# Accounts and launch through the central server (central.client)

## What it is for

`central.client` is the game side of the studio's central server (`gripforge create central-server`): player accounts (sign up,
sign in, sign out, resume a kept session), the directory of rooms servers, and `launch()`: central picks a rooms server and hands
a short signed ticket, then `net.rooms` connects to that server with it. The accounts and tickets belong to central; the kit only
asks.

## Turn it on

```text
gripforge_gamekit_install   { project_id: "gkp_…", id: "central.client" }
gripforge_gamekit_configure { project_id: "gkp_…", id: "central.client",
                              config: { "url": "https://central.example.com" } }
```

Install `net.rooms` (with `net.transport`) too: `launch()` needs it.

## First example

<!-- test: kits/game_engine/host/tests/net_kits.rs::central_client_signs_in_reads_the_directory_and_launches_net_rooms_with_the_ticket -->
Calls answer at once and the outcome arrives as events and in `view()`:

```text
central.client.signUp("Ann", "secret")   -> central.signed_in { account: { id, name } }
central.client.directory()               -> the known list; view().directory fills when central answers
central.client.launch({})                -> central.launched { rooms, url }; net.rooms is connected as Ann
central.client.signOut()                 -> central.signed_out
```

`view()` answers `{ signedIn, account, busy, error, directory, rooms }`. Central's own codes (`bad_credentials`, `name_taken`...)
pass through in `error`.

## Settings and defaults

| Setting | Default | Meaning |
|---|---|---|
| `url` | `""` | address of the central server (http(s)://host:port); empty: every call ends with `central_unavailable` |
| `view` | `true` | show the ready-made account view (sign in, create an account, directory, Play online); off: draw your own menu from `view()` |

## Services, events, variables

- `central.client` (service): `signUp(name, password)`, `signIn(name, password)`, `signOut()`, `resume(session)`, `session()`,
  `view()`, `directory()`, `launch({ rooms?, server? })`.
- Events: `central.signed_in`, `central.signed_out`, `central.launched`, `central.error` (payload `code`: `central_unavailable`,
  `rooms_unavailable`, `rooms_module_missing`, `not_signed_in` or central's own code).

## Hooks and modding

None: it is a pure service. No hook, no setting open to mods.

## Limits

Native engines talk to central over `http://` only (no TLS yet); the web uses `fetch`. One central server per game.

## Versions

Kit 1.0.0, service `central.client` 1.0.0 (exclusive).