# $Header: /raid/cvsroot/rt/lib/RT/Interface/Email.pm,v 1.2 2001/11/06 23:04:52 jesse Exp $
# RT is (c) 1996-2001 Jesse Vincent <jesse@fsck.com>

package RT::Interface::Email;

use strict;
use Mail::Address;
use MIME::Entity;

BEGIN {
    use Exporter ();
    use vars qw ($VERSION  @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
    
    # set the version for version checking
    $VERSION = do { my @r = (q$Revision: 1.2 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; # must be all one line, for MakeMaker
    
    @ISA         = qw(Exporter);
    
    # your exported package globals go here,
    # as well as any optionally exported functions
    @EXPORT_OK   = qw(&CleanEnv 
		      &LoadConfig 
		      &DBConnect 
		      &GetCurrentUser
		      &GetMessageContent
		      &CheckForLoops 
		      &CheckForSuspiciousSender
		      &CheckForAutoGenerated 
		      &ParseMIMEEntityFromSTDIN
		      &ParseTicketId 
		      &MailError 
		      &ParseCcAddressesFromHead
		      &ParseSenderAddressFromHead 
		      &ParseErrorsToAddressFromHead
		      
		      &debug);
}

=head1 NAME

  RT::Interface::CLI - helper functions for creating a commandline RT interface

=head1 SYNOPSIS

  use lib "!!RT_LIB_PATH!!";
  use lib "!!RT_ETC_PATH!!";

  use RT::Interface::Email  qw(CleanEnv LoadConfig DBConnect 
			      );

  #Clean out all the nasties from the environment
  CleanEnv();

  #Load etc/config.pm and drop privs
  LoadConfig();

  #Connect to the database and get RT::SystemUser and RT::Nobody loaded
  DBConnect();


  #Get the current user all loaded
  my $CurrentUser = GetCurrentUser();

=head1 DESCRIPTION


=begin testing

ok(require RT::TestHarness);
ok(require RT::Interface::Email);

=end testing


=head1 METHODS

=cut


=head2 CleanEnv

Removes some of the nastiest nasties from the user\'s environment.

=cut

sub CleanEnv {
    $ENV{'PATH'} = '/bin:/usr/bin';    # or whatever you need
    $ENV{'CDPATH'} = '' if defined $ENV{'CDPATH'};
    $ENV{'SHELL'} = '/bin/sh' if defined $ENV{'SHELL'};
    $ENV{'ENV'} = '' if defined $ENV{'ENV'};
    $ENV{'IFS'} = '' if defined $ENV{'IFS'};
}



=head2 LoadConfig

Loads RT's config file and then drops setgid privileges.

=cut

sub LoadConfig {
    
    #This drags in  RT's config.pm
    use config;
    
}	



=head2 DBConnect

  Calls RT::Init, which creates a database connection and then creates $RT::Nobody
  and $RT::SystemUser

=cut


sub DBConnect {
    use RT;
    RT::Init();
}



# {{{ sub debug

sub debug {
    my $val = shift;
    my ($debug);
    if ($val) {
	$RT::Logger->debug($val."\n");
	if ($debug) {
	    print STDERR "$val\n";
	}
    }
    if ($debug) {
	return(1);
    }	
}

# }}}


# {{{ sub CheckForLoops 

sub CheckForLoops  {
    my $head = shift;
    
    #If this instance of RT sent it our, we don't want to take it in
    my $RTLoop = $head->get("X-RT-Loop-Prevention") || "";
    chomp ($RTLoop); #remove that newline
    if ($RTLoop eq "$RT::rtname") {
	return (1);
    }
    
    # TODO: We might not trap the case where RT instance A sends a mail
    # to RT instance B which sends a mail to ...
    return (undef);
}

# }}}

# {{{ sub CheckForSuspiciousSender

sub CheckForSuspiciousSender {
    my $head = shift;

    #if it's from a postmaster or mailer daemon, it's likely a bounce.
    
    #TODO: better algorithms needed here - there is no standards for
    #bounces, so it's very difficult to separate them from anything
    #else.  At the other hand, the Return-To address is only ment to be
    #used as an error channel, we might want to put up a separate
    #Return-To address which is treated differently.
    
    #TODO: search through the whole email and find the right Ticket ID.

    my ($From, $junk) = ParseSenderAddressFromHead($head);
    
    if (($From =~ /^mailer-daemon/i) or
	($From =~ /^postmaster/i)){
	return (1);
	
    }
    
    return (undef);

}

# }}}

# {{{ sub CheckForAutoGenerated
sub CheckForAutoGenerated {
    my $head = shift;
    
    my $Precedence = $head->get("Precedence") || "" ;
    if ($Precedence =~ /^(bulk|junk)/i) {
	return (1);
    }
    else {
	return (0);
    }
}

# }}}

# {{{ sub ParseMIMEEntityFromSTDIN

sub ParseMIMEEntityFromSTDIN {

    # Create a new parser object:
    
    my $parser = new MIME::Parser;
    
    # {{{ Config $parser to store large attacments in temp dir

    ## TODO: Does it make sense storing to disk at all?  After all, we
    ## need to put each msg as an in-core scalar before saving it to
    ## the database, don't we?

    ## At the same time, we should make sure that we nuke attachments 
    ## Over max size and return them

    ## TODO: Remove the temp dir when we don't need it any more.

    my $AttachmentDir = File::Temp::tempdir (TMPDIR => 1, CLEANUP => 1);
    
    # Set up output directory for files:
    $parser->output_dir("$AttachmentDir");
  
    #If someone includes a message, don't extract it
    $parser->extract_nested_messages(0);

   
    # Set up the prefix for files with auto-generated names:
    $parser->output_prefix("part");

    # If content length is <= 20000 bytes, store each msg as in-core scalar;
    # Else, write to a disk file (the default action):
  
    $parser->output_to_core(20000);

    # }}} (temporary directory)

    #Ok. now that we're set up, let's get the stdin.
    my $entity;
    unless ($entity = $parser->read(\*STDIN)) {
	die "couldn't parse MIME stream";
    }
    #Now we've got a parsed mime object. 
    
    # Get the head, a MIME::Head:
    my $head = $entity->head;
    
    # TODO - information about the charset is lost here!
    $head->decode;

    return ($entity, $head);

}
# }}}

# {{{ sub ParseTicketId 

sub ParseTicketId {
    my $Subject = shift;
    my ($Id);
    
    if ($Subject =~ s/\[$RT::rtname \#(\d+)\]//i) {
	$Id = $1;
	$RT::Logger->debug("Found a ticket ID. It's $Id");
	return($Id);
    }
    else {
	return(undef);
    }
}
# }}}

# {{{ sub MailError 
sub MailError {
    my %args = (To => $RT::OwnerEmail,
		Bcc => undef,
		From => $RT::CorrespondAddress,
		Subject => 'There has been an error',
		Explanation => 'Unexplained error',
		MIMEObj => undef,
		LogLevel => 'crit',
		@_);


    $RT::Logger->log(level => $args{'LogLevel'}, 
		     message => $args{'Explanation'}
		    );
    my $entity = MIME::Entity->build( Type  =>"multipart/mixed",
				      From => $args{'From'},
				      Bcc => $args{'Bcc'},
				      To => $args{'To'},
				      Subject => $args{'Subject'},
				      'X-RT-Loop-Prevention' => $RT::rtname,
				    );

    $entity->attach(  Data => $args{'Explanation'}."\n");
    
    my $mimeobj = $args{'MIMEObj'};
    $mimeobj->sync_headers();
    $entity->add_part($mimeobj);
    
    if ($RT::MailCommand eq 'sendmailpipe') {
        open (MAIL, "|$RT::SendmailPath $RT::SendmailArguments") || return(0);
        print MAIL $entity->as_string;
        close(MAIL);
    }
    else {
	$entity->send($RT::MailCommand, $RT::MailParams);
    }
}

# }}}

# {{{ sub GetCurrentUser 

sub GetCurrentUser  {
    my $head = shift;
    my $entity = shift;
    my $ErrorsTo = shift;

    my %UserInfo = ();

    #Suck the address of the sender out of the header
    my ($Address, $Name) = ParseSenderAddressFromHead($head);
    
    #This will apply local address canonicalization rules
    $Address = RT::CanonicalizeAddress($Address);
  
    #If desired, synchronize with an external database

    my $UserFoundInExternalDatabase = 0;

    # Username is the 'Name' attribute of the user that RT uses for things
    # like authentication
    my $Username = undef;
    if ($RT::LookupSenderInExternalDatabase) {
	($UserFoundInExternalDatabase, %UserInfo) = 
	  RT::LookupExternalUserInfo($Address, $Name);
   
       $Address = $UserInfo{'EmailAddress'};
       $Username = $UserInfo{'Name'}; 
    }
    
    my $CurrentUser = RT::CurrentUser->new();
    
    # First try looking up by a username, if we got one from the external
    # db lookup. Next, try looking up by email address. Failing that,
    # try looking up by users who have this user's email address as their
    # username.

    if ($Username) {
	$CurrentUser->LoadByName($Username);
    }	
    
    unless ($CurrentUser->Id) {
	$CurrentUser->LoadByEmail($Address);
    }	

    #If we can't get it by email address, try by name.  
    unless ($CurrentUser->Id) {
	$CurrentUser->LoadByName($Address);
    }
    
    
    unless ($CurrentUser->Id) {
        #If we couldn't load a user, determine whether to create a user

        # {{{ If we require an incoming address to be found in the external
	# user database, reject the incoming message appropriately
        if ( $RT::LookupSenderInExternalDatabase &&
	     $RT::SenderMustExistInExternalDatabase && 
	     !$UserFoundInExternalDatabase) {
	    
	    my $Message = "Sender's email address was not found in the user database.";

	    # {{{  This code useful only if you've defined an AutoRejectRequest template
	    
	    require RT::Template;
	    my $template = new RT::Template($RT::Nobody);
	    $template->Load('AutoRejectRequest');
	    $Message = $template->Content || $Message;
	    
	    # }}}
	    
	    MailError( To => $ErrorsTo,
		       Subject => "Ticket Creation failed: user could not be created",
		       Explanation => $Message,
		       MIMEObj => $entity,
		       LogLevel => 'notice'
		     );

	    return($CurrentUser);

	} 
	# }}}
	
	else {
	    my $NewUser = RT::User->new($RT::SystemUser);
	    
	    my ($Val, $Message) = 
	      $NewUser->Create(Name => ($Username || $Address),
			       EmailAddress => $Address,
			       RealName => "$Name",
			       Password => undef,
			       Privileged => 0,
			       Comments => 'Autocreated on ticket submission'
			      );
	    
	    unless ($Val) {
		
		# Deal with the race condition of two account creations at once
		#
           	if ($Username) {
		    $NewUser->LoadByName($Username);
		}
		
		unless ($NewUser->Id) {
	            $NewUser->LoadByEmail($Address);
		}
		
		unless ($NewUser->Id) {  
		    MailError( To => $ErrorsTo,
			       Subject => "User could not be created",
			       Explanation => "User creation failed in mailgateway: $Message",
			       MIMEObj => $entity,
			       LogLevel => 'crit'
			     );
		}
	    }
	}
	
	#Load the new user object
	$CurrentUser->LoadByEmail($Address);
	
	unless ($CurrentUser->id) {
	    $RT::Logger->warning("Couldn't load user '$Address'.".  "giving up");
		MailError( To => $ErrorsTo,
			   Subject => "User could not be loaded",
			   Explanation => "User  '$Address' could not be loaded in the mail gateway",
			   MIMEObj => $entity,
			   LogLevel => 'crit'
			 );
	    
	}
    }
    
    return ($CurrentUser);
    
}
# }}}

# {{{ ParseCcAddressesFromHead 

=head2 ParseCcAddressesFromHead HASHREF

Takes a hashref object containing QueueObj, Head and CurrentUser objects.
Returns a list of all email addresses in the To and Cc 
headers b<except> the current Queue\'s email addresses, the CurrentUser\'s 
email address  and anything that the configuration sub RT::IsRTAddress matches.

=cut
  
sub ParseCcAddressesFromHead {
    my %args = ( Head => undef,
		 QueueObj => undef,
		 CurrentUser => undef,
		 @_ );
    
    my (@Addresses);
        
    my @ToObjs = Mail::Address->parse($args{'Head'}->get('To'));
    my @CcObjs = Mail::Address->parse($args{'Head'}->get('Cc'));
    
    foreach my $AddrObj (@ToObjs, @CcObjs) {
	my $Address = $AddrObj->address;
	$Address = RT::CanonicalizeAddress($Address);
 	next if ($args{'CurrentUser'}->EmailAddress =~ /^$Address$/i);
	next if ($args{'QueueObj'}->CorrespondAddress =~ /^$Address$/i);
	next if ($args{'QueueObj'}->CommentAddress =~ /^$Address$/i);
	next if (RT::IsRTAddress($Address));
	
	push (@Addresses, $Address);
    }
    return (@Addresses);
}


# }}}

# {{{ ParseSenderAdddressFromHead

=head2 ParseSenderAddressFromHead

Takes a MIME::Header object. Returns a tuple: (user@host, friendly name) 
of the From (evaluated in order of Reply-To:, From:, Sender)

=cut

sub ParseSenderAddressFromHead {
    my $head = shift;
    #Figure out who's sending this message.
    my $From = $head->get('Reply-To') || 
      $head->get('From') || 
	$head->get('Sender');
    return (ParseAddressFromHeader($From));
}
# }}}

# {{{ ParseErrorsToAdddressFromHead

=head2 ParseErrorsToAddressFromHead

Takes a MIME::Header object. Return a single value : user@host
of the From (evaluated in order of Errors-To:,Reply-To:, From:, Sender)

=cut

sub ParseErrorsToAddressFromHead {
    my $head = shift;
    #Figure out who's sending this message.

    foreach my $header ('Errors-To' , 'Reply-To', 'From', 'Sender' ) {
	# If there's a header of that name
	my $headerobj = $head->get($header);
	if ($headerobj) {
		my ($addr, $name ) = ParseAddressFromHeader($headerobj);
		# If it's got actual useful content...
		return ($addr) if ($addr);
	}
    }
}
# }}}

# {{{ ParseAddressFromHeader

=head2 ParseAddressFromHeader ADDRESS

Takes an address from $head->get('Line') and returns a tuple: user@host, friendly name

=cut


sub ParseAddressFromHeader{
    my $Addr = shift;
    
    my @Addresses = Mail::Address->parse($Addr);
    
    my $AddrObj = $Addresses[0];

    unless (ref($AddrObj)) {
	return(undef,undef);
    }
 
    my $Name =  ($AddrObj->phrase || $AddrObj->comment || $AddrObj->address);
    
    #Lets take the from and load a user object.
    my $Address = $AddrObj->address;

    return ($Address, $Name);
}
# }}}


1;
