# Order composer

This doc covers the local order draft: the per-game in-memory list
of commands the player has composed but not yet submitted, the
`Cache`-backed persistence that survives reloads, and the
`historyMode` flag that hides the composer when the user is browsing
past turns. The user-facing spec — the IA section's sidebar
description, the `Order` tab placement, the per-command status
display — lives in [`../PLAN.md`](../PLAN.md), section
`Information Architecture and Navigation`. This doc is the source of
truth for how those rules are implemented.

## Draft replaces server order

The client's view of "the player's intent for the next turn" lives
entirely in the local draft. The gateway exposes a turn-scoped
`user.games.order` endpoint that the submit pipeline drains the
draft into; until the player explicitly submits, the server has no
view of pending commands. The composer never reads back the
server's idea of an order — it reads its own draft and renders it.

The motivation is operational: a draft can be edited, reordered,
or partially removed without round-trips, and a half-composed order
during a connectivity hiccup keeps every line the player typed. A
remote-first composer that reflects the gateway's pending-orders
queue would force a sync on every keystroke.

Phase 14 lands the submit pipeline with batch semantics: every
entry the user has marked `valid` is collected into one signed
`user.games.order` request. The engine validates and stores the
order, returning per-command `cmdApplied` / `cmdErrorCode` in the
response body. The gateway re-encodes that JSON into the FBS
`UserGamesOrderResponse` envelope (with `commands: [CommandItem]`
populated), and `submitOrder` rejoins the verdict to each draft
entry by `cmdId`. Successfully applied entries stay visible in
the draft (the player keeps composing until turn cutoff);
rejected entries stay until the player edits or removes them.

Phase 25 is reserved for one extension on top of this: per-line
sequencing if a future use case needs to submit commands
individually rather than in one batch. The wire shape is already
flexible enough — the response carries an array of results — so
Phase 25 only changes the client-side iteration policy.

## Local-validation invariant

Every command in the draft is *locally valid as of submission time*.
A command may live in the draft as `draft` (not yet validated) or
`valid`; `invalid` is allowed during composition but the submit
pipeline refuses to drain a draft that contains any `invalid`
entries. The validation step is per-command and pure — it consults
the current `GameStateStore` snapshot only, never the network.

Phase 14's `planetRename` is the first variant that exercises the
`draft → valid | invalid` transition. The validator
(`lib/util/entity-name.ts`) is a TS port of
`pkg/util/string.go.ValidateTypeName`, exercised on every render
in the inline editor and re-run by the store on every `add`. The
submit pipeline filters the draft to `valid` entries only — any
`invalid` row blocks the Submit button.

## Command status state machine

```text
draft ──validate──▶ valid ──submit──▶ submitting ──ack──▶ applied
   ╲                  │                                  ╲
    ╲──validate──▶ invalid                                ╲──nack──▶ rejected
```

Transitions:

- **`draft → valid` / `draft → invalid`**: local validation. May
  re-run when the underlying `GameStateStore` snapshot changes
  (Phase 14+).
- **`valid → submitting`**: the submit pipeline picks the entry off
  the draft and sends it to the gateway.
- **`submitting → applied` / `submitting → rejected`**: the gateway
  responded; the entry is no longer in flight.

Phase 14 lands the local validators (`draft → valid | invalid`),
the submit pipeline (`valid → submitting → applied | rejected`),
and the optimistic overlay that shows the player's intent on the
map and inspector while the order is in flight.

Statuses are runtime-only — they are not persisted alongside the
commands themselves. On every `init` the store re-runs
`validateEntityName` over each command and seeds `draft → valid` /
`invalid`. Submitted-then-applied entries lose their `applied`
status on reload but stay in the draft as `valid`; the user sees
the same row, the overlay reapplies, and re-submitting is
idempotent on the engine side (the rename already matches the
stored value).

## Discriminated union shape

`OrderCommand` is a discriminated union on the `kind` field. Phase
12 shipped the skeleton with a single content-free variant; Phase
14 adds the first real one:

```ts
interface PlaceholderCommand {
    readonly kind: "placeholder";
    readonly id: string;
    readonly label: string;
}

interface PlanetRenameCommand {
    readonly kind: "planetRename";
    readonly id: string;
    readonly planetNumber: number;
    readonly name: string;
}

type OrderCommand = PlaceholderCommand | PlanetRenameCommand;
```

The `id` field is the canonical identifier the store uses for
remove and reorder; later variants must keep `id: string` so the
store API stays uniform. The whole draft round-trips through
IndexedDB structured clone, so every variant must use only
JSON-friendly value types. Phase 14 lands `planetRename` together
with the inline editor in `lib/inspectors/planet.svelte`, the
local validator (`lib/util/entity-name.ts`, parity with
`pkg/util/string.go.ValidateTypeName`), and the submit pipeline.

## Store

`OrderDraftStore` lives in
[`../frontend/src/sync/order-draft.svelte.ts`](../frontend/src/sync/order-draft.svelte.ts).
The class is a Svelte 5 runes store, so the file extension is
`.svelte.ts` (the original PLAN.md artifact line listed `.ts` —
the deviation is documented inline in `PLAN.md`'s Phase 12
"Decisions" subsection).

Lifecycle:

| Method                               | Effect                                                                                                                                |
| ------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------- |
| `init({ cache, gameId })`            | Reads the persisted draft from `cache`; sets `commands` and flips `status` to `ready`. Errors flow into `status = "error"`.           |
| `add(cmd)`                           | Appends to the end and persists.                                                                                                      |
| `remove(id)`                         | Drops the matching entry and persists. A miss is a no-op.                                                                             |
| `move(fromIndex, toIndex)`           | Reorders within the list and persists. Out-of-range and identical indices are no-ops.                                                 |
| `dispose()`                          | Marks the store destroyed; subsequent `persist()` calls are no-ops so a fast game-switch does not write stale state into the next id. |

Mutations made before `init` resolves are silently ignored — the
layout always awaits `init` through `Promise.all([...])` next to
`gameState.init` before exposing the store.

Layout integration mirrors `GameStateStore`:

- One instance per game, created in
  [`../frontend/src/routes/games/[id]/+layout.svelte`](../frontend/src/routes/games/[id]/+layout.svelte).
- Exposed through the `ORDER_DRAFT_CONTEXT_KEY` Svelte context.
- Disposed in the layout's `onDestroy`.

The order tab consumes the store via
`getContext(ORDER_DRAFT_CONTEXT_KEY)`; Phase 14's planet inspector
will use the same key to push a new command.

## Submit pipeline

`sync/submit.ts` wraps `GalaxyClient.executeCommand("user.games.order", …)`:

1. The order tab filters the draft to `valid` entries, calls
   `markSubmitting(ids)` so each row reads `submitting`, then
   posts the snapshot through `submitOrder`.
2. `submitOrder` builds the FBS `UserGamesOrder` request (game_id,
   `updatedAt = 0` in Phase 14, every command encoded as a
   `CommandItem` with the typed payload union) and signs it via
   the existing `executeCommand` orchestration.
3. The engine validates, stores, and answers `202 Accepted` with
   the stored order body — `game_id`, `updatedAt`, plus each
   command echoed with `cmdApplied` and (on rejection)
   `cmdErrorCode`.
4. The gateway re-encodes that JSON into FBS
   `UserGamesOrderResponse`, and the frontend parses it back into
   `Map<cmdId, "applied" | "rejected">`.
5. The order tab calls `applyResults` on the draft, then
   `gameState.refresh()` to fetch a fresh report. The optimistic
   overlay (`api/game-state.ts.applyOrderOverlay`) keeps the
   player's intent visible on the map / inspector even if the
   engine has not yet applied the rename — turn cutoff resolves
   the divergence on the next report.

If the gateway answers with a non-`ok` `resultCode` (auth /
transcoder / engine validation), the submit pipeline marks every
in-flight entry as `rejected` and surfaces the gateway's error
message inline; no refresh is issued. Network exceptions revert
in-flight entries back to `valid` so the operator can retry.

## Optimistic overlay

`applyOrderOverlay(report, commands, statuses)` (in
`api/game-state.ts`) returns a copy of the server `GameReport`
with every command in `applied` or `submitting` status projected
on top. Phase 14 understands `planetRename` only; future phases
extend the switch.

The overlay has its own context (`RENDERED_REPORT_CONTEXT_KEY`,
`lib/rendered-report.svelte.ts`) — the in-game shell layout owns
the source and exposes it to the inspector tab, the mobile sheet,
and the map renderer. Raw `gameState.report` stays available for
debugging and for any future consumer that needs the un-overlaid
snapshot (history mode is the planned reader).

## Server hydration on cache miss

`OrderDraftStore` records `needsServerHydration = true` when no
cache row exists for the active game (fresh install, cleared
storage, switching device). After the layout boot resolves both
`gameState.init` and `orderDraft.init`, it calls
`orderDraft.hydrateFromServer({ client, turn })` which issues
`user.games.order.get` against the gateway. A `found = false`
answer leaves the draft empty; a stored order is decoded into
`OrderCommand[]` and persisted to the local cache so subsequent
reloads use the cached copy.

An *explicitly* empty cache row (the user has removed every
command they composed) does not trigger hydration — local intent
always wins over the server snapshot. The "did this row exist?"
distinction matters: `Cache.get` returns `undefined` on a miss
and `[]` on an explicitly stored empty array.

## Persistence

Cache row layout:

| Namespace      | Key                | Value type       |
| -------------- | ------------------ | ---------------- |
| `order-drafts` | `{gameId}/draft`   | `OrderCommand[]` |

The store writes the full draft on every mutation. Phase 25 may
profile the submit pipeline and batch into a microtask if write
amplification becomes a problem; until then the deterministic
write-on-every-mutation model is what tests assert and what the
layout relies on for crash safety.

The namespace is registered in [`storage.md`](storage.md). Cache
implementation details live there; this doc only describes how the
order composer uses the namespace.

## History mode wiring

Phase 26 introduces a global history-mode flag. The IA section
specifies that the Order tab is hidden when history mode is active —
the player is browsing a past turn snapshot, and composing commands
against an immutable snapshot would be confusing.

Phase 12 wires the flag end-to-end as a prop. The layout owns the
flag (a constant `false` until Phase 26) and passes it to:

- `Sidebar` as `historyMode`. The sidebar forwards it to its
  `TabBar` as `hideOrder`. The Order entry is filtered out of the
  tab list when true. If a `?sidebar=order` URL seed lands while
  the flag is true, the sidebar falls back to `inspector`. If the
  active tab is `order` when the flag flips on, an effect resets
  it to `inspector`.
- `BottomTabs` as `hideOrder`. The mobile bottom-tab `Order`
  button is suppressed when true.

The store itself stays alive across history-mode round-trips so
the draft survives. Phase 26 will replace the constant with the
real signal from `lib/history-mode.ts` and exercise the toggle in
its own test suite.

## Testing

Phase 12 + Phase 14 test artifacts:

- [`../frontend/tests/order-draft.test.ts`](../frontend/tests/order-draft.test.ts)
  — Vitest unit tests for the store. Drives `OrderDraftStore`
  directly with `IDBCache` over `fake-indexeddb`. Covers init,
  add, remove, move, per-game isolation, mutations-before-init,
  dispose hygiene, the Phase 14 status machine
  (`validate` / `markSubmitting` / `applyResults` /
  `revertSubmittingToValid`), and the
  `hydrateFromServer` cache-miss fallback.
- [`../frontend/tests/entity-name.test.ts`](../frontend/tests/entity-name.test.ts)
  — Vitest tests for the validator. Aligned with
  `pkg/util/string_test.go.TestValidateString` for parity.
- [`../frontend/tests/submit.test.ts`](../frontend/tests/submit.test.ts)
  — Vitest tests for the submit pipeline. Hand-builds FBS
  responses to verify per-command parsing and batch-level
  fallback.
- [`../frontend/tests/order-load.test.ts`](../frontend/tests/order-load.test.ts)
  — Vitest tests for `fetchOrder`. Covers the populated /
  not-found / negative-turn / non-ok paths.
- [`../frontend/tests/order-overlay.test.ts`](../frontend/tests/order-overlay.test.ts)
  — Vitest tests for the pure `applyOrderOverlay` projection.
- [`../frontend/tests/order-tab.test.ts`](../frontend/tests/order-tab.test.ts)
  — Vitest component tests for the Submit button states and the
  applied / rejected verdict flow.
- [`../frontend/tests/inspector-planet.test.ts`](../frontend/tests/inspector-planet.test.ts)
  — Vitest component tests for the rename action and the inline
  editor's local validation.
- [`../frontend/tests/e2e/order-composer.spec.ts`](../frontend/tests/e2e/order-composer.spec.ts)
  — Playwright spec for the Phase 12 skeleton (seed three
  commands, reload, persistence).
- [`../frontend/tests/e2e/rename-planet.spec.ts`](../frontend/tests/e2e/rename-planet.spec.ts)
  — Phase 14 end-to-end: select a planet, rename, submit, observe
  the overlay-applied name on the inspector + map, reload, and
  see the rename hydrated from `user.games.order.get`.

The `__galaxyDebug.seedOrderDraft(gameId, commands)` and
`__galaxyDebug.clearOrderDraft(gameId)` helpers in
[`../frontend/src/routes/__debug/store/+page.svelte`](../frontend/src/routes/__debug/store/+page.svelte)
write directly to the cache namespace, so seeding is independent
of any mounted store.