<?php

declare(strict_types=1);

namespace OpenTelemetry\SDK\Trace;

use Http\Discovery\Exception\NotFoundException;
use Http\Discovery\Psr17FactoryDiscovery;
use Nyholm\Psr7Server\ServerRequestCreator;
use OpenTelemetry\API\Behavior\LogsMessagesTrait;
use OpenTelemetry\API\Common\Time\ClockInterface;
use OpenTelemetry\API\Globals;
use OpenTelemetry\API\Trace\Span;
use OpenTelemetry\API\Trace\SpanKind;
use OpenTelemetry\Context\Context;
use OpenTelemetry\SDK\Common\Configuration\Configuration;
use OpenTelemetry\SDK\Common\Configuration\Variables;
use OpenTelemetry\SDK\Common\Util\ShutdownHandler;
use OpenTelemetry\SemConv\TraceAttributes;
use OpenTelemetry\SemConv\Version;
use Psr\Http\Message\ServerRequestInterface;

class AutoRootSpan
{
    use LogsMessagesTrait;

    public static function isEnabled(): bool
    {
        return
            !empty($_SERVER['REQUEST_METHOD'] ?? null)
            && Configuration::getBoolean(Variables::OTEL_PHP_EXPERIMENTAL_AUTO_ROOT_SPAN);
    }

    /**
     * @psalm-suppress ArgumentTypeCoercion
     * @internal
     */
    public static function create(ServerRequestInterface $request): void
    {
        $tracer = Globals::tracerProvider()->getTracer(
            'io.opentelemetry.php.auto-root-span',
            null,
            Version::VERSION_1_25_0->url(),
        );
        $parent = Globals::propagator()->extract($request->getHeaders());
        $startTime = array_key_exists('REQUEST_TIME_FLOAT', $request->getServerParams())
            ? $request->getServerParams()['REQUEST_TIME_FLOAT']
            : (int) microtime(true);
        $span = $tracer->spanBuilder($request->getMethod())
            ->setSpanKind(SpanKind::KIND_SERVER)
            ->setStartTimestamp((int) ($startTime*ClockInterface::NANOS_PER_SECOND))
            ->setParent($parent)
            ->setAttribute(TraceAttributes::URL_FULL, (string) $request->getUri())
            ->setAttribute(TraceAttributes::HTTP_REQUEST_METHOD, $request->getMethod())
            ->setAttribute(TraceAttributes::HTTP_REQUEST_BODY_SIZE, $request->getHeaderLine('Content-Length'))
            ->setAttribute(TraceAttributes::USER_AGENT_ORIGINAL, $request->getHeaderLine('User-Agent'))
            ->setAttribute(TraceAttributes::SERVER_ADDRESS, $request->getUri()->getHost())
            ->setAttribute(TraceAttributes::SERVER_PORT, $request->getUri()->getPort())
            ->setAttribute(TraceAttributes::URL_SCHEME, $request->getUri()->getScheme())
            ->setAttribute(TraceAttributes::URL_PATH, $request->getUri()->getPath())
            ->startSpan();
        Context::storage()->attach($span->storeInContext($parent));
    }

    /**
     * @internal
     */
    public static function createRequest(): ?ServerRequestInterface
    {
        assert(array_key_exists('REQUEST_METHOD', $_SERVER) && !empty($_SERVER['REQUEST_METHOD']));

        try {
            $creator = new ServerRequestCreator(
                Psr17FactoryDiscovery::findServerRequestFactory(),
                Psr17FactoryDiscovery::findUriFactory(),
                Psr17FactoryDiscovery::findUploadedFileFactory(),
                Psr17FactoryDiscovery::findStreamFactory(),
            );

            return $creator->fromGlobals();
        } catch (NotFoundException $e) {
            self::logError('Unable to initialize server request creator for auto root span creation', ['exception' => $e]);
        }

        return null;
    }

    /**
     * @internal
     */
    public static function registerShutdownHandler(): void
    {
        ShutdownHandler::register(self::shutdownHandler(...));
    }

    /**
     * @internal
     */
    public static function shutdownHandler(): void
    {
        $scope = Context::storage()->scope();
        if (!$scope) {
            return;
        }
        $scope->detach();
        $span = Span::fromContext($scope->context());
        $span->end();
    }
}