# Hub protocol (version 1)

The contract between a **Cross Events install** (the church's site) and the **Cross Events
Hub** (`events-hub.crosscode.co.za`). A copy of this file lives in both repositories
(`joshua/hope-events` → `docs/hub-protocol.md`, `joshua/events-hub` → `docs/hub-protocol.md`);
change both together.

Principles:

- **Install → Hub only.** The install always starts the conversation; the Hub never calls
  into an install. Works behind firewalls, and the Hub has no access to church data.
- **No personal information** is ever sent — counts, versions and health only. Income is
  sent as a range, never an amount.
- **A Hub outage never switches a church off.** Licences are signed tokens the install
  verifies offline with the Hub's public key.
- Every request carries `protocolVersion`. The Hub accepts the current and the previous
  version, so installs waiting to update keep working.

All bodies are JSON (`Content-Type: application/json`). Times are ISO 8601 UTC strings.
Errors are `{ "message": "...", "code": "..." }` with a 4xx/5xx status.

---

## 1. Public key

```
GET /api/public-key
→ 200 { "protocolVersions": [1], "keyId": "k1", "algorithm": "Ed25519", "publicKey": "-----BEGIN PUBLIC KEY-----\n…" }
```

Installs ship with the Hub's public key built in (and may refresh it from here). The private
key exists only on the Hub server.

## 2. Register an install

Sent once, at the end of `/setup` (licence step) or from Site settings → "Connect to Hub".

```
POST /api/installs/register
{
  "protocolVersion": 1,
  "licenceKey": "CEH-7K2M-9QXA-P4RT-WD8C",
  "install": {
    "name": "Hope Family Church",
    "url": "https://events.hopefamily.co.za",
    "adminContact": { "name": "Jane Admin", "email": "jane@hopefamily.co.za" },
    "version": "1.41.0",
    "timezone": "Africa/Johannesburg",
    "server": { "node": "20.18.0", "postgres": "16.4", "os": "linux 6.8" },
    "features": { "whatsapp": true, "paymentProviders": ["yoco", "payfast"], "campuses": false }
  }
}
→ 201 {
  "installId": "inst_…",
  "installSecret": "…",            // shown once; the install stores it encrypted
  "licence": "<licence token>",
  "heartbeatIntervalMinutes": 15,
  "latestVersion": "1.41.0"
}
```

- `404 LICENCE_NOT_FOUND` — unknown key. `403 LICENCE_REVOKED` — revoked licences can't register.
- One licence = one install. Registering again **from the same URL** re-registers (new
  secret, same `installId`). From a different URL → `409 LICENCE_IN_USE` until Joshua releases
  the licence in the Hub (e.g. after a move to a new domain).
- The `adminContact` is the one piece of personal information: a work contact for the
  church's admin, so Joshua can reach them. It is not used for anything else.
- Rate-limited per IP.

## 3. Heartbeat

Every `heartbeatIntervalMinutes` (15) from the install's job queue.

```
POST /api/installs/heartbeat
X-Hub-Install:   inst_…
X-Hub-Timestamp: 2026-10-24T08:15:00.000Z
X-Hub-Signature: <hex HMAC-SHA256(installSecret, timestamp + "." + rawBody)>
{
  "protocolVersion": 1,
  "version": "1.41.0",
  "health": {
    "uptimeSeconds": 86400,
    "db": true,
    "jobs": { "mode": "queue", "failedLast24h": 0 },
    "lastBackupAt": "2026-10-24T00:00:12.000Z",       // null if none
    "disk": { "freeBytes": 21474836480, "totalBytes": 53687091200 },  // null if unknown
    "errorsLast24h": 0,                                // null if not tracked
    "pendingMigrations": 0
  },
  "stats": {
    "users": 412,
    "events": { "active": 3, "upcoming": 5, "total": 61 },
    "registrations": { "last30d": 88, "total": 2310 },
    "tickets": { "last30d": 140, "total": 3901 },
    "checkIns": { "last30d": 96 },
    "messages": { "email30d": 610, "whatsapp30d": 233 },
    "paymentProviders": ["yoco", "payfast"],
    "campuses": false,                                 // Site settings → Campuses on/off
    "campusCount": 0,                                  // active campuses (0 while off; Cross Events 1.43.0+)
    "income": { "last30d": "R5 001–R20 000", "allTime": "over R100 000" }
  }
}
→ 200 { "licence": "<fresh licence token>", "latestVersion": "1.42.0", "serverTime": "…" }
```

- The signature covers the exact bytes sent. Requests more than **5 minutes** off the Hub's
  clock are refused (`401 STALE_REQUEST`); a bad signature is `401 BAD_SIGNATURE`; an unknown or
  released install is `404 INSTALL_NOT_FOUND` (the install should show "Reconnect to Hub").
- **Income bands** (worked out on the install; the amount never leaves it): `R0–R1 000`,
  `R1 001–R5 000`, `R5 001–R20 000`, `R20 001–R50 000`, `R50 001–R100 000`, `over R100 000`.
- The Hub keeps every heartbeat for 30 days, then one per install per day.

## 3a. Update request

Sent when a site admin presses **Request update** (Site settings → Licence). Installs never update
themselves and never show the deploy command; the request tells Joshua, who updates the server.
Signed exactly like the heartbeat.

```
POST /api/installs/update-request
X-Hub-Install / X-Hub-Timestamp / X-Hub-Signature   (as in §3)
{ "protocolVersion": 1, "version": "1.41.2" }
→ 201 { "requestedAt": "2026-10-27T09:00:00.000Z", "version": "1.42.0", "alreadyRequested": false }
→ 200 { …, "alreadyRequested": true }    // a request is already open: not emailed again
```

- The Hub opens an `update_requested` alert on the install (shown under Alerts) and emails the
  alert address once. It is resolved when a heartbeat reports a newer version than before.
- `409 UP_TO_DATE` — the install already runs the Hub's latest version (or none is set).
- Errors as in §3 (`INSTALL_NOT_FOUND`, `STALE_REQUEST`, `BAD_SIGNATURE`). Rate-limited (10 an
  hour per IP). A Hub older than this section answers `404 NOT_FOUND`.
- No personal information: not who pressed the button (the Hub already has the admin contact).

## 4. Licence token

`hel1.<payload>.<signature>` — `payload` is base64url JSON, `signature` is the base64url
Ed25519 signature of the ASCII string `hel1.<payload>`.

```json
{
  "v": 1,
  "licenceId": "lic_…",
  "installId": "inst_…",
  "customer": "Hope Family Church",
  "plan": "standard",
  "status": "active",                       // active | suspended | revoked
  "licenceExpiresAt": "2027-10-31T21:59:59.000Z",   // null = no end date
  "graceDays": 14,
  "issuedAt": "2026-10-24T08:15:00.000Z",
  "validUntil": "2026-11-23T08:15:00.000Z",          // issuedAt + 30 days
  "limits": { "aiMonthlyCapCents": 0 }
}
```

### What the install does with it

The install keeps the newest valid token (signature checks out, `installId` matches) and works
out its state:

| State | When | What happens |
|-------|------|--------------|
| **active** | `status` is active and now is before `min(licenceExpiresAt, validUntil)` | Everything works |
| **grace** | after that date, for up to `graceDays` | Everything works; **only site admins** see a banner "Licence needs renewing — X days left" |
| **suspended** | `status` is suspended, or grace has run out | Read-only: events can't be created or edited; no new registrations or payments. Tickets still scan; admins can view and export all data; privacy requests still work |
| **revoked** | `status` is revoked | Same as suspended, with a permanent banner |
| **unlicensed** | never connected, or the Hub answered `INSTALL_NOT_FOUND` (the install drops its token) | Same as suspended (events can't be created or edited either); admins see "Connect to Hub" |

`validUntil` is refreshed by every heartbeat, so a Hub outage only matters after 30 days (then
grace starts). Blocking the Hub can't keep a suspended licence active for more than 30 days.

## 5. Versioning

- `protocolVersion` goes up only for changes an older install can't handle. Adding optional
  fields to a heartbeat or a token doesn't need a new version — both sides ignore fields they
  don't know.
- The Hub accepts protocol `N` and `N-1`; anything else is `400 UNSUPPORTED_PROTOCOL`.

## 6. Later (not in v1)

- **AI proxy** (Cross Events 2.0): `POST /api/ai/complete`, signed like the heartbeat; the Hub holds
  the Claude API key, meters each call in rand and enforces `limits.aiMonthlyCapCents`.