package Email::Sender::Transport::Mbox 2.500;
# ABSTRACT: deliver mail to an mbox on disk

use Moo;
with 'Email::Sender::Transport';

use Carp;
use File::Path;
use File::Basename;
use IO::File 1.11; # binmode
use Email::Simple 1.998;  # needed for ->header_obj
use Fcntl ':flock';

#pod =head1 DESCRIPTION
#pod
#pod This transport delivers into an mbox.  The mbox file may be given by the 
#pod F<filename> argument to the constructor, and defaults to F<mbox>.
#pod
#pod The transport I<currently> assumes that the mbox is in F<mboxo> format, but
#pod this may change or be configurable in the future.
#pod
#pod =cut

has 'filename' => (is => 'ro', default => sub { 'mbox' }, required => 1);

sub send_email {
  my ($self, $email, $env) = @_;

  my $filename = $self->filename;
  my $fh       = $self->_open_fh($filename);

  my $ok = eval {
    if ($fh->tell > 0) {
      $fh->print("\n") or Carp::confess("couldn't write to $filename: $!");
    }

    $fh->print($self->_from_line($email, $env))
      or Carp::confess("couldn't write to $filename: $!");

    $fh->print($self->_escape_from_body($email))
      or Carp::confess("couldn't write to $filename: $!");

    # This will make streaming a bit more annoying. -- rjbs, 2007-05-25
    $fh->print("\n")
      or Carp::confess("couldn't write to $filename: $!")
      unless $email->as_string =~ /\n$/;

    $self->_close_fh($fh)
      or Carp::confess "couldn't close file $filename: $!";

     1;
  };

  die unless $ok;
  # Email::Sender::Failure->throw($@ || 'unknown error') unless $ok;

  return $self->success;
}

sub _open_fh {
  my ($class, $file) = @_;
  my $dir = dirname($file);
  Carp::confess "couldn't make path $dir: $!" if not -d $dir or mkpath($dir);

  my $fh = IO::File->new($file, '>>')
    or Carp::confess "couldn't open $file for appending: $!";

  $fh->binmode(':raw');

  $class->_getlock($fh, $file);

  $fh->seek(0, 2);
  return $fh;
}

sub _close_fh {
  my ($class, $fh, $file) = @_;
  $class->_unlock($fh);
  return $fh->close;
}

sub _escape_from_body {
  my ($class, $email) = @_;

  my $body = $email->get_body;
  $body =~ s/^(From )/>$1/gm;

  my $simple = $email->cast('Email::Simple');
  return $simple->header_obj->as_string . $simple->crlf . $body;
}

sub _from_line {
  my ($class, $email, $envelope) = @_;

  my $fromtime = localtime;
  $fromtime =~ s/(:\d\d) \S+ (\d{4})$/$1 $2/;  # strip timezone.
  return "From $envelope->{from}  $fromtime\n";
}

sub _getlock {
  my ($class, $fh, $fn) = @_;
  for (1 .. 10) {
    return 1 if flock($fh, LOCK_EX | LOCK_NB);
    sleep $_;
  }
  Carp::confess "couldn't lock file $fn";
}

sub _unlock {
  my ($class, $fh) = @_;
  flock($fh, LOCK_UN);
}

no Moo;
1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Email::Sender::Transport::Mbox - deliver mail to an mbox on disk

=head1 VERSION

version 2.500

=head1 DESCRIPTION

This transport delivers into an mbox.  The mbox file may be given by the 
F<filename> argument to the constructor, and defaults to F<mbox>.

The transport I<currently> assumes that the mbox is in F<mboxo> format, but
this may change or be configurable in the future.

=head1 PERL VERSION

This library should run on perls released even a long time ago.  It should work
on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the
minimum required version will not be increased.  The version may be increased
for any reason, and there is no promise that patches will be accepted to lower
the minimum required perl.

=head1 AUTHOR

Ricardo Signes <rjbs@semiotic.systems>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2021 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut
