use strict;
use warnings;
package Postfix::Parse::Mailq;
# ABSTRACT: parse the output of the postfix mailq command
$Postfix::Parse::Mailq::VERSION = '1.005';
use Mixin::Linewise::Readers -readers;

#pod =head1 SYNOPSIS
#pod
#pod   use Postfix::Parse::Mailq;
#pod
#pod   my $mailq_output = `mailq`;
#pod   my $entries = Postfix::Parse::Mailq->read_string($mailq_output);
#pod
#pod   my $bytes = 0;
#pod   for my $entry (@$entries) {
#pod     next unless grep { /\@aol.com$/ } @{ $entry->{remaining_rcpts} };
#pod     $bytes += $entry->{size};
#pod   }
#pod   
#pod   print "$bytes bytes remain to send to AOL destinations\n";
#pod
#pod =head1 WARNING
#pod
#pod This code is really rough and the interface will change.  Entries will be
#pod objects.  There will be some more methods.  Still, the basics are likely to
#pod keep working, or keep pretty close to what you see here now.
#pod
#pod =method read_file
#pod
#pod =method read_handle
#pod
#pod =method read_string
#pod
#pod   my $entries = Postfix::Parse::Mailq->read_string($string, \%arg);
#pod
#pod This methods read the output of postfix's F<mailq> from a file (by name), a
#pod filehandle, or a string, respectively.  They return an arrayref of hashrefs,
#pod each hashref representing one entry in the queue as reported by F<mailq>.
#pod
#pod Valid arguments are:
#pod
#pod   spool - a hashref of { queue_id -> spool_name } pairs
#pod           if given, this will be used to attempt to indicate in which
#pod           spool messages currently are; it is not entirely reliable (race!)
#pod
#pod =cut

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;
}

#pod =method parse_block
#pod
#pod   my $entry = Mailq->parse_block(\@lines);
#pod
#pod Given all the lines in a single entry's block of lines in mailq output, this
#pod returns data about the entry.
#pod
#pod =cut

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

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

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

  my ($qid, $status_chr, $size, $date, $sender) = $first =~ m/
    \A
    ([A-F0-9]+|[0-9B-Zb-z]+)
    ([*!])?
    \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

=encoding UTF-8

=head1 NAME

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

=head1 VERSION

version 1.005

=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 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 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 AUTHOR

Ricardo SIGNES <rjbs@cpan.org>

=head1 CONTRIBUTOR

=for stopwords Johan Carlquist

Johan Carlquist <jocar@su.se>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2015 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