TypeScript, in layers, with a strict linter

The client was one main.js, one preload.js, three files in lib/ and one renderer
script. It is now a typed application whose imports point inward: domain (models,
ports, errors) knows nothing about Electron, Node or Python; application orchestrates
it through those ports; infrastructure holds the adapters — the Python CLI, HTTP, the
filesystem, Electron itself — and main, preload and renderer sit on top as hosts.

STRUCTURE.md is the map, and the deliverable as much as the code is: every layer, every
pattern in use (ports and adapters, repository vs gateway, service, DTO and mapper,
composition root, controller and router, single flight, observer streams, state store
with unidirectional flow, passive view, coded error hierarchy, frozen constant tables,
untrusted-data readers) and the naming rules — files, classes, and a verb vocabulary
for methods where find/require/read/list/apply/render/handle each state a contract.

Two properties fell out of the move, and they are why it was worth doing:

  - The catalog can be driven with no window and no Electron at all. The smoke test
    assembles the same services against the same ports in a plain Node process; it used
    to be a script that reimplemented the bridge.
  - The window never receives a filesystem path. A title crosses the bridge without
    one, and launching is asked for by name, resolved in the main process from the
    store's own state. Verified with a fake launcher: an unknown name answers false, a
    native title resolves to its menu entry, a hosted one to its catalog URL.

Types are mandatory, including where inference would manage: explicit return,
parameter and property types, strict plus noUncheckedIndexedAccess,
exactOptionalPropertyTypes, noImplicitOverride and noPropertyAccessFromIndexSignature,
typescript-eslint strictTypeChecked and stylisticTypeChecked, exhaustive switches, no
any, no non-null assertions, and no casts on foreign data — engine stdout and the
registry go through readers that turn unknown into typed values. naming-convention
enforces the patterns rather than trusting them.

Two rule conflicts had to be decided rather than papered over. typedef and
no-inferrable-types disagree about `fallback: string = ''`: the annotation wins, since a
signature states its types. erasableSyntaxOnly is off, because it forbids constructor
parameter properties, which are how dependencies are declared here.

The preload and the renderer are bundled by esbuild into one file each: a sandboxed
preload may not require its own modules, and a module script over file:// is blocked by
the page's own origin rules. tsc compiles the rest. The package ships build/** and
package.json — 111 entries, no sources, no toolchain.

New targets: build, typecheck, lint, lint-fix, and check — typecheck, lint, then both
test suites, cheapest failure first. Every script that runs the app builds first, so a
stale bundle cannot be tested.

Nothing about the window changed: same side menu, same categories, same switcher, same
two languages. make check is clean, both test suites pass with one store and with two,
the packaged 1.3.0 bundle drives the real store, and the window was photographed before
and after — the two are the same picture.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/shared/i18n/EnglishMessages.ts

@@ -0,0 +1,63 @@
+/**
+ * The English message bundle, and the source of the key set.
+ *
+ * Every other language is typed against these keys, so a missing or misspelled
+ * translation is a compile error rather than a blank label at runtime.
+ */
+export const ENGLISH_MESSAGES = {
+  appName: 'WarpEngine Store',
+  syncAll: 'Install all',
+  refresh: 'Refresh',
+  install: 'Install',
+  update: 'Update',
+  play: 'Play',
+  open: 'Open',
+  remove: 'Remove',
+  installed: 'installed',
+  native: 'native',
+  hosted: 'hosted',
+  hostedHint: 'Opens in your browser — needs the network',
+  nativeHint: 'Installed on this machine — works offline',
+  updateAvailable: 'update available',
+  log: 'Log',
+  menu: 'Menu',
+  stores: 'Stores',
+  addStore: 'Add a store…',
+  switchFailed: 'That store could not be opened',
+  actions: 'Actions',
+  categories: 'Categories',
+  catAll: 'Everything',
+  catInstalled: 'Installed',
+  catUpdates: 'Updates',
+  catAvailable: 'Not installed',
+  catPlatform: 'Platform',
+  catMode: 'Kind',
+  language: 'Language',
+  noGames: 'No installable titles in the catalog.',
+  noMatch: 'Nothing in this category.',
+  setupTitle: 'Set up a store',
+  setupBody: 'No store on this machine yet. Pick one and it will be downloaded — the same files the shell installer would place, in the same folder.',
+  setupAction: 'Download the store',
+  setupWorking: 'Setting up…',
+  setupChoose: 'Store',
+  registryFailed: 'The list of stores could not be fetched',
+  registryEmpty: 'The list of stores came back empty. Nothing to install from yet.',
+  registryRetry: 'Try again',
+  oldEngineTitle: 'The store needs refreshing',
+  oldEngineBody: 'The store engine on this machine is older than this client can drive. Refreshing it downloads the current engine and keeps your settings and installed games.',
+  oldEngineAction: 'Refresh the store',
+  noPythonTitle: 'Python 3 is required',
+  noPythonBody: 'The store is a Python program, so Python 3 has to be installed. Install it, then reopen this window.',
+  pythonLink: 'python.org/downloads',
+  paths: 'Where things go',
+  openStoreFolder: 'Open the store folder',
+  openMenuFolder: 'Open the menu folder',
+  busy: 'Working…',
+  failed: 'failed',
+  removed: 'removed',
+  upToDate: 'Everything is up to date.',
+  of: 'of'
+} as const
+
+/** Every string the window can show, by key. */
+export type MessageKey = keyof typeof ENGLISH_MESSAGES

src/shared/i18n/HungarianMessages.ts

@@ -0,0 +1,60 @@
+import type { MessageBundle } from './MessageBundle'
+
+/**
+ * Hungarian. Catalog text — titles, descriptions — is never translated here: it
+ * arrives from the store as it was published.
+ */
+export const HUNGARIAN_MESSAGES: MessageBundle = {
+  appName: 'WarpEngine Store',
+  syncAll: 'Mind telepítése',
+  refresh: 'Frissítés',
+  install: 'Telepítés',
+  update: 'Frissítés',
+  play: 'Indítás',
+  open: 'Megnyitás',
+  remove: 'Eltávolítás',
+  installed: 'telepítve',
+  native: 'natív',
+  hosted: 'hosztolt',
+  hostedHint: 'A böngészőben nyílik meg — internet kell hozzá',
+  nativeHint: 'Erre a gépre telepítve — internet nélkül is megy',
+  updateAvailable: 'frissítés elérhető',
+  log: 'Napló',
+  menu: 'Menü',
+  stores: 'Store-ok',
+  addStore: 'Store hozzáadása…',
+  switchFailed: 'Ez a store nem nyitható meg',
+  actions: 'Műveletek',
+  categories: 'Kategóriák',
+  catAll: 'Minden',
+  catInstalled: 'Telepítve',
+  catUpdates: 'Frissítés',
+  catAvailable: 'Nincs telepítve',
+  catPlatform: 'Platform',
+  catMode: 'Fajta',
+  language: 'Nyelv',
+  noGames: 'Nincs telepíthető cím a katalógusban.',
+  noMatch: 'Ebben a kategóriában nincs semmi.',
+  setupTitle: 'Store beállítása',
+  setupBody: 'Ezen a gépen még nincs store. Válassz egyet, és letöltöm — ugyanazokat a fájlokat, ugyanabba a könyvtárba, ahová a shell-telepítő tenné.',
+  setupAction: 'Store letöltése',
+  setupWorking: 'Beállítás…',
+  setupChoose: 'Store',
+  registryFailed: 'A store-ok listája nem érhető el',
+  registryEmpty: 'A store-ok listája üresen jött vissza. Egyelőre nincs miből telepíteni.',
+  registryRetry: 'Újra',
+  oldEngineTitle: 'A store frissítésre vár',
+  oldEngineBody: 'A gépen lévő store-motor régebbi, mint amit ez a kliens vezérelni tud. A frissítés letölti a mostani motort, a beállításaid és a telepített játékok pedig megmaradnak.',
+  oldEngineAction: 'Store frissítése',
+  noPythonTitle: 'Python 3 kell hozzá',
+  noPythonBody: 'A store egy Python program, tehát Python 3 kell a gépre. Telepítsd, majd nyisd meg újra ezt az ablakot.',
+  pythonLink: 'python.org/downloads',
+  paths: 'Hova kerül',
+  openStoreFolder: 'Store könyvtár megnyitása',
+  openMenuFolder: 'Menü könyvtár megnyitása',
+  busy: 'Dolgozom…',
+  failed: 'hiba',
+  removed: 'eltávolítva',
+  upToDate: 'Minden naprakész.',
+  of: '/'
+}

src/shared/i18n/MessageBundle.ts

@@ -0,0 +1,9 @@
+import type { MessageKey } from './EnglishMessages'
+
+/** One complete language. Partial bundles are not a thing: the type forbids them. */
+export type MessageBundle = Readonly<Record<MessageKey, string>>
+
+/** The languages the window speaks. The public site has the same two. */
+export const LOCALES = ['en', 'hu'] as const
+
+export type Locale = (typeof LOCALES)[number]

src/shared/i18n/TranslationCatalog.ts

@@ -0,0 +1,30 @@
+import { ENGLISH_MESSAGES } from './EnglishMessages'
+import { HUNGARIAN_MESSAGES } from './HungarianMessages'
+import { LOCALES, type Locale, type MessageBundle } from './MessageBundle'
+
+const BUNDLES: Readonly<Record<Locale, MessageBundle>> = {
+  en: ENGLISH_MESSAGES,
+  hu: HUNGARIAN_MESSAGES
+}
+
+const FALLBACK_LOCALE: Locale = 'en'
+
+/**
+ * Which language, and its strings.
+ *
+ * Used on both sides of the bridge: the main process resolves the locale and
+ * ships the bundle, the window renders from it.
+ */
+export class TranslationCatalog {
+  public readonly locales: readonly Locale[] = LOCALES
+
+  /** A system locale like `hu-HU`, or anything at all, mapped onto a language. */
+  public resolveLocale (candidate: string | null | undefined): Locale {
+    const short = (candidate ?? '').slice(0, 2).toLowerCase()
+    return LOCALES.find((locale: Locale): boolean => locale === short) ?? FALLBACK_LOCALE
+  }
+
+  public readBundle (candidate: string | null | undefined): MessageBundle {
+    return BUNDLES[this.resolveLocale(candidate)]
+  }
+}