When using the php mail() function, the To: header encoded in the Mail_mime
library was not properly transferred to the $to variable passed to the mail
backend. The mail() function will add its own To: header which will
mimic the received destination address.

This patch ensures that the $to parameter is properly encoded.

This allows for specifying that attachments from something like a new
message should be brokered with autoresponses and alerts.

Add in the ability for an agent to resend a response. Optionally editing the
response before sending it, and setting the signature as is possible with
the usual responses.

When the response is resent, the edited version is marked as GUARDED, and
subsequent edits will result in new links in the history chain. That is,
when a response is edited and resent by an agent, that response will remain
in the history chain.

Several mail clients do not return the Message-ID header in a In-Reply-To or
References header as they should. The assumption by such mail clients is
that the email be threaded based on the Subject header. However, osTicket
does not require the ticket number to be placed in the Subject header and so
has trouble threading email from such systems. osTicket embeds a copy of the
Message-ID header (or compatible version) in the body of the message in
hopes part of the message will be returned.

Many mail clients (such as osTicket) strip and clean the HTML when
processing HTML email. Previously, the message-id token was embedded in a
@data-mid attribute, which was likely stripped before the HTML email would
be returned back to osTicket.

This patch suggests that the token be placed in a @class attribute, which
has a much better chance of returning to osTicket.

Ensure that the References header that is included with outbound email
definitely includes the References header from an email received into the
system, if at all possible.

It seems that most systems handle the newline character alone without a
problem; however, some systems cannot handle the standard CRLF line ending
at all.

This patch includes a slight database migration, and adjusts the
functionality of a few core components.

  * Move collaborators from the ticket to the thread.
    This concept allows collaborators on any object which has a thread,
    including tasks.

  * Add flags to the thread entry
    This will allow flagging thread entries for different purposes.
    Initially this can be used to flag the original message of a thread in
    case a ticket / thread is created without an initial message.

  * Lock becomes more of a utility
    The lock is now disconnected from the ticket and is a separate utility.
    Separately, the ticket and task objects can have a reference to a lock
    object. Furthermore, when submitting some activities to tickets, the
    lock is verified to be owned by the respective agent, and the lock code
    must match a current lock code. The code is rotated on each acquire()
    call to guard against double submissions.

  * Collaborator is an ORM model
    The TicketUser class is broken up now so that the collaborator instance
    can exist apart from a ticket. Email message ids are now generated for
    collaborators without respect for a ticket so that collaborators can be
    properly supported on any thread.

  * Fix matching of collaborators on return emails. Previously the
    collaborator ID was used instead of the related user ID. Also, the 'C'
    user class (collaborator) was not handled in ::decodeMessageId()
  * Only send a reply separator for email related to a thread
  * Always generate a tag for the email message id. This will allow reply
    from the help desk administrator for the new ticket alert

This would be required for new ticket auto-responses to tickets created
without an initial message.

Since tickets can be created without a message now, the emailing system
should also identify the thread the message is associated with, so that a
returning email can be associated with the ticket or task's thread in the
event that it was created without an initial message.

Also try harder to send a relevant In-Reply-To and References header back
to the client with the email message.

This patch suggests a change to the message-id creation process that
includes stamping the receiving user-id (staff or client) along with the
thread-id of the originating notice. This allows detection of threading if
the clinically brain-dead mail client drops all the other header detection
mechanisms, including the tag placed in the email body, on response.

This patch works for both client and agent communication.

This patch converts the central file and threading classes over to use the
ORM.

Also try harder to send a relevant In-Reply-To and References header back
to the client with the email message.

This patch suggests a change to the message-id creation process that
includes stamping the receiving user-id (staff or client) along with the
thread-id of the originating notice. This allows detection of threading if
the clinically brain-dead mail client drops all the other header detection
mechanisms, including the tag placed in the email body, on response.

This patch works for both client and agent communication.

This setting allows administrators to add (uncomment) a MAIL_EOL setting in
the ost-config.php config file to define the line ending used for mail
headers and encoded bodies in outbound mail (SMTP, for instance).

By default, CRLF is used by the SMTP email generator as per the RFC 822
standard. However, many administrators can benefit by setting LF (\n) as the
line ending.

Previously, if the quoted response mechanism was disabled, then outgoing
mail would also not include the message-id token. This breaks the
correlation of email to ticket-thread. Now, the message-id token is always
embedded in HTML emails even if the quoted-response removal system is
disabled.

(Turns out that the message-id token was always included in text bodies.)

Send an empty return-path envelope when sending out system alerts. If they
should happen to bounce for any reason, they should not return to the system
and create tickets.

Multilanguage Support via gettext

- added gettext encapsulations to all texts i thought necessary
- added fallback function for the case that the gettext extension isn't loaded
- added browser language detection
- added gettext to the list of optional extensions in setup
- rewritten some of the texts to use sprintf instead of appending strings
- added german translation file
- removed mark_overdue-confirm from cannedresponses.inc.php

extend multi language support and a fex fixes

- Better detection of translation files
- Added functionality to redirect language codes (see redirecting
language codes)
- Ticket Status can be translated
- The Datepicker can be translated
- Extended functionality of 'testlang.php' to show what language code is
used to translate

Forgotten to apply a patch from RC5 to RC6

- Forgotten to change $var to $vars in line 380 of class.mailfetch.php
- Removed unneeded comment

Added php_gettext as primary translation engine

- Added php_gettext support (thanks to Danilo Segan and Steven
Armstrong)
- php_gettext is now the primary translation engine
- Extended language detection functionality

Add error/misconfiguration checks and fix undefined variables

If the HTML ticket thread is disabled, outgoing emails will have a text
thread body placed inside an HTML template. The template and message are
then sanitized and converted to text. However, htmLawed will munge the white
space in the message before converting to text.

This patch disables sanitizing. I think it's fair to assume that the
template and the message by the client or agent have been properly sanitized
prior to sending out the email.

Outbound message-ids are predictable, with a consistent code unique and
static to each osTicket installation. This will help detect email loops
where message is delivered back to the system in an email loop.

This approach will help detect responses to the ticket thread from mail
clients which do not include the References and In-Reply-To MIME headers.
This also allows the Subject line to continue to omit the ticket number.

This should speed up the system where several emails and alerts will be sent
through the same SMTP account in the same request.

Some emails providers (e.g gmail/google) won't deliver emails marked
bulk/autoreply to group email address.

  * Include a `bk` column to store the storage backend
  * Include a `signature` column which represents a repeatable hash of the
    file contents
  * Rename `hash` to `key` since it isn't a real hash

This is especially important if the html ticket thread is disabled. In such
a case the message body will still be HTML, but an HTML email should not be
sent out.

The detection of inline images in the mail processor causes inline images to
be removed from the attachment list, if listed there. However, the
attachments in the attachment list were not keyed by the attachment-id, so
there was no proper way to detect and remove the attachments from the list.

This patch properly keys the attachment list by the attachment file_id