<?php

declare(strict_types=1);

namespace Tests\Core;

use App\Core\Locale;
use PHPUnit\Framework\Attributes\DataProvider;
use PHPUnit\Framework\TestCase;

class LocaleTest extends TestCase
{
    // ──────────────────────────────────────────────
    // resolve(): priority order
    // ──────────────────────────────────────────────

    public function testResolveReturnsDefaultWhenNoSignals(): void
    {
        $this->assertSame('de', Locale::resolve());
    }

    public function testQueryParamWinsOverCookieAndHeader(): void
    {
        $this->assertSame('en', Locale::resolve('en', 'ru', 'uk'));
    }

    public function testCookieWinsOverHeader(): void
    {
        $this->assertSame('ru', Locale::resolve(null, 'ru', 'en'));
    }

    public function testHeaderUsedWhenNoQueryOrCookie(): void
    {
        $this->assertSame('en', Locale::resolve(null, null, 'en-US,de;q=0.9'));
    }

    public function testFallsBackToDefaultWhenHeaderDoesNotMatch(): void
    {
        $this->assertSame('de', Locale::resolve(null, null, 'fr-FR,it-IT'));
    }

    public function testInvalidQueryParamIsSkippedAndCookieWins(): void
    {
        // Invalid query (e.g. 'fr' which is not supported) is treated as
        // "no signal" from that source — we fall through to the next source.
        $this->assertSame('en', Locale::resolve('fr', 'en', 'en'));
    }

    public function testEmptyStringsAreTreatedAsNoSignal(): void
    {
        $this->assertSame('en', Locale::resolve('', '', 'en'));
    }

    // ──────────────────────────────────────────────
    // isSupported()
    // ──────────────────────────────────────────────

    #[DataProvider('provideSupportedLocales')]
    public function testIsSupportedReturnsTrueForKnownLocales(string $code): void
    {
        $this->assertTrue(Locale::isSupported($code));
    }

    #[DataProvider('provideUnsupportedLocales')]
    public function testIsSupportedReturnsFalseForUnknownLocales(string $code): void
    {
        $this->assertFalse(Locale::isSupported($code));
    }

    public static function provideSupportedLocales(): array
    {
        return [
            'german'    => ['de'],
            'uk-english' => ['en'],
            'ukrainian' => ['uk'],
            'russian'   => ['ru'],
        ];
    }

    public static function provideUnsupportedLocales(): array
    {
        return [
            'french'   => ['fr'],
            'empty'    => [''],
            'upper'    => ['DE'],
            'region'   => ['de-DE'],
            'wildcard' => ['*'],
            'garbage'  => ['xx'],
        ];
    }

    // ──────────────────────────────────────────────
    // parseAcceptLanguage()
    // ──────────────────────────────────────────────

    public function testParseAcceptLanguageReturnsEmptyForEmptyHeader(): void
    {
        $this->assertSame([], Locale::parseAcceptLanguage(''));
    }

    public function testParseAcceptLanguageHandlesSingleTag(): void
    {
        $this->assertSame(['en'], Locale::parseAcceptLanguage('en'));
    }

    public function testParseAcceptLanguageSortsByQValue(): void
    {
        $this->assertSame(
            ['ru', 'en', 'de'],
            Locale::parseAcceptLanguage('de;q=0.5,en;q=0.8,ru;q=0.9')
        );
    }

    public function testParseAcceptLanguageDefaultsQTo1(): void
    {
        $this->assertSame(['de', 'en'], Locale::parseAcceptLanguage('de,en;q=0.5'));
    }

    public function testParseAcceptLanguageDropsQ0(): void
    {
        // 'en;q=0' is explicitly forbidden by the client → drop it.
        // 'de;q=1' is the only one left.
        $this->assertSame(['de'], Locale::parseAcceptLanguage('en;q=0,de;q=1'));
    }

    public function testParseAcceptLanguageStripsBcp47Region(): void
    {
        $this->assertSame(['en', 'de'], Locale::parseAcceptLanguage('en-US,de-DE'));
    }

    public function testParseAcceptLanguageDropsWildcard(): void
    {
        $this->assertSame([], Locale::parseAcceptLanguage('*'));
        // Wildcard plus q=0 → nothing to use
        $this->assertSame([], Locale::parseAcceptLanguage('*,en;q=0'));
    }

    public function testParseAcceptLanguageIsStableForEqualQValues(): void
    {
        $this->assertSame(
            ['en', 'de', 'uk'],
            Locale::parseAcceptLanguage('en;q=0.8,de;q=0.8,uk;q=0.8')
        );
    }

    public function testParseAcceptLanguageHandlesWhitespace(): void
    {
        $this->assertSame(['en', 'de'], Locale::parseAcceptLanguage('  en  ,  de  ;  q=0.5  '));
    }

    // ──────────────────────────────────────────────
    // toOgLocale()
    // ──────────────────────────────────────────────

    public function testToOgLocaleMapsToBcp47(): void
    {
        $this->assertSame('de_DE', Locale::toOgLocale('de'));
        $this->assertSame('en_GB', Locale::toOgLocale('en'));
        $this->assertSame('uk_UA', Locale::toOgLocale('uk'));
        $this->assertSame('ru_RU', Locale::toOgLocale('ru'));
    }

    public function testToOgLocaleFallsBackToDeForUnknown(): void
    {
        $this->assertSame('de_DE', Locale::toOgLocale('fr'));
    }

    // ──────────────────────────────────────────────
    // hreflangAlternates()
    // ──────────────────────────────────────────────

    public function testHreflangAlternatesBuildsFullSet(): void
    {
        $alts = Locale::hreflangAlternates('/');

        $this->assertCount(4, $alts);
        $locales = array_column($alts, 'locale');
        $this->assertSame(['de', 'en', 'uk', 'ru'], $locales);

        $en = array_values(array_filter($alts, static fn ($a) => $a['locale'] === 'en'))[0];
        $this->assertSame('en-GB', $en['hreflang']);
        $this->assertStringContainsString('?lang=en', $en['href']);
    }
}