<?php

namespace App\Tests;

use App\Infrastructure\ConnectionFactory;
use App\Ops\Backup;
use App\Ops\CommandRunner;
use Doctrine\DBAL\Connection;
use PHPUnit\Framework\TestCase;

/**
 * Backups, and above all the half nobody practises: putting one back.
 *
 * The test that matters is testARestorePutsDeletedContentBack - everything else is bookkeeping.
 * A backup function whose restore has never run is a guess.
 */
final class BackupTest extends TestCase
{
    private string $root;
    private Connection $db;
    private Backup $backup;

    protected function setUp(): void
    {
        $this->root = str_replace('\\', '/', sys_get_temp_dir()).'/kant-backup-'.bin2hex(random_bytes(6));
        mkdir($this->root.'/var/media', 0o775, true);
        file_put_contents($this->root.'/VERSION', "1.1.0\n");
        // Not part of a backup, and the test says so below.
        file_put_contents($this->root.'/.env', "APP_SECRET=geheim\n");

        $url = 'sqlite:///'.$this->root.'/var/cms.db';
        $this->db = ConnectionFactory::create($url);
        TestSchema::build($this->db);
        $this->db->insert('website', ['id' => 'default', 'name' => 'Test', 'default_locale' => 'de', 'theme' => '{}']);
        foreach (['p1' => 'home', 'p2' => 'leistungen'] as $id => $slug) {
            $this->db->insert('page', ['id' => $id, 'slug' => $slug, 'path' => $slug, 'type' => 'page', 'locale' => 'de', 'website_id' => 'default', 'version' => 0, 'created_at' => gmdate('Y-m-d H:i:s')]);
        }
        file_put_contents($this->root.'/var/media/bild-480.webp', 'erstes bild');

        $this->backup = new Backup($this->root, $url, $this->root.'/var/media', $this->db, new CommandRunner());
    }

    public function testABackupWorksOnAnOlderSqliteToo(): void
    {
        // Auf Umuts Hosting endete „Sicherung anlegen" mit 500. Der Grund: `VACUUM INTO` gibt es
        // erst seit SQLite 3.27, und dort läuft eine ältere Fassung - alt genug für die
        // Installation (die braucht 3.16), zu alt für die Sicherung. Statt VACUUM wird dann unter
        // einer Schreibsperre kopiert. Geprüft wird das hier wirklich und nicht nur versprochen:
        // die Schwelle wird so hoch gesetzt, dass der Ersatzweg läuft.
        $url = 'sqlite:///'.str_replace('\\', '/', $this->root).'/var/cms.db';
        $alt = new Backup($this->root, $url, $this->root.'/var/media', $this->db, new CommandRunner(), '99.0.0');

        $sicherung = $alt->create('auf altem SQLite');

        $datei = $sicherung['path'].'/cms.db';
        self::assertFileExists($datei);
        self::assertGreaterThan(0, (int) filesize($datei));

        // Und es ist eine vollständige, lesbare Datenbank - nicht ein halb geschriebener Torso.
        $kopie = new \PDO('sqlite:'.$datei);
        self::assertSame(
            (int) $this->db->fetchOne('SELECT COUNT(*) FROM revision'),
            (int) $kopie->query('SELECT COUNT(*) FROM revision')->fetchColumn(),
            'Die Kopie muss denselben Inhalt haben wie das Original.',
        );
        self::assertSame(
            $sicherung['manifest']['datenbank']['sha256'],
            hash_file('sha256', $datei),
            'Die Prüfsumme im Manifest gehört zu genau dieser Datei.',
        );
    }

    protected function tearDown(): void
    {
        $this->db->close();
        gc_collect_cycles();
        $this->remove($this->root);
    }

    public function testABackupHoldsTheDatabaseTheMediaAndAManifestButNoSecrets(): void
    {
        $result = $this->backup->create('Test');
        $path = $result['path'];

        self::assertFileExists($path.'/cms.db');
        self::assertFileExists($path.'/medien/bild-480.webp');
        self::assertFileExists($path.'/'.Backup::MANIFEST);
        // The secret stays out: a backup gets downloaded and passed around.
        self::assertFileDoesNotExist($path.'/.env');
        self::assertFileDoesNotExist($path.'/.env.local');

        $manifest = $result['manifest'];
        self::assertSame('1.1.0', $manifest['fassung']);
        self::assertSame(2, $manifest['inhalt']['seiten']);
        self::assertSame(1, $manifest['medien']['dateien']);
        self::assertSame(hash_file('sha256', $path.'/cms.db'), $manifest['datenbank']['sha256']);
        self::assertContains('.env', $manifest['enthaelt_nicht']);

        // The copy is a usable database, not a file that merely exists.
        $copy = ConnectionFactory::create('sqlite:///'.$path.'/cms.db');
        self::assertSame(2, (int) $copy->fetchOne('SELECT COUNT(*) FROM page'));
        $copy->close();

        $listed = $this->backup->all();
        self::assertCount(1, $listed);
        self::assertTrue($listed[0]['intact']);
        self::assertGreaterThan(0, $listed[0]['bytes']);
    }

    public function testARestorePutsDeletedContentBack(): void
    {
        $backup = $this->backup->create('vor dem Unfall');

        // The accident: a page and an image are gone.
        $this->db->executeStatement('DELETE FROM page WHERE id = ?', ['p2']);
        unlink($this->root.'/var/media/bild-480.webp');
        self::assertSame(1, (int) $this->db->fetchOne('SELECT COUNT(*) FROM page'));

        $result = $this->backup->restore($backup['name']);
        self::assertTrue($result['ok'], $this->explain($result));

        // A fresh connection, because the file underneath was replaced.
        $after = ConnectionFactory::create('sqlite:///'.$this->root.'/var/cms.db');
        self::assertSame(2, (int) $after->fetchOne('SELECT COUNT(*) FROM page'));
        self::assertSame('leistungen', $after->fetchOne('SELECT path FROM page WHERE id = ?', ['p2']));
        $after->close();
        self::assertFileExists($this->root.'/var/media/bild-480.webp');

        // A safety copy of the state before the restore was taken first.
        self::assertContains('Aktuellen Stand sichern', array_column($result['steps'], 'step'));
        self::assertCount(2, $this->backup->all(), 'The safety copy is a backup of its own.');
    }

    public function testARestoreKeepsFilesThatWereAddedAfterTheBackup(): void
    {
        $backup = $this->backup->create('Test');
        // Uploaded after the backup: a restore must not delete it, or the operation meant to
        // prevent loss would cause one.
        file_put_contents($this->root.'/var/media/spaeter-480.webp', 'neueres bild');

        self::assertTrue($this->backup->restore($backup['name'])['ok']);
        self::assertFileExists($this->root.'/var/media/spaeter-480.webp');
        self::assertFileExists($this->root.'/var/media/bild-480.webp');
    }

    public function testATamperedBackupIsNotRestored(): void
    {
        $backup = $this->backup->create('Test');
        file_put_contents($backup['path'].'/cms.db', 'kaputt');

        self::assertFalse($this->backup->all()[0]['intact']);
        $result = $this->backup->restore($backup['name']);
        self::assertFalse($result['ok']);
        self::assertSame('Unversehrt', $this->firstFailed($result)['step']);
        // Nothing was touched - not even a safety copy, because it never got that far.
        self::assertCount(1, $this->backup->all());
        self::assertSame(2, (int) $this->db->fetchOne('SELECT COUNT(*) FROM page'));
    }

    public function testABackupFromANewerVersionIsRefusedUnlessForced(): void
    {
        $backup = $this->backup->create('Test');
        // The installation goes back to an older version, as after a rollback.
        file_put_contents($this->root.'/VERSION', "1.0.0\n");

        $refused = $this->backup->restore($backup['name']);
        self::assertFalse($refused['ok']);
        self::assertSame('Fassung passt', $this->firstFailed($refused)['step']);
        self::assertStringContainsString('Erst aktualisieren', $this->firstFailed($refused)['detail']);

        // With force it runs, because sometimes that is exactly what is wanted.
        self::assertTrue($this->backup->restore($backup['name'], true)['ok']);
    }

    public function testAMissingBackupIsSaidSoRatherThanGuessed(): void
    {
        $result = $this->backup->restore('sicherung-gibt-es-nicht');
        self::assertFalse($result['ok']);
        self::assertSame('Sicherung finden', $this->firstFailed($result)['step']);
    }

    public function testRotationKeepsTheNewestAndRemovesTheRest(): void
    {
        $names = [];
        for ($index = 0; $index < 4; ++$index) {
            $names[] = $this->backup->create('Test', new \DateTimeImmutable('2026-09-1'.$index.' 10:00:00', new \DateTimeZone('UTC')))['name'];
        }
        self::assertCount(4, $this->backup->all());

        $removed = $this->backup->rotate(2);
        $left = array_column($this->backup->all(), 'name');
        self::assertCount(2, $left);
        // The newest two survive; rotation without a limit would let the disk fill up and the
        // next backup fail exactly when it is needed.
        self::assertSame([$names[3], $names[2]], $left);
        self::assertSame([$names[1], $names[0]], $removed);
    }

    public function testTwoBackupsInTheSameSecondGetTwoDirectories(): void
    {
        // This is not academic: a restore takes a safety copy, and that lands in the same second
        // as the backup it is about to restore.
        $moment = new \DateTimeImmutable('2026-09-12 10:00:00', new \DateTimeZone('UTC'));
        $first = $this->backup->create('Test', $moment);
        $second = $this->backup->create('Test', $moment);

        self::assertNotSame($first['name'], $second['name']);
        self::assertSame('sicherung-20260912-100000', $first['name']);
        self::assertSame('sicherung-20260912-100000-2', $second['name']);
        self::assertCount(2, $this->backup->all());
    }

    private function firstFailed(array $result): array
    {
        foreach ($result['steps'] as $step) {
            if (!$step['ok']) {
                return $step;
            }
        }
        self::fail('Kein gescheiterter Schritt: '.$this->explain($result));
    }

    private function explain(array $result): string
    {
        return implode("\n", array_map(
            static fn (array $step): string => sprintf('%s %s: %s', $step['ok'] ? 'ok' : 'FEHLER', $step['step'], $step['detail']),
            $result['steps'],
        ));
    }

    private function remove(string $path): void
    {
        if (!is_dir($path)) {
            @unlink($path);

            return;
        }
        foreach (scandir($path) ?: [] as $entry) {
            if ('.' !== $entry && '..' !== $entry) {
                $this->remove($path.'/'.$entry);
            }
        }
        @rmdir($path);
    }
}