docs: add reverse proxy security note to login rate limiting section

Add a token-bucket rate limiter (golang.org/x/time/rate) that limits
login attempts per client IP on POST /api/v1/login. Returns 429 Too
Many Requests with a Retry-After header when the limit is exceeded.

Configurable via LOGIN_RATE_LIMIT (requests/sec, default 1) and
LOGIN_RATE_BURST (burst size, default 5). Stale per-IP entries are
automatically cleaned up every 10 minutes.

Only the login endpoint is rate-limited per sneak's instruction —
session creation and registration use hashcash proof-of-work instead.

README.md

@@ -113,8 +113,9 @@ mechanisms or stuffing data into CTCP.
 Everything else is IRC. `PRIVMSG`, `JOIN`, `PART`, `NICK`, `TOPIC`, `MODE`,
 `KICK`, `353`, `433` — same commands, same semantics. Channels start with `#`.
 Joining a nonexistent channel creates it. Channels disappear when empty. Nicks
-are unique per server. There are no accounts — identity is a key, a nick is a
-display name.
+are unique per server. Identity starts with a key — a nick is a display name.
+Accounts are optional: you can create an anonymous session instantly, or
+register with a password for multi-client access to a single session.
 
 ### On the resemblance to JSON-RPC
 
@@ -148,16 +149,45 @@ not arbitrary choices — each one follows from the project's core thesis that
 IRC's command model is correct and only the transport and session management
 need to change.
 
-### Identity & Sessions — No Accounts
+### Identity & Sessions — Dual Authentication Model
 
-There are no accounts, no registration, no passwords. Identity is a signing
-key; a nick is just a display name. The two are decoupled.
+The server supports two authentication paths: **anonymous sessions** for
+instant access, and **optional account registration** for multi-client access.
+
+#### Anonymous Sessions (No Account Required)
+
+The simplest entry point. No registration, no passwords.
 
 - **Session creation**: client sends `POST /api/v1/session` with a desired
   nick → server assigns an **auth token** (64 hex characters of
   cryptographically random bytes) and returns the user ID, nick, and token.
 - The auth token implicitly identifies the client. Clients present it via
   `Authorization: Bearer <token>`.
+- Anonymous sessions are ephemeral — when the session expires or the user
+  QUITs, the nick is released and there is no way to reclaim it.
+
+#### Registered Accounts (Optional)
+
+For users who want multi-client access (multiple devices sharing one session):
+
+- **Registration**: client sends `POST /api/v1/register` with a nick and
+  password (minimum 8 characters) → server creates a session with the
+  password hashed via bcrypt, and returns the user ID, nick, and auth token.
+- **Login**: client sends `POST /api/v1/login` with nick and password →
+  server verifies the password against the stored bcrypt hash and creates a
+  new client token for the existing session. This enables multi-client
+  access: logging in from a new device adds a client to the existing session
+  rather than creating a new one, so channel memberships and message queues
+  are shared. Note: login only works while the session still exists — if all
+  clients have logged out or the user has sent QUIT, the session is deleted
+  and the registration is lost.
+- Registered accounts cannot be logged into via `POST /api/v1/session` —
+  that endpoint is for anonymous sessions only.
+- Anonymous sessions (created via `/session`) cannot be logged into via
+  `/login` because they have no password set.
+
+#### Common Properties (Both Paths)
+
 - Nicks are changeable via the `NICK` command; the server-assigned user ID is
   the stable identity.
 - Server-assigned IDs — clients do not choose their own IDs.
@@ -165,11 +195,17 @@ key; a nick is just a display name. The two are decoupled.
   in the token, no client-side decode. The server is the sole authority on
   token validity.
 
-**Rationale:** IRC has no accounts. You connect, pick a nick, and talk. Adding
-registration, email verification, or OAuth would solve a problem nobody asked
-about and add complexity that drives away casual users. Identity verification
-is handled at the message layer via cryptographic signatures (see
-[Security Model](#security-model)), not at the session layer.
+**Rationale:** IRC has no accounts. You connect, pick a nick, and talk.
+Anonymous sessions preserve that simplicity — instant access, zero friction.
+But some users want to access the same session from multiple devices without
+a bouncer. Optional registration with password enables multi-client login
+without adding friction for casual users: if you don't want an account,
+don't create one. Note: in the current implementation, both anonymous and
+registered sessions are deleted when the last client disconnects (QUIT or
+logout); registration does not make a session survive all-client
+removal. Identity verification at the message layer via cryptographic
+signatures (see [Security Model](#security-model)) remains independent
+of account registration.
 
 ### Nick Semantics
 
@@ -207,12 +243,12 @@ User Session
 └── Client C (token_c, queue_c)
 ```
 
-**Current MVP note:** The current implementation creates a new user (with new
-nick) per `POST /api/v1/session` call. True multi-client (multiple tokens
-sharing one nick/session) is supported by the schema (`client_queues` is keyed
-by user_id, and multiple tokens can point to the same user) but the session
-creation endpoint does not yet support "add a client to an existing session."
-This will be added post-MVP.
+**Multi-client via login:** The `POST /api/v1/login` endpoint adds a new
+client to an existing registered session, enabling true multi-client support
+(multiple tokens sharing one nick/session with independent message queues).
+Anonymous sessions created via `POST /api/v1/session` always create a new
+user with a new nick. A future endpoint to "add a client to an existing
+anonymous session" is planned but not yet implemented.
 
 **Rationale:** The fundamental IRC mobile problem is that you can't have your
 phone and laptop connected simultaneously without a bouncer. Server-side
@@ -327,8 +363,8 @@ needs to revoke a token, change the expiry model, or add/remove claims, JWT
 clients may break or behave incorrectly.
 
 Opaque tokens are simpler:
-- Server generates 32 random bytes → hex-encodes → stores hash
-- Client presents the token; server looks it up
+- Server generates 32 random bytes → hex-encodes → stores SHA-256 hash
+- Client presents the raw token; server hashes and looks it up
 - Revocation is a database delete
 - No clock skew issues, no algorithm confusion, no "none" algorithm attacks
 - Token format can change without breaking clients
@@ -355,6 +391,8 @@ The entire read/write loop for a client is two endpoints. Everything else
 
 ### Session Lifecycle
 
+#### Anonymous Session
+
 ```
 ┌─ Client ──────────────────────────────────────────────────┐
 │                                                            │
@@ -385,6 +423,30 @@ The entire read/write loop for a client is two endpoints. Everything else
 └────────────────────────────────────────────────────────────┘
 ```
 
+#### Registered Account
+
+```
+┌─ Client ──────────────────────────────────────────────────┐
+│                                                            │
+│  1. POST /api/v1/register                                  │
+│     {"nick":"alice", "password":"s3cret!!"}                │
+│     → {"id":1, "nick":"alice", "token":"a1b2c3..."}       │
+│     (Session created with bcrypt-hashed password)          │
+│                                                            │
+│  ... use the API normally (JOIN, PRIVMSG, poll, etc.) ...  │
+│                                                            │
+│  (From another device, while session is still active)      │
+│                                                            │
+│  2. POST /api/v1/login                                     │
+│     {"nick":"alice", "password":"s3cret!!"}                │
+│     → {"id":1, "nick":"alice", "token":"d4e5f6..."}       │
+│     (New client added to existing session — channels       │
+│      and message queues are preserved. If all clients      │
+│      have logged out, session no longer exists.)           │
+│                                                            │
+└────────────────────────────────────────────────────────────┘
+```
+
 ### Queue Architecture
 
 ```
@@ -989,18 +1051,18 @@ Create a new user session. This is the entry point for all clients.
 
 If the server requires hashcash proof-of-work (see
 [Hashcash Proof-of-Work](#hashcash-proof-of-work)), the client must include a
-valid stamp in the `hashcash` field of the JSON request body. The required
+valid stamp in the `pow_token` field of the JSON request body. The required
 difficulty is advertised via `GET /api/v1/server` in the `hashcash_bits` field.
 
 **Request Body:**
 ```json
-{"nick": "alice", "hashcash": "1:20:260310:neoirc::3a2f1"}
+{"nick": "alice", "pow_token": "1:20:260310:neoirc::3a2f1"}
 ```
 
 | Field      | Type   | Required    | Constraints |
 |------------|--------|-------------|-------------|
 | `nick`     | string | Yes         | 1–32 characters, must be unique on the server |
-| `hashcash` | string | Conditional | Hashcash stamp (required when server has `hashcash_bits` > 0) |
+| `pow_token` | string | Conditional | Hashcash stamp (required when server has `hashcash_bits` > 0) |
 
 **Response:** `201 Created`
 ```json
@@ -1022,7 +1084,7 @@ difficulty is advertised via `GET /api/v1/server` in the `hashcash_bits` field.
 | Status | Error | When |
 |--------|-------|------|
 | 400    | `nick must be 1-32 characters` | Empty or too-long nick |
-| 402    | `hashcash proof-of-work required` | Missing `hashcash` field in request body when hashcash is enabled |
+| 402    | `hashcash proof-of-work required` | Missing `pow_token` field in request body when hashcash is enabled |
 | 402    | `invalid hashcash stamp: ...` | Stamp fails validation (wrong bits, expired, reused, etc.) |
 | 409    | `nick already taken` | Another active session holds this nick |
 
@@ -1030,7 +1092,106 @@ difficulty is advertised via `GET /api/v1/server` in the `hashcash_bits` field.
 ```bash
 TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/session \
   -H 'Content-Type: application/json' \
-  -d '{"nick":"alice","hashcash":"1:20:260310:neoirc::3a2f1"}' | jq -r .token)
+  -d '{"nick":"alice","pow_token":"1:20:260310:neoirc::3a2f1"}' | jq -r .token)
+echo $TOKEN
+```
+
+### POST /api/v1/register — Register Account
+
+Create a new user session with a password. The password is hashed
+with bcrypt and stored server-side. The password enables login from
+additional clients via `POST /api/v1/login` while the session
+remains active.
+
+**Request Body:**
+```json
+{"nick": "alice", "password": "mypassword"}
+```
+
+| Field      | Type   | Required | Constraints |
+|------------|--------|----------|-------------|
+| `nick`     | string | Yes      | 1–32 characters, must be unique on the server |
+| `password` | string | Yes      | Minimum 8 characters |
+
+**Response:** `201 Created`
+```json
+{
+  "id": 1,
+  "nick": "alice",
+  "token": "494ba9fc0f2242873fc5c285dd4a24fc3844ba5e67789a17e69b6fe5f8c132e3"
+}
+```
+
+| Field   | Type    | Description |
+|---------|---------|-------------|
+| `id`    | integer | Server-assigned user ID |
+| `nick`  | string  | Confirmed nick |
+| `token` | string  | 64-character hex auth token |
+
+**Errors:**
+
+| Status | Error | When |
+|--------|-------|------|
+| 400    | `invalid nick format` | Nick doesn't match allowed format |
+| 400    | `password must be at least 8 characters` | Password too short |
+| 409    | `nick already taken` | Another active session holds this nick |
+
+**curl example:**
+```bash
+TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/register \
+  -H 'Content-Type: application/json' \
+  -d '{"nick":"alice","password":"mypassword"}' | jq -r .token)
+echo $TOKEN
+```
+
+### POST /api/v1/login — Login to Account
+
+Authenticate with a previously registered nick and password. Creates a new
+client token for the existing session, preserving channel memberships and
+message queues. This is how multi-client access works for registered accounts:
+each login adds a new client to the session.
+
+On successful login, the server enqueues MOTD messages and synthetic channel
+state (JOIN + TOPIC + NAMES for each channel the session belongs to) into the
+new client's queue, so the client can immediately restore its UI state.
+
+**Request Body:**
+```json
+{"nick": "alice", "password": "mypassword"}
+```
+
+| Field      | Type   | Required | Constraints |
+|------------|--------|----------|-------------|
+| `nick`     | string | Yes      | Must match a registered account |
+| `password` | string | Yes      | Must match the account's password |
+
+**Response:** `200 OK`
+```json
+{
+  "id": 1,
+  "nick": "alice",
+  "token": "7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f"
+}
+```
+
+| Field   | Type    | Description |
+|---------|---------|-------------|
+| `id`    | integer | Session ID (same as when registered) |
+| `nick`  | string  | Current nick |
+| `token` | string  | New 64-character hex auth token for this client |
+
+**Errors:**
+
+| Status | Error | When |
+|--------|-------|------|
+| 400    | `nick and password required` | Missing nick or password |
+| 401    | `invalid credentials` | Wrong password, nick not found, or account has no password |
+
+**curl example:**
+```bash
+TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/login \
+  -H 'Content-Type: application/json' \
+  -d '{"nick":"alice","password":"mypassword"}' | jq -r .token)
 echo $TOKEN
 ```
 
@@ -1399,13 +1560,40 @@ Return server metadata. No authentication required.
 
 ### GET /.well-known/healthcheck.json — Health Check
 
-Standard health check endpoint. No authentication required.
+Standard health check endpoint. No authentication required. Returns server
+health status and runtime statistics.
 
 **Response:** `200 OK`
+
 ```json
-{"status": "ok"}
+{
+  "status": "ok",
+  "now": "2024-01-15T12:00:00.000000000Z",
+  "uptimeSeconds": 3600,
+  "uptimeHuman": "1h0m0s",
+  "version": "0.1.0",
+  "appname": "neoirc",
+  "maintenanceMode": false,
+  "sessions": 42,
+  "clients": 85,
+  "queuedLines": 128,
+  "channels": 7,
+  "connectionsSinceBoot": 200,
+  "sessionsSinceBoot": 150,
+  "messagesSinceBoot": 5000
+}
 ```
 
+| Field                  | Description                                       |
+| ---------------------- | ------------------------------------------------- |
+| `sessions`             | Current number of active sessions                 |
+| `clients`              | Current number of connected clients               |
+| `queuedLines`          | Total entries in client output queues              |
+| `channels`             | Current number of channels                        |
+| `connectionsSinceBoot` | Total client connections since server start        |
+| `sessionsSinceBoot`    | Total sessions created since server start          |
+| `messagesSinceBoot`    | Total PRIVMSG/NOTICE messages sent since server start |
+
 ---
 
 ## Message Flow
@@ -1590,9 +1778,16 @@ authenticity.
 ### Authentication
 
 - **Session auth**: Opaque bearer tokens (64 hex chars = 256 bits of entropy).
-  Tokens are stored in the database and validated on every request.
-- **No passwords**: Session creation requires only a nick. The token is the
-  sole credential.
+  Tokens are hashed (SHA-256) before storage and validated on every request.
+- **Anonymous sessions**: `POST /api/v1/session` requires only a nick. No
+  password, instant access. The token is the sole credential.
+- **Registered accounts**: `POST /api/v1/register` accepts a nick and password
+  (minimum 8 characters). The password is hashed with bcrypt at the default
+  cost factor and stored alongside the session. `POST /api/v1/login`
+  authenticates against the stored hash and issues a new client token.
+- **Password security**: Passwords are never stored in plain text. bcrypt
+  handles salting and key stretching automatically. Anonymous sessions have
+  an empty `password_hash` and cannot be logged into via `/login`.
 - **Token security**: Tokens should be treated like session cookies. Transmit
   only over HTTPS in production. If a token is compromised, the attacker has
   full access to the session until QUIT or expiry.
@@ -1740,13 +1935,26 @@ The database schema is managed via embedded SQL migration files in
 
 **Current tables:**
 
-#### `users`
+#### `sessions`
+| Column         | Type     | Description |
+|----------------|----------|-------------|
+| `id`           | INTEGER  | Primary key (auto-increment) |
+| `uuid`         | TEXT     | Unique session UUID |
+| `nick`         | TEXT     | Unique nick |
+| `password_hash`| TEXT     | bcrypt hash (empty string for anonymous sessions) |
+| `signing_key`  | TEXT     | Public signing key (empty string if unset) |
+| `away_message` | TEXT     | Away message (empty string if not away) |
+| `created_at`   | DATETIME | Session creation time |
+| `last_seen`    | DATETIME | Last API request time |
+
+#### `clients`
 | Column      | Type     | Description |
 |-------------|----------|-------------|
 | `id`        | INTEGER  | Primary key (auto-increment) |
-| `nick`      | TEXT     | Unique nick |
-| `token`     | TEXT     | Unique auth token (64 hex chars) |
-| `created_at`| DATETIME | Session creation time |
+| `uuid`      | TEXT     | Unique client UUID |
+| `session_id`| INTEGER  | FK → sessions.id (cascade delete) |
+| `token`     | TEXT     | Unique auth token (SHA-256 hash of 64 hex chars) |
+| `created_at`| DATETIME | Client creation time |
 | `last_seen` | DATETIME | Last API request time |
 
 #### `channels`
@@ -1803,10 +2011,19 @@ skew issues) and simpler than UUIDs (integer comparison vs. string comparison).
 - **Client output queue entries**: Pruned automatically when older than
   `QUEUE_MAX_AGE` (default 30 days).
 - **Channels**: Deleted when the last member leaves (ephemeral).
-- **Users/sessions**: Deleted on `QUIT` or `POST /api/v1/logout`. Idle
-  sessions are automatically expired after `SESSION_IDLE_TIMEOUT` (default
-  30 days) — the server runs a background cleanup loop that parts idle users
-  from all channels, broadcasts QUIT, and releases their nicks.
+- **Sessions**: Both anonymous and registered sessions are deleted on `QUIT`
+  or when the last client logs out (`POST /api/v1/logout` with no remaining
+  clients triggers session cleanup). There is no distinction between session
+  types in the cleanup path — `handleQuit` and `cleanupUser` both call
+  `DeleteSession` unconditionally. Idle sessions are automatically expired
+  after `SESSION_IDLE_TIMEOUT`
+  (default 30 days) — the server runs a background cleanup loop that parts
+  idle users from all channels, broadcasts QUIT, and releases their nicks.
+- **Clients**: Individual client tokens are deleted on `POST /api/v1/logout`.
+  A session can have multiple clients; removing one doesn't affect others.
+  However, when the last client is removed (via logout), the entire session
+  is deleted — the user is parted from all channels, QUIT is broadcast, and
+  the nick is released.
 
 ---
 
@@ -1834,6 +2051,8 @@ directory is also loaded automatically via
 | `METRICS_USERNAME` | string  | `""`                                 | Basic auth username for `/metrics` endpoint. If empty, metrics endpoint is disabled. |
 | `METRICS_PASSWORD` | string  | `""`                                 | Basic auth password for `/metrics` endpoint |
 | `NEOIRC_HASHCASH_BITS` | int | `20`                               | Required hashcash proof-of-work difficulty (leading zero bits in SHA-256) for session creation. Set to `0` to disable. |
+| `LOGIN_RATE_LIMIT` | float   | `1`                                  | Allowed login attempts per second per IP address. |
+| `LOGIN_RATE_BURST`  | int    | `5`                                  | Maximum burst of login attempts per IP before rate limiting kicks in. |
 | `MAINTENANCE_MODE` | bool    | `false`                              | Maintenance mode flag (reserved) |
 
 ### Example `.env` file
@@ -1955,11 +2174,21 @@ A complete client needs only four HTTP calls:
 ### Step-by-Step with curl
 
 ```bash
-# 1. Create a session
+# 1a. Create an anonymous session (no account)
 export TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/session \
   -H 'Content-Type: application/json' \
   -d '{"nick":"testuser"}' | jq -r .token)
 
+# 1b. Or register an account (multi-client support)
+export TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/register \
+  -H 'Content-Type: application/json' \
+  -d '{"nick":"testuser","password":"mypassword"}' | jq -r .token)
+
+# 1c. Or login to an existing account
+export TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/login \
+  -H 'Content-Type: application/json' \
+  -d '{"nick":"testuser","password":"mypassword"}' | jq -r .token)
+
 # 2. Join a channel
 curl -s -X POST http://localhost:8080/api/v1/messages \
   -H "Authorization: Bearer $TOKEN" \
@@ -2092,9 +2321,11 @@ Clients should handle these message commands from the queue:
 
 ### Error Handling
 
-- **HTTP 401**: Token expired or invalid. Re-create session.
+- **HTTP 401**: Token expired or invalid. Re-create session (anonymous) or
+  re-login (registered account).
 - **HTTP 404**: Channel or user not found.
-- **HTTP 409**: Nick already taken (on session creation or NICK change).
+- **HTTP 409**: Nick already taken (on session creation, registration, or
+  NICK change).
 - **HTTP 400**: Malformed request. Check the `error` field in the response.
 - **Network errors**: Back off exponentially (1s, 2s, 4s, ..., max 30s).
 
@@ -2111,8 +2342,10 @@ Clients should handle these message commands from the queue:
 4. **DM tab logic**: When you receive a PRIVMSG where `to` is not a channel
    (no `#` prefix), the DM tab should be keyed by the **other** user's nick:
    if `from` is you, use `to`; if `from` is someone else, use `from`.
-5. **Reconnection**: If the poll loop fails with 401, the session is gone.
-   Create a new session. If it fails with a network error, retry with backoff.
+5. **Reconnection**: If the poll loop fails with 401, the token is invalid.
+   For anonymous sessions, create a new session. For registered accounts,
+   log in again via `POST /api/v1/login` to get a fresh token on the same
+   session. If it fails with a network error, retry with backoff.
 
 ---
 
@@ -2132,7 +2365,7 @@ account registration, no IP-based rate limits that punish shared networks.
 2. Client computes a hashcash stamp: find a counter value such that the
    SHA-256 hash of the stamp string has the required number of leading zero
    bits.
-3. Client includes the stamp in the `hashcash` field of the JSON request body when creating
+3. Client includes the stamp in the `pow_token` field of the JSON request body when creating
    a session: `POST /api/v1/session`.
 4. Server validates the stamp:
    - Version is `1`
@@ -2189,7 +2422,7 @@ Both the embedded web SPA and the CLI client automatically handle hashcash:
 
 1. Fetch `GET /api/v1/server` to read `hashcash_bits`
 2. If `hashcash_bits > 0`, compute a valid stamp
-3. Include the stamp in the `hashcash` field of the JSON body on `POST /api/v1/session`
+3. Include the stamp in the `pow_token` field of the JSON body on `POST /api/v1/session`
 
 The web SPA uses the Web Crypto API (`crypto.subtle.digest`) for SHA-256
 computation with batched parallelism. The CLI client uses Go's `crypto/sha256`.
@@ -2224,6 +2457,49 @@ creating one session pays once and keeps their session.
 - **Language-agnostic**: SHA-256 is available in every programming language.
   The proof computation is trivially implementable in any client.
 
+### Login Rate Limiting
+
+The login endpoint (`POST /api/v1/login`) has per-IP rate limiting to prevent
+brute-force password attacks. This uses a token-bucket algorithm
+(`golang.org/x/time/rate`) with configurable rate and burst.
+
+| Environment Variable | Default | Description |
+|---------------------|---------|-------------|
+| `LOGIN_RATE_LIMIT`  | `1`     | Allowed login attempts per second per IP |
+| `LOGIN_RATE_BURST`  | `5`     | Maximum burst of login attempts per IP |
+
+When the limit is exceeded, the server returns **429 Too Many Requests** with a
+`Retry-After: 1` header. Stale per-IP entries are automatically cleaned up
+every 10 minutes.
+
+> **⚠️ Security: Reverse Proxy Required for Production Use**
+>
+> The rate limiter extracts the client IP by checking the `X-Forwarded-For`
+> header first, then `X-Real-IP`, and finally falling back to the TCP
+> `RemoteAddr`. Both `X-Forwarded-For` and `X-Real-IP` are **client-controlled
+> request headers** — any client can set them to arbitrary values.
+>
+> Without a properly configured reverse proxy in front of this server:
+>
+> - An attacker can **bypass rate limiting entirely** by rotating
+>   `X-Forwarded-For` values on each request (each value is treated as a
+>   distinct IP).
+> - An attacker can **deny service to a specific user** by spoofing that user's
+>   IP in the `X-Forwarded-For` header, exhausting their rate limit bucket.
+>
+> **Recommendation:** Always deploy behind a reverse proxy (e.g. nginx, Caddy,
+> Traefik) that strips or overwrites incoming `X-Forwarded-For` and `X-Real-IP`
+> headers with the actual client IP. If running without a reverse proxy, be
+> aware that the rate limiting provides no meaningful protection against a
+> targeted attack.
+
+**Why rate limits here but not on session creation?** Session creation is
+protected by hashcash proof-of-work (stateless, no IP tracking needed). Login
+involves bcrypt password verification against a registered account — a
+fundamentally different threat model where an attacker targets a specific
+account. Per-IP rate limiting is appropriate here because the cost of a wrong
+guess is borne by the server (bcrypt), not the client.
+
 ---
 
 ## Roadmap
@@ -2332,6 +2608,8 @@ neoirc/
 │   │   └── healthcheck.go  # Health check handler
 │   ├── healthcheck/        # Health check logic
 │   │   └── healthcheck.go
+│   ├── stats/              # Runtime statistics (atomic counters)
+│   │   └── stats.go
 │   ├── logger/             # slog-based logging
 │   │   └── logger.go
 │   ├── middleware/          # HTTP middleware (logging, CORS, metrics, auth)
@@ -2383,9 +2661,13 @@ neoirc/
    build a working IRC-style TUI client against this API in an afternoon, the
    API is too complex.
 
-2. **No accounts** — identity is a signing key, nick is a display name. No
-   registration, no passwords, no email verification. Session creation is
-   instant. The cost of entry is a hashcash proof, not bureaucracy.
+2. **Accounts optional** — anonymous sessions are instant: pick a nick and
+   talk. No registration, no email verification. The cost of entry is a
+   hashcash proof, not bureaucracy. For users who want multi-client access
+   (multiple devices sharing one session), optional account registration
+   with password is available — but never required. Identity
+   verification at the message layer uses cryptographic signing,
+   independent of account status.
 
 3. **IRC semantics over HTTP** — command names and numeric codes from
    RFC 1459/2812. If you've built an IRC client or bot, you already know the

cmd/neoircd/main.go

@@ -10,6 +10,7 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/logger"
 	"git.eeqj.de/sneak/neoirc/internal/middleware"
 	"git.eeqj.de/sneak/neoirc/internal/server"
+	"git.eeqj.de/sneak/neoirc/internal/stats"
 	"go.uber.org/fx"
 )
 
@@ -35,6 +36,7 @@ func main() {
 			server.New,
 			middleware.New,
 			healthcheck.New,
+			stats.New,
 		),
 		fx.Invoke(func(*server.Server) {}),
 	).Run()

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8
 	github.com/gdamore/tcell/v2 v2.13.8
 	github.com/getsentry/sentry-go v0.42.0
-	github.com/go-chi/chi v1.5.5
+	github.com/go-chi/chi/v5 v5.2.1
 	github.com/go-chi/cors v1.2.2
 	github.com/google/uuid v1.6.0
 	github.com/joho/godotenv v1.5.1
@@ -16,6 +16,7 @@ require (
 	github.com/spf13/viper v1.21.0
 	go.uber.org/fx v1.24.0
 	golang.org/x/crypto v0.48.0
+	golang.org/x/time v0.6.0
 	modernc.org/sqlite v1.45.0
 )
 

go.sum

@@ -18,8 +18,8 @@ github.com/gdamore/tcell/v2 v2.13.8 h1:Mys/Kl5wfC/GcC5Cx4C2BIQH9dbnhnkPgS9/wF3Rl
 github.com/gdamore/tcell/v2 v2.13.8/go.mod h1:+Wfe208WDdB7INEtCsNrAN6O2m+wsTPk1RAovjaILlo=
 github.com/getsentry/sentry-go v0.42.0 h1:eeFMACuZTbUQf90RE8dE4tXeSe4CZyfvR1MBL7RLEt8=
 github.com/getsentry/sentry-go v0.42.0/go.mod h1:eRXCoh3uvmjQLY6qu63BjUZnaBu5L5WhMV1RwYO8W5s=
-github.com/go-chi/chi v1.5.5 h1:vOB/HbEMt9QqBqErz07QehcOKHaWFtuj87tTDVz2qXE=
-github.com/go-chi/chi v1.5.5/go.mod h1:C9JqLr3tIYjDOZpzn+BCuxY8z8vmca43EeMgyZt7irw=
+github.com/go-chi/chi/v5 v5.2.1 h1:KOIHODQj58PmL80G2Eak4WdvUzjSJSm0vG72crDCqb8=
+github.com/go-chi/chi/v5 v5.2.1/go.mod h1:L2yAIGWB3H+phAw1NxKwWM+7eUH/lU8pOMm5hHcoops=
 github.com/go-chi/cors v1.2.2 h1:Jmey33TE+b+rB7fT8MUy1u0I4L+NARQlK6LhzKPSyQE=
 github.com/go-chi/cors v1.2.2/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
 github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
@@ -151,6 +151,8 @@ golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
 golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
+golang.org/x/time v0.6.0 h1:eTDhh4ZXt5Qf0augr54TN6suAUudPcawVZeIAPU7D4U=
+golang.org/x/time v0.6.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=

internal/cli/api/client.go

@@ -14,7 +14,7 @@ import (
 	"strings"
 	"time"
 
-	"git.eeqj.de/sneak/neoirc/internal/irc"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
 )
 
 const (

internal/cli/api/types.go

@@ -5,7 +5,7 @@ import "time"
 // SessionRequest is the body for POST /api/v1/session.
 type SessionRequest struct {
 	Nick     string `json:"nick"`
-	Hashcash string `json:"hashcash,omitempty"`
+	Hashcash string `json:"pow_token,omitempty"` //nolint:tagliatelle
 }
 
 // SessionResponse is the response from session creation.

internal/cli/app.go

@@ -9,7 +9,7 @@ import (
 	"time"
 
 	api "git.eeqj.de/sneak/neoirc/internal/cli/api"
-	"git.eeqj.de/sneak/neoirc/internal/irc"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
 )
 
 const (

internal/config/config.go

@@ -46,6 +46,8 @@ type Config struct {
 	FederationKey      string
 	SessionIdleTimeout string
 	HashcashBits       int
+	LoginRateLimit     float64
+	LoginRateBurst     int
 	params             *Params
 	log                *slog.Logger
 }
@@ -78,6 +80,8 @@ func New(
 	viper.SetDefault("FEDERATION_KEY", "")
 	viper.SetDefault("SESSION_IDLE_TIMEOUT", "720h")
 	viper.SetDefault("NEOIRC_HASHCASH_BITS", "20")
+	viper.SetDefault("LOGIN_RATE_LIMIT", "1")
+	viper.SetDefault("LOGIN_RATE_BURST", "5")
 
 	err := viper.ReadInConfig()
 	if err != nil {
@@ -104,6 +108,8 @@ func New(
 		FederationKey:      viper.GetString("FEDERATION_KEY"),
 		SessionIdleTimeout: viper.GetString("SESSION_IDLE_TIMEOUT"),
 		HashcashBits:       viper.GetInt("NEOIRC_HASHCASH_BITS"),
+		LoginRateLimit:     viper.GetFloat64("LOGIN_RATE_LIMIT"),
+		LoginRateBurst:     viper.GetInt("LOGIN_RATE_BURST"),
 		log:                log,
 		params:             &params,
 	}

internal/db/queries.go

@@ -11,7 +11,7 @@ import (
 	"strconv"
 	"time"
 
-	"git.eeqj.de/sneak/neoirc/internal/irc"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
 	"github.com/google/uuid"
 )
 
@@ -746,8 +746,8 @@ func scanMessages(
 			code, _ := strconv.Atoi(msg.Command)
 			msg.Code = code
 
-			if name := irc.Name(code); name != "" {
-				msg.Command = name
+			if mt, err := irc.FromInt(code); err == nil {
+				msg.Command = mt.Name()
 			}
 		}
 
@@ -1110,6 +1110,121 @@ func (database *Database) GetSessionCreatedAt(
 	return createdAt, nil
 }
 
+// SetAway sets the away message for a session.
+// An empty message clears the away status.
+func (database *Database) SetAway(
+	ctx context.Context,
+	sessionID int64,
+	message string,
+) error {
+	_, err := database.conn.ExecContext(ctx,
+		"UPDATE sessions SET away_message = ? WHERE id = ?",
+		message, sessionID)
+	if err != nil {
+		return fmt.Errorf("set away: %w", err)
+	}
+
+	return nil
+}
+
+// GetAway returns the away message for a session.
+// Returns an empty string if the user is not away.
+func (database *Database) GetAway(
+	ctx context.Context,
+	sessionID int64,
+) (string, error) {
+	var msg string
+
+	err := database.conn.QueryRowContext(ctx,
+		"SELECT away_message FROM sessions WHERE id = ?",
+		sessionID,
+	).Scan(&msg)
+	if err != nil {
+		return "", fmt.Errorf("get away: %w", err)
+	}
+
+	return msg, nil
+}
+
+// SetTopicMeta sets the topic along with who set it and
+// when.
+func (database *Database) SetTopicMeta(
+	ctx context.Context,
+	channelName, topic, setBy string,
+) error {
+	now := time.Now()
+
+	_, err := database.conn.ExecContext(ctx,
+		`UPDATE channels
+		 SET topic = ?, topic_set_by = ?,
+		     topic_set_at = ?, updated_at = ?
+		 WHERE name = ?`,
+		topic, setBy, now, now, channelName)
+	if err != nil {
+		return fmt.Errorf("set topic meta: %w", err)
+	}
+
+	return nil
+}
+
+// TopicMeta holds topic metadata for a channel.
+type TopicMeta struct {
+	SetBy string
+	SetAt time.Time
+}
+
+// GetTopicMeta returns who set the topic and when.
+func (database *Database) GetTopicMeta(
+	ctx context.Context,
+	channelID int64,
+) (*TopicMeta, error) {
+	var (
+		setBy string
+		setAt sql.NullTime
+	)
+
+	err := database.conn.QueryRowContext(ctx,
+		`SELECT topic_set_by, topic_set_at
+		 FROM channels WHERE id = ?`,
+		channelID,
+	).Scan(&setBy, &setAt)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get topic meta: %w", err,
+		)
+	}
+
+	if setBy == "" || !setAt.Valid {
+		return nil, nil //nolint:nilnil
+	}
+
+	return &TopicMeta{
+		SetBy: setBy,
+		SetAt: setAt.Time,
+	}, nil
+}
+
+// GetSessionLastSeen returns the last_seen time for a
+// session.
+func (database *Database) GetSessionLastSeen(
+	ctx context.Context,
+	sessionID int64,
+) (time.Time, error) {
+	var lastSeen time.Time
+
+	err := database.conn.QueryRowContext(ctx,
+		"SELECT last_seen FROM sessions WHERE id = ?",
+		sessionID,
+	).Scan(&lastSeen)
+	if err != nil {
+		return time.Time{}, fmt.Errorf(
+			"get session last_seen: %w", err,
+		)
+	}
+
+	return lastSeen, nil
+}
+
 // PruneOldQueueEntries deletes client output queue entries
 // older than cutoff and returns the number of rows removed.
 func (database *Database) PruneOldQueueEntries(
@@ -1151,3 +1266,42 @@ func (database *Database) PruneOldMessages(
 
 	return deleted, nil
 }
+
+// GetClientCount returns the total number of clients.
+func (database *Database) GetClientCount(
+	ctx context.Context,
+) (int64, error) {
+	var count int64
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		"SELECT COUNT(*) FROM clients",
+	).Scan(&count)
+	if err != nil {
+		return 0, fmt.Errorf(
+			"get client count: %w", err,
+		)
+	}
+
+	return count, nil
+}
+
+// GetQueueEntryCount returns the total number of entries
+// in the client output queues.
+func (database *Database) GetQueueEntryCount(
+	ctx context.Context,
+) (int64, error) {
+	var count int64
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		"SELECT COUNT(*) FROM client_queues",
+	).Scan(&count)
+	if err != nil {
+		return 0, fmt.Errorf(
+			"get queue entry count: %w", err,
+		)
+	}
+
+	return count, nil
+}

internal/db/schema/001_initial.sql

@@ -8,6 +8,7 @@ CREATE TABLE IF NOT EXISTS sessions (
     nick TEXT NOT NULL UNIQUE,
     password_hash TEXT NOT NULL DEFAULT '',
     signing_key TEXT NOT NULL DEFAULT '',
+    away_message TEXT NOT NULL DEFAULT '',
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
     last_seen DATETIME DEFAULT CURRENT_TIMESTAMP
 );
@@ -30,6 +31,8 @@ CREATE TABLE IF NOT EXISTS channels (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     name TEXT NOT NULL UNIQUE,
     topic TEXT NOT NULL DEFAULT '',
+    topic_set_by TEXT NOT NULL DEFAULT '',
+    topic_set_at DATETIME,
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
     updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );

internal/handlers/api.go

@@ -11,8 +11,8 @@ import (
 	"time"
 
 	"git.eeqj.de/sneak/neoirc/internal/db"
-	"git.eeqj.de/sneak/neoirc/internal/irc"
-	"github.com/go-chi/chi"
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
+	"github.com/go-chi/chi/v5"
 )
 
 var validNickRe = regexp.MustCompile(
@@ -71,11 +71,10 @@ func (hdlr *Handlers) requireAuth(
 	sessionID, clientID, nick, err :=
 		hdlr.authSession(request)
 	if err != nil {
-		hdlr.respondError(
-			writer, request,
-			"unauthorized",
-			http.StatusUnauthorized,
-		)
+		hdlr.respondJSON(writer, request, map[string]any{
+			"error":   "not registered",
+			"numeric": irc.ErrNotRegistered,
+		}, http.StatusUnauthorized)
 
 		return 0, 0, "", false
 	}
@@ -147,7 +146,7 @@ func (hdlr *Handlers) handleCreateSession(
 ) {
 	type createRequest struct {
 		Nick     string `json:"nick"`
-		Hashcash string `json:"hashcash,omitempty"`
+		Hashcash string `json:"pow_token,omitempty"` //nolint:tagliatelle
 	}
 
 	var payload createRequest
@@ -213,6 +212,9 @@ func (hdlr *Handlers) handleCreateSession(
 		return
 	}
 
+	hdlr.stats.IncrSessions()
+	hdlr.stats.IncrConnections()
+
 	hdlr.deliverMOTD(request, clientID, sessionID, payload.Nick)
 
 	hdlr.respondJSON(writer, request, map[string]any{
@@ -425,12 +427,12 @@ func (hdlr *Handlers) serverName() string {
 func (hdlr *Handlers) enqueueNumeric(
 	ctx context.Context,
 	clientID int64,
-	code int,
+	code irc.IRCMessageType,
 	nick string,
 	params []string,
 	text string,
 ) {
-	command := fmt.Sprintf("%03d", code)
+	command := code.Code()
 
 	body, err := json.Marshal([]string{text})
 	if err != nil {
@@ -837,6 +839,11 @@ func (hdlr *Handlers) dispatchCommand(
 	bodyLines func() []string,
 ) {
 	switch command {
+	case irc.CmdAway:
+		hdlr.handleAway(
+			writer, request,
+			sessionID, clientID, nick, bodyLines,
+		)
 	case irc.CmdPrivmsg, irc.CmdNotice:
 		hdlr.handlePrivmsg(
 			writer, request,
@@ -947,8 +954,8 @@ func (hdlr *Handlers) handlePrivmsg(
 	if target == "" {
 		hdlr.enqueueNumeric(
 			request.Context(), clientID,
-			irc.ErrNeedMoreParams, nick, []string{command},
-			"Not enough parameters",
+			irc.ErrNoRecipient, nick, []string{command},
+			"No recipient given",
 		)
 		hdlr.broker.Notify(sessionID)
 		hdlr.respondJSON(writer, request,
@@ -962,8 +969,8 @@ func (hdlr *Handlers) handlePrivmsg(
 	if len(lines) == 0 {
 		hdlr.enqueueNumeric(
 			request.Context(), clientID,
-			irc.ErrNeedMoreParams, nick, []string{command},
-			"Not enough parameters",
+			irc.ErrNoTextToSend, nick, []string{command},
+			"No text to send",
 		)
 		hdlr.broker.Notify(sessionID)
 		hdlr.respondJSON(writer, request,
@@ -973,6 +980,8 @@ func (hdlr *Handlers) handlePrivmsg(
 		return
 	}
 
+	hdlr.stats.IncrMessages()
+
 	if strings.HasPrefix(target, "#") {
 		hdlr.handleChannelMsg(
 			writer, request,
@@ -996,7 +1005,7 @@ func (hdlr *Handlers) respondIRCError(
 	writer http.ResponseWriter,
 	request *http.Request,
 	clientID, sessionID int64,
-	code int,
+	code irc.IRCMessageType,
 	nick string,
 	params []string,
 	text string,
@@ -1050,8 +1059,8 @@ func (hdlr *Handlers) handleChannelMsg(
 	if !isMember {
 		hdlr.respondIRCError(
 			writer, request, clientID, sessionID,
-			irc.ErrNotOnChannel, nick, []string{target},
-			"You're not on that channel",
+			irc.ErrCannotSendToChan, nick, []string{target},
+			"Cannot send to channel",
 		)
 
 		return
@@ -1147,6 +1156,19 @@ func (hdlr *Handlers) handleDirectMsg(
 		return
 	}
 
+	// If the target is away, send RPL_AWAY to the sender.
+	awayMsg, awayErr := hdlr.params.Database.GetAway(
+		request.Context(), targetSID,
+	)
+	if awayErr == nil && awayMsg != "" {
+		hdlr.enqueueNumeric(
+			request.Context(), clientID,
+			irc.RplAway, nick,
+			[]string{target}, awayMsg,
+		)
+		hdlr.broker.Notify(sessionID)
+	}
+
 	hdlr.respondJSON(writer, request,
 		map[string]string{"id": msgUUID, "status": "sent"},
 		http.StatusOK)
@@ -1257,14 +1279,25 @@ func (hdlr *Handlers) deliverJoinNumerics(
 ) {
 	ctx := request.Context()
 
-	chInfo, err := hdlr.params.Database.GetChannelByName(
-		ctx, channel,
+	hdlr.deliverTopicNumerics(
+		ctx, clientID, sessionID, nick, channel, chID,
 	)
-	if err == nil {
-		_ = chInfo // chInfo is the ID; topic comes from DB.
+
+	hdlr.deliverNamesNumerics(
+		ctx, clientID, nick, channel, chID,
+	)
+
+	hdlr.broker.Notify(sessionID)
 }
 
-	// Get topic from channel info.
+// deliverTopicNumerics sends RPL_TOPIC or RPL_NOTOPIC,
+// plus RPL_TOPICWHOTIME when topic metadata is available.
+func (hdlr *Handlers) deliverTopicNumerics(
+	ctx context.Context,
+	clientID, sessionID int64,
+	nick, channel string,
+	chID int64,
+) {
 	channels, listErr := hdlr.params.Database.ListChannels(
 		ctx, sessionID,
 	)
@@ -1286,14 +1319,39 @@ func (hdlr *Handlers) deliverJoinNumerics(
 			ctx, clientID, irc.RplTopic, nick,
 			[]string{channel}, topic,
 		)
+
+		topicMeta, tmErr := hdlr.params.Database.
+			GetTopicMeta(ctx, chID)
+		if tmErr == nil && topicMeta != nil {
+			hdlr.enqueueNumeric(
+				ctx, clientID,
+				irc.RplTopicWhoTime, nick,
+				[]string{
+					channel,
+					topicMeta.SetBy,
+					strconv.FormatInt(
+						topicMeta.SetAt.Unix(), 10,
+					),
+				},
+				"",
+			)
+		}
 	} else {
 		hdlr.enqueueNumeric(
 			ctx, clientID, irc.RplNoTopic, nick,
 			[]string{channel}, "No topic is set",
 		)
 	}
+}
 
-	// Get member list for NAMES reply.
+// deliverNamesNumerics sends RPL_NAMREPLY and
+// RPL_ENDOFNAMES for a channel.
+func (hdlr *Handlers) deliverNamesNumerics(
+	ctx context.Context,
+	clientID int64,
+	nick, channel string,
+	chID int64,
+) {
 	members, memErr := hdlr.params.Database.ChannelMembers(
 		ctx, chID,
 	)
@@ -1316,8 +1374,6 @@ func (hdlr *Handlers) deliverJoinNumerics(
 		ctx, clientID, irc.RplEndOfNames, nick,
 		[]string{channel}, "End of /NAMES list",
 	)
-
-	hdlr.broker.Notify(sessionID)
 }
 
 func (hdlr *Handlers) handlePart(
@@ -1585,6 +1641,32 @@ func (hdlr *Handlers) handleTopic(
 		return
 	}
 
+	isMember, err := hdlr.params.Database.IsChannelMember(
+		request.Context(), chID, sessionID,
+	)
+	if err != nil {
+		hdlr.log.Error(
+			"check membership failed", "error", err,
+		)
+		hdlr.respondError(
+			writer, request,
+			"internal error",
+			http.StatusInternalServerError,
+		)
+
+		return
+	}
+
+	if !isMember {
+		hdlr.respondIRCError(
+			writer, request, clientID, sessionID,
+			irc.ErrNotOnChannel, nick, []string{channel},
+			"You're not on that channel",
+		)
+
+		return
+	}
+
 	hdlr.executeTopic(
 		writer, request,
 		sessionID, clientID, nick,
@@ -1601,8 +1683,8 @@ func (hdlr *Handlers) executeTopic(
 	body json.RawMessage,
 	chID int64,
 ) {
-	setErr := hdlr.params.Database.SetTopic(
-		request.Context(), channel, topic,
+	setErr := hdlr.params.Database.SetTopicMeta(
+		request.Context(), channel, topic, nick,
 	)
 	if setErr != nil {
 		hdlr.log.Error(
@@ -1629,6 +1711,25 @@ func (hdlr *Handlers) executeTopic(
 		request.Context(), clientID,
 		irc.RplTopic, nick, []string{channel}, topic,
 	)
+
+	// 333 RPL_TOPICWHOTIME
+	topicMeta, tmErr := hdlr.params.Database.
+		GetTopicMeta(request.Context(), chID)
+	if tmErr == nil && topicMeta != nil {
+		hdlr.enqueueNumeric(
+			request.Context(), clientID,
+			irc.RplTopicWhoTime, nick,
+			[]string{
+				channel,
+				topicMeta.SetBy,
+				strconv.FormatInt(
+					topicMeta.SetAt.Unix(), 10,
+				),
+			},
+			"",
+		)
+	}
+
 	hdlr.broker.Notify(sessionID)
 
 	hdlr.respondJSON(writer, request,
@@ -2018,6 +2119,11 @@ func (hdlr *Handlers) executeWhois(
 		"neoirc server",
 	)
 
+	// 317 RPL_WHOISIDLE
+	hdlr.deliverWhoisIdle(
+		ctx, clientID, nick, queryNick, targetSID,
+	)
+
 	// 319 RPL_WHOISCHANNELS
 	hdlr.deliverWhoisChannels(
 		ctx, clientID, nick, queryNick, targetSID,
@@ -2435,3 +2541,95 @@ func (hdlr *Handlers) HandleServerInfo() http.HandlerFunc {
 		)
 	}
 }
+
+// handleAway handles the AWAY command. An empty body
+// clears the away status; a non-empty body sets it.
+func (hdlr *Handlers) handleAway(
+	writer http.ResponseWriter,
+	request *http.Request,
+	sessionID, clientID int64,
+	nick string,
+	bodyLines func() []string,
+) {
+	ctx := request.Context()
+
+	lines := bodyLines()
+
+	awayMsg := ""
+	if len(lines) > 0 {
+		awayMsg = strings.Join(lines, " ")
+	}
+
+	err := hdlr.params.Database.SetAway(
+		ctx, sessionID, awayMsg,
+	)
+	if err != nil {
+		hdlr.log.Error("set away failed", "error", err)
+		hdlr.respondError(
+			writer, request,
+			"internal error",
+			http.StatusInternalServerError,
+		)
+
+		return
+	}
+
+	if awayMsg == "" {
+		// 305 RPL_UNAWAY
+		hdlr.enqueueNumeric(
+			ctx, clientID, irc.RplUnaway, nick, nil,
+			"You are no longer marked as being away",
+		)
+	} else {
+		// 306 RPL_NOWAWAY
+		hdlr.enqueueNumeric(
+			ctx, clientID, irc.RplNowAway, nick, nil,
+			"You have been marked as being away",
+		)
+	}
+
+	hdlr.broker.Notify(sessionID)
+	hdlr.respondJSON(writer, request,
+		map[string]string{"status": "ok"},
+		http.StatusOK)
+}
+
+// deliverWhoisIdle sends RPL_WHOISIDLE (317) with idle
+// time and signon time.
+func (hdlr *Handlers) deliverWhoisIdle(
+	ctx context.Context,
+	clientID int64,
+	nick, queryNick string,
+	targetSID int64,
+) {
+	lastSeen, lsErr := hdlr.params.Database.
+		GetSessionLastSeen(ctx, targetSID)
+	if lsErr != nil {
+		return
+	}
+
+	createdAt, caErr := hdlr.params.Database.
+		GetSessionCreatedAt(ctx, targetSID)
+	if caErr != nil {
+		return
+	}
+
+	idleSeconds := int64(time.Since(lastSeen).Seconds())
+	if idleSeconds < 0 {
+		idleSeconds = 0
+	}
+
+	signonUnix := strconv.FormatInt(
+		createdAt.Unix(), 10,
+	)
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, irc.RplWhoisIdle, nick,
+		[]string{
+			queryNick,
+			strconv.FormatInt(idleSeconds, 10),
+			signonUnix,
+		},
+		"seconds idle, signon time",
+	)
+}

internal/handlers/api_test.go

@@ -26,6 +26,7 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/logger"
 	"git.eeqj.de/sneak/neoirc/internal/middleware"
 	"git.eeqj.de/sneak/neoirc/internal/server"
+	"git.eeqj.de/sneak/neoirc/internal/stats"
 	"go.uber.org/fx"
 	"go.uber.org/fx/fxtest"
 )
@@ -90,6 +91,7 @@ func newTestServer(
 				return cfg, nil
 			},
 			newTestDB,
+			stats.New,
 			newTestHealthcheck,
 			newTestMiddleware,
 			newTestHandlers,
@@ -144,12 +146,14 @@ func newTestHealthcheck(
 	cfg *config.Config,
 	log *logger.Logger,
 	database *db.Database,
+	tracker *stats.Tracker,
 ) (*healthcheck.Healthcheck, error) {
 	hcheck, err := healthcheck.New(lifecycle, healthcheck.Params{ //nolint:exhaustruct
 		Globals:  globs,
 		Config:   cfg,
 		Logger:   log,
 		Database: database,
+		Stats:    tracker,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("test healthcheck: %w", err)
@@ -183,6 +187,7 @@ func newTestHandlers(
 	cfg *config.Config,
 	database *db.Database,
 	hcheck *healthcheck.Healthcheck,
+	tracker *stats.Tracker,
 ) (*handlers.Handlers, error) {
 	hdlr, err := handlers.New(lifecycle, handlers.Params{ //nolint:exhaustruct
 		Logger:      log,
@@ -190,6 +195,7 @@ func newTestHandlers(
 		Config:      cfg,
 		Database:    database,
 		Healthcheck: hcheck,
+		Stats:       tracker,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("test handlers: %w", err)
@@ -811,9 +817,9 @@ func TestMessageMissingBody(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(token, lastID)
 
-	if !findNumeric(msgs, "461") {
+	if !findNumeric(msgs, "412") {
 		t.Fatalf(
-			"expected ERR_NEEDMOREPARAMS (461), got %v",
+			"expected ERR_NOTEXTTOSEND (412), got %v",
 			msgs,
 		)
 	}
@@ -835,9 +841,9 @@ func TestMessageMissingTo(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(token, lastID)
 
-	if !findNumeric(msgs, "461") {
+	if !findNumeric(msgs, "411") {
 		t.Fatalf(
-			"expected ERR_NEEDMOREPARAMS (461), got %v",
+			"expected ERR_NORECIPIENT (411), got %v",
 			msgs,
 		)
 	}
@@ -870,9 +876,9 @@ func TestNonMemberCannotSend(t *testing.T) {
 
 	msgs, _ := tserver.pollMessages(aliceToken, lastID)
 
-	if !findNumeric(msgs, "442") {
+	if !findNumeric(msgs, "404") {
 		t.Fatalf(
-			"expected ERR_NOTONCHANNEL (442), got %v",
+			"expected ERR_CANNOTSENDTOCHAN (404), got %v",
 			msgs,
 		)
 	}
@@ -1134,6 +1140,42 @@ func TestTopicMissingBody(t *testing.T) {
 	}
 }
 
+func TestTopicNonMember(t *testing.T) {
+	tserver := newTestServer(t)
+	aliceToken := tserver.createSession("alice_topic")
+	bobToken := tserver.createSession("bob_topic")
+
+	// Only alice joins the channel.
+	tserver.sendCommand(aliceToken, map[string]any{
+		commandKey: joinCmd, toKey: "#topicpriv",
+	})
+
+	// Drain bob's initial messages.
+	_, lastID := tserver.pollMessages(bobToken, 0)
+
+	// Bob tries to set topic without joining.
+	status, _ := tserver.sendCommand(
+		bobToken,
+		map[string]any{
+			commandKey: "TOPIC",
+			toKey:      "#topicpriv",
+			bodyKey:    []string{"Hijacked topic"},
+		},
+	)
+	if status != http.StatusOK {
+		t.Fatalf("expected 200, got %d", status)
+	}
+
+	msgs, _ := tserver.pollMessages(bobToken, lastID)
+
+	if !findNumeric(msgs, "442") {
+		t.Fatalf(
+			"expected ERR_NOTONCHANNEL (442), got %v",
+			msgs,
+		)
+	}
+}
+
 func TestPing(t *testing.T) {
 	tserver := newTestServer(t)
 	token := tserver.createSession("ping_user")
@@ -1657,6 +1699,133 @@ func TestHealthcheck(t *testing.T) {
 	}
 }
 
+func TestHealthcheckRuntimeStatsFields(t *testing.T) {
+	tserver := newTestServer(t)
+
+	resp, err := doRequest(
+		t,
+		http.MethodGet,
+		tserver.url("/.well-known/healthcheck.json"),
+		nil,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf(
+			"expected 200, got %d", resp.StatusCode,
+		)
+	}
+
+	var result map[string]any
+
+	decErr := json.NewDecoder(resp.Body).Decode(&result)
+	if decErr != nil {
+		t.Fatalf("decode healthcheck: %v", decErr)
+	}
+
+	requiredFields := []string{
+		"sessions", "clients", "queuedLines",
+		"channels", "connectionsSinceBoot",
+		"sessionsSinceBoot", "messagesSinceBoot",
+	}
+
+	for _, field := range requiredFields {
+		if _, ok := result[field]; !ok {
+			t.Errorf(
+				"missing field %q in healthcheck", field,
+			)
+		}
+	}
+}
+
+func TestHealthcheckRuntimeStatsValues(t *testing.T) {
+	tserver := newTestServer(t)
+
+	token := tserver.createSession("statsuser")
+
+	tserver.sendCommand(token, map[string]any{
+		commandKey: joinCmd, toKey: "#statschan",
+	})
+	tserver.sendCommand(token, map[string]any{
+		commandKey: privmsgCmd,
+		toKey:      "#statschan",
+		bodyKey:    []string{"hello stats"},
+	})
+
+	result := tserver.fetchHealthcheck(t)
+
+	assertFieldGTE(t, result, "sessions", 1)
+	assertFieldGTE(t, result, "clients", 1)
+	assertFieldGTE(t, result, "channels", 1)
+	assertFieldGTE(t, result, "queuedLines", 0)
+	assertFieldGTE(t, result, "sessionsSinceBoot", 1)
+	assertFieldGTE(t, result, "connectionsSinceBoot", 1)
+	assertFieldGTE(t, result, "messagesSinceBoot", 1)
+}
+
+func (tserver *testServer) fetchHealthcheck(
+	t *testing.T,
+) map[string]any {
+	t.Helper()
+
+	resp, err := doRequest(
+		t,
+		http.MethodGet,
+		tserver.url("/.well-known/healthcheck.json"),
+		nil,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf(
+			"expected 200, got %d", resp.StatusCode,
+		)
+	}
+
+	var result map[string]any
+
+	decErr := json.NewDecoder(resp.Body).Decode(&result)
+	if decErr != nil {
+		t.Fatalf("decode healthcheck: %v", decErr)
+	}
+
+	return result
+}
+
+func assertFieldGTE(
+	t *testing.T,
+	result map[string]any,
+	field string,
+	minimum float64,
+) {
+	t.Helper()
+
+	val, ok := result[field].(float64)
+	if !ok {
+		t.Errorf(
+			"field %q: not a number (got %T)",
+			field, result[field],
+		)
+
+		return
+	}
+
+	if val < minimum {
+		t.Errorf(
+			"expected %s >= %v, got %v",
+			field, minimum, val,
+		)
+	}
+}
+
 func TestRegisterValid(t *testing.T) {
 	tserver := newTestServer(t)
 
@@ -1961,6 +2130,121 @@ func TestSessionStillWorks(t *testing.T) {
 	}
 }
 
+func TestLoginRateLimitExceeded(t *testing.T) {
+	tserver := newTestServer(t)
+
+	// Exhaust the burst (default: 5 per IP) using
+	// nonexistent users. These fail fast (no bcrypt),
+	// preventing token replenishment between requests.
+	for range 5 {
+		loginBody, mErr := json.Marshal(
+			map[string]string{
+				"nick":     "nosuchuser",
+				"password": "doesnotmatter",
+			},
+		)
+		if mErr != nil {
+			t.Fatal(mErr)
+		}
+
+		loginResp, rErr := doRequest(
+			t,
+			http.MethodPost,
+			tserver.url("/api/v1/login"),
+			bytes.NewReader(loginBody),
+		)
+		if rErr != nil {
+			t.Fatal(rErr)
+		}
+
+		_ = loginResp.Body.Close()
+	}
+
+	// The next request should be rate-limited.
+	loginBody, err := json.Marshal(map[string]string{
+		"nick": "nosuchuser", "password": "doesnotmatter",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resp, err := doRequest(
+		t,
+		http.MethodPost,
+		tserver.url("/api/v1/login"),
+		bytes.NewReader(loginBody),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusTooManyRequests {
+		t.Fatalf(
+			"expected 429, got %d",
+			resp.StatusCode,
+		)
+	}
+
+	retryAfter := resp.Header.Get("Retry-After")
+	if retryAfter == "" {
+		t.Fatal("expected Retry-After header")
+	}
+}
+
+func TestLoginRateLimitAllowsNormalUse(t *testing.T) {
+	tserver := newTestServer(t)
+
+	// Register a user.
+	regBody, err := json.Marshal(map[string]string{
+		"nick": "normaluser", "password": "password123",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resp, err := doRequest(
+		t,
+		http.MethodPost,
+		tserver.url("/api/v1/register"),
+		bytes.NewReader(regBody),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_ = resp.Body.Close()
+
+	// A single login should succeed without rate limiting.
+	loginBody, err := json.Marshal(map[string]string{
+		"nick": "normaluser", "password": "password123",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resp2, err := doRequest(
+		t,
+		http.MethodPost,
+		tserver.url("/api/v1/login"),
+		bytes.NewReader(loginBody),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() { _ = resp2.Body.Close() }()
+
+	if resp2.StatusCode != http.StatusOK {
+		respBody, _ := io.ReadAll(resp2.Body)
+		t.Fatalf(
+			"expected 200, got %d: %s",
+			resp2.StatusCode, respBody,
+		)
+	}
+}
+
 func TestNickBroadcastToChannels(t *testing.T) {
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("nick_a")

internal/handlers/auth.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"net"
 	"net/http"
 	"strings"
 
@@ -10,6 +11,33 @@ import (
 
 const minPasswordLength = 8
 
+// clientIP extracts the client IP address from the request.
+// It checks X-Forwarded-For and X-Real-IP headers before
+// falling back to RemoteAddr.
+func clientIP(request *http.Request) string {
+	if forwarded := request.Header.Get("X-Forwarded-For"); forwarded != "" {
+		// X-Forwarded-For may contain a comma-separated list;
+		// the first entry is the original client.
+		parts := strings.SplitN(forwarded, ",", 2) //nolint:mnd // split into two parts
+		ip := strings.TrimSpace(parts[0])
+
+		if ip != "" {
+			return ip
+		}
+	}
+
+	if realIP := request.Header.Get("X-Real-IP"); realIP != "" {
+		return strings.TrimSpace(realIP)
+	}
+
+	host, _, err := net.SplitHostPort(request.RemoteAddr)
+	if err != nil {
+		return request.RemoteAddr
+	}
+
+	return host
+}
+
 // HandleRegister creates a new user with a password.
 func (hdlr *Handlers) HandleRegister() http.HandlerFunc {
 	return func(
@@ -82,6 +110,9 @@ func (hdlr *Handlers) handleRegister(
 		return
 	}
 
+	hdlr.stats.IncrSessions()
+	hdlr.stats.IncrConnections()
+
 	hdlr.deliverMOTD(request, clientID, sessionID, payload.Nick)
 
 	hdlr.respondJSON(writer, request, map[string]any{
@@ -134,6 +165,21 @@ func (hdlr *Handlers) handleLogin(
 	writer http.ResponseWriter,
 	request *http.Request,
 ) {
+	ip := clientIP(request)
+
+	if !hdlr.loginLimiter.Allow(ip) {
+		writer.Header().Set(
+			"Retry-After", "1",
+		)
+		hdlr.respondError(
+			writer, request,
+			"too many login attempts, try again later",
+			http.StatusTooManyRequests,
+		)
+
+		return
+	}
+
 	type loginRequest struct {
 		Nick     string `json:"nick"`
 		Password string `json:"password"`
@@ -180,6 +226,8 @@ func (hdlr *Handlers) handleLogin(
 		return
 	}
 
+	hdlr.stats.IncrConnections()
+
 	hdlr.deliverMOTD(
 		request, clientID, sessionID, payload.Nick,
 	)

internal/handlers/handlers.go

@@ -16,6 +16,8 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/hashcash"
 	"git.eeqj.de/sneak/neoirc/internal/healthcheck"
 	"git.eeqj.de/sneak/neoirc/internal/logger"
+	"git.eeqj.de/sneak/neoirc/internal/ratelimit"
+	"git.eeqj.de/sneak/neoirc/internal/stats"
 	"go.uber.org/fx"
 )
 
@@ -30,6 +32,7 @@ type Params struct {
 	Config      *config.Config
 	Database    *db.Database
 	Healthcheck *healthcheck.Healthcheck
+	Stats       *stats.Tracker
 }
 
 const defaultIdleTimeout = 30 * 24 * time.Hour
@@ -41,6 +44,8 @@ type Handlers struct {
 	hc            *healthcheck.Healthcheck
 	broker        *broker.Broker
 	hashcashVal   *hashcash.Validator
+	loginLimiter  *ratelimit.Limiter
+	stats         *stats.Tracker
 	cancelCleanup context.CancelFunc
 }
 
@@ -54,12 +59,24 @@ func New(
 		resource = "neoirc"
 	}
 
+	loginRate := params.Config.LoginRateLimit
+	if loginRate <= 0 {
+		loginRate = ratelimit.DefaultRate
+	}
+
+	loginBurst := params.Config.LoginRateBurst
+	if loginBurst <= 0 {
+		loginBurst = ratelimit.DefaultBurst
+	}
+
 	hdlr := &Handlers{ //nolint:exhaustruct // cancelCleanup set in startCleanup
 		params:       &params,
 		log:          params.Logger.Get(),
 		hc:           params.Healthcheck,
 		broker:       broker.New(),
 		hashcashVal:  hashcash.NewValidator(resource),
+		loginLimiter: ratelimit.New(loginRate, loginBurst),
+		stats:        params.Stats,
 	}
 
 	lifecycle.Append(fx.Hook{
@@ -151,6 +168,10 @@ func (hdlr *Handlers) stopCleanup() {
 	if hdlr.cancelCleanup != nil {
 		hdlr.cancelCleanup()
 	}
+
+	if hdlr.loginLimiter != nil {
+		hdlr.loginLimiter.Stop()
+	}
 }
 
 func (hdlr *Handlers) cleanupLoop(ctx context.Context) {

internal/handlers/healthcheck.go

@@ -12,7 +12,7 @@ func (hdlr *Handlers) HandleHealthCheck() http.HandlerFunc {
 		writer http.ResponseWriter,
 		request *http.Request,
 	) {
-		resp := hdlr.hc.Healthcheck()
+		resp := hdlr.hc.Healthcheck(request.Context())
 		hdlr.respondJSON(writer, request, resp, httpStatusOK)
 	}
 }

internal/hashcash/hashcash_test.go

@@ -0,0 +1,261 @@
+package hashcash_test
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"testing"
+	"time"
+
+	"git.eeqj.de/sneak/neoirc/internal/hashcash"
+)
+
+const testBits = 2
+
+// mintStampWithDate creates a valid hashcash stamp using
+// the given date string.
+func mintStampWithDate(
+	tb testing.TB,
+	bits int,
+	resource string,
+	date string,
+) string {
+	tb.Helper()
+
+	prefix := fmt.Sprintf(
+		"1:%d:%s:%s::", bits, date, resource,
+	)
+
+	for {
+		counterVal, err := rand.Int(
+			rand.Reader, big.NewInt(1<<48),
+		)
+		if err != nil {
+			tb.Fatalf("random counter: %v", err)
+		}
+
+		stamp := prefix + hex.EncodeToString(
+			counterVal.Bytes(),
+		)
+		hash := sha256.Sum256([]byte(stamp))
+
+		if hasLeadingZeroBits(hash[:], bits) {
+			return stamp
+		}
+	}
+}
+
+// hasLeadingZeroBits checks if hash has at least numBits
+// leading zero bits. Duplicated here for test minting.
+func hasLeadingZeroBits(
+	hash []byte,
+	numBits int,
+) bool {
+	fullBytes := numBits / 8
+	remainBits := numBits % 8
+
+	for idx := range fullBytes {
+		if hash[idx] != 0 {
+			return false
+		}
+	}
+
+	if remainBits > 0 && fullBytes < len(hash) {
+		mask := byte(0xFF << (8 - remainBits))
+
+		if hash[fullBytes]&mask != 0 {
+			return false
+		}
+	}
+
+	return true
+}
+
+func todayDate() string {
+	return time.Now().UTC().Format("060102")
+}
+
+func TestMintAndValidate(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", todayDate(),
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err != nil {
+		t.Fatalf("valid stamp rejected: %v", err)
+	}
+}
+
+func TestReplayDetection(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", todayDate(),
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err != nil {
+		t.Fatalf("first use failed: %v", err)
+	}
+
+	err = validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("replay not detected")
+	}
+}
+
+func TestResourceMismatch(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("correct-resource")
+	stamp := mintStampWithDate(
+		t, testBits, "wrong-resource", todayDate(),
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("expected resource mismatch error")
+	}
+}
+
+func TestInvalidStampFormat(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+
+	err := validator.Validate(
+		"not:a:valid:stamp", testBits,
+	)
+	if err == nil {
+		t.Fatal("expected error for bad format")
+	}
+}
+
+func TestBadVersion(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := fmt.Sprintf(
+		"2:%d:%s:%s::abc123",
+		testBits, todayDate(), "test-resource",
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("expected bad version error")
+	}
+}
+
+func TestInsufficientDifficulty(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	// Claimed bits=1, but we require testBits=2.
+	stamp := fmt.Sprintf(
+		"1:1:%s:%s::counter",
+		todayDate(), "test-resource",
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("expected insufficient bits error")
+	}
+}
+
+func TestExpiredStamp(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	oldDate := time.Now().Add(-72 * time.Hour).
+		UTC().Format("060102")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", oldDate,
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("expected expired stamp error")
+	}
+}
+
+func TestZeroBitsSkipsValidation(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+
+	err := validator.Validate("garbage", 0)
+	if err != nil {
+		t.Fatalf("zero bits should skip: %v", err)
+	}
+}
+
+func TestLongDateFormat(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	longDate := time.Now().UTC().Format("060102150405")
+	stamp := mintStampWithDate(
+		t, testBits, "test-resource", longDate,
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err != nil {
+		t.Fatalf("long date stamp rejected: %v", err)
+	}
+}
+
+func TestBadDateFormat(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+	stamp := fmt.Sprintf(
+		"1:%d:BADDATE:%s::counter",
+		testBits, "test-resource",
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err == nil {
+		t.Fatal("expected bad date error")
+	}
+}
+
+func TestMultipleUniqueStamps(t *testing.T) {
+	t.Parallel()
+
+	validator := hashcash.NewValidator("test-resource")
+
+	for range 5 {
+		stamp := mintStampWithDate(
+			t, testBits, "test-resource", todayDate(),
+		)
+
+		err := validator.Validate(stamp, testBits)
+		if err != nil {
+			t.Fatalf("unique stamp rejected: %v", err)
+		}
+	}
+}
+
+func TestHigherBitsStillValid(t *testing.T) {
+	t.Parallel()
+
+	// Mint with bits=4 but validate requiring only 2.
+	validator := hashcash.NewValidator("test-resource")
+	stamp := mintStampWithDate(
+		t, 4, "test-resource", todayDate(),
+	)
+
+	err := validator.Validate(stamp, testBits)
+	if err != nil {
+		t.Fatalf(
+			"higher-difficulty stamp rejected: %v",
+			err,
+		)
+	}
+}

internal/healthcheck/healthcheck.go

@@ -10,6 +10,7 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/db"
 	"git.eeqj.de/sneak/neoirc/internal/globals"
 	"git.eeqj.de/sneak/neoirc/internal/logger"
+	"git.eeqj.de/sneak/neoirc/internal/stats"
 	"go.uber.org/fx"
 )
 
@@ -21,6 +22,7 @@ type Params struct {
 	Config   *config.Config
 	Logger   *logger.Logger
 	Database *db.Database
+	Stats    *stats.Tracker
 }
 
 // Healthcheck tracks server uptime and provides health status.
@@ -64,11 +66,22 @@ type Response struct {
 	Version       string `json:"version"`
 	Appname       string `json:"appname"`
 	Maintenance   bool   `json:"maintenanceMode"`
+
+	// Runtime statistics.
+	Sessions             int64 `json:"sessions"`
+	Clients              int64 `json:"clients"`
+	QueuedLines          int64 `json:"queuedLines"`
+	Channels             int64 `json:"channels"`
+	ConnectionsSinceBoot int64 `json:"connectionsSinceBoot"`
+	SessionsSinceBoot    int64 `json:"sessionsSinceBoot"`
+	MessagesSinceBoot    int64 `json:"messagesSinceBoot"`
 }
 
 // Healthcheck returns the current health status of the server.
-func (hcheck *Healthcheck) Healthcheck() *Response {
-	return &Response{
+func (hcheck *Healthcheck) Healthcheck(
+	ctx context.Context,
+) *Response {
+	resp := &Response{
 		Status:        "ok",
 		Now:           time.Now().UTC().Format(time.RFC3339Nano),
 		UptimeSeconds: int64(hcheck.uptime().Seconds()),
@@ -76,6 +89,64 @@ func (hcheck *Healthcheck) Healthcheck() *Response {
 		Appname:       hcheck.params.Globals.Appname,
 		Version:       hcheck.params.Globals.Version,
 		Maintenance:   hcheck.params.Config.MaintenanceMode,
+
+		Sessions:             0,
+		Clients:              0,
+		QueuedLines:          0,
+		Channels:             0,
+		ConnectionsSinceBoot: hcheck.params.Stats.ConnectionsSinceBoot(),
+		SessionsSinceBoot:    hcheck.params.Stats.SessionsSinceBoot(),
+		MessagesSinceBoot:    hcheck.params.Stats.MessagesSinceBoot(),
+	}
+
+	hcheck.populateDBStats(ctx, resp)
+
+	return resp
+}
+
+// populateDBStats fills in database-derived counters.
+func (hcheck *Healthcheck) populateDBStats(
+	ctx context.Context,
+	resp *Response,
+) {
+	sessions, err := hcheck.params.Database.GetUserCount(ctx)
+	if err != nil {
+		hcheck.log.Error(
+			"healthcheck: session count failed",
+			"error", err,
+		)
+	} else {
+		resp.Sessions = sessions
+	}
+
+	clients, err := hcheck.params.Database.GetClientCount(ctx)
+	if err != nil {
+		hcheck.log.Error(
+			"healthcheck: client count failed",
+			"error", err,
+		)
+	} else {
+		resp.Clients = clients
+	}
+
+	queued, err := hcheck.params.Database.GetQueueEntryCount(ctx)
+	if err != nil {
+		hcheck.log.Error(
+			"healthcheck: queue entry count failed",
+			"error", err,
+		)
+	} else {
+		resp.QueuedLines = queued
+	}
+
+	channels, err := hcheck.params.Database.GetChannelCount(ctx)
+	if err != nil {
+		hcheck.log.Error(
+			"healthcheck: channel count failed",
+			"error", err,
+		)
+	} else {
+		resp.Channels = channels
 	}
 }
 

internal/irc/numerics.go

@@ -1,150 +0,0 @@
-// Package irc provides constants and utilities for the
-// IRC protocol, including numeric reply codes from
-// RFC 1459 and RFC 2812, and standard command names.
-package irc
-
-// Connection registration replies (001-005).
-const (
-	RplWelcome  = 1
-	RplYourHost = 2
-	RplCreated  = 3
-	RplMyInfo   = 4
-	RplIsupport = 5
-)
-
-// Command responses (200-399).
-const (
-	RplUmodeIs       = 221
-	RplLuserClient   = 251
-	RplLuserOp       = 252
-	RplLuserUnknown  = 253
-	RplLuserChannels = 254
-	RplLuserMe       = 255
-	RplAway          = 301
-	RplUserHost      = 302
-	RplIson          = 303
-	RplUnaway        = 305
-	RplNowAway       = 306
-	RplWhoisUser     = 311
-	RplWhoisServer   = 312
-	RplWhoisOperator = 313
-	RplEndOfWho      = 315
-	RplWhoisIdle     = 317
-	RplEndOfWhois    = 318
-	RplWhoisChannels = 319
-	RplList          = 322
-	RplListEnd       = 323
-	RplChannelModeIs = 324
-	RplCreationTime  = 329
-	RplNoTopic       = 331
-	RplTopic         = 332
-	RplTopicWhoTime  = 333
-	RplInviting      = 341
-	RplWhoReply      = 352
-	RplNamReply      = 353
-	RplEndOfNames    = 366
-	RplBanList       = 367
-	RplEndOfBanList  = 368
-	RplMotd          = 372
-	RplMotdStart     = 375
-	RplEndOfMotd     = 376
-)
-
-// Error replies (400-599).
-const (
-	ErrNoSuchNick        = 401
-	ErrNoSuchServer      = 402
-	ErrNoSuchChannel     = 403
-	ErrCannotSendToChan  = 404
-	ErrTooManyChannels   = 405
-	ErrNoRecipient       = 411
-	ErrNoTextToSend      = 412
-	ErrUnknownCommand    = 421
-	ErrNoNicknameGiven   = 431
-	ErrErroneusNickname  = 432
-	ErrNicknameInUse     = 433
-	ErrUserNotInChannel  = 441
-	ErrNotOnChannel      = 442
-	ErrNotRegistered     = 451
-	ErrNeedMoreParams    = 461
-	ErrAlreadyRegistered = 462
-	ErrChannelIsFull     = 471
-	ErrInviteOnlyChan    = 473
-	ErrBannedFromChan    = 474
-	ErrBadChannelKey     = 475
-	ErrChanOpPrivsNeeded = 482
-)
-
-// names maps numeric codes to their standard IRC names.
-//
-//nolint:gochecknoglobals
-var names = map[int]string{
-	RplWelcome:       "RPL_WELCOME",
-	RplYourHost:      "RPL_YOURHOST",
-	RplCreated:       "RPL_CREATED",
-	RplMyInfo:        "RPL_MYINFO",
-	RplIsupport:      "RPL_ISUPPORT",
-	RplUmodeIs:       "RPL_UMODEIS",
-	RplLuserClient:   "RPL_LUSERCLIENT",
-	RplLuserOp:       "RPL_LUSEROP",
-	RplLuserUnknown:  "RPL_LUSERUNKNOWN",
-	RplLuserChannels: "RPL_LUSERCHANNELS",
-	RplLuserMe:       "RPL_LUSERME",
-	RplAway:          "RPL_AWAY",
-	RplUserHost:      "RPL_USERHOST",
-	RplIson:          "RPL_ISON",
-	RplUnaway:        "RPL_UNAWAY",
-	RplNowAway:       "RPL_NOWAWAY",
-	RplWhoisUser:     "RPL_WHOISUSER",
-	RplWhoisServer:   "RPL_WHOISSERVER",
-	RplWhoisOperator: "RPL_WHOISOPERATOR",
-	RplEndOfWho:      "RPL_ENDOFWHO",
-	RplWhoisIdle:     "RPL_WHOISIDLE",
-	RplEndOfWhois:    "RPL_ENDOFWHOIS",
-	RplWhoisChannels: "RPL_WHOISCHANNELS",
-	RplList:          "RPL_LIST",
-	RplListEnd:       "RPL_LISTEND", //nolint:misspell
-	RplChannelModeIs: "RPL_CHANNELMODEIS",
-	RplCreationTime:  "RPL_CREATIONTIME",
-	RplNoTopic:       "RPL_NOTOPIC",
-	RplTopic:         "RPL_TOPIC",
-	RplTopicWhoTime:  "RPL_TOPICWHOTIME",
-	RplInviting:      "RPL_INVITING",
-	RplWhoReply:      "RPL_WHOREPLY",
-	RplNamReply:      "RPL_NAMREPLY",
-	RplEndOfNames:    "RPL_ENDOFNAMES",
-	RplBanList:       "RPL_BANLIST",
-	RplEndOfBanList:  "RPL_ENDOFBANLIST",
-	RplMotd:          "RPL_MOTD",
-	RplMotdStart:     "RPL_MOTDSTART",
-	RplEndOfMotd:     "RPL_ENDOFMOTD",
-
-	ErrNoSuchNick:        "ERR_NOSUCHNICK",
-	ErrNoSuchServer:      "ERR_NOSUCHSERVER",
-	ErrNoSuchChannel:     "ERR_NOSUCHCHANNEL",
-	ErrCannotSendToChan:  "ERR_CANNOTSENDTOCHAN",
-	ErrTooManyChannels:   "ERR_TOOMANYCHANNELS",
-	ErrNoRecipient:       "ERR_NORECIPIENT",
-	ErrNoTextToSend:      "ERR_NOTEXTTOSEND",
-	ErrUnknownCommand:    "ERR_UNKNOWNCOMMAND",
-	ErrNoNicknameGiven:   "ERR_NONICKNAMEGIVEN",
-	ErrErroneusNickname:  "ERR_ERRONEUSNICKNAME",
-	ErrNicknameInUse:     "ERR_NICKNAMEINUSE",
-	ErrUserNotInChannel:  "ERR_USERNOTINCHANNEL",
-	ErrNotOnChannel:      "ERR_NOTONCHANNEL",
-	ErrNotRegistered:     "ERR_NOTREGISTERED",
-	ErrNeedMoreParams:    "ERR_NEEDMOREPARAMS",
-	ErrAlreadyRegistered: "ERR_ALREADYREGISTERED",
-	ErrChannelIsFull:     "ERR_CHANNELISFULL",
-	ErrInviteOnlyChan:    "ERR_INVITEONLYCHAN",
-	ErrBannedFromChan:    "ERR_BANNEDFROMCHAN",
-	ErrBadChannelKey:     "ERR_BADCHANNELKEY",
-	ErrChanOpPrivsNeeded: "ERR_CHANOPRIVSNEEDED",
-}
-
-// Name returns the standard IRC name for a numeric code
-// (e.g., Name(2) returns "RPL_YOURHOST"). Returns an
-// empty string if the code is unknown.
-func Name(code int) string {
-	return names[code]
-}

internal/middleware/middleware.go

@@ -11,7 +11,7 @@ import (
 	"git.eeqj.de/sneak/neoirc/internal/globals"
 	"git.eeqj.de/sneak/neoirc/internal/logger"
 	basicauth "github.com/99designs/basicauth-go"
-	chimw "github.com/go-chi/chi/middleware"
+	chimw "github.com/go-chi/chi/v5/middleware"
 	"github.com/go-chi/cors"
 	metrics "github.com/slok/go-http-metrics/metrics/prometheus"
 	ghmm "github.com/slok/go-http-metrics/middleware"

internal/ratelimit/ratelimit.go

@@ -0,0 +1,122 @@
+// Package ratelimit provides per-IP rate limiting for HTTP endpoints.
+package ratelimit
+
+import (
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+)
+
+const (
+	// DefaultRate is the default number of allowed requests per second.
+	DefaultRate = 1.0
+
+	// DefaultBurst is the default maximum burst size.
+	DefaultBurst = 5
+
+	// DefaultSweepInterval controls how often stale entries are pruned.
+	DefaultSweepInterval = 10 * time.Minute
+
+	// DefaultEntryTTL is how long an unused entry lives before eviction.
+	DefaultEntryTTL = 15 * time.Minute
+)
+
+// entry tracks a per-IP rate limiter and when it was last used.
+type entry struct {
+	limiter  *rate.Limiter
+	lastSeen time.Time
+}
+
+// Limiter manages per-key rate limiters with automatic cleanup
+// of stale entries.
+type Limiter struct {
+	mu       sync.Mutex
+	entries  map[string]*entry
+	rate     rate.Limit
+	burst    int
+	entryTTL time.Duration
+	stopCh   chan struct{}
+}
+
+// New creates a new per-key rate Limiter.
+// The ratePerSec parameter sets how many requests per second are
+// allowed per key.  The burst parameter sets the maximum number of
+// requests that can be made in a single burst.
+func New(ratePerSec float64, burst int) *Limiter {
+	limiter := &Limiter{
+		mu:       sync.Mutex{},
+		entries:  make(map[string]*entry),
+		rate:     rate.Limit(ratePerSec),
+		burst:    burst,
+		entryTTL: DefaultEntryTTL,
+		stopCh:   make(chan struct{}),
+	}
+
+	go limiter.sweepLoop()
+
+	return limiter
+}
+
+// Allow reports whether a request from the given key should be
+// allowed.  It consumes one token from the key's rate limiter.
+func (l *Limiter) Allow(key string) bool {
+	l.mu.Lock()
+	ent, exists := l.entries[key]
+
+	if !exists {
+		ent = &entry{
+			limiter:  rate.NewLimiter(l.rate, l.burst),
+			lastSeen: time.Now(),
+		}
+		l.entries[key] = ent
+	} else {
+		ent.lastSeen = time.Now()
+	}
+	l.mu.Unlock()
+
+	return ent.limiter.Allow()
+}
+
+// Stop terminates the background sweep goroutine.
+func (l *Limiter) Stop() {
+	close(l.stopCh)
+}
+
+// Len returns the number of tracked keys (for testing).
+func (l *Limiter) Len() int {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	return len(l.entries)
+}
+
+// sweepLoop periodically removes entries that haven't been seen
+// within the TTL.
+func (l *Limiter) sweepLoop() {
+	ticker := time.NewTicker(DefaultSweepInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			l.sweep()
+		case <-l.stopCh:
+			return
+		}
+	}
+}
+
+// sweep removes stale entries.
+func (l *Limiter) sweep() {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	cutoff := time.Now().Add(-l.entryTTL)
+
+	for key, ent := range l.entries {
+		if ent.lastSeen.Before(cutoff) {
+			delete(l.entries, key)
+		}
+	}
+}

internal/ratelimit/ratelimit_test.go

@@ -0,0 +1,106 @@
+package ratelimit_test
+
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/neoirc/internal/ratelimit"
+)
+
+func TestNewCreatesLimiter(t *testing.T) {
+	t.Parallel()
+
+	limiter := ratelimit.New(1.0, 5)
+	defer limiter.Stop()
+
+	if limiter == nil {
+		t.Fatal("expected non-nil limiter")
+	}
+}
+
+func TestAllowWithinBurst(t *testing.T) {
+	t.Parallel()
+
+	limiter := ratelimit.New(1.0, 3)
+	defer limiter.Stop()
+
+	for i := range 3 {
+		if !limiter.Allow("192.168.1.1") {
+			t.Fatalf(
+				"request %d should be allowed within burst",
+				i+1,
+			)
+		}
+	}
+}
+
+func TestAllowExceedsBurst(t *testing.T) {
+	t.Parallel()
+
+	// Rate of 0 means no token replenishment, only burst.
+	limiter := ratelimit.New(0, 3)
+	defer limiter.Stop()
+
+	for range 3 {
+		limiter.Allow("10.0.0.1")
+	}
+
+	if limiter.Allow("10.0.0.1") {
+		t.Fatal("fourth request should be denied after burst exhausted")
+	}
+}
+
+func TestAllowSeparateKeys(t *testing.T) {
+	t.Parallel()
+
+	// Rate of 0, burst of 1 — only one request per key.
+	limiter := ratelimit.New(0, 1)
+	defer limiter.Stop()
+
+	if !limiter.Allow("10.0.0.1") {
+		t.Fatal("first request for key A should be allowed")
+	}
+
+	if !limiter.Allow("10.0.0.2") {
+		t.Fatal("first request for key B should be allowed")
+	}
+
+	if limiter.Allow("10.0.0.1") {
+		t.Fatal("second request for key A should be denied")
+	}
+
+	if limiter.Allow("10.0.0.2") {
+		t.Fatal("second request for key B should be denied")
+	}
+}
+
+func TestLenTracksKeys(t *testing.T) {
+	t.Parallel()
+
+	limiter := ratelimit.New(1.0, 5)
+	defer limiter.Stop()
+
+	if limiter.Len() != 0 {
+		t.Fatalf("expected 0 entries, got %d", limiter.Len())
+	}
+
+	limiter.Allow("10.0.0.1")
+	limiter.Allow("10.0.0.2")
+
+	if limiter.Len() != 2 {
+		t.Fatalf("expected 2 entries, got %d", limiter.Len())
+	}
+
+	// Same key again should not increase count.
+	limiter.Allow("10.0.0.1")
+
+	if limiter.Len() != 2 {
+		t.Fatalf("expected 2 entries, got %d", limiter.Len())
+	}
+}
+
+func TestStopDoesNotPanic(t *testing.T) {
+	t.Parallel()
+
+	limiter := ratelimit.New(1.0, 5)
+	limiter.Stop()
+}

internal/server/routes.go

@@ -8,8 +8,8 @@ import (
 	"git.eeqj.de/sneak/neoirc/web"
 
 	sentryhttp "github.com/getsentry/sentry-go/http"
-	"github.com/go-chi/chi"
-	"github.com/go-chi/chi/middleware"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/spf13/viper"
 )

internal/server/server.go

@@ -20,7 +20,7 @@ import (
 	"go.uber.org/fx"
 
 	"github.com/getsentry/sentry-go"
-	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/v5"
 
 	_ "github.com/joho/godotenv/autoload" // loads .env file
 )

internal/stats/stats.go

@@ -0,0 +1,52 @@
+// Package stats tracks runtime statistics since server boot.
+package stats
+
+import (
+	"sync/atomic"
+)
+
+// Tracker holds atomic counters for runtime statistics
+// that accumulate since the server started.
+type Tracker struct {
+	connectionsSinceBoot atomic.Int64
+	sessionsSinceBoot    atomic.Int64
+	messagesSinceBoot    atomic.Int64
+}
+
+// New creates a new Tracker with all counters at zero.
+func New() *Tracker {
+	return &Tracker{} //nolint:exhaustruct // atomic fields have zero-value defaults
+}
+
+// IncrConnections increments the total connection count.
+func (t *Tracker) IncrConnections() {
+	t.connectionsSinceBoot.Add(1)
+}
+
+// IncrSessions increments the total session count.
+func (t *Tracker) IncrSessions() {
+	t.sessionsSinceBoot.Add(1)
+}
+
+// IncrMessages increments the total PRIVMSG/NOTICE count.
+func (t *Tracker) IncrMessages() {
+	t.messagesSinceBoot.Add(1)
+}
+
+// ConnectionsSinceBoot returns the total number of
+// client connections since boot.
+func (t *Tracker) ConnectionsSinceBoot() int64 {
+	return t.connectionsSinceBoot.Load()
+}
+
+// SessionsSinceBoot returns the total number of sessions
+// created since boot.
+func (t *Tracker) SessionsSinceBoot() int64 {
+	return t.sessionsSinceBoot.Load()
+}
+
+// MessagesSinceBoot returns the total number of
+// PRIVMSG/NOTICE messages sent since boot.
+func (t *Tracker) MessagesSinceBoot() int64 {
+	return t.messagesSinceBoot.Load()
+}

internal/stats/stats_test.go

@@ -0,0 +1,117 @@
+package stats_test
+
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/neoirc/internal/stats"
+)
+
+func TestNew(t *testing.T) {
+	t.Parallel()
+
+	tracker := stats.New()
+	if tracker == nil {
+		t.Fatal("expected non-nil tracker")
+	}
+
+	if tracker.ConnectionsSinceBoot() != 0 {
+		t.Errorf(
+			"expected 0 connections, got %d",
+			tracker.ConnectionsSinceBoot(),
+		)
+	}
+
+	if tracker.SessionsSinceBoot() != 0 {
+		t.Errorf(
+			"expected 0 sessions, got %d",
+			tracker.SessionsSinceBoot(),
+		)
+	}
+
+	if tracker.MessagesSinceBoot() != 0 {
+		t.Errorf(
+			"expected 0 messages, got %d",
+			tracker.MessagesSinceBoot(),
+		)
+	}
+}
+
+func TestIncrConnections(t *testing.T) {
+	t.Parallel()
+
+	tracker := stats.New()
+
+	tracker.IncrConnections()
+	tracker.IncrConnections()
+	tracker.IncrConnections()
+
+	got := tracker.ConnectionsSinceBoot()
+	if got != 3 {
+		t.Errorf(
+			"expected 3 connections, got %d", got,
+		)
+	}
+}
+
+func TestIncrSessions(t *testing.T) {
+	t.Parallel()
+
+	tracker := stats.New()
+
+	tracker.IncrSessions()
+	tracker.IncrSessions()
+
+	got := tracker.SessionsSinceBoot()
+	if got != 2 {
+		t.Errorf(
+			"expected 2 sessions, got %d", got,
+		)
+	}
+}
+
+func TestIncrMessages(t *testing.T) {
+	t.Parallel()
+
+	tracker := stats.New()
+
+	tracker.IncrMessages()
+
+	got := tracker.MessagesSinceBoot()
+	if got != 1 {
+		t.Errorf(
+			"expected 1 message, got %d", got,
+		)
+	}
+}
+
+func TestCountersAreIndependent(t *testing.T) {
+	t.Parallel()
+
+	tracker := stats.New()
+
+	tracker.IncrConnections()
+	tracker.IncrSessions()
+	tracker.IncrMessages()
+	tracker.IncrMessages()
+
+	if tracker.ConnectionsSinceBoot() != 1 {
+		t.Errorf(
+			"expected 1 connection, got %d",
+			tracker.ConnectionsSinceBoot(),
+		)
+	}
+
+	if tracker.SessionsSinceBoot() != 1 {
+		t.Errorf(
+			"expected 1 session, got %d",
+			tracker.SessionsSinceBoot(),
+		)
+	}
+
+	if tracker.MessagesSinceBoot() != 2 {
+		t.Errorf(
+			"expected 2 messages, got %d",
+			tracker.MessagesSinceBoot(),
+		)
+	}
+}

pkg/irc/commands.go

@@ -2,6 +2,7 @@ package irc
 
 // IRC command names (RFC 1459 / RFC 2812).
 const (
+	CmdAway    = "AWAY"
 	CmdJoin    = "JOIN"
 	CmdList    = "LIST"
 	CmdLusers  = "LUSERS"

pkg/irc/numerics.go

@@ -0,0 +1,391 @@
+// Package irc provides constants and utilities for the
+// IRC protocol, including numeric reply codes from
+// RFC 1459 and RFC 2812, and standard command names.
+package irc
+
+import (
+	"errors"
+	"fmt"
+)
+
+// IRCMessageType represents an IRC numeric reply or error code.
+type IRCMessageType int //nolint:revive // Name requested by project owner.
+
+// Name returns the standard IRC name for this numeric code
+// (e.g., IRCMessageType(252).Name() returns "RPL_LUSEROP").
+// Returns an empty string if the code is unknown.
+func (t IRCMessageType) Name() string {
+	return names[t]
+}
+
+// String returns the name and numeric code in angle brackets
+// (e.g., IRCMessageType(252).String() returns "RPL_LUSEROP <252>").
+// If the code is unknown, returns "UNKNOWN <NNN>".
+func (t IRCMessageType) String() string {
+	n := names[t]
+	if n == "" {
+		n = "UNKNOWN"
+	}
+
+	return fmt.Sprintf("%s <%03d>", n, int(t))
+}
+
+// Code returns the three-digit zero-padded string representation
+// of the numeric code (e.g., IRCMessageType(252).Code() returns "252").
+func (t IRCMessageType) Code() string {
+	return fmt.Sprintf("%03d", int(t))
+}
+
+// Int returns the bare integer value of the numeric code.
+func (t IRCMessageType) Int() int {
+	return int(t)
+}
+
+// ErrUnknownNumeric is returned by FromInt when the numeric code is not recognized.
+var ErrUnknownNumeric = errors.New("unknown IRC numeric code")
+
+// FromInt converts an integer to an IRCMessageType, returning an error
+// if the numeric code is not a known IRC reply or error code.
+func FromInt(n int) (IRCMessageType, error) {
+	t := IRCMessageType(n)
+	if _, ok := names[t]; !ok {
+		return 0, fmt.Errorf("%w: %d", ErrUnknownNumeric, n)
+	}
+
+	return t, nil
+}
+
+// Connection registration replies (001-005).
+const (
+	RplWelcome  IRCMessageType = 1
+	RplYourHost IRCMessageType = 2
+	RplCreated  IRCMessageType = 3
+	RplMyInfo   IRCMessageType = 4
+	RplBounce   IRCMessageType = 5 // RFC 2812; also known as RPL_ISUPPORT in practice
+	RplIsupport IRCMessageType = 5 // De-facto standard (same numeric as RplBounce)
+)
+
+// Command responses (200-399).
+const (
+	// RFC 2812 trace/stats/links replies (200-219).
+	RplTraceLink       IRCMessageType = 200
+	RplTraceConnecting IRCMessageType = 201
+	RplTraceHandshake  IRCMessageType = 202
+	RplTraceUnknown    IRCMessageType = 203
+	RplTraceOperator   IRCMessageType = 204
+	RplTraceUser       IRCMessageType = 205
+	RplTraceServer     IRCMessageType = 206
+	RplTraceService    IRCMessageType = 207
+	RplTraceNewType    IRCMessageType = 208
+	RplTraceClass      IRCMessageType = 209
+	RplStatsLinkInfo   IRCMessageType = 211
+	RplStatsCommands   IRCMessageType = 212
+	RplStatsCLine      IRCMessageType = 213
+	RplStatsNLine      IRCMessageType = 214
+	RplStatsILine      IRCMessageType = 215
+	RplStatsKLine      IRCMessageType = 216
+	RplStatsQLine      IRCMessageType = 217
+	RplStatsYLine      IRCMessageType = 218
+	RplEndOfStats      IRCMessageType = 219
+
+	RplUmodeIs      IRCMessageType = 221
+	RplServList     IRCMessageType = 234
+	RplServListEnd  IRCMessageType = 235
+	RplStatsLLine   IRCMessageType = 241
+	RplStatsUptime  IRCMessageType = 242
+	RplStatsOLine   IRCMessageType = 243
+	RplStatsHLine   IRCMessageType = 244
+	RplLuserClient  IRCMessageType = 251
+	RplLuserOp      IRCMessageType = 252
+	RplLuserUnknown IRCMessageType = 253
+
+	RplLuserChannels IRCMessageType = 254
+	RplLuserMe       IRCMessageType = 255
+	RplAdminMe       IRCMessageType = 256
+	RplAdminLoc1     IRCMessageType = 257
+	RplAdminLoc2     IRCMessageType = 258
+	RplAdminEmail    IRCMessageType = 259
+	RplTraceLog      IRCMessageType = 261
+	RplTraceEnd      IRCMessageType = 262
+	RplTryAgain      IRCMessageType = 263
+
+	RplAway          IRCMessageType = 301
+	RplUserHost      IRCMessageType = 302
+	RplIson          IRCMessageType = 303
+	RplUnaway        IRCMessageType = 305
+	RplNowAway       IRCMessageType = 306
+	RplWhoisUser     IRCMessageType = 311
+	RplWhoisServer   IRCMessageType = 312
+	RplWhoisOperator IRCMessageType = 313
+	RplWhoWasUser    IRCMessageType = 314
+	RplEndOfWho      IRCMessageType = 315
+	RplWhoisIdle     IRCMessageType = 317
+	RplEndOfWhois    IRCMessageType = 318
+	RplWhoisChannels IRCMessageType = 319
+	RplListStart     IRCMessageType = 321
+	RplList          IRCMessageType = 322
+	RplListEnd       IRCMessageType = 323
+	RplChannelModeIs IRCMessageType = 324
+
+	RplUniqOpIs        IRCMessageType = 325
+	RplCreationTime    IRCMessageType = 329
+	RplNoTopic         IRCMessageType = 331
+	RplTopic           IRCMessageType = 332
+	RplTopicWhoTime    IRCMessageType = 333
+	RplInviting        IRCMessageType = 341
+	RplSummoning       IRCMessageType = 342
+	RplInviteList      IRCMessageType = 346
+	RplEndOfInviteList IRCMessageType = 347
+	RplExceptList      IRCMessageType = 348
+	RplEndOfExceptList IRCMessageType = 349
+	RplVersion         IRCMessageType = 351
+	RplWhoReply        IRCMessageType = 352
+	RplNamReply        IRCMessageType = 353
+	RplLinks           IRCMessageType = 364
+	RplEndOfLinks      IRCMessageType = 365
+	RplEndOfNames      IRCMessageType = 366
+	RplBanList         IRCMessageType = 367
+	RplEndOfBanList    IRCMessageType = 368
+	RplEndOfWhowas     IRCMessageType = 369
+	RplInfo            IRCMessageType = 371
+	RplMotd            IRCMessageType = 372
+	RplEndOfInfo       IRCMessageType = 374
+	RplMotdStart       IRCMessageType = 375
+	RplEndOfMotd       IRCMessageType = 376
+	RplYoureOper       IRCMessageType = 381
+	RplRehashing       IRCMessageType = 382
+	RplYoureService    IRCMessageType = 383
+	RplTime            IRCMessageType = 391
+	RplUsersStart      IRCMessageType = 392
+	RplUsers           IRCMessageType = 393
+	RplEndOfUsers      IRCMessageType = 394
+	RplNoUsers         IRCMessageType = 395
+)
+
+// Error replies (400-599).
+const (
+	ErrNoSuchNick       IRCMessageType = 401
+	ErrNoSuchServer     IRCMessageType = 402
+	ErrNoSuchChannel    IRCMessageType = 403
+	ErrCannotSendToChan IRCMessageType = 404
+	ErrTooManyChannels  IRCMessageType = 405
+	ErrWasNoSuchNick    IRCMessageType = 406
+	ErrTooManyTargets   IRCMessageType = 407
+	ErrNoSuchService    IRCMessageType = 408
+	ErrNoOrigin         IRCMessageType = 409
+	ErrNoRecipient      IRCMessageType = 411
+	ErrNoTextToSend     IRCMessageType = 412
+	ErrNoTopLevel       IRCMessageType = 413
+	ErrWildTopLevel     IRCMessageType = 414
+	ErrBadMask          IRCMessageType = 415
+	ErrUnknownCommand   IRCMessageType = 421
+	ErrNoMotd           IRCMessageType = 422
+	ErrNoAdminInfo      IRCMessageType = 423
+	ErrFileError        IRCMessageType = 424
+	ErrNoNicknameGiven  IRCMessageType = 431
+	ErrErroneusNickname IRCMessageType = 432
+	ErrNicknameInUse    IRCMessageType = 433
+	ErrNickCollision    IRCMessageType = 436
+	ErrUnavailResource  IRCMessageType = 437
+
+	ErrUserNotInChannel  IRCMessageType = 441
+	ErrNotOnChannel      IRCMessageType = 442
+	ErrUserOnChannel     IRCMessageType = 443
+	ErrNoLogin           IRCMessageType = 444
+	ErrSummonDisabled    IRCMessageType = 445
+	ErrUsersDisabled     IRCMessageType = 446
+	ErrNotRegistered     IRCMessageType = 451
+	ErrNeedMoreParams    IRCMessageType = 461
+	ErrAlreadyRegistered IRCMessageType = 462
+	ErrNoPermForHost     IRCMessageType = 463
+	ErrPasswdMismatch    IRCMessageType = 464
+	ErrYoureBannedCreep  IRCMessageType = 465
+	ErrYouWillBeBanned   IRCMessageType = 466
+	ErrKeySet            IRCMessageType = 467
+	ErrChannelIsFull     IRCMessageType = 471
+	ErrUnknownMode       IRCMessageType = 472
+	ErrInviteOnlyChan    IRCMessageType = 473
+	ErrBannedFromChan    IRCMessageType = 474
+	ErrBadChannelKey     IRCMessageType = 475
+	ErrBadChanMask       IRCMessageType = 476
+	ErrNoChanModes       IRCMessageType = 477
+	ErrBanListFull       IRCMessageType = 478
+	ErrNoPrivileges      IRCMessageType = 481
+	ErrChanOpPrivsNeeded IRCMessageType = 482
+	ErrCantKillServer    IRCMessageType = 483
+	ErrRestricted        IRCMessageType = 484
+	ErrUniqOpPrivsNeeded IRCMessageType = 485
+	ErrNoOperHost        IRCMessageType = 491
+
+	ErrUmodeUnknownFlag IRCMessageType = 501
+	ErrUsersDoNotMatch  IRCMessageType = 502
+)
+
+// names maps numeric codes to their standard IRC names.
+//
+//nolint:gochecknoglobals
+var names = map[IRCMessageType]string{
+	RplWelcome:  "RPL_WELCOME",
+	RplYourHost: "RPL_YOURHOST",
+	RplCreated:  "RPL_CREATED",
+	RplMyInfo:   "RPL_MYINFO",
+	RplBounce:   "RPL_BOUNCE",
+
+	RplTraceLink:       "RPL_TRACELINK",
+	RplTraceConnecting: "RPL_TRACECONNECTING",
+	RplTraceHandshake:  "RPL_TRACEHANDSHAKE",
+	RplTraceUnknown:    "RPL_TRACEUNKNOWN",
+	RplTraceOperator:   "RPL_TRACEOPERATOR",
+	RplTraceUser:       "RPL_TRACEUSER",
+	RplTraceServer:     "RPL_TRACESERVER",
+	RplTraceService:    "RPL_TRACESERVICE",
+	RplTraceNewType:    "RPL_TRACENEWTYPE",
+	RplTraceClass:      "RPL_TRACECLASS",
+	RplStatsLinkInfo:   "RPL_STATSLINKINFO",
+	RplStatsCommands:   "RPL_STATSCOMMANDS",
+	RplStatsCLine:      "RPL_STATSCLINE",
+	RplStatsNLine:      "RPL_STATSNLINE",
+	RplStatsILine:      "RPL_STATSILINE",
+	RplStatsKLine:      "RPL_STATSKLINE",
+	RplStatsQLine:      "RPL_STATSQLINE",
+	RplStatsYLine:      "RPL_STATSYLINE",
+	RplEndOfStats:      "RPL_ENDOFSTATS",
+
+	RplUmodeIs:      "RPL_UMODEIS",
+	RplServList:     "RPL_SERVLIST",
+	RplServListEnd:  "RPL_SERVLISTEND",
+	RplStatsLLine:   "RPL_STATSLLINE",
+	RplStatsUptime:  "RPL_STATSUPTIME",
+	RplStatsOLine:   "RPL_STATSOLINE",
+	RplStatsHLine:   "RPL_STATSHLINE",
+	RplLuserClient:  "RPL_LUSERCLIENT",
+	RplLuserOp:      "RPL_LUSEROP",
+	RplLuserUnknown: "RPL_LUSERUNKNOWN",
+
+	RplLuserChannels: "RPL_LUSERCHANNELS",
+	RplLuserMe:       "RPL_LUSERME",
+	RplAdminMe:       "RPL_ADMINME",
+	RplAdminLoc1:     "RPL_ADMINLOC1",
+	RplAdminLoc2:     "RPL_ADMINLOC2",
+	RplAdminEmail:    "RPL_ADMINEMAIL",
+	RplTraceLog:      "RPL_TRACELOG",
+	RplTraceEnd:      "RPL_TRACEEND",
+	RplTryAgain:      "RPL_TRYAGAIN",
+
+	RplAway:          "RPL_AWAY",
+	RplUserHost:      "RPL_USERHOST",
+	RplIson:          "RPL_ISON",
+	RplUnaway:        "RPL_UNAWAY",
+	RplNowAway:       "RPL_NOWAWAY",
+	RplWhoisUser:     "RPL_WHOISUSER",
+	RplWhoisServer:   "RPL_WHOISSERVER",
+	RplWhoisOperator: "RPL_WHOISOPERATOR",
+	RplWhoWasUser:    "RPL_WHOWASUSER",
+	RplEndOfWho:      "RPL_ENDOFWHO",
+	RplWhoisIdle:     "RPL_WHOISIDLE",
+	RplEndOfWhois:    "RPL_ENDOFWHOIS",
+	RplWhoisChannels: "RPL_WHOISCHANNELS",
+	RplListStart:     "RPL_LISTSTART",
+	RplList:          "RPL_LIST",
+	RplListEnd:       "RPL_LISTEND", //nolint:misspell
+	RplChannelModeIs: "RPL_CHANNELMODEIS",
+
+	RplUniqOpIs:        "RPL_UNIQOPIS",
+	RplCreationTime:    "RPL_CREATIONTIME",
+	RplNoTopic:         "RPL_NOTOPIC",
+	RplTopic:           "RPL_TOPIC",
+	RplTopicWhoTime:    "RPL_TOPICWHOTIME",
+	RplInviting:        "RPL_INVITING",
+	RplSummoning:       "RPL_SUMMONING",
+	RplInviteList:      "RPL_INVITELIST",
+	RplEndOfInviteList: "RPL_ENDOFINVITELIST",
+	RplExceptList:      "RPL_EXCEPTLIST",
+	RplEndOfExceptList: "RPL_ENDOFEXCEPTLIST",
+	RplVersion:         "RPL_VERSION",
+	RplWhoReply:        "RPL_WHOREPLY",
+	RplNamReply:        "RPL_NAMREPLY",
+	RplLinks:           "RPL_LINKS",
+	RplEndOfLinks:      "RPL_ENDOFLINKS",
+	RplEndOfNames:      "RPL_ENDOFNAMES",
+	RplBanList:         "RPL_BANLIST",
+	RplEndOfBanList:    "RPL_ENDOFBANLIST",
+	RplEndOfWhowas:     "RPL_ENDOFWHOWAS",
+	RplInfo:            "RPL_INFO",
+	RplMotd:            "RPL_MOTD",
+	RplEndOfInfo:       "RPL_ENDOFINFO",
+	RplMotdStart:       "RPL_MOTDSTART",
+	RplEndOfMotd:       "RPL_ENDOFMOTD",
+	RplYoureOper:       "RPL_YOUREOPER",
+	RplRehashing:       "RPL_REHASHING",
+	RplYoureService:    "RPL_YOURESERVICE",
+	RplTime:            "RPL_TIME",
+	RplUsersStart:      "RPL_USERSSTART",
+	RplUsers:           "RPL_USERS",
+	RplEndOfUsers:      "RPL_ENDOFUSERS",
+	RplNoUsers:         "RPL_NOUSERS",
+
+	ErrNoSuchNick:       "ERR_NOSUCHNICK",
+	ErrNoSuchServer:     "ERR_NOSUCHSERVER",
+	ErrNoSuchChannel:    "ERR_NOSUCHCHANNEL",
+	ErrCannotSendToChan: "ERR_CANNOTSENDTOCHAN",
+	ErrTooManyChannels:  "ERR_TOOMANYCHANNELS",
+	ErrWasNoSuchNick:    "ERR_WASNOSUCHNICK",
+	ErrTooManyTargets:   "ERR_TOOMANYTARGETS",
+	ErrNoSuchService:    "ERR_NOSUCHSERVICE",
+	ErrNoOrigin:         "ERR_NOORIGIN",
+	ErrNoRecipient:      "ERR_NORECIPIENT",
+	ErrNoTextToSend:     "ERR_NOTEXTTOSEND",
+	ErrNoTopLevel:       "ERR_NOTOPLEVEL",
+	ErrWildTopLevel:     "ERR_WILDTOPLEVEL",
+	ErrBadMask:          "ERR_BADMASK",
+	ErrUnknownCommand:   "ERR_UNKNOWNCOMMAND",
+	ErrNoMotd:           "ERR_NOMOTD",
+	ErrNoAdminInfo:      "ERR_NOADMININFO",
+	ErrFileError:        "ERR_FILEERROR",
+	ErrNoNicknameGiven:  "ERR_NONICKNAMEGIVEN",
+	ErrErroneusNickname: "ERR_ERRONEUSNICKNAME",
+	ErrNicknameInUse:    "ERR_NICKNAMEINUSE",
+	ErrNickCollision:    "ERR_NICKCOLLISION",
+	ErrUnavailResource:  "ERR_UNAVAILRESOURCE",
+
+	ErrUserNotInChannel:  "ERR_USERNOTINCHANNEL",
+	ErrNotOnChannel:      "ERR_NOTONCHANNEL",
+	ErrUserOnChannel:     "ERR_USERONCHANNEL",
+	ErrNoLogin:           "ERR_NOLOGIN",
+	ErrSummonDisabled:    "ERR_SUMMONDISABLED",
+	ErrUsersDisabled:     "ERR_USERSDISABLED",
+	ErrNotRegistered:     "ERR_NOTREGISTERED",
+	ErrNeedMoreParams:    "ERR_NEEDMOREPARAMS",
+	ErrAlreadyRegistered: "ERR_ALREADYREGISTERED",
+	ErrNoPermForHost:     "ERR_NOPERMFORHOST",
+	ErrPasswdMismatch:    "ERR_PASSWDMISMATCH",
+	ErrYoureBannedCreep:  "ERR_YOUREBANNEDCREEP",
+	ErrYouWillBeBanned:   "ERR_YOUWILLBEBANNED",
+	ErrKeySet:            "ERR_KEYSET",
+	ErrChannelIsFull:     "ERR_CHANNELISFULL",
+	ErrUnknownMode:       "ERR_UNKNOWNMODE",
+	ErrInviteOnlyChan:    "ERR_INVITEONLYCHAN",
+	ErrBannedFromChan:    "ERR_BANNEDFROMCHAN",
+	ErrBadChannelKey:     "ERR_BADCHANNELKEY",
+	ErrBadChanMask:       "ERR_BADCHANMASK",
+	ErrNoChanModes:       "ERR_NOCHANMODES",
+	ErrBanListFull:       "ERR_BANLISTFULL",
+	ErrNoPrivileges:      "ERR_NOPRIVILEGES",
+	ErrChanOpPrivsNeeded: "ERR_CHANOPRIVSNEEDED",
+	ErrCantKillServer:    "ERR_CANTKILLSERVER",
+	ErrRestricted:        "ERR_RESTRICTED",
+	ErrUniqOpPrivsNeeded: "ERR_UNIQOPPRIVSNEEDED",
+	ErrNoOperHost:        "ERR_NOOPERHOST",
+
+	ErrUmodeUnknownFlag: "ERR_UMODEUNKNOWNFLAG",
+	ErrUsersDoNotMatch:  "ERR_USERSDONTMATCH",
+}
+
+// Name returns the standard IRC name for a numeric code
+// (e.g., Name(2) returns "RPL_YOURHOST"). Returns an
+// empty string if the code is unknown.
+//
+// Deprecated: Use IRCMessageType.Name() instead.
+func Name(code IRCMessageType) string {
+	return names[code]
+}

pkg/irc/numerics_test.go

@@ -0,0 +1,163 @@
+package irc_test
+
+import (
+	"errors"
+	"testing"
+
+	"git.eeqj.de/sneak/neoirc/pkg/irc"
+)
+
+func TestName(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		numeric irc.IRCMessageType
+		want    string
+	}{
+		{irc.RplWelcome, "RPL_WELCOME"},
+		{irc.RplBounce, "RPL_BOUNCE"},
+		{irc.RplLuserOp, "RPL_LUSEROP"},
+		{irc.ErrCannotSendToChan, "ERR_CANNOTSENDTOCHAN"},
+		{irc.ErrNicknameInUse, "ERR_NICKNAMEINUSE"},
+	}
+
+	for _, tc := range tests {
+		if got := tc.numeric.Name(); got != tc.want {
+			t.Errorf("IRCMessageType(%d).Name() = %q, want %q", tc.numeric.Int(), got, tc.want)
+		}
+	}
+}
+
+func TestString(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		numeric irc.IRCMessageType
+		want    string
+	}{
+		{irc.RplWelcome, "RPL_WELCOME <001>"},
+		{irc.RplBounce, "RPL_BOUNCE <005>"},
+		{irc.RplLuserOp, "RPL_LUSEROP <252>"},
+		{irc.ErrCannotSendToChan, "ERR_CANNOTSENDTOCHAN <404>"},
+	}
+
+	for _, tc := range tests {
+		if got := tc.numeric.String(); got != tc.want {
+			t.Errorf("IRCMessageType(%d).String() = %q, want %q", tc.numeric.Int(), got, tc.want)
+		}
+	}
+}
+
+func TestCode(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		numeric irc.IRCMessageType
+		want    string
+	}{
+		{irc.RplWelcome, "001"},
+		{irc.RplBounce, "005"},
+		{irc.RplLuserOp, "252"},
+		{irc.ErrCannotSendToChan, "404"},
+	}
+
+	for _, tc := range tests {
+		if got := tc.numeric.Code(); got != tc.want {
+			t.Errorf("IRCMessageType(%d).Code() = %q, want %q", tc.numeric.Int(), got, tc.want)
+		}
+	}
+}
+
+func TestInt(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		numeric irc.IRCMessageType
+		want    int
+	}{
+		{irc.RplWelcome, 1},
+		{irc.RplBounce, 5},
+		{irc.RplLuserOp, 252},
+		{irc.ErrCannotSendToChan, 404},
+	}
+
+	for _, tc := range tests {
+		if got := tc.numeric.Int(); got != tc.want {
+			t.Errorf("IRCMessageType(%d).Int() = %d, want %d", tc.want, got, tc.want)
+		}
+	}
+}
+
+func TestFromInt_Known(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		code int
+		want irc.IRCMessageType
+	}{
+		{1, irc.RplWelcome},
+		{5, irc.RplBounce},
+		{252, irc.RplLuserOp},
+		{404, irc.ErrCannotSendToChan},
+		{433, irc.ErrNicknameInUse},
+	}
+
+	for _, test := range tests {
+		got, err := irc.FromInt(test.code)
+		if err != nil {
+			t.Errorf("FromInt(%d) returned unexpected error: %v", test.code, err)
+
+			continue
+		}
+
+		if got != test.want {
+			t.Errorf("FromInt(%d) = %v, want %v", test.code, got, test.want)
+		}
+	}
+}
+
+func TestFromInt_Unknown(t *testing.T) {
+	t.Parallel()
+
+	unknowns := []int{0, 999, 600, -1}
+	for _, code := range unknowns {
+		_, err := irc.FromInt(code)
+		if err == nil {
+			t.Errorf("FromInt(%d) expected error, got nil", code)
+
+			continue
+		}
+
+		if !errors.Is(err, irc.ErrUnknownNumeric) {
+			t.Errorf("FromInt(%d) error = %v, want ErrUnknownNumeric", code, err)
+		}
+	}
+}
+
+func TestUnknownNumeric_Name(t *testing.T) {
+	t.Parallel()
+
+	unknown := irc.IRCMessageType(999)
+	if got := unknown.Name(); got != "" {
+		t.Errorf("IRCMessageType(999).Name() = %q, want empty string", got)
+	}
+}
+
+func TestUnknownNumeric_String(t *testing.T) {
+	t.Parallel()
+
+	unknown := irc.IRCMessageType(999)
+	want := "UNKNOWN <999>"
+
+	if got := unknown.String(); got != want {
+		t.Errorf("IRCMessageType(999).String() = %q, want %q", got, want)
+	}
+}
+
+func TestDeprecatedNameFunc(t *testing.T) {
+	t.Parallel()
+
+	if got := irc.Name(irc.RplYourHost); got != "RPL_YOURHOST" {
+		t.Errorf("Name(RplYourHost) = %q, want %q", got, "RPL_YOURHOST")
+	}
+}

web/src/app.jsx

@@ -146,7 +146,7 @@ function LoginScreen({ onLogin }) {
       }
       const reqBody = { nick: nick.trim() };
       if (hashcashStamp) {
-        reqBody.hashcash = hashcashStamp;
+        reqBody.pow_token = hashcashStamp;
       }
       const res = await api("/session", {
         method: "POST",