<?php

declare(strict_types=1);

namespace App\Infrastructure\Jobs;

use App\Domain\Jobs\Job;
use App\Domain\Jobs\JobContext;
use App\Domain\Jobs\JobOutcome;
use App\Domain\Jobs\JobStatus;
use App\Domain\Time\Clock;
use App\Infrastructure\Logging\SafeTrace;
use Psr\Log\LoggerInterface;
use Throwable;

/**
 * Orchestrates a single job invocation:
 *  - Tries to acquire the job_locks row; on collision returns
 *    `skipped_locked` (still writes a `job_runs` row so the failure is
 *    auditable).
 *  - On acquisition: writes a `running` row, runs the job, captures
 *    success or exception, updates the row, releases the lock.
 *  - Returns a `JobOutcome` describing what happened.
 *
 * Each invocation gets a unique `owner` string (`pid/random_hex`) so
 * `release()` can refuse to delete a lock that's been re-acquired by a
 * different process after an `expires_at` reclaim.
 */
final class JobRunner
{
    public function __construct(
        private readonly JobLockRepository $locks,
        private readonly JobRunRepository $runs,
        private readonly Clock $clock,
        private readonly LoggerInterface $logger,
        private readonly int $lockBufferSeconds = 30,
    ) {
    }

    /**
     * @param array<string, mixed> $params
     */
    public function run(Job $job, array $params, string $triggeredBy): JobOutcome
    {
        $owner = sprintf('%d/%s', getmypid() ?: 0, bin2hex(random_bytes(4)));
        $start = $this->clock->now();
        $expires = $start->modify(sprintf('+%d seconds', $job->maxRuntimeSeconds() + $this->lockBufferSeconds));

        if (!$this->locks->tryAcquire($job->name(), $start, $expires, $owner)) {
            $finish = $this->clock->now();
            $runId = $this->runs->recordCompleted(
                $job->name(),
                JobStatus::SkippedLocked,
                0,
                $start,
                $finish,
                $triggeredBy,
                'lock held by another worker',
            );

            return new JobOutcome(
                jobName: $job->name(),
                status: JobStatus::SkippedLocked,
                itemsProcessed: 0,
                durationMs: self::elapsedMs($start, $finish),
                runId: $runId,
                errorMessage: 'lock held by another worker',
            );
        }

        $runId = $this->runs->startRun($job->name(), $start, $triggeredBy);
        $context = new JobContext($this->clock, $this->logger, $params);

        try {
            $result = $job->run($context);
            $finish = $this->clock->now();
            $this->runs->finishRun($runId, JobStatus::Success, $result->itemsProcessed, $finish);

            return new JobOutcome(
                jobName: $job->name(),
                status: JobStatus::Success,
                itemsProcessed: $result->itemsProcessed,
                durationMs: self::elapsedMs($start, $finish),
                runId: $runId,
            );
        } catch (Throwable $e) {
            $finish = $this->clock->now();
            $this->logger->error('job_failed', [
                'job' => $job->name(),
                'run_id' => $runId,
                'error' => $e->getMessage(),
                'trace' => SafeTrace::format($e),
            ]);
            $this->runs->finishRun($runId, JobStatus::Failure, 0, $finish, $e->getMessage());

            return new JobOutcome(
                jobName: $job->name(),
                status: JobStatus::Failure,
                itemsProcessed: 0,
                durationMs: self::elapsedMs($start, $finish),
                runId: $runId,
                errorMessage: $e->getMessage(),
            );
        } finally {
            $this->locks->release($job->name(), $owner);
        }
    }

    private static function elapsedMs(\DateTimeImmutable $start, \DateTimeImmutable $finish): int
    {
        $diffMicros = $finish->getTimestamp() - $start->getTimestamp();
        $diffMicros = $diffMicros * 1_000_000
            + ((int) $finish->format('u') - (int) $start->format('u'));

        return (int) max(0, intdiv($diffMicros, 1000));
    }
}