# Watch Party for Emby

An Emby Server plugin that lets a group of users on the same server watch the
same title together. Nobody switches players: everyone keeps using their
normal Emby app (web, mobile, TV, whatever), and the plugin nudges playback
back in sync using the same remote-control commands Emby already uses for
casting / "play on another device".

See [docs/architecture.md](docs/architecture.md) for the full design,
including which parts are solidly confirmed against Emby's SDK docs and which
still need verification against your exact server build.

## How it's meant to work

1. You start playing a title in your normal Emby app.
2. You open the Watch Party control panel (a small web page the plugin
   serves) and start a party. You get a 6-character join code.
3. Friends open the control panel, sign in with their own Emby account, start
   playing the *same* title in their own Emby app, and enter the code to join.
4. The server treats one member (the host, by default) as the reference
   position, and periodically nudges everyone else's session back in sync
   (seek correction, and mirroring pause/unpause) — see
   [docs/architecture.md](docs/architecture.md#sync-algorithm).

The control panel is a companion page, not a video player — it never touches
the actual video stream.

## Status

Builds clean (0 errors, 0 warnings) against the real `MediaBrowser.Server.Core`
/ `MediaBrowser.Common` 4.9.1.90 assemblies from NuGet. Not yet installed or
run against an actual Emby Server — a few things (auth header format, HTTP
status codes, the dashboard settings page rendering) are only compile-checked
so far, not runtime-verified. See
[docs/architecture.md](docs/architecture.md#assumptions-to-verify) for
exactly what was wrong on the first guess, what was fixed, and what's still
open.

## Requirements

- Emby Server (developed against 4.9.5.0; should work on nearby 4.9.x/4.8.x
  builds, but the plugin ABI does shift between versions)
- [.NET SDK](https://dotnet.microsoft.com/download) 8.0 to build (installed
  per-user under `%USERPROFILE%\.dotnet` in this environment, since the
  machine-wide winget install needed admin elevation that wasn't available —
  see git history if you need to redo this on another machine)

## Project layout

```
src/WatchParty/          the plugin itself (C#, netstandard2.0)
  Plugin.cs              plugin registration + admin settings page
  Configuration/         plugin settings + the dashboard config page HTML
  Parties/               Party / PartyMember model + in-memory PartyManager
  Sync/                  the drift-correction background loop
  Api/                   REST endpoints + serving the control panel's static files
web/control-panel/       the user-facing page (plain HTML/JS/CSS, no build step)
docs/architecture.md     full design doc
```

## Building

```bash
dotnet build src/WatchParty/WatchParty.csproj
```

To have a build drop the DLL straight into a local Emby Server's plugin
folder, set `EMBY_PLUGINS_DIR` before building, e.g.:

```bash
EMBY_PLUGINS_DIR="C:/ProgramData/Emby-Server/programdata/plugins" dotnet build src/WatchParty/WatchParty.csproj
```

Adjust the path for however your server is installed (Windows service vs.
portable install vs. Docker volume).

## Roadmap

- [x] Design doc + scaffold
- [x] Build against the real SDK, fix whatever the `TODO(verify)` spots got wrong
- [ ] Try it against a real Emby Server + two clients
- [ ] Live (WebSocket) updates in the control panel instead of polling
- [ ] Optional text chat, reusing the same realtime channel
- [ ] Per-party override of sync settings instead of only server-wide defaults

## License

MIT — see [LICENSE](LICENSE).