<?php

namespace App\Util\Localization;

use Illuminate\Support\Arr;

class Localization
{
    /**
     * List of available UI language codes.
     *
     * Reads the static manifest generated by `php artisan i18n:export`
     * (lang/locales.json) so the list is deterministic and never served from
     * a runtime cache that can go stale. Falls back to scanning the lang/
     * directory if the manifest is missing.
     *
     * @return array<int, string>
     */
    public static function languages()
    {
        return static::localesFromManifest() ?? static::localesFromScan();
    }

    /**
     * Full locale metadata (code, name, nativeName) from the manifest,
     * sorted by display name. Empty array if the manifest is missing.
     *
     * @return array<int, array{code: string, name: string, nativeName: string}>
     */
    public static function locales(): array
    {
        $path = lang_path('locales.json');

        if (! is_file($path)) {
            return [];
        }

        $data = json_decode((string) file_get_contents($path), true);

        return is_array($data) ? $data : [];
    }

    /**
     * @return array<int, string>|null
     */
    protected static function localesFromManifest(): ?array
    {
        $locales = static::locales();

        if (empty($locales)) {
            return null;
        }

        return array_values(array_filter(array_map(
            fn ($l) => $l['code'] ?? null,
            $locales
        )));
    }

    /**
     * @return array<int, string>
     */
    protected static function localesFromScan(): array
    {
        $dir = lang_path();

        return Arr::flatten(array_diff(scandir($dir), ['..', '.', 'vendor', '.DS_Store', 'locales.json']));
    }
}