<?php

declare(strict_types=1);

namespace OCA\NgBackup\Tests\Unit\Job;

use OCA\NgBackup\Backend\LocalBackend;
use OCA\NgBackup\Crypto\KeyRing;
use OCA\NgBackup\Job\BackupRun;
use OCA\NgBackup\Repository\Repository;
use OCA\NgBackup\Tests\Unit\TempDirTrait;
use PHPUnit\Framework\TestCase;

class BackupRunTest extends TestCase {
	use TempDirTrait;

	public function testRunInManyTinyStepsRestoresIdentically(): void {
		$src = $this->tempDir();
		mkdir("$src/a", 0700, true);
		for ($i = 0; $i < 50; $i++) {
			file_put_contents("$src/a/f$i.txt", random_bytes(20000));
		}
		file_put_contents("$src/big.bin", random_bytes(13 * 1048576));
		$backend = new LocalBackend($this->tempDir());
		$keys = KeyRing::generate();
		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));

		$state = BackupRun::start($src);
		$steps = 0;
		while ($state['phase'] !== 'commit' && $steps < 500) {
			// Fresh repository object per step, state through JSON: as separate processes would.
			$repo = Repository::openWithKey($backend, $keys);
			$state = json_decode(json_encode(BackupRun::step($repo, $state, microtime(true) + 0.05)), true);
			$steps++;
		}
		$this->assertSame('commit', $state['phase']);
		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
		$this->assertGreaterThan(2, $steps, 'the run was actually split into steps');

		$target = $this->tempDir();
		Repository::openWithKey($backend, $keys)->restore($state['snapshot'], $target);
		$this->assertSame(self::hashTree($src), self::hashTree($target));
	}

	public function testFileChangedBetweenStepsIsReadAgain(): void {
		$src = $this->tempDir();
		file_put_contents("$src/big.bin", random_bytes(20 * 1048576));
		$backend = new LocalBackend($this->tempDir());
		$keys = KeyRing::generate();
		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));

		$state = BackupRun::start($src);
		$mutated = false;
		for ($i = 0; $i < 500 && $state['phase'] !== 'commit'; $i++) {
			$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 0.01);
			if (!$mutated && $state['cur'] !== null && $state['cur']['offset'] > 0) {
				$fh = fopen("$src/big.bin", 'r+b');
				fwrite($fh, random_bytes(1024)); // same size, new content at the start
				fclose($fh);
				touch("$src/big.bin", time() + 10);
				$mutated = true;
			}
		}
		$this->assertSame('commit', $state['phase']);
		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
		$this->assertTrue($mutated);
		$this->assertGreaterThanOrEqual(1, $state['stats']['retried'] ?? 0);
		$target = $this->tempDir();
		Repository::openWithKey($backend, $keys)->restore($state['snapshot'], $target);
		$this->assertSame(self::hashTree($src), self::hashTree($target));
	}

	public function testIncrementalRunInTinyStepsReadsNothing(): void {
		$src = $this->tempDir();
		for ($i = 0; $i < 200; $i++) {
			@mkdir("$src/d" . ($i % 7), 0700, true);
			file_put_contents("$src/d" . ($i % 7) . "/f$i", random_bytes(3000));
		}
		$backend = new LocalBackend($this->tempDir());
		$keys = KeyRing::generate();
		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
		$run = function (?string $parent) use ($backend, $src, $keys): array {
			$state = BackupRun::start(['data' => $src], $parent);
			for ($i = 0; $i < 2000 && $state['phase'] !== 'commit'; $i++) {
				$state = json_decode(json_encode(BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true))), true);
			}
			if ($state['phase'] === 'commit') {
				Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
			}
			return $state;
		};
		$first = $run(null);
		$second = $run($first['snapshot']);
		$this->assertSame('commit', $second['phase']);
		$this->assertGreaterThan(150, $second["steps"], "one file per step");
		$this->assertSame(0, $second['stats']['read'], 'merge-join with the parent across steps reuses every file');
		$this->assertSame(200, $second['stats']['reused']);
		$target = $this->tempDir();
		Repository::openWithKey($backend, $keys)->restore($second['snapshot'], $target);
		$this->assertSame(self::hashTree($src), self::hashTree("$target/data"));
	}
}