package Email::Send;
use strict;

use vars qw[$VERSION];
$VERSION   = '2.194';

use Email::Simple;
use Module::Pluggable
  search_path => 'Email::Send',
  except      => $Email::Send::__plugin_exclusion;
use Return::Value;
use Scalar::Util ();

=head1 NAME

Email::Send - Simply Sending Email

=head1 WAIT!  ACHTUNG!

Email::Send is going away... well, not really going away, but it's being
officially marked "out of favor."  It has API design problems that make it hard
to usefully extend and rather than try to deprecate features and slowly ease in
a new interface, we've released Email::SendB<er> which fixes these problems and
others.  As of today, 2008-12-19, Email::Sender is young, but it's fairly
well-tested.  Please consider using it instead for any new work.

=head1 SYNOPSIS

  use Email::Send;

  my $message = <<'__MESSAGE__';
  To: recipient@example.com
  From: sender@example.com
  Subject: Hello there folks
  
  How are you? Enjoy!
  __MESSAGE__

  my $sender = Email::Send->new({mailer => 'SMTP'});
  $sender->mailer_args([Host => 'smtp.example.com']);
  $sender->send($message);
  
  # more complex
  my $bulk = Email::Send->new;
  for ( qw[SMTP Sendmail Qmail] ) {
      $bulk->mailer($_) and last if $bulk->mailer_available($_);
  }

  $bulk->message_modifier(sub {
      my ($sender, $message, $to) = @_;
      $message->header_set(To => qq[$to\@geeknest.com])
  });
  
  my @to = qw[casey chastity evelina casey_jr marshall];
  my $rv = $bulk->send($message, $_) for @to;

=head1 DESCRIPTION

This module provides a very simple, very clean, very specific interface
to multiple Email mailers. The goal of this software is to be small
and simple, easy to use, and easy to extend.

=head2 Constructors

=over 4

=item new

  my $sender = Email::Send->new({
      mailer      => 'NNTP',
      mailer_args => [ Host => 'nntp.example.com' ],
  });

Create a new mailer object. This method can take parameters for any of the data
properties of this module. Those data properties, which have their own accessors,
are listed under L<"Properties">.

=back

=head2 Properties

=over 4

=item mailer

The mailing system you'd like to use for sending messages with this object.
This is not defined by default. If you don't specify a mailer, all available
plugins will be tried when the C<send> method is called until one succeeds.

=item mailer_args

Arguments passed into the mailing system you're using.

=item message_modifier

If defined, this callback is invoked every time the C<send> method is called
on an object. The mailer object will be passed as the first argument. Second,
the actual C<Email::Simple> object for a message will be passed. Finally, any
additional arguments passed to C<send> will be passed to this method in the
order they were recieved.

This is useful if you are sending in bulk.

=back

=cut

sub new {
    my ($class, $args) = @_;
    $args->{mailer_args} ||= [];
    my %plugins = map {
        my ($short_name) = /^Email::Send::(.+)/;
        ($short_name, $_);
    } $class->plugins;
    $args->{_plugin_list} = \%plugins;
    return bless $args => $class;
}

BEGIN {
  for my $field (qw(mailer mailer_args message_modifier _plugin_list)) {
    my $code = sub {
      return $_[0]->{$field} unless @_ > 1;
      my $self = shift;
      $self->{$field} = (@_ == 1 ? $_[0] : [@_]);
    };

    no strict 'refs';
    *$field = $code;
  }
}

=head2 METHODS

=over 4

=item send

  my $result = $sender->send($message, @modifier_args);

Send a message using the predetermined mailer and mailer arguments. If you
have defined a C<message_modifier> it will be called prior to sending.

The first argument you pass to send is an email message. It must be in some
format that C<Email::Abstract> can understand. If you don't have
C<Email::Abstract> installed then sending as plain text or an C<Email::Simple>
object will do.

Any remaining arguments will be passed directly into your defined
C<message_modifier>.

=cut

sub send {
    goto &_send_function unless eval { $_[0]->isa('Email::Send') };
    my ($self, $message, @args) = @_;

    my $simple = $self->_objectify_message($message);
    return failure "No message found." unless $simple;

    $self->message_modifier->(
        $self, $simple,
        @args,
    ) if $self->message_modifier;

    if ( $self->mailer ) {
        return $self->_send_it($self->mailer, $simple);
    }

    return $self->_try_all($simple);
}

=item all_mailers

  my @available = $sender->all_mailers;

Returns a list of availabe mailers. These are mailers that are
installed on your computer and register themselves as available.

=cut

sub all_mailers {
    my ($self) = @_;
    my @mailers;
    for ( keys %{$self->_plugin_list} ) {
        push @mailers, $_ if $self->mailer_available($_);
    }
    return @mailers;
}

=item mailer_available

  # is SMTP over SSL avaialble?
  $sender->mailer('SMTP')
    if $sender->mailer_available('SMTP', ssl => 1);

Given the name of a mailer, such as C<SMTP>, determine if it is
available. Any additional arguments passed to this method are passed
directly to the C<is_available> method of the mailer being queried.

=back

=cut

sub mailer_available {
  my ($self, $mailer, @args) = @_;

  my $invocant = $self->_mailer_invocant($mailer);

  return $invocant unless $invocant;

  $invocant->can('is_available')
    or return failure "Mailer $mailer doesn't report availability.";

  my $test = $invocant->is_available(@args);
  return $test unless $test;
  return success;
}

sub _objectify_message {
    my ($self, $message) = @_;

    return undef unless defined $message;
    return $message if UNIVERSAL::isa($message, 'Email::Simple');
    return Email::Simple->new($message) unless ref($message);
    return Email::Abstract->cast($message => 'Email::Simple')
      if eval { require Email::Abstract };
    return undef;
}

sub _mailer_invocant {
  my ($self, $mailer) = @_;

  return $mailer if Scalar::Util::blessed($mailer);

  # is the mailer a plugin given by short name?
  my $package = exists $self->_plugin_list->{$mailer}
               ? $self->_plugin_list->{$mailer}
               : $mailer;

  eval "require $package" or return failure "$@";

  return $package;
}

sub _send_it {
    my ($self, $mailer, $message) = @_;
    my $test = $self->mailer_available($mailer);
    return $test unless $test;

    my $invocant = $self->_mailer_invocant($mailer);

    return $invocant->send($message, @{$self->mailer_args});
}

sub _try_all {
    my ($self, $simple) = @_;
    foreach ( $self->all_mailers ) {
      my $sent = $self->_send_it($_, $simple);
      return $sent if $sent;
    }
    return failure "Unable to send message.";
}

# Classic Interface.

sub import {
    no strict 'refs';
    *{(caller)[0] . '::send'} = __PACKAGE__->can('_send_function');
}

sub _send_function {
    my ($mailer, $message, @args) = @_;
    __PACKAGE__->new({
        mailer => $mailer,
        mailer_args => \@args,
    })->send($message);
}

1;

__END__

=head2 Writing Mailers

  package Email::Send::Example;

  sub is_available {
      eval { use Net::Example }
  }

  sub send {
      my ($class, $message, @args) = @_;
      use Net::Example;
      Net::Example->do_it($message) or return;
  }
  
  1;

Writing new mailers is very simple. If you want to use a short name
when calling C<send>, name your mailer under the C<Email::Send> namespace.
If you don't, the full name will have to be used. A mailer only needs
to implement a single function, C<send>. It will be called from
C<Email::Send> exactly like this.

  Your::Sending::Package->send($message, @args);

C<$message> is an Email::Simple object, C<@args> are the extra
arguments passed into C<Email::Send::send>.

Here's an example of a mailer that sends email to a URL.

  package Email::Send::HTTP::Post;
  use strict;

  use vars qw[$AGENT $URL $FIELD];
  use Return::Value;
  
  sub is_available {
      eval { use LWP::UserAgent }
  }

  sub send {
      my ($class, $message, @args);

      require LWP::UserAgent;

      if ( @args ) {
          my ($URL, $FIELD) = @args;
          $AGENT = LWP::UserAgent->new;
      }
      return failure "Can't send to URL if no URL and field are named"
          unless $URL && $FIELD;
      $AGENT->post($URL => { $FIELD => $message->as_string });
      return success;
  }

  1;

This example will keep a UserAgent singleton unless new arguments are
passed to C<send>. It is used by calling C<Email::Send::send>.

  my $sender = Email::Send->new({ mailer => 'HTTP::Post' });
  
  $sender->mailer_args([ 'http://example.com/incoming', 'message' ]);

  $sender->send($message);
  $sender->send($message2); # uses saved $URL and $FIELD

=head1 SEE ALSO

L<Email::Simple>,
L<Email::Abstract>,
L<Email::Send::IO>,
L<Email::Send::NNTP>,
L<Email::Send::Qmail>,
L<Email::Send::SMTP>,
L<Email::Send::Sendmail>,
L<perl>.

=head1 PERL EMAIL PROJECT

This module is maintained by the Perl Email Project.

L<http://emailproject.perl.org/wiki/Email::Send>

=head1 AUTHOR

Current maintainer: Ricardo SIGNES, <F<rjbs@cpan.org>>.

Original author: Casey West, <F<casey@geeknest.com>>.

=head1 COPYRIGHT

  Copyright (c) 2005 Casey West.  All rights reserved.
  This module is free software; you can redistribute it and/or modify it
  under the same terms as Perl itself.

=cut
