# Windows build

JellyTau targets Linux and Android primarily, but a working Windows build —
including an **NSIS installer cross-compiled from Linux** — is produced by the
Docker tooling. It is not yet a first-class release target (no code signing / CI
job / SMTC lockscreen), but it runs and plays media.

## How playback works on Windows

- **Video** — renders through the webview HTML5 `<video>` element (hls.js) on
  *every* platform; on Windows that is WebView2 (Chromium/Edge), which plays HLS +
  h264 fine. No Windows-specific code.
- **Audio-only (music)** — the native audio backends are libmpv (Linux) and
  ExoPlayer (Android); neither exists on Windows. Instead
  `create_player_backend()` in [../src-tauri/src/lib.rs](../../src-tauri/src/lib.rs)
  uses `WebviewAudioBackend` on non-Linux/non-Android targets: it hands the stream
  URL to a webview `<audio>` element (see
  [../src/lib/services/webviewAudio.ts](../../src/lib/services/webviewAudio.ts)),
  which reports state back through the same `player_report_*` round-trip the video
  path uses. Pure Rust + Tauri events.

## Cross-compiling from Linux (MSVC + cargo-xwin)

We use the [official Tauri cross-compile path](https://v2.tauri.app/distribute/windows-installer/):
the **MSVC** target (`x86_64-pc-windows-msvc`) driven by
[`cargo-xwin`](https://github.com/rust-cross/cargo-xwin), which downloads the MSVC
CRT / Windows SDK headers and links with `lld`. MSVC is the target Tauri
officially supports for Windows (mingw/GNU is not), and — unlike GNU — it lets the
Tauri CLI bundle the **NSIS installer from a Linux host**.

> Why not mingw/GNU? The GNU target *does* link a valid `.exe`, but the Tauri CLI
> gates `--bundles` by the host OS unless it recognizes a real Windows build.
> `--runner cargo-xwin --target x86_64-pc-windows-msvc` is what flips it into
> Windows mode and enables the `nsis`/`msi` bundlers on Linux.

The builder image ([../Dockerfile.builder](../../Dockerfile.builder)) bakes in the
whole toolchain: the `x86_64-pc-windows-msvc` rust target, `cargo-xwin`, `lld`,
`llvm`, and `nsis`.

```bash
bun run docker:build:windows            # NSIS installer + .exe -> ./dist
WIN_BUNDLES=none bun run docker:build:windows   # exe only, skip bundling
```

Or directly on a host that has the toolchain:

```bash
scripts/build-windows-cross.sh                    # nsis installer + exe
WIN_BUNDLES=none scripts/build-windows-cross.sh   # exe only
```

Under the hood the build runs:

```bash
tauri build --runner cargo-xwin --target x86_64-pc-windows-msvc --bundles nsis
```

Outputs:
- `.exe` — `src-tauri/target/x86_64-pc-windows-msvc/release/jellytau.exe`
- NSIS installer — `.../release/bundle/nsis/*-setup.exe`

(both copied to `./dist` when `OUTPUT_DIR` is set).

## Caveats

- **Cross-compilation is a last resort** per Tauri's own docs — it's less tested
  than building on Windows. If it misbehaves, a `windows-latest` CI job or a
  Windows VM building natively (`tauri build --bundles nsis`) is the fallback.
- **Code signing is not wired up** — the installer is unsigned, so Windows
  SmartScreen will warn on first run.

## Outstanding for a first-class Windows release

1. Gapless/crossfade + SMTC (lockscreen) — currently no-ops in the webview audio
   path.
2. Downloaded (`Local` source) file playback needs `convertFileSrc` on the
   frontend; streaming works today.
3. Code signing + a Windows packaging CI job.
