core/docs/localization.md

# Localization

Storefront routes can be locale-prefixed (`/el/proionta`, `/en/products`) using a middleware
that reads directly from Lunar's `languages` table — the same table the Filament **Languages**
resource manages, so there's no separate locale config to keep in sync.

---

## Why prefix every locale, including the default

Leaving the default locale bare at the root (`/proionta` for Greek, `/en/products` for English)
creates ambiguity: is `/` the language-neutral homepage or specifically the Greek version? It
also complicates `hreflang` (needs a self-referencing tag on the root plus a possibly-duplicate
`x-default`) and risks duplicate content if a bot or campaign link reaches the root without a
language signal.

Prefixing every locale avoids this: every URL unambiguously declares its language, `hreflang`
tags are symmetrical, and adding a locale later requires no URL restructuring.

---

## Opt-in, not global

The middleware is registered as a **named alias** (`locale`), not pushed onto the `web`
middleware group. Apply it explicitly to the route group(s) that make up your storefront:

```php
// routes/web.php
use Illuminate\Support\Facades\Route;

Route::middleware('locale')->group(function () {
    Route::get('/{locale}', HomeController::class);
    Route::get('/{locale}/proionta', ProductIndexController::class);
    Route::get('/{locale}/proionta/{slug}', ProductShowController::class);
});
```

It is **not** applied automatically because storefront routes aren't the only routes living
under `web` in a shop:

- The Filament admin panel (`/boboko*`, see `PanelServiceProvider`) has its own routing/auth
  concerns and must never be locale-redirected.
- Livewire's internal update endpoint (`/livewire/update`) must resolve without a locale prefix.
- Webhooks, health checks, and other non-storefront routes shouldn't be touched.

If a shop's entire `web.php` *is* the storefront, wrapping the whole file in the group above is
fine — just keep admin/Livewire/webhook routes registered outside of it (as they already are).

---

## Behavior

`Modules\Core\Localization\LocaleMiddleware`:

1. Reads the first path segment (`request()->segment(1)`).
2. Matches it against `Lunar\Models\Language::code`.
   - **Match** — `App::setLocale($code)` is set, and `locale` / `language` request attributes
     are populated for controllers/views to use.
   - **No match** (missing, wrong, or unknown segment) — redirects to the same path prefixed
     with a resolved locale:
     - the best match from the `Accept-Language` header against available language codes, or
     - the language flagged `default` in the `languages` table, or
     - the first language row, as a last resort.

The language list is cached with `Cache::rememberForever()` under `core.localization.languages`
and invalidated automatically by `Modules\Core\Localization\LanguageCacheObserver`, which
observes `Lunar\Models\Language` `saved`/`deleted` events. Adding, editing, or removing a
language via the Filament **Languages** resource clears the cache immediately — no TTL, no
stale reads.

---

## Reading the resolved locale/language downstream

```php
// In a controller or view composer
$locale = $request->attributes->get('locale');      // e.g. "el"
$language = $request->attributes->get('language');   // Lunar\Models\Language instance
```

Use `$language->id` when querying Lunar's translatable content (e.g. `Url::where('language_id', ...)`).

---

## Single-language shops

If a shop has only one row in `languages`, the middleware still enforces the prefix (e.g. every
URL under `/en/...`) rather than special-casing it away — this keeps behavior identical across
shops and avoids a silent restructuring if a second language is added later. If a shop genuinely
never wants locale prefixes, don't apply the `locale` middleware to its routes at all.

---

## Storefront UI labels (`__('storefront.*')`)

The `locale` middleware resolves *which* language a request is in — routing/redirects,
`Lunar\Models\Language`, and Lunar's own translatable product/collection content. It has nothing
to do with static UI chrome like "Cart", "Back", "Add to Cart". Those are handled separately by
[`spatie/laravel-translation-loader`](https://github.com/spatie/laravel-translation-loader),
stored in the `language_lines` table.

### Why a separate system, not another `languages`-table lookup

Lunar's translatable fields (`TranslatedText`, `Url`, etc.) are all tied to specific *model
records* — a product's name, a collection's description. UI labels aren't attached to any model;
they're static strings the app itself owns. `laravel-translation-loader` is Laravel's own
`__()`/`trans()` mechanism with a DB-backed source layered on top of the normal file-based one —
no new helper to learn, no bespoke table shape.

**Nothing existing breaks.** The package's `TranslationLoaderManager` *extends* Laravel's
`FileLoader` and merges DB translations on top of file-based ones
(`array_replace_recursive()`) — Filament's own vendor `lang/en/product.php`-style strings
keep working exactly as before. The package registers itself via Laravel's standard Composer
package auto-discovery (`extra.laravel.providers` in its own `composer.json`) — nothing needed
in `CoreServiceProvider` to wire it up.

### Usage

```blade
{{ __('storefront.nav.cart') }}
{{ __('storefront.product.add_to_cart') }}
```

`group` is `storefront` for e-shop UI labels — kept separate from Lunar/Filament's own `lunar::`
namespaced groups so nothing collides. `__()` resolves the translation for whatever
`App::getLocale()` currently is, which `LocaleMiddleware` already sets per-request (see
"Behavior" above) — no extra wiring needed between the two systems.

### Seeding

A starter set of common e-shop labels (`nav.*`, `cart.*`, `product.*`, `auth.*`, `search.*`,
English + Greek) is seeded by `Modules\Core\Command\InstallLunarCommand` (overrides Lunar's own
`lunar:install`), guarded by `LanguageLine::where('group', 'storefront')->exists()` — same
idempotent pattern as the rest of that command, safe to run unattended on every boot.

**Editing existing labels or adding new ones is a normal Eloquent operation**, not a
re-seed:

```php
use Spatie\TranslationLoader\LanguageLine;

LanguageLine::create([
    'group' => 'storefront',
    'key' => 'nav.wishlist',
    'text' => ['en' => 'Wishlist', 'el' => 'Λίστα Επιθυμιών'],
]);
```

There is currently no Filament resource for editing `language_lines` — labels are edited via
tinker/seeder until one is built. `LanguageLine` caches per group+locale
(`Cache::rememberForever`) and flushes itself automatically on `saved`/`deleted`, so edits take
effect immediately with no manual cache-clear step.