<?php
declare(strict_types=1);

final class TaskCertCronRuntime
{
    public static function parseOptions(array $argv, bool $allowTaskId = true): array
    {
        $options = [
            'apply' => false,
            'dry_run' => false,
            'json' => false,
            'no_lock' => false,
            'task_id' => null,
            'help' => false,
        ];

        $count = count($argv);
        for ($i = 1; $i < $count; $i++) {
            $arg = (string) $argv[$i];

            if ($arg === '--apply') {
                $options['apply'] = true;
                continue;
            }

            if ($arg === '--dry-run') {
                $options['dry_run'] = true;
                continue;
            }

            if ($arg === '--json') {
                $options['json'] = true;
                continue;
            }

            if ($arg === '--no-lock') {
                $options['no_lock'] = true;
                continue;
            }

            if ($arg === '--help') {
                $options['help'] = true;
                continue;
            }

            if (strpos($arg, '--task_id=') === 0) {
                if (!$allowTaskId) {
                    throw new InvalidArgumentException('--task_id wird für diesen Job nicht unterstützt.');
                }
                $raw = trim(substr($arg, strlen('--task_id=')));
                if ($raw === '' || !ctype_digit($raw)) {
                    throw new InvalidArgumentException('Ungültiger Wert für --task_id.');
                }
                $options['task_id'] = (int) $raw;
                continue;
            }

            if ($arg === '--task_id') {
                if (!$allowTaskId) {
                    throw new InvalidArgumentException('--task_id wird für diesen Job nicht unterstützt.');
                }
                $next = $argv[$i + 1] ?? null;
                if (!is_string($next) || trim($next) === '' || !ctype_digit(trim($next))) {
                    throw new InvalidArgumentException('Ungültiger Wert für --task_id.');
                }
                $options['task_id'] = (int) trim($next);
                $i++;
                continue;
            }

            throw new InvalidArgumentException('Unbekannte Option: ' . $arg);
        }

        if ($options['apply'] && $options['dry_run']) {
            throw new InvalidArgumentException('--apply und --dry-run können nicht gleichzeitig gesetzt werden.');
        }

        if ($options['task_id'] !== null && (int) $options['task_id'] <= 0) {
            throw new InvalidArgumentException('--task_id muss > 0 sein.');
        }

        return $options;
    }

    public static function runWithHandling(string $jobName, array $options, callable $runner): int
    {
        $startedAt = microtime(true);
        $runId = self::buildRunId($jobName);
        $mode = $options['apply'] ? 'apply' : 'dry_run';
        $lockHandle = null;

        $basePayload = [
            'timestamp' => date('c'),
            'job' => $jobName,
            'job_run_id' => $runId,
            'mode' => $mode,
            'task_id' => $options['task_id'],
        ];

        try {
            if (!$options['no_lock']) {
                $lockResult = self::acquireLock($jobName);
                $lockHandle = $lockResult['handle'] ?? null;
                $acquired = (bool) ($lockResult['acquired'] ?? false);
                if (!$acquired) {
                    $payload = $basePayload + [
                        'success' => false,
                        'skipped' => true,
                        'skip_reason' => 'lock_active',
                        'duration_ms' => (int) round((microtime(true) - $startedAt) * 1000),
                    ];
                    self::writeCronLog($payload);
                    if ((bool) ($options['json'] ?? false)) {
                        self::emitJson($payload);
                    } else {
                        fwrite(STDOUT, '[SKIP] ' . $jobName . ': Lock aktiv, Job wird übersprungen.' . PHP_EOL);
                    }
                    return 3;
                }
            }

            $context = [
                'job_run_id' => $runId,
                'mode' => $mode,
                'task_id' => $options['task_id'],
            ];

            $summary = $runner($context);
            if (!is_array($summary)) {
                $summary = [];
            }

            $payload = $basePayload + [
                'success' => true,
                'duration_ms' => (int) round((microtime(true) - $startedAt) * 1000),
                'summary' => $summary,
            ];
            self::writeCronLog($payload);
            if ((bool) ($options['json'] ?? false)) {
                self::emitJson($payload);
            } else {
                fwrite(STDOUT, '[OK] ' . $jobName . ' (' . $mode . ') abgeschlossen in ' . $payload['duration_ms'] . 'ms.' . PHP_EOL);
            }
            return 0;
        } catch (Throwable $throwable) {
            $payload = $basePayload + [
                'success' => false,
                'duration_ms' => (int) round((microtime(true) - $startedAt) * 1000),
                'error' => $throwable->getMessage(),
            ];
            self::writeCronLog($payload);
            if ((bool) ($options['json'] ?? false)) {
                self::emitJson($payload);
            } else {
                fwrite(STDERR, '[ERROR] ' . $jobName . ' (' . $mode . '): ' . $throwable->getMessage() . PHP_EOL);
            }
            return 1;
        } finally {
            self::releaseLock($lockHandle);
        }
    }

    public static function printUsage(string $usage): void
    {
        fwrite(STDOUT, trim($usage) . PHP_EOL);
    }

    public static function printOptionError(string $message, string $usage): void
    {
        fwrite(STDERR, $message . PHP_EOL . PHP_EOL . trim($usage) . PHP_EOL);
    }

    private static function acquireLock(string $jobName): array
    {
        $lockDir = self::logsDir() . '/locks';
        if (!is_dir($lockDir)) {
            @mkdir($lockDir, 0775, true);
        }

        $lockPath = $lockDir . '/task_cert_' . $jobName . '.lock';
        $handle = @fopen($lockPath, 'c+');
        if ($handle === false) {
            throw new RuntimeException('Lock-Datei konnte nicht geöffnet werden: ' . $lockPath);
        }

        $acquired = flock($handle, LOCK_EX | LOCK_NB);
        if (!$acquired) {
            return [
                'acquired' => false,
                'handle' => $handle,
            ];
        }

        $meta = [
            'pid' => getmypid(),
            'started_at' => date('c'),
        ];
        ftruncate($handle, 0);
        rewind($handle);
        fwrite($handle, json_encode($meta, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) . PHP_EOL);
        fflush($handle);

        return [
            'acquired' => true,
            'handle' => $handle,
        ];
    }

    private static function releaseLock($lockHandle): void
    {
        if (!is_resource($lockHandle)) {
            return;
        }

        @flock($lockHandle, LOCK_UN);
        @fclose($lockHandle);
    }

    private static function writeCronLog(array $payload): void
    {
        $logDir = self::logsDir();
        if (!is_dir($logDir)) {
            @mkdir($logDir, 0775, true);
        }

        $file = $logDir . '/task_cert_cron.log';
        $line = json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        if (!is_string($line) || $line === '') {
            $line = json_encode([
                'timestamp' => date('c'),
                'success' => false,
                'error' => 'cron_log_encode_failed',
            ]);
        }

        @file_put_contents($file, $line . PHP_EOL, FILE_APPEND | LOCK_EX);
    }

    private static function emitJson(array $payload): void
    {
        echo json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) . PHP_EOL;
    }

    private static function logsDir(): string
    {
        return dirname(__DIR__) . '/logs';
    }

    private static function buildRunId(string $jobName): string
    {
        try {
            $entropy = bin2hex(random_bytes(6));
        } catch (Throwable $throwable) {
            $entropy = substr(sha1((string) microtime(true)), 0, 12);
        }

        return $jobName . '-' . date('YmdHis') . '-' . $entropy;
    }
}