feat(locale): add Locale::default() function to retrieve default lo…

…cale (#447) Signed-off-by: azjezz <azjezz@protonmail.com>
azjezz · Mar 24, 2024 · 69728d2 · 69728d2
1 parent 5f0aeac
commit 69728d2
Show file tree

Hide file tree

Showing 3 changed files with 165 additions and 1 deletion.
diff --git a/docs/component/locale.md b/docs/component/locale.md
@@ -12,6 +12,6 @@
 
 #### `Enums`
 
-- [Locale](./../../src/Psl/Locale/Locale.php#L12)
+- [Locale](./../../src/Psl/Locale/Locale.php#L13)
 
 
diff --git a/src/Psl/Locale/Locale.php b/src/Psl/Locale/Locale.php
@@ -5,6 +5,7 @@
 namespace Psl\Locale;
 
 use Locale as NativeLocale;
+use Psl\Str;
 
 /**
  * Represents a locale identifier.
@@ -686,8 +687,11 @@ enum Locale: string
     case AlbanianNorthMacedonia = "sq_MK";
     case AlbanianKosovo = "sq_XK";
     case Serbian = "sr";
+    case SerbianSerbia = "sr_RS";
     case SerbianCyrillic = "sr_Cyrl";
+    case SerbianCyrillicSerbia = "sr_Cyrl_RS";
     case SerbianLatin = "sr_Latn";
+    case SerbianLatinSerbia = "sr_Latn_RS";
     case Sundanese = "su";
     case SundaneseLatin = "su_Latn";
     case Swedish = "sv";
@@ -791,6 +795,48 @@ enum Locale: string
     case Zulu = "zu";
     case ZuluSouthAfrica = "zu_ZA";
 
+    /**
+     * Retrieves the system's default locale from the PHP environment settings.
+     *
+     * This method returns the locale configured via `intl.default_locale`. Should the PHP environment lack a specific
+     * locale configuration or if the configured locale is unsupported, it defaults to `self::English` representing
+     * the English language.
+     *
+     * The choice of English as the fallback is motivated by its global comprehension, role as a base language in
+     * technology and international communication, predominance in technical documentation and support resources,
+     * and its historical precedence in the tech industry. These factors ensure the fallback locale is both broadly
+     * accessible and consistent with international standards.
+     *
+     * @return self The default locale as an enum instance, sourced from PHP settings or `self::English` as the fallback.
+     *
+     * @see https://www.php.net/manual/en/locale.getdefault.php
+     */
+    public static function default(): self
+    {
+        $full_locale = NativeLocale::getDefault();
+        if (!$full_locale) {
+            // Fallback to English if no locale is set or supported.
+            return self::English;
+        }
+
+        $language = NativeLocale::getPrimaryLanguage($full_locale);
+        $script = NativeLocale::getScript($full_locale);
+        $region = NativeLocale::getRegion($full_locale);
+
+        $locale = Str\lowercase($language);
+        if ($script) {
+            $locale .= '_' . Str\capitalize($script);
+        }
+
+        if ($region) {
+            $locale .= '_' . Str\uppercase($region);
+        }
+
+        // Attempt to match the system-configured locale with a supported enum instance,
+        // defaulting to English if a precise match is unavailable.
+        return self::tryFrom($locale) ?? self::tryFrom($language) ?? self::English;
+    }
+
     /**
      * Get a human-readable name for the locale, suitable for display.
      *

diff --git a/tests/unit/Locale/LocaleTest.php b/tests/unit/Locale/LocaleTest.php
@@ -9,8 +9,125 @@
 use Psl\Locale\Locale;
 use Psl\Str;
 
+use function locale_get_default;
+use function locale_set_default;
+
 final class LocaleTest extends TestCase
 {
+    private ?string $defaultLocale = null;
+    protected function setUp(): void
+    {
+        $this->defaultLocale = locale_get_default();
+    }
+
+    protected function tearDown(): void
+    {
+        if (null !== $this->defaultLocale) {
+            locale_set_default($this->defaultLocale);
+        }
+    }
+
+    public function testDefault(): void
+    {
+        foreach (Locale::cases() as $locale) {
+            locale_set_default($locale->value);
+
+            static::assertSame($locale, Locale::default());
+        }
+    }
+
+    public function testDefaultIgnoresCharset(): void
+    {
+        locale_set_default('sr_RS.UTF-8');
+        static::assertSame(Locale::SerbianSerbia, Locale::default());
+
+        locale_set_default('sr_Cyrl.UTF-8');
+        static::assertSame(Locale::SerbianCyrillic, Locale::default());
+        locale_set_default('sr_Cyrl_RS.UTF-8');
+        static::assertSame(Locale::SerbianCyrillicSerbia, Locale::default());
+
+        locale_set_default('sr_Latn.UTF-8');
+        static::assertSame(Locale::SerbianLatin, Locale::default());
+        locale_set_default('sr_Latn_RS.UTF-8');
+        static::assertSame(Locale::SerbianLatinSerbia, Locale::default());
+    }
+
+    public function testDefaultIgnoresVariant(): void
+    {
+        locale_set_default('sr_RS@ekavsk');
+        static::assertSame(Locale::SerbianSerbia, Locale::default());
+
+        locale_set_default('sr_Cyrl@ekavsk');
+        static::assertSame(Locale::SerbianCyrillic, Locale::default());
+        locale_set_default('sr_Cyrl_RS@ekavsk');
+        static::assertSame(Locale::SerbianCyrillicSerbia, Locale::default());
+
+        locale_set_default('sr_Latn@ekavsk');
+        static::assertSame(Locale::SerbianLatin, Locale::default());
+        locale_set_default('sr_Latn_RS@ekavsk');
+        static::assertSame(Locale::SerbianLatinSerbia, Locale::default());
+    }
+
+    public function testDefaultIgnoresExtension(): void
+    {
+        locale_set_default('sr_RS-u-currency-EUR');
+        static::assertSame(Locale::SerbianSerbia, Locale::default());
+
+        locale_set_default('sr_Cyrl-u-currency-EUR');
+        static::assertSame(Locale::SerbianCyrillic, Locale::default());
+        locale_set_default('sr_Cyrl_RS-u-currency-EUR');
+        static::assertSame(Locale::SerbianCyrillicSerbia, Locale::default());
+
+        locale_set_default('sr_Latn-u-currency-EUR');
+        static::assertSame(Locale::SerbianLatin, Locale::default());
+        locale_set_default('sr_Latn_RS-u-currency-EUR');
+        static::assertSame(Locale::SerbianLatinSerbia, Locale::default());
+    }
+
+    public function testDefaultIgnoresCasing(): void
+    {
+        locale_set_default('ar_TN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('AR_TN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('AR_tn');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('aR_Tn');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('Ar_tN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('Ar_TN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('aR_TN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('AR_Tn');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+
+        locale_set_default('AR_tN');
+        static::assertSame(Locale::ArabicTunisia, Locale::default());
+    }
+
+    public function testFallbackToJustLanguage(): void
+    {
+        locale_set_default('zh_CN');
+
+        static::assertSame(Locale::Chinese, Locale::default());
+    }
+
+    public function testDefaultFallbacksToEnglish(): void
+    {
+        locale_set_default('xx_XX');
+
+        static::assertSame(Locale::English, Locale::default());
+    }
+
     /**
      * @return Generator<string, array{Locale}, void, null>
      */
@@ -119,6 +236,7 @@ public function getLocalesWithoutRegion(): Generator
             }
         }
     }
+
     /**
      * @dataProvider getLocalesWithoutRegion
      */