<?php

declare(strict_types=1);

namespace LIT\MCP\Tests\Unit\Integrations\SuperCache;

use Brain\Monkey\Functions;
use Closure;
use LIT\MCP\Compatibility\ThrowawayPost;
use LIT\MCP\Integrations\SuperCache\SuperCacheProbe;
use LIT\MCP\Tests\Unit\TestCase;
use Mockery;
use RuntimeException;
use WP_Post;

final class SuperCacheProbeTest extends TestCase
{
    private string $cacheRoot = '';

    /** @var list<int> */
    private array $deleted = [];

    /** @var list<string> "<id>:<status>" in call order. */
    private array $statuses = [];

    /** @var array<string, mixed>|null The wp_insert_post arguments. */
    private ?array $inserted = null;

    /** @var array<string, mixed> Globals the test changes (only those that existed). */
    private array $savedGlobals = [];

    private const GLOBALS_CHANGED = ['cache_enabled', 'cache_path', 'wpdb', 'wp_cache_clear_on_post_edit'];

    /** The status the fake status switch refuses to set (returns false); null = none. */
    private ?string $refusedStatus = null;

    /** The status the fake status switch throws for; null = none. */
    private ?string $throwingStatus = null;

    protected function setUp(): void
    {
        parent::setUp();
        $this->cacheRoot = sys_get_temp_dir() . '/lit-mcp-wpsc-' . bin2hex(random_bytes(4)) . '/';
        mkdir($this->cacheRoot . 'supercache/example.test/', 0777, true);
        $this->deleted = [];
        $this->statuses = [];
        $this->inserted = null;
        $this->refusedStatus = null;
        $this->throwingStatus = null;
        $this->savedGlobals = [];
        foreach (self::GLOBALS_CHANGED as $name) {
            if (array_key_exists($name, $GLOBALS)) {
                $this->savedGlobals[$name] = $GLOBALS[$name];
            }
        }
        Functions\when('wp_insert_post')->alias(function (array $post): int {
            $this->inserted = $post;

            return 77;
        });
        Functions\when('wp_delete_post')->alias(function (int $id, bool $force): WP_Post {
            self::assertTrue($force, 'never to the trash');
            $this->deleted[] = $id;

            return new WP_Post(['ID' => $id]);
        });
        Functions\when('wp_mkdir_p')->alias(static fn (string $dir): bool => is_dir($dir) || @mkdir($dir, 0777, true));
    }

    protected function tearDown(): void
    {
        foreach (self::GLOBALS_CHANGED as $name) {
            if (array_key_exists($name, $this->savedGlobals)) {
                $GLOBALS[$name] = $this->savedGlobals[$name];
            } else {
                unset($GLOBALS[$name]);
            }
        }
        self::removeTree($this->cacheRoot);
        parent::tearDown();
    }

    private static function removeTree(string $path): void
    {
        foreach (glob(rtrim($path, '/') . '/{,.}*', GLOB_BRACE) ?: [] as $entry) {
            if (in_array(basename($entry), ['.', '..'], true)) {
                continue;
            }
            is_dir($entry) ? self::removeTree($entry) : unlink($entry);
        }
        @rmdir($path);
    }

    private function pageDir(): string
    {
        return $this->cacheRoot . 'supercache/example.test/lit-mcp-check-77/';
    }

    /** @param (Closure(int): void)|null $purge */
    private function probe(?Closure $purge = null, ?Closure $cacheDir = null, bool $enabled = true): SuperCacheProbe
    {
        return new SuperCacheProbe(
            static fn (): bool => $enabled,
            $cacheDir ?? fn (int $id): string => $this->pageDir(),
            $purge ?? fn (int $id) => unlink($this->pageDir() . 'index.html'),
            function (int $id, string $status): bool {
                $this->statuses[] = $id . ':' . $status;
                if ($status === $this->throwingStatus) {
                    throw new RuntimeException('Status kaputt');
                }

                return $status !== $this->refusedStatus;
            }
        );
    }

    /** Purge fake that does what WPSC does: the page's cache file disappears. */
    private function purgingProbe(): SuperCacheProbe
    {
        return $this->probe(function (int $id): void {
            self::assertFileExists($this->pageDir() . 'index.html', 'the file is there before the purge');
            unlink($this->pageDir() . 'index.html');
        });
    }

    /** Captures what Log writes to the PHP error log while $run runs. */
    private function logged(Closure $run): string
    {
        $log = (string) tempnam(sys_get_temp_dir(), 'lit-mcp-log');
        $previous = ini_set('error_log', $log);
        try {
            $run();

            return (string) file_get_contents($log);
        } finally {
            ini_set('error_log', (string) $previous);
            unlink($log);
        }
    }

    public function testGreenWhenThePurgeRemovesTheCacheFileAndNothingIsLeftBehind(): void
    {
        self::assertSame([], $this->purgingProbe()->run());

        self::assertDirectoryDoesNotExist($this->pageDir());
        self::assertSame([77], $this->deleted);
    }

    public function testCreatesAMarkedDraftPageAndOnlyPassesThroughPrivateForThePurge(): void
    {
        $this->purgingProbe()->run();

        self::assertSame('page', $this->inserted['post_type']);
        self::assertSame('draft', $this->inserted['post_status']);
        self::assertStringStartsWith(ThrowawayPost::TITLE, $this->inserted['post_title']);
        self::assertSame([ThrowawayPost::MARKER => '1'], $this->inserted['meta_input']);
        self::assertSame(['77:private', '77:draft'], $this->statuses);
    }

    public function testACacheFileThatSurvivesThePurgeIsAFixedTextAndIsRemovedAnyway(): void
    {
        $problems = [];
        $logged = $this->logged(function () use (&$problems): void {
            $problems = $this->probe(static fn (int $id) => null)->run();
        });

        self::assertSame(['Die Testdatei im Cache blieb nach dem Leeren durch WP Super Cache bestehen.'], $problems);
        self::assertStringContainsString('lit-mcp-check-77', $logged);
        self::assertDirectoryDoesNotExist($this->pageDir());
        self::assertSame([77], $this->deleted);
    }

    public function testARenamedRebuildFileCountsAsPurgedAndIsCleanedUp(): void
    {
        $problems = $this->probe(function (int $id): void {
            rename($this->pageDir() . 'index.html', $this->pageDir() . 'index.html.needs-rebuild');
        })->run();

        self::assertSame([], $problems);
        self::assertDirectoryDoesNotExist($this->pageDir());
    }

    public function testADirectoryThePurgeAlreadyRemovedIsNoProblem(): void
    {
        $problems = $this->probe(function (int $id): void {
            unlink($this->pageDir() . 'index.html');
            rmdir($this->pageDir());
        })->run();

        self::assertSame([], $problems);
    }

    public function testAnExceptionOfThePurgeIsAFixedTextALogLineAndEverythingIsCleanedUp(): void
    {
        $problems = [];
        $logged = $this->logged(function () use (&$problems): void {
            $problems = $this->probe(static function (int $id): never {
                throw new RuntimeException('WPSC kaputt');
            })->run();
        });

        self::assertSame(['Super-Cache-Probe abgebrochen (Details im PHP-Error-Log).'], $problems);
        self::assertStringContainsString('WPSC kaputt', $logged);
        self::assertDirectoryDoesNotExist($this->pageDir());
        self::assertSame([77], $this->deleted);
        self::assertSame(['77:private', '77:draft'], $this->statuses);
    }

    public function testNothingToProbeWhileTheCacheIsSwitchedOff(): void
    {
        self::assertNull($this->probe(null, null, false)->run());
        self::assertNull($this->inserted);
    }

    public function testNothingToProbeWithoutACachePathForThePage(): void
    {
        self::assertNull($this->probe(null, static fn (int $id): ?string => null)->run());
        self::assertSame([77], $this->deleted);
    }

    public function testACacheDirectoryThatCannotBeCreatedIsAFixedText(): void
    {
        $blocker = $this->cacheRoot . 'blocker';
        file_put_contents($blocker, 'x');
        $problems = [];
        $logged = $this->logged(function () use (&$problems, $blocker): void {
            $problems = $this->probe(null, static fn (int $id): string => $blocker . '/seite/')->run();
        });

        self::assertSame(['Die Testdatei konnte nicht im Cache-Verzeichnis angelegt werden (Details im PHP-Error-Log).'], $problems);
        self::assertStringContainsString('seite', $logged);
        self::assertSame([77], $this->deleted);
    }

    public function testTheDefaultPurgeIsWpCachePostEdit(): void
    {
        Functions\expect('wp_cache_post_edit')->once()->with(77)->andReturnUsing(function (int $id): int {
            unlink($this->pageDir() . 'index.html');

            return $id;
        });

        $probe = new SuperCacheProbe(
            static fn (): bool => true,
            fn (int $id): string => $this->pageDir(),
            null,
            static fn (): bool => true
        );

        self::assertSame([], $probe->run());
    }

    public function testTheDefaultStatusSwitchWritesStatusAndSlugStraightToTheDatabaseWithoutHooks(): void
    {
        $wpdb = Mockery::mock();
        $wpdb->posts = 'wp_posts';
        $wpdb->expects('update')->with('wp_posts', ['post_status' => 'private', 'post_name' => 'lit-mcp-check-77'], ['ID' => 77])->andReturn(1);
        $wpdb->expects('update')->with('wp_posts', ['post_status' => 'draft', 'post_name' => 'lit-mcp-check-77'], ['ID' => 77])->andReturn(1);
        $GLOBALS['wpdb'] = $wpdb;
        Functions\expect('clean_post_cache')->never();
        $dropped = [];
        Functions\when('wp_cache_delete')->alias(static function (int $id, string $group) use (&$dropped): bool {
            $dropped[] = $group . ':' . $id;

            return true;
        });

        $probe = new SuperCacheProbe(
            static fn (): bool => true,
            fn (int $id): string => $this->pageDir(),
            fn (int $id) => unlink($this->pageDir() . 'index.html')
        );

        self::assertSame([], $probe->run());
        self::assertSame(['posts:77', 'posts:77'], $dropped, 'the object cache must not keep the old status');
    }

    public function testTheDefaultEnabledCheckReadsTheWpscGlobal(): void
    {
        $GLOBALS['cache_enabled'] = false;
        self::assertNull((new SuperCacheProbe())->run());

        $GLOBALS['cache_enabled'] = null;
        self::assertNull((new SuperCacheProbe())->run());
    }

    private function wpscDirs(string $home, string $current): void
    {
        Functions\when('get_supercache_dir')->justReturn($this->cacheRoot . 'supercache/' . $home . '/');
        Functions\when('get_current_url_supercache_dir')->justReturn($this->cacheRoot . 'supercache/' . $current . '/');
    }

    public function testTheDefaultCachePathIsTheProbePageDirectoryBelowTheHomeHostDirectory(): void
    {
        $this->wpscDirs('example.test', 'example.test/lit-mcp-check-77');

        self::assertSame($this->pageDir(), SuperCacheProbe::cacheDirFor(77));
    }

    /** WPSC derives the host from the request's Host header; the probe must not follow it somewhere else. */
    public function testTheDefaultCachePathIsNullWhenWpscWouldUseAnotherHostThanTheHomeUrl(): void
    {
        $this->wpscDirs('example.test', 'www.example.test/lit-mcp-check-77');

        self::assertNull(SuperCacheProbe::cacheDirFor(77));
    }

    public function testTheDefaultCachePathIsNullForAnythingButTheProbePageOfThisSite(): void
    {
        // A plain "?page_id=" address or an empty slug: WPSC resolves it to the home page's directory.
        $this->wpscDirs('example.test', 'example.test');
        self::assertNull(SuperCacheProbe::cacheDirFor(77));

        $this->wpscDirs('example.test', 'example.test/seite');
        self::assertNull(SuperCacheProbe::cacheDirFor(77));

        $this->wpscDirs('example.test', 'example.test/lit-mcp-check-77/../../x');
        self::assertNull(SuperCacheProbe::cacheDirFor(77));

        $this->wpscDirs('example.test', 'example.test/lit-mcp-check-78');
        self::assertNull(SuperCacheProbe::cacheDirFor(77));

        Functions\when('get_current_url_supercache_dir')->justReturn('/var/www/html/lit-mcp-check-77/');
        self::assertNull(SuperCacheProbe::cacheDirFor(77));
    }

    public function testTheDefaultCachePathIsNullWhenWpscKnowsNoDirectory(): void
    {
        Functions\when('get_supercache_dir')->justReturn(false);
        Functions\when('get_current_url_supercache_dir')->justReturn(false);

        self::assertNull(SuperCacheProbe::cacheDirFor(77));
    }

    public function testOnlyTheKnownCacheFilesOfTheProbePageAreRemoved(): void
    {
        $problems = $this->probe(function (int $id): void {
            // What WPSC leaves after a rebuild-style purge, plus a file that is none of its names.
            rename($this->pageDir() . 'index.html', $this->pageDir() . 'index.html.needs-rebuild');
            touch($this->pageDir() . 'index-https.html');
            touch($this->pageDir() . 'index-https.html.needs-rebuild');
            touch($this->pageDir() . 'fremd.txt');
        })->run();

        self::assertSame([], $problems);
        self::assertSame(['fremd.txt'], array_values(array_diff(scandir($this->pageDir()), ['.', '..'])));
    }

    public function testTheCacheDirectoryOfThePageIsRemovedWhenEmpty(): void
    {
        $this->purgingProbe()->run();

        self::assertDirectoryDoesNotExist($this->pageDir());
        self::assertDirectoryExists($this->cacheRoot . 'supercache/example.test/');
    }

    // --- P1: the purge must not empty the live cache ------------------------------------------------------------------

    private function defaultPurgeProbe(): SuperCacheProbe
    {
        return new SuperCacheProbe(
            static fn (): bool => true,
            fn (int $id): string => $this->pageDir(),
            null,
            static fn (): bool => true
        );
    }

    public function testTheDefaultPurgeRunsWithClearOnEditOffAndTheRelatedPagesFilterOffAndRestoresBoth(): void
    {
        $GLOBALS['wp_cache_clear_on_post_edit'] = 1;
        $events = [];
        $added = null;
        Functions\expect('add_filter')->once()->with('wpsc_delete_related_pages_on_edit', Mockery::type(Closure::class), PHP_INT_MAX)
            ->andReturnUsing(static function (string $hook, Closure $callback) use (&$events, &$added): bool {
                $events[] = 'add_filter returning ' . var_export($callback(true), true);
                $added = $callback;

                return true;
            });
        Functions\expect('remove_filter')->once()->with('wpsc_delete_related_pages_on_edit', Mockery::type(Closure::class), PHP_INT_MAX)
            ->andReturnUsing(static function (string $hook, Closure $callback) use (&$events, &$added): bool {
                $events[] = $callback === $added ? 'remove_filter of the same callback' : 'remove_filter of ANOTHER callback';

                return true;
            });
        Functions\expect('wp_cache_post_edit')->once()->with(77)->andReturnUsing(function (int $id) use (&$events): int {
            $events[] = 'purge with clear_on_post_edit=' . var_export($GLOBALS['wp_cache_clear_on_post_edit'], true);
            unlink($this->pageDir() . 'index.html');

            return $id;
        });

        self::assertSame([], $this->defaultPurgeProbe()->run());

        self::assertSame(
            ['add_filter returning false', 'purge with clear_on_post_edit=0', 'remove_filter of the same callback'],
            $events
        );
        self::assertSame(1, $GLOBALS['wp_cache_clear_on_post_edit']);
    }

    public function testTheDefaultPurgeLeavesAnUnsetClearOnEditGlobalUnset(): void
    {
        unset($GLOBALS['wp_cache_clear_on_post_edit']);
        Functions\when('add_filter')->justReturn(true);
        Functions\when('remove_filter')->justReturn(true);
        Functions\expect('wp_cache_post_edit')->once()->andReturnUsing(function (int $id): int {
            self::assertSame(0, $GLOBALS['wp_cache_clear_on_post_edit']);
            unlink($this->pageDir() . 'index.html');

            return $id;
        });

        self::assertSame([], $this->defaultPurgeProbe()->run());
        self::assertArrayNotHasKey('wp_cache_clear_on_post_edit', $GLOBALS);
    }

    public function testTheDefaultPurgeRestoresGlobalAndFilterWhenWpscThrows(): void
    {
        $GLOBALS['wp_cache_clear_on_post_edit'] = '1';
        Functions\expect('add_filter')->once()->andReturn(true);
        Functions\expect('remove_filter')->once()->with('wpsc_delete_related_pages_on_edit', Mockery::type(Closure::class), PHP_INT_MAX)->andReturn(true);
        Functions\expect('wp_cache_post_edit')->once()->andThrow(new RuntimeException('WPSC kaputt'));

        $problems = [];
        $this->logged(function () use (&$problems): void {
            $problems = $this->defaultPurgeProbe()->run();
        });

        self::assertSame(['Super-Cache-Probe abgebrochen (Details im PHP-Error-Log).'], $problems);
        self::assertSame('1', $GLOBALS['wp_cache_clear_on_post_edit']);
    }

    // --- P2: a status the database refused is no purge result ---------------------------------------------------------

    public function testARefusedPrivateStatusIsItsOwnFixedProblemAndTheProbeNeverPurges(): void
    {
        $this->refusedStatus = 'private';
        $purged = false;
        $problems = [];
        $logged = $this->logged(function () use (&$problems, &$purged): void {
            $problems = $this->probe(static function (int $id) use (&$purged): void {
                $purged = true;
            })->run();
        });

        self::assertSame(['Der Status der Testseite konnte nicht gesetzt werden (Details im PHP-Error-Log).'], $problems);
        self::assertStringContainsString('77', $logged);
        self::assertStringContainsString('private', $logged);
        self::assertFalse($purged);
        self::assertSame([77], $this->deleted);
        self::assertSame(['77:private', '77:draft'], $this->statuses);
    }

    /** @return array<string, array{0: int|false}> */
    public static function refusedUpdates(): array
    {
        return ['database error' => [false], 'no row changed' => [0]];
    }

    /** @dataProvider refusedUpdates */
    public function testTheDefaultStatusSwitchTreatsAFailedOrEmptyUpdateAsRefused(int|false $result): void
    {
        $wpdb = Mockery::mock();
        $wpdb->posts = 'wp_posts';
        $wpdb->shouldReceive('update')->andReturn($result);
        $GLOBALS['wpdb'] = $wpdb;
        Functions\when('wp_cache_delete')->justReturn(true);
        Functions\expect('wp_cache_post_edit')->never();

        $problems = [];
        $this->logged(function () use (&$problems): void {
            $problems = (new SuperCacheProbe(
                static fn (): bool => true,
                fn (int $id): string => $this->pageDir(),
                fn (int $id) => null
            ))->run();
        });

        self::assertSame(['Der Status der Testseite konnte nicht gesetzt werden (Details im PHP-Error-Log).'], $problems);
        self::assertSame([77], $this->deleted);
    }

    public function testAFailingResetToDraftNeitherHidesTheResultNorEndsTheCheck(): void
    {
        $this->throwingStatus = 'draft';
        $problems = [];
        $logged = $this->logged(function () use (&$problems): void {
            $problems = $this->purgingProbe()->run();
        });

        self::assertSame([], $problems);
        self::assertStringContainsString('Status kaputt', $logged);
        self::assertSame([77], $this->deleted);
        self::assertDirectoryDoesNotExist($this->pageDir());
    }

    public function testAFailingResetToDraftDoesNotReplaceAnExceptionOfThePurge(): void
    {
        $this->throwingStatus = 'draft';
        $problems = [];
        $logged = $this->logged(function () use (&$problems): void {
            $problems = $this->probe(static function (int $id): never {
                throw new RuntimeException('WPSC kaputt');
            })->run();
        });

        self::assertSame(['Super-Cache-Probe abgebrochen (Details im PHP-Error-Log).'], $problems);
        self::assertStringContainsString('WPSC kaputt', $logged);
        self::assertSame([77], $this->deleted);
    }

    public function testARefusedResetToDraftIsLoggedOnly(): void
    {
        $this->refusedStatus = 'draft';
        $problems = [];
        $logged = $this->logged(function () use (&$problems): void {
            $problems = $this->purgingProbe()->run();
        });

        self::assertSame([], $problems);
        self::assertStringContainsString('draft', $logged);
    }
}