# Caffeinate

> Keep your computer awake from [Vicinae](https://vicinae.com). One toggle, no terminal.

![Caffeinate icon](./assets/caffeinate.png)

## Why this exists

The Raycast [`coffee`](https://www.raycast.com/mooxl/coffee) extension does not work on Vicinae. Its `index` command is a `menu-bar` command, which Vicinae cannot run at all, and its `status` command crashes because it gates on `LocalStorage.getItem(key) === undefined` — Vicinae resolves a missing key to `null` instead of `undefined`.

This is a native `@vicinae/api` extension, so none of that applies.

## Commands

| Command | Mode | What it does |
| --- | --- | --- |
| **Toggle Caffeination** | no-view | Flips sleep prevention on or off, whichever is appropriate. The fast path. |
| **Caffeination Status** | view | Whether sleep is being blocked, since when, and the exact process holding it. Start/stop from here. |

## How it works

Sleep prevention is an OS-level assertion, so the extension delegates to the platform tool and then gets out of the way:

| Platform | Mechanism |
| --- | --- |
| macOS | `/usr/bin/caffeinate -i [-d] [-s]` (defaults to `-i -d`) |
| Linux | `systemd-inhibit --what=idle:sleep --why=<reason> sleep infinity` |

Both run until signalled — there is no timer, so nothing needs to be refreshed or babysat.

The process is spawned **detached and unref'd**. That is required: Vicinae unloads a `no-view` command as soon as its function returns, so a child process would otherwise be torn down with it.

## The process is the state

**Nothing is persisted.** The running process carries its own identity in its command line:

```
vicinae-caffeinate:v1:<startedAt>:<flags>        e.g. vicinae-caffeinate:v1:1789895271765:id
```

- **macOS** has no free-form field on `caffeinate`, so the marker is installed as `argv[0]` via the shell's `exec -a`. `exec` replaces the shell in place, so the pid Node receives *is* the `caffeinate` pid.
- **Linux** passes it in `systemd-inhibit`'s `--why`, alongside a human-readable reason.

Status is therefore a `ps` scan for that marker, and stopping signals every match.

### Why this design

The obvious approach — remember the pid in `LocalStorage` — has a failure mode that is worse than it sounds. Two pieces of state have to stay in sync: the record, and the actual process. If the record is ever lost (extension reinstalled, storage cleared, a crash between spawning and saving) the process keeps holding a sleep assertion that **nothing will ever release**. A laptop that silently never sleeps, with no way to find the culprit.

Making the process self-describing removes the class of bug rather than guarding against it: there is no record to lose, so the extension cannot lose track of a session. Any `status` or `toggle` reconciles against the truth, and `start` always clears existing sessions first so assertions cannot stack.

Verified by deleting the installed extension while a session was active, restarting Vicinae, then reinstalling: the fresh install saw the leftover as **active** and stopped it, instead of starting a second one and orphaning the first.

Signals go to the **process group** (`kill -TERM -<pid>`). Sessions are spawned detached, so the child is a group leader; on Linux that matters because `systemd-inhibit` forks a `sleep`, and signalling only the parent can leave the child behind.

A `caffeinate` you started yourself is never touched — only processes carrying the marker are ever signalled. If a session ever does need to be cleared by hand:

```sh
pkill -f vicinae-caffeinate
```

## Preferences

| Preference | Default | Notes |
| --- | --- | --- |
| Prevent Display Sleep | **on** | macOS only. On by default: `caffeinate -i` alone blocks *system* idle sleep, so the screen still blanks and the extension looks broken. Turn it off to save battery. `systemd-inhibit` cannot hold the display awake — that is the compositor's job, and the UI says so rather than pretending. |
| Also Prevent System Sleep | off | On macOS this assertion only takes effect while on AC power. |

## Development

```sh
npm install
npm run dev        # vici develop — Vicinae must be running
```

Other scripts: `npm run lint` (manifest), `npm run lint:code` (ESLint), `npm run typecheck`, `npm test`.

To install a production build into Vicinae:

```sh
npm run build      # writes to ~/.local/share/vicinae/extensions/caffeinate
```

## No top bar indicator

Vicinae has no menu-bar command support. This is not a Raycast-compat gap — a native `mode: "menu-bar"` command is accepted by the manifest and builds cleanly, then is **silently dropped** at registration, with no warning. `@vicinae/api` exports a `MenuBarExtra` component, but there is no host to render it into.

For a real top bar indicator you need a standalone macOS menu-bar app; it cannot be part of a Vicinae extension.

## Not implemented

- **Windows.** `detectPlatform` throws with a clear message instead of failing obscurely. `powercfg` would be the path.
- **Timed windows** (`caffeinate -t`), **while-an-app-is-running** (`caffeinate -w <pid>`), and **scheduled** windows. Deliberately omitted — on/off covers the common case.

## License

MIT