<?php declare(strict_types=1);

namespace AeonDumpManager\Service;

use AeonDumpManager\Service\Exception\DumpNotFoundException;
use AeonDumpManager\Struct\DumpFile;
use Doctrine\DBAL\Connection;
use League\Flysystem\FilesystemOperator;
use Shopware\Core\System\SystemConfig\SystemConfigService;
use Symfony\Component\Process\Exception\ProcessFailedException;
use Symfony\Component\Process\Process;

/**
 * Orchestrates dump create/delete — the single entry point every caller
 * (console commands, the async Messenger handler, the retention task) goes
 * through, so maxDumps/retantionDays enforcement only lives in one place.
 */
class DumpService
{
    public function __construct(
        private readonly DumpLister $dumpLister,
        private readonly FilesystemOperator $aeonDumpManagerFilesystemPrivate,
        private readonly DumpBinaryLocator $dumpBinaryLocator,
        private readonly Connection $connection,
        private readonly SystemConfigService $systemConfigService,
        private readonly DumpFilenameParser $filenameParser,
    ) {
    }

    public function createSync(): DumpFile
    {
        $dumpFile = $this->create();
        $this->enforceMaxDumps();

        return $dumpFile;
    }

    public function createAsync(string $jobId, DumpJobStatusService $jobStatus): void
    {
        $estimatedTotalBytes = $this->estimateTotalBytes();
        $lastUpdate = 0.0;

        $dumpFile = $this->create(function (int $bytesWritten) use ($jobStatus, $jobId, $estimatedTotalBytes, &$lastUpdate): void {
            $now = microtime(true);
            if ($now - $lastUpdate < 1.0) {
                return;
            }
            $lastUpdate = $now;

            $percent = $estimatedTotalBytes > 0
                ? (int) min(99, ($bytesWritten / $estimatedTotalBytes) * 100)
                : 0;
            $jobStatus->updateProgress($jobId, $percent);
        });

        $jobStatus->markDone($jobId, $dumpFile->filename);
        $this->enforceMaxDumps();
    }

    public function delete(string $filename): void
    {
        if (!$this->filenameParser->isValid($filename)) {
            throw DumpNotFoundException::create($filename);
        }

        $path = DumpLister::path($filename);
        if (!$this->aeonDumpManagerFilesystemPrivate->fileExists($path)) {
            throw DumpNotFoundException::create($filename);
        }

        $this->aeonDumpManagerFilesystemPrivate->delete($path);
    }

    /**
     * @return resource
     */
    public function readStream(string $filename)
    {
        if (!$this->filenameParser->isValid($filename)) {
            throw DumpNotFoundException::create($filename);
        }

        $path = DumpLister::path($filename);
        if (!$this->aeonDumpManagerFilesystemPrivate->fileExists($path)) {
            throw DumpNotFoundException::create($filename);
        }

        return $this->aeonDumpManagerFilesystemPrivate->readStream($path);
    }

    public function enforceMaxDumps(): void
    {
        $maxDumps = $this->systemConfigService->getInt('AeonDumpManager.config.maxDumps');
        if ($maxDumps <= 0) {
            return;
        }

        $dumps = $this->dumpLister->list(); // newest first
        $excess = \array_slice($dumps, $maxDumps);

        foreach ($excess as $dumpFile) {
            $this->aeonDumpManagerFilesystemPrivate->delete(DumpLister::path($dumpFile->filename));
        }
    }

    public function purgeOlderThan(\DateTimeImmutable $threshold): void
    {
        foreach ($this->dumpLister->list() as $dumpFile) {
            if ($dumpFile->datetime < $threshold) {
                $this->aeonDumpManagerFilesystemPrivate->delete(DumpLister::path($dumpFile->filename));
            }
        }
    }

    /**
     * @param (callable(int $bytesWritten): void)|null $onProgress
     */
    private function create(?callable $onProgress = null): DumpFile
    {
        $dateTime = new \DateTimeImmutable();
        $filename = $this->filenameParser->format($dateTime);
        $tempPath = sys_get_temp_dir() . '/' . uniqid('aeon_dump_', true) . '.sql.gz';

        $process = $this->buildProcess();
        $gzHandle = gzopen($tempPath, 'wb6');

        try {
            $process->run(function (string $type, string $buffer) use ($gzHandle, $onProgress, $tempPath): void {
                if ($type !== Process::OUT) {
                    return;
                }

                gzwrite($gzHandle, $buffer);

                if ($onProgress !== null) {
                    clearstatcache(true, $tempPath);
                    $onProgress((int) filesize($tempPath));
                }
            });
        } finally {
            gzclose($gzHandle);
        }

        if (!$process->isSuccessful()) {
            @unlink($tempPath);

            throw new ProcessFailedException($process);
        }

        $sizeBytes = (int) filesize($tempPath);
        $stream = fopen($tempPath, 'rb');
        $this->aeonDumpManagerFilesystemPrivate->writeStream(DumpLister::path($filename), $stream);
        fclose($stream);
        @unlink($tempPath);

        return new DumpFile($filename, $dateTime, $sizeBytes);
    }

    private function buildProcess(): Process
    {
        $binary = $this->dumpBinaryLocator->locate();
        $params = $this->connection->getParams();

        $command = [
            $binary,
            '--single-transaction',
            '--quick',
            '-h', (string) ($params['host'] ?? '127.0.0.1'),
            '-P', (string) ($params['port'] ?? 3306),
            '-u', (string) ($params['user'] ?? 'root'),
            (string) ($params['dbname'] ?? ''),
        ];

        $process = new Process($command, null, ['MYSQL_PWD' => (string) ($params['password'] ?? '')]);
        $process->setTimeout(null);

        return $process;
    }

    private function estimateTotalBytes(): int
    {
        $bytes = $this->connection->fetchOne(
            'SELECT SUM(data_length) FROM information_schema.tables WHERE table_schema = DATABASE()'
        );

        return (int) ($bytes ?? 0);
    }
}