use strict;
use warnings;
package Postfix::Parse::Mailq;
our $VERSION = '1.001';

use Mixin::Linewise::Readers -readers;
# ABSTRACT: parse the output of the postfix mailq command


sub read_handle {
  my ($self, $handle, $arg) = @_;
  $arg ||= {};
  $arg->{spool} ||= {};

  my $first = $handle->getline;

  chomp $first;
  return [] if $first eq 'Mail queue is empty';

  Carp::confess("first line did not appear to be first line of mailq output")
    unless $first =~ m{\A-Queue ID-};

  my @current;
  my @entries;
  LINE: while (my $line = $handle->getline) {
    if ($line eq "\n") {
      my $entry = $self->parse_block(\@current);
      $entry->{spool} = $arg->{spool}{ $entry->{queue_id} } if $arg->{spool};
      push @entries, $entry;
      @current = ();
      next LINE;
    }

    push @current, $line;
  }

  if (@current and $current[0] !~ /^-- \d+ .?bytes/i) {
    my $entry = $self->parse_block(\@current);
    $entry->{spool} = $arg->{spool}{ $entry->{queue_id} } if $arg->{spool};
    push @entries, $entry;
  }

  return \@entries;
}


my %STATUS_FOR = (
  '!' => 'held',
  '*' => 'active',
);

sub parse_block {
  my ($self, $block) = @_;

  chomp @$block;
  my $first = shift @$block;
  my $error = $block->[0] =~ /\A\S/ ? (shift @$block) : undef;
  my @dest  = map { s/^\s+//; $_; } @$block;

  my ($qid, $status_chr, $size, $date, $sender) = $first =~ m/
    \A
    ([A-F0-9]+)
    ([*!])?
    \s+
    (\d+)
    \s+
    (.{19})
    \s+
    (\S.+)
    \z
  /x;

  my $status = $status_chr ? ($STATUS_FOR{$status_chr} || 'unknown') : 'queued';

  return {
    queue_id        => $qid,
    status          => $status,
    size            => $size,
    date            => $date,
    sender          => $sender,
    error_string    => $error,
    remaining_rcpts => \@dest,
  }
}

1;

__END__

=pod

=head1 NAME

Postfix::Parse::Mailq - parse the output of the postfix mailq command

=head1 VERSION

version 1.001

=head1 SYNOPSIS

    use Postfix::Parse::Mailq;

    my $mailq_output = `mailq`;
    my $entries = Postfix::Parse::Mailq->read_string($mailq_output);

    my $bytes = 0;
    for my $entry (@$entries) {
      next unless grep { /\@aol.com$/ } @{ $entry->{remaining_rcpts} };
      $bytes += $entry->{size};
    }
    
    print "$bytes bytes remain to send to AOL destinations\n";

=head1 WARNING

This code is really rough and the interface will change.  Entries will be
objects.  There will be some more methods.  Still, the basics are likely to
keep working, or keep pretty close to what you see here now.

=head1 METHODS

=head2 read_file

=head2 read_handle

=head2 read_string

    my $entries = Postfix::Parse::Mailq->read_string($string, \%arg);

This methods read the output of postfix's F<mailq> from a file (by name), a
filehandle, or a string, respectively.  They return an arrayref of hashrefs,
each hashref representing one entry in the queue as reported by F<mailq>.

Valid arguments are:

    spool - a hashref of { queue_id -> spool_name } pairs
            if given, this will be used to attempt to indicate in which
            spool messages currently are; it is not entirely reliable (race!)

=head2 parse_block

    my $entry = Mailq->parse_block(\@lines);

Given all the lines in a single entry's block of lines in mailq output, this
returns data about the entry.

=head1 AUTHOR

  Ricardo SIGNES <rjbs@cpan.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2008 by Ricardo SIGNES.

This is free software; you can redistribute it and/or modify it under
the same terms as perl itself.

=cut