<?php

declare (strict_types=1);
namespace Rector\Parallel\Application;

use RectorPrefix202602\Clue\React\NDJson\Decoder;
use RectorPrefix202602\Clue\React\NDJson\Encoder;
use RectorPrefix202602\Nette\Utils\Random;
use RectorPrefix202602\React\EventLoop\StreamSelectLoop;
use RectorPrefix202602\React\Socket\ConnectionInterface;
use RectorPrefix202602\React\Socket\TcpServer;
use Rector\Configuration\Option;
use Rector\Configuration\Parameter\SimpleParameterProvider;
use Rector\Console\Command\ProcessCommand;
use Rector\Parallel\Command\WorkerCommandLineFactory;
use Rector\Parallel\ValueObject\Bridge;
use Rector\ValueObject\Error\SystemError;
use Rector\ValueObject\ProcessResult;
use Rector\ValueObject\Reporting\FileDiff;
use RectorPrefix202602\Symfony\Component\Console\Command\Command;
use RectorPrefix202602\Symfony\Component\Console\Input\InputInterface;
use RectorPrefix202602\Symplify\EasyParallel\Enum\Action;
use RectorPrefix202602\Symplify\EasyParallel\Enum\Content;
use RectorPrefix202602\Symplify\EasyParallel\Enum\ReactCommand;
use RectorPrefix202602\Symplify\EasyParallel\Enum\ReactEvent;
use RectorPrefix202602\Symplify\EasyParallel\ValueObject\ParallelProcess;
use RectorPrefix202602\Symplify\EasyParallel\ValueObject\ProcessPool;
use RectorPrefix202602\Symplify\EasyParallel\ValueObject\Schedule;
use Throwable;
/**
 * Inspired from @see
 * https://github.com/phpstan/phpstan-src/commit/9124c66dcc55a222e21b1717ba5f60771f7dda92#diff-39c7a3b0cbb217bbfff96fbb454e6e5e60c74cf92fbb0f9d246b8bebbaad2bb0
 *
 * https://github.com/phpstan/phpstan-src/commit/b84acd2e3eadf66189a64fdbc6dd18ff76323f67#diff-7f625777f1ce5384046df08abffd6c911cfbb1cfc8fcb2bdeaf78f337689e3e2R150
 */
final class ParallelFileProcessor
{
    /**
     * @readonly
     */
    private WorkerCommandLineFactory $workerCommandLineFactory;
    /**
     * @var int
     */
    private const SYSTEM_ERROR_LIMIT = 50;
    /**
     * The number of chunks a worker can process before getting killed.
     * In contrast the jobSize defines the maximum size of a chunk, a worker process at a time.
     * @var int
     */
    private const MAX_CHUNKS_PER_WORKER = 8;
    /**
     * @var \Symplify\EasyParallel\ValueObject\ProcessPool|null
     */
    private $processPool = null;
    public function __construct(WorkerCommandLineFactory $workerCommandLineFactory)
    {
        $this->workerCommandLineFactory = $workerCommandLineFactory;
    }
    /**
     * @param callable(int $stepCount): void $postFileCallback Used for progress bar jump
     */
    public function process(Schedule $schedule, string $mainScript, callable $postFileCallback, InputInterface $input): ProcessResult
    {
        $jobs = array_reverse($schedule->getJobs());
        $streamSelectLoop = new StreamSelectLoop();
        // basic properties setup
        $numberOfProcesses = $schedule->getNumberOfProcesses();
        // initial counters
        /** @var FileDiff[] $fileDiffs */
        $fileDiffs = [];
        /** @var SystemError[] $systemErrors */
        $systemErrors = [];
        $tcpServer = new TcpServer('127.0.0.1:0', $streamSelectLoop);
        $this->processPool = new ProcessPool($tcpServer);
        $tcpServer->on(ReactEvent::CONNECTION, function (ConnectionInterface $connection) use (&$jobs): void {
            $inDecoder = new Decoder($connection, \true, 512, 0, 4 * 1024 * 1024);
            $outEncoder = new Encoder($connection);
            $inDecoder->on(ReactEvent::DATA, function (array $data) use (&$jobs, $inDecoder, $outEncoder): void {
                $action = $data[ReactCommand::ACTION];
                if ($action !== Action::HELLO) {
                    return;
                }
                $processIdentifier = $data[Option::PARALLEL_IDENTIFIER];
                $parallelProcess = $this->processPool->getProcess($processIdentifier);
                $parallelProcess->bindConnection($inDecoder, $outEncoder);
                if ($jobs === []) {
                    $this->processPool->quitProcess($processIdentifier);
                    return;
                }
                $jobsChunk = array_pop($jobs);
                $parallelProcess->request([ReactCommand::ACTION => Action::MAIN, Content::FILES => $jobsChunk]);
            });
        });
        /** @var string $serverAddress */
        $serverAddress = $tcpServer->getAddress();
        /** @var int $serverPort */
        $serverPort = parse_url($serverAddress, \PHP_URL_PORT);
        $systemErrorsCount = 0;
        $reachedSystemErrorsCountLimit = \false;
        $totalChanged = 0;
        $handleErrorCallable = function (Throwable $throwable) use (&$systemErrors, &$systemErrorsCount, &$reachedSystemErrorsCountLimit): void {
            $systemErrors[] = new SystemError($throwable->getMessage(), $throwable->getFile(), $throwable->getLine());
            ++$systemErrorsCount;
            $reachedSystemErrorsCountLimit = \true;
            $this->processPool->quitAll();
            // This sleep has to be here, because event though we have called $this->processPool->quitAll(),
            // it takes some time for the child processes to actually die, during which they can still write to cache
            // @see https://github.com/rectorphp/rector-src/pull/3834/files#r1231696531
            sleep(1);
        };
        $timeoutInSeconds = SimpleParameterProvider::provideIntParameter(Option::PARALLEL_JOB_TIMEOUT_IN_SECONDS);
        $fileChunksBudgetPerProcess = [];
        $processSpawner = function () use (&$systemErrors, &$fileDiffs, &$jobs, $postFileCallback, &$systemErrorsCount, &$reachedInternalErrorsCountLimit, $mainScript, $input, $serverPort, $streamSelectLoop, $timeoutInSeconds, $handleErrorCallable, &$fileChunksBudgetPerProcess, &$processSpawner, &$totalChanged): void {
            $processIdentifier = Random::generate();
            $workerCommandLine = $this->workerCommandLineFactory->create($mainScript, ProcessCommand::class, 'worker', $input, $processIdentifier, $serverPort);
            $fileChunksBudgetPerProcess[$processIdentifier] = self::MAX_CHUNKS_PER_WORKER;
            $parallelProcess = new ParallelProcess($workerCommandLine, $streamSelectLoop, $timeoutInSeconds);
            $parallelProcess->start(
                // 1. callable on data
                function (array $json) use ($parallelProcess, &$systemErrors, &$fileDiffs, &$jobs, $postFileCallback, &$systemErrorsCount, &$reachedInternalErrorsCountLimit, $processIdentifier, &$fileChunksBudgetPerProcess, &$processSpawner, &$totalChanged): void {
                    /** @var array{
                     *      total_changed: int,
                     *      system_errors: mixed[],
                     *      file_diffs: array<string, mixed>,
                     *      files_count: int,
                     *      system_errors_count: int
                     * } $json */
                    $totalChanged += $json[Bridge::TOTAL_CHANGED];
                    // decode arrays to objects
                    foreach ($json[Bridge::SYSTEM_ERRORS] as $jsonError) {
                        if (is_string($jsonError)) {
                            $systemErrors[] = new SystemError('System error: ' . $jsonError);
                            continue;
                        }
                        $systemErrors[] = SystemError::decode($jsonError);
                    }
                    foreach ($json[Bridge::FILE_DIFFS] as $jsonFileDiff) {
                        $fileDiffs[] = FileDiff::decode($jsonFileDiff);
                    }
                    $postFileCallback($json[Bridge::FILES_COUNT]);
                    $systemErrorsCount += $json[Bridge::SYSTEM_ERRORS_COUNT];
                    if ($systemErrorsCount >= self::SYSTEM_ERROR_LIMIT) {
                        $reachedInternalErrorsCountLimit = \true;
                        $this->processPool->quitAll();
                    }
                    if ($fileChunksBudgetPerProcess[$processIdentifier] <= 0) {
                        // kill the current worker, and spawn a fresh one to free memory
                        $this->processPool->quitProcess($processIdentifier);
                        $processSpawner();
                        return;
                    }
                    if ($jobs === []) {
                        $this->processPool->quitProcess($processIdentifier);
                        return;
                    }
                    $jobsChunk = array_pop($jobs);
                    $parallelProcess->request([ReactCommand::ACTION => Action::MAIN, Content::FILES => $jobsChunk]);
                    --$fileChunksBudgetPerProcess[$processIdentifier];
                },
                // 2. callable on error
                $handleErrorCallable,
                // 3. callable on exit
                function ($exitCode, string $stdErr) use (&$systemErrors, $processIdentifier): void {
                    $this->processPool->tryQuitProcess($processIdentifier);
                    if ($exitCode === Command::SUCCESS) {
                        return;
                    }
                    if ($exitCode === null) {
                        return;
                    }
                    $systemErrors[] = new SystemError('Child process error: ' . $stdErr);
                }
            );
            $this->processPool->attachProcess($processIdentifier, $parallelProcess);
        };
        for ($i = 0; $i < $numberOfProcesses; ++$i) {
            // nothing else to process, stop now
            if ($jobs === []) {
                break;
            }
            $processSpawner();
        }
        $streamSelectLoop->run();
        if ($reachedSystemErrorsCountLimit) {
            $systemErrors[] = new SystemError(sprintf('Reached system errors count limit of %d, exiting...', self::SYSTEM_ERROR_LIMIT));
        }
        return new ProcessResult($systemErrors, $fileDiffs, $totalChanged);
    }
}
