# Apple II Email Suite

<p align="center"><img src="img/emailler-logo.png" alt="emai//er-logo" height="200px"></p>

The AppleII Email Suite consists of the following four ProDOS programs:

 - `POP65.SYSTEM` is a Post Office Protocol version 3 (POP3) client for the Apple II with Uthernet-II card.
 - `EMAIL.SYSTEM` is a simple user interface for reading and managing email.  It works together with `POP65` and `SMTP65`.
 - `SMTP65.SYSTEM` is a Simple Mail Transport Protocol (SMTP) client for the Apple II with Uthernet-II card.
 - `REBUILD.SYSTEM` is a utility for rebuilding mailbox databases, should they become corrupted.  This can also be used for bulk import of messages.

## Overview

The software has been designed to be modular, which allows new protocols to be added later for handling incoming and outgoing mail.  POP3 was selected as the email download/ingest protocol because it is simple and there are many available server implementations.  SMTP was chosen as the outgoing protocol due to its almost universal adoption for this purpose.  Once again, there are many server-side implementations to choose from.  It may be possible, for example, to add an NNTP module to allow reading and posting of Usenet articles.

One problem faced by any retrocomputing project of this type is that Transport Layer Security (TLS) is endemic on today's Internet.  While this is great for security, the encryption algorithms are not feasible to implement on a 6502-based system.  In order to bridge the plain text world of the Apple II to today's encrypted Internet, I have set up a Raspberry Pi using several common open source packages as a gateway.  The Raspberry Pi uses Fetchmail to download messages from Gmail's servers using the IMAPS protocol (with TLS) and hands them off to Postfix, which is used at the system mailer (MTA) on the Pi.  I use Dovecot as a POP3 server to offer a plain text connection to the `POP65.SYSTEM` application on the Apple II.  For outgoing messages, I configured Postfix to accept plain text SMTP connections from `SMTP65.SYSTEM` on the Apple II and to relay the messages to Gmail's servers using secure SMTPS.  The configuration of the Raspberry Pi (which was originally set up as a gateway for SAM2 email under GSOS on the Apple IIgs) is documented [here](README-gmail-gateway.md).

A few design principles that I have tried to apply:

  - *Simplicity* This software runs on the Apple //e and currently fits within 64KB of RAM (although I may use the 64KB of aux memory for future enhancements.)  It is important that it be as simple and small as possible.  The code is written in C using cc65, which allows more rapid evolution when compared to writing in assembly language, at the expense of larger code which uses more memory.
  - *Modularity* Where it makes sense to split the functionality into separate modules it makes sense to do so in order to make the best use of available memory.
  - *Speed* The software should make the most of the limited hardware of the Apple //e in order to allow speedy browsing of emails without needing much processor or disk activity.
  - *Avoidance of Limits* I tried to avoid the imposition of arbitrary limits to message length or the number of messages in a folder.
  - *Veracity* The software should never modify or discard information. Incoming emails are saved to disk verbatim, including all headers.  The system hides the headers when displaying the emails, but they are available for inspection or further processing.  The only change that is made to incoming messages is to convert the CR+LF line endings to Apple II CR-only line endings.

`POP65.SYSTEM` and `SMTP65.SYSTEM` are based on Oliver Schmitd's excellent IP65 TCP/IP framework (in particular they follow the design of `WGET65.SYSTEM`.)  Without IP65, this software would not have been possible.

## System Setup and Configuration

### Configuration File

The system configuration file is called `EMAIL.CFG`.  It is a straightforward ProDOS text file, with one parameter per line.  You may edit this file using any ProDOS text editor.  When editing the file be careful not to add or delete any lines - this file has no grammar and the lines *must* appear in the expected order.

All three of the mail programs `POP65.SYSTEM`, `EMAIL.SYSTEM` and `SMTP65.SYSTEM` share this configuration file.

Here is an example config file (with passwords replaced with `****` for obvious reasons):

```
192.168.10.2
pi
******
NODELETE
192.168.10.2
apple2.local
/H1/DOCUMENTS/EMAIL
bobbi.8bit@gmail.com
```

The lines are as follows, in order:

 1) IP address of the POP3 server for receiving new mail.
 2) Username to use when connecting to POP3.
 3) Password for POP3 connection (in plaintext).
 4) If this string is exactly `DELETE` then messages will be deleted from the POP3 server after downloading.  Otherwise they are left on the server.  `DELETE` is the normal setting, but `NODELETE` (or any other nonsense value) can be helpful for debugging, allowing the same messages to be downloaded from the POP3 server again and again.
 5) IP address of the SMTP server for sending outgoing mail.
 6) Domain name that is passed to the SMTP server on connection.  The way my SMTP server (Postfix) is configured, it doesn't seem to care about this.
 7) ProDOS path to the root of the email folder tree.  Mailboxes will be created and managed under this root path.
 8) Your email address.  Used as the sender's address in outgoing messages.

### Creating Directories

To get started, you will need to create the following directories:

 - The email root directory (`/H1/DOCUMENTS/EMAIL` in the example config)
 - The `SPOOL` directory, used by POP65, within the email root directory.  This will be `/H1/DOCUMENTS/EMAIL/SPOOL` for our example configuration.
 - The `INBOX` directory, used by POP65, within the email root directory.  This will be `/H1/DOCUMENTS/EMAIL/INBOX` for our example configuration.
 - The `OUTBOX` directory, used by SMTP65, within the email root directory.  This will be `/H1/DOCUMENTS/EMAIL/OUTBOX` for our example configuration.
 - The `ATTACHMENTS` directory, used by EMAIL for storing downloaded MIME attachments, within the email root directory.  This will be `/H1/DOCUMENTS/EMAIL/ATTACHMENTS` for our example configuration.

You can create these directories in ProDOS `BASIC.SYSTEM` as follows:

```
] CREATE /H1/DOCUMENTS/EMAIL
] CREATE /H1/DOCUMENTS/EMAIL/SPOOL
] CREATE /H1/DOCUMENTS/EMAIL/INBOX
] CREATE /H1/DOCUMENTS/EMAIL/OUTBOX
] CREATE /H1/DOCUMENTS/EMAIL/ATTACHMENTS
```

You will also want to create a couple of mailboxes such as `RECEIVED` and `SENT`.  If you do not create a `SENT` mailbox then SMTP65 will be unable to complete the sending of messages and will give an error.  To create these mailboxes, run `EMAIL.SYSTEM` and press `N` for N)ew mailbox.  At the prompt, enter the name of the mailbox to be created: `RECEIVED`, and press return.  Repeat this to create the `SENT` mailbox.

These are the minimum mailboxes you need to get started.  You may create more mailboxes to organize your mail at any time.

### Mailboxes

Each mailbox consists of the following:

 - A directory under the email root, and within this directory
 - Email messages are stored on per file, in plain Apple II text files (with CR line endings) named `EMAIL.nn` where `nn` is an integer value
 - A text file called `NEXT.EMAIL`.  This file initially contains the number 1.  It is used when naming the individual `EMAIL.nn` files, and is incremented by one each time.  If messages are added to a mailbox and nothing is ever deleted they will be sequentially numbered `EMAIL.1`, `EMAIL.2`, etc.
 - A binary file called `EMAIL.DB`.  This file contains essential information about each email message in a quickly accessed format.  This allows the user interface to show the email summary without having to open and read each individual email file.  This file is initially empty and a fixed size record is added for each email message.

The easiest way to create additional mailboxes is using the `N)ew` command in `EMAIL.SYSTEM`.

`POP65.SYSTEM` knows how to initialize `INBOX` but the directory must have been created first.

Note that `SPOOL` is