# Archon Mail Bridge

> Bidirectional SMTP ↔ DMail bridge with email threading

## Overview

Bridge external email to Archon's encrypted DMail system:

- **Inbound**: SMTP email → encrypted DMail
- **Outbound**: DMail reply → SMTP email (with proper threading)

```
alice@gmail.com ←──── SMTP ────→ Bridge ←──── DMail ────→ bob@archon.social
                                   │
                                   └─ Standard email threading
                                      (In-Reply-To, References)
```

## Quick Start

```bash
# Install
npm install

# Configure
cp .env.example .env
# Edit .env with your settings

# Build & run
npm run build
npm start

# Test
swaks --to bob@archon.social --server localhost:2525 --from alice@test.com
```

## How It Works

### Inbound (Email → DMail)

1. Email arrives at `bob@archon.social`
2. Bridge resolves `bob` → DID via archon.social API
3. Creates encrypted DMail, delivers to Bob
4. Stores conversation with email threading headers

### Outbound (DMail → Email)

1. Bob sends DMail to bridge identity
2. Bridge finds Bob's active conversation
3. Sends email to original sender with proper threading
4. Email clients thread the conversation automatically

### Threading

Uses standard email headers — no tokens or special formatting:

| Header | Purpose |
|--------|---------|
| `Message-ID` | Unique ID for each message |
| `In-Reply-To` | Parent message reference |
| `References` | Full conversation chain |

## Configuration

See `.env.example` for all options.

Key settings:
- `SMTP_PORT` — Inbound SMTP port (default: 2525)
- `SMTP_DOMAIN` — Email domain (default: archon.social)
- `GATEKEEPER_URL` — Archon Gatekeeper API
- `ARCHON_PASSPHRASE` — Bridge wallet passphrase
- `CONVERSATION_TIMEOUT_DAYS` — Auto-cleanup (default: 30)

## Database

SQLite with two tables:

- **conversations** — Tracks (external_email, archon_did) pairs
- **messages** — Individual messages with threading headers

Automatic garbage collection removes old conversations.

## Production Deployment

### DNS

```dns
mail.archon.social.   A      YOUR_IP
archon.social.        MX  10 mail.archon.social.
archon.social.        TXT    "v=spf1 a mx -all"
```

### Port Redirect

```bash
# Redirect 25 → 2525 (run bridge unprivileged)
sudo iptables -t nat -A PREROUTING -p tcp --dport 25 -j REDIRECT --to-port 2525
```

### Systemd

```ini
[Unit]
Description=Archon Mail Bridge
After=network.target

[Service]
Type=simple
User=archon
WorkingDirectory=/opt/archon-mail-bridge
ExecStart=/usr/bin/node dist/index.js
Restart=always
EnvironmentFile=/opt/archon-mail-bridge/.env

[Install]
WantedBy=multi-user.target
```

## Architecture

```
src/
├── index.ts           # Entry point
├── config.ts          # Environment config
├── db/
│   ├── schema.ts      # SQLite schema
│   ├── conversations.ts
│   └── messages.ts
├── inbound/
│   ├── smtp-server.ts # SMTP listener
│   ├── handler.ts     # Email → DMail
│   └── formatter.ts
├── outbound/
│   ├── poller.ts      # Watch for replies
│   ├── handler.ts     # DMail → Email
│   ├── smtp-client.ts # Send emails
│   └── formatter.ts
└── lib/
    └── resolver.ts    # name → DID lookup
```

## License

MIT