# CLAUDE.md

## Running the app

```bash
npm install
npm run dev      # development (nodemon)
npm start        # production
```

Requires `.env` — copy from `.env.example`. Database is created automatically on startup (better-sqlite3 runs migrations on init).

## Stack

- **Node.js** · Express · EJS templates
- **better-sqlite3** — SQLite, synchronous, simple
- **ws** — WebSocket server for pushing alerts to overlay clients
- **tmi.js** — Twitch IRC, runs in the browser on the overlay page (no server-side IRC)
- **multer** — file uploads
- **uuid** — UUID generation
- **dotenv** — env vars
- **express-session** — session management (signed cookie)

## Architecture

```
Twitch ──EventSub WebSocket──► src/eventsub.js ──► dispatch.js ──► ws.js ──► OBS overlay
Twitch ──IRC (tmi.js in browser) ────────────────────────────────────────► OBS overlay
```

- `eventsub.js` opens a WebSocket to Twitch on startup, managed as a module-level singleton
- On notification it calls `dispatch.dispatchEvent()`
- `dispatch.dispatchEvent()` queries matching `event_actions` rows, checks cooldowns, logs to `activity_log`, calls `wss.broadcast()`
- `wss` (ws.js) holds all active WebSocket connections from `/ws/overlay`
- The overlay JS receives the broadcast and plays the action
- Chat messages come directly from tmi.js running in the browser — no server relay

## Project structure

```
src/
  app.js           — Express app setup, middleware, router mounting
  server.js        — HTTP server + WebSocket server startup, EventSub init
  db.js            — better-sqlite3 setup, migrations, singleton helpers
  eventsub.js      — Twitch EventSub WebSocket client (module singleton)
  dispatch.js      — event → action resolution, cooldowns, DB log, broadcast
  ws.js            — WebSocket connection manager
  cooldowns.js     — in-memory cooldown tracking
  routers/
    auth.js        — /auth/* (Twitch OAuth)
    dashboard.js   — / (activity log, EventSub status)
    overlay.js     — /overlay/:uuid, /overlay/:uuid/preview, /ws/overlay
    actions.js     — /actions CRUD
    media.js       — /media upload/delete
    layout.js      — /layout editor + /layout/positions
    settings.js    — /settings
views/
  layout.ejs       — base shell (nav, Pico CSS)
  login.ejs
  dashboard.ejs
  overlay.ejs      — OBS browser source
  overlay_preview.ejs
  layout_editor.ejs
  actions.ejs
  media.ejs
  settings.ejs
public/
  media/           — uploaded files (gitignored)
```

## Key conventions

**No passwords anywhere.** Auth is Twitch OAuth only. Session stored via `express-session` with a signed cookie. `req.session.userId` stores the DB user ID after login.

**Singleton tables.** `settings` and `overlay_layout` each have one row (id=1). `db.getSettings()` and `db.getLayout()` create the row on first call if missing.

**Cooldowns are in-memory.** `cooldowns.js` tracks `{ actionId: triggeredAt }`. Restarting the server resets all cooldowns. Intentional — DB cooldowns not worth the complexity.

**Multiple actions per event.** `dispatchEvent()` loops through ALL matching `event_actions` rows and fires each one (subject to its own cooldown). No "first match wins".

**Event matching rules:**
- `event_type="command"`: `event_detail` must match the command name (case-insensitive)
- `event_type="bits"`: if `event_detail` set, treat as minimum bits threshold
- `event_type="channel_points"`: `event_detail` is the reward ID; null matches any reward
- `event_type="sub"/"gift_sub"`: `event_detail` is tier ("1000", "2000", "3000"); null matches any
- `event_type="follow"/"raid"`: `event_detail` not used

**UUID overlays.** `settings.overlay_id` is a UUID generated on first run. OBS browser source URL is `/overlay/:uuid`. Future multi-user support creates multiple settings rows.

## Route map

| Method | Path | File | Notes |
|---|---|---|---|
| GET | `/` | routers/dashboard.js | Activity log, EventSub status |
| GET | `/auth/login` | routers/auth.js | Login page |
| GET | `/auth/twitch` | routers/auth.js | Redirect to Twitch OAuth |
| GET | `/auth/callback` | routers/auth.js | Exchange code, save user, start EventSub |
| GET | `/auth/logout` | routers/auth.js | Clear session |
| GET | `/overlay/:uuid` | routers/overlay.js | Live OBS browser source |
| GET | `/overlay/:uuid/preview` | routers/overlay.js | Mock preview for layout editor |
| WS | `/ws/overlay` | routers/overlay.js | Bidirectional: commands up, actions down |
| GET/POST | `/actions` | routers/actions.js | List and create actions |
| POST | `/actions/:id/test` | routers/actions.js | Fire immediately, skip cooldown |
| POST | `/actions/:id/toggle` | routers/actions.js | Enable/disable |
| DELETE | `/actions/:id` | routers/actions.js | Delete |
| GET/POST | `/media` | routers/media.js | Upload, list |
| DELETE | `/media/:id` | routers/media.js | Delete file + DB row |
| GET/POST | `/layout` | routers/layout.js | Style form |
| POST | `/layout/positions` | routers/layout.js | JSON, called by drag JS |
| GET/POST | `/settings` | routers/settings.js | Channel, gap audio, custom CSS/JS |
| POST | `/settings/reconnect` | routers/settings.js | Restart EventSub |

## Overlay CSS variable system

All overlay positioning and styling uses CSS custom properties rendered into `overlay.ejs` and `overlay_preview.ejs` from the `overlay_layout` row:

| Variable | Controls |
|---|---|
| `--chat-left`, `--chat-top` | Chat box position (%) |
| `--chat-width`, `--chat-height` | Chat box size (%) |
| `--chat-font-size` | Chat font size (px) |
| `--chat-font-family` | Chat font family |
| `--chat-bg-opacity` | Chat message background opacity |
| `--chat-text-color` | Chat message text colour |
| `--chat-border-radius` | Message border radius (px) |
| `--alert-left`, `--alert-top` | Alert position (%, centered via transform) |
| `--alert-font-size` | Alert font size (px) |
| `--alert-bg-opacity` | Alert background opacity |
| `--alert-text-color` | Alert text colour |

The layout editor (`/layout`) overlays drag handles on an iframe pointing to `/overlay/:uuid/preview`. Same-origin, so the editor sets CSS variables directly on the iframe's document for live preview. Saved via `POST /layout/positions`.

## Gap / new-message audio

Configured in `settings`. When a chat message arrives in the overlay, tmi.js checks:
1. Is `gap_audio_enabled` true and `gap_audio_url` set?
2. Has at least `gap_audio_min_silence` seconds passed since the last message?
3. If yes: play the audio. Volume = linear interpolation between `gap_audio_min_volume` and `gap_audio_max_volume` based on silence duration vs `gap_audio_loud_after`.

All logic runs in the browser. The server only serves the config.

## Custom events dispatched to overlay JS

When the overlay WebSocket receives an action broadcast:

```javascript
document.dispatchEvent(new CustomEvent(`bashyoverlay:${msg.event_type}`, { detail: msg }));
```

Available: `sub`, `gift_sub`, `bits`, `channel_points`, `command`, `follow`, `raid`.

`msg` shape: `{ event_type, action_type, media_url, alert_text, username }`.

## Database schema

```sql
users            — Twitch OAuth user (twitch_id unique)
settings         — singleton id=1: overlay_id, channel, gap audio, message_timeout, custom_css/js
overlay_layout   — singleton id=1: widget positions and styles
media_files      — uploaded sounds/videos
event_actions    — event → action mapping (media_file_id FK)
activity_log     — append-only event log
```

## EventSub subscriptions

| Twitch event | Version | Condition | Scope |
|---|---|---|---|
| `channel.subscribe` | 1 | `broadcaster_user_id` | `channel:read:subscriptions` |
| `channel.subscription.message` | 1 | `broadcaster_user_id` | `channel:read:subscriptions` |
| `channel.subscription.gift` | 1 | `broadcaster_user_id` | `channel:read:subscriptions` |
| `channel.cheer` | 1 | `broadcaster_user_id` | `bits:read` |
| `channel.channel_points_custom_reward_redemption.add` | 1 | `broadcaster_user_id` | `channel:read:redemptions` |
| `channel.follow` | 2 | `broadcaster_user_id` + `moderator_user_id` | `moderator:read:followers` |
| `channel.raid` | 1 | `to_broadcaster_user_id` | none |

Token refresh triggered on 401 during subscription.

## Production deployment

Runs behind Apache on the VPS as a reverse proxy to Node on port 3000.
Production domain: `https://overlay.bashynx.com`

Minimal Apache vhost config (requires `mod_proxy`, `mod_proxy_http`, `mod_proxy_wstunnel`):
```apache
<VirtualHost *:443>
    ServerName overlay.bashynx.com

    ProxyPreserveHost On
    ProxyPass /ws/overlay ws://127.0.0.1:3000/ws/overlay
    ProxyPassReverse /ws/overlay ws://127.0.0.1:3000/ws/overlay
    ProxyPass / http://127.0.0.1:3000/
    ProxyPassReverse / http://127.0.0.1:3000/

    # SSL config here (certbot/Let's Encrypt)
</VirtualHost>
```

The `/ws/overlay` must be proxied separately with `ws://` via `mod_proxy_wstunnel` — if it's not listed before the catch-all `/`, WebSocket connections will fail. Enable the required modules with:
```bash
sudo a2enmod proxy proxy_http proxy_wstunnel
sudo systemctl reload apache2
```

Twitch requires HTTPS for OAuth redirect URIs in production. Register both in the Twitch dev console:
- `http://localhost:3000/auth/callback` (dev)
- `https://overlay.bashynx.com/auth/callback` (production)

## Not yet implemented

- Alert variable interpolation (`{username}` in alert text)
- Mod access (streamer-only login for now)
- Chat commands triggering actions
- Stripe / PayPal / ETH payment notifications
- Multiple overlays (multi-user; UUID foundation is in place)
- HudFX integration