# dsh-arrowkey-nav

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Arrow-key navigation for the DSH Web GUI. Switch sessions without leaving the
keyboard:

| Key | Action | Scope |
| --- | --- | --- |
| `↑` | previous session | inside the current workspace |
| `↓` | next session | inside the current workspace |
| `←` | previous workspace | all workspaces |
| `→` | next workspace | all workspaces |

`↑`/`↓` wrap around at the ends of the workspace and never cross into a
neighbouring one; crossing is what `←`/`→` are for. After a switch the target
row is scrolled into view, and focus returns to the composer if that is where
the press started, so typing can continue immediately.

## Version and DSH lines

One version serves every supported host line. Version `0.5.0` is tested with
all rc releases of the DSH 0.1.0–0.2.0 lines — the exact whitelist is
`engines.dsh`, distributed from the single source `scripts/hosts.mjs` by
`scripts/sync-hosts.mjs` (hand edits fail `npm run hosts:check`):

| DSH line | tested rc releases |
| --- | --- |
| 0.1.0 | rc.2, rc.3, rc.6, rc.7, rc.8 |
| 0.1.1 | rc.1, rc.2 |
| 0.1.2 | rc.1 |
| 0.1.5 | rc.1, rc.2, rc.3 |
| 0.1.7 | rc.1, rc.2 |
| 0.2.0 | rc.1, rc.2 |

- There is no per-line build: both switching generations are dispatched by
  capability probing in one bundle (`uiWorkspace.openSession` on the 0.1.6+
  generations, `sessions.open` on the older ones), so every host line runs the
  same code.
- On the 0.1.0/0.1.1 lines (`dsh-client-runtime` generation) support is
  declaration-complete and unit-tested, but real-host keystroke verification is
  still pending; until then treat those cells as best effort.

## Install

```sh
dsh plugin --profile web add dsh-arrowkey-nav -w
```

The registry's `latest` is the one version for every line. Each line also has a
dist-tag pointing at the same build — `dsh-arrowkey-nav@dsh-0.2.0`,
`dsh-arrowkey-nav@dsh-0.1.5`, and so on — if you prefer naming the line; the
install target is identical. A host release outside the table above is
rejected by the `engines.dsh` whitelist instead of mounting half-broken.

Restart the profile afterwards — a running instance does not hot-load a new
bundle layer. Then reload `http://127.0.0.1:3080`.

Confirm the row is in the composed tree:

```sh
dsh web --dump-config | Select-String dsh-arrowkey-nav
```

A local checkout can be registered instead with
`dsh plugin --profile web add <absolute path to the checkout> -w`; see
[INSTALL.md](./INSTALL.md) for the full guide, including upgrades, verification
and removal.

### Remove

```sh
dsh plugin --profile web remove dsh-arrowkey-nav
```

Restart, and the keys behave exactly as before the install: the listener is
owned by the plugin's Cordis effect and is removed with it.

## How it works

Identity comes from the two client controllers, never from the DOM: rows carry
no `data-*` and no `id`, so a row cannot be asked what session it is.

- Every switch goes through the capability-probed executor: `ctx.uiWorkspace.openSession(id)`
  on the DSH 0.1.6+ generations, `ctx.sessions.open(id)` on the older lines — one
  bundle, no per-line build. The details panel needs no
  handling: the shipped frame already closes it when the current session
  changes.
- `ctx.workspaces.list.getSnapshot()` supplies the workspace order — the order
  `←`/`→` walks, and the source of each workspace's member list.

**Which session is "next" follows the order the sidebar is drawing**, not the
controller's member order. Those disagree in exactly the case you notice: the
sidebar reconciles its own persisted order with the membership and promotes
recently-active sessions to the top, so an old session jumps to the first row
the moment you open it. The plugin therefore reads the rendered row order out of
the sidebar, and falls back to the controller order when the sidebar is not
mounted (collapsed rail). A section is accepted only when its rows account for
every session the controller reports for that workspace; an ambiguous or
mismatched section falls back instead of guessing.

Keys are left alone when the event already belongs to somebody else: any
modifier, IME composition, an event already handled upstream, or a focus inside
a dialog, menu or another editable field (the sidebar's session search, a rename
box). The listener registers in the capture phase but only calls
`preventDefault()` when it actually navigates.

The composer is the one conditional case. An **empty composer yields its arrow
keys** — there is no caret to move, so the key is free — which is what lets you
navigate right after sending a message, while the composer still holds focus.
Once the composer **holds a draft, its arrow keys belong to the caret again**,
so editing a prompt is never hijacked.

The browser half has no React components, no CSS and no platform-module
requests, and the package has no runtime dependencies — `lib/client.js` is
generated by `scripts/build-client.mjs` into the module-loader contract the page
expects.

## Development

```sh
npm run typecheck   # both compiler faces
npm test            # resolver unit tests + built-bundle smoke tests
npm run build       # regenerate lib/client.js after editing src/client
```

`npm run build` needs `typescript`; if it is not installed in this package, point
`DSH_TYPESCRIPT` at an existing `typescript` module directory.

## Known limitations

- **A collapsed workspace group does not scroll.** Its rows are not mounted, and
  dsh exposes no public way to expand a group, so the switch happens but the
  target row stays out of sight. The workspace holding the current session is
  kept expanded by dsh itself, so `↑`/`↓` are unaffected.
- **A rail-collapsed sidebar does not scroll** for the same reason: the tree is
  not mounted. The switch still happens.
- **"In one list" mode** has no workspace sections, but `←`/`→` still walk the
  controller's workspace order, so the list may appear to jump between sections.
- **Scrolling is best effort.** Any lookup failure is swallowed: the selection
  has already moved, and a missing row must never turn into a wrong one.
- **Snapshot fields are pre-stable.** `sessions` and `workspaces` snapshot shapes are
  pre-stable — the tested host releases are exactly the `engines.dsh` whitelist
  (`engines.dsh: 0.1.0-rc.2 || 0.1.0-rc.3 || 0.1.0-rc.6 || 0.1.0-rc.7 || 0.1.0-rc.8 || 0.1.1-rc.1 || 0.1.1-rc.2 || 0.1.2-rc.1 || 0.1.5-rc.1 || 0.1.5-rc.2 || 0.1.5-rc.3 || 0.1.7-rc.1 || 0.1.7-rc.2 || 0.2.0-rc.1 || 0.2.0-rc.2`).
  If a dsh upgrade changes them, `src/client/navigate.ts` and
  `src/client/apply.ts` are the only files to revisit; a host that exposes
  neither switching API leaves the plugin inert rather than failing the page.

## Layout

```
src/index.ts                node half: loader entry, installs nothing
src/client/constants.ts     keys owned, DOM anchors read
src/client/navigate.ts      narrow waist: snapshot types + arrow resolver
src/client/apply.ts         execution: open / blank-first / connectWorkspace
src/client/dom.ts           read-only DOM: scroller, section binding, scroll, focus
src/client/session-nav.ts   key guards + one arrow press end to end
src/client/index.ts         Cordis entry: inject + one capturing listener
scripts/build-client.mjs    generates lib/client.js
tests/                      resolver unit tests + bundle smoke tests
```

## License

MIT