOPSIS

mailer.pl options ...

 Options:
    --help, -h               short help message
    --to <email or file>     recipient(s)
    --from <email>           from
    --subject <string>       subject
    --content-html <file>    body of the mail (html part) (optional)
    --content-txt <file>     body of the mail (text part)
    --debug                  output extra debug information

=cut