<?php

declare(strict_types=1);

namespace Shlinkio\Shlink\Rest\Middleware;

use Fig\Http\Message\RequestMethodInterface;
use JsonException;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Shlinkio\Shlink\Core\Exception\MalformedBodyException;

use function Shlinkio\Shlink\Core\ArrayUtils\contains;
use function Shlinkio\Shlink\Json\json_decode;

class BodyParserMiddleware implements MiddlewareInterface, RequestMethodInterface
{
    public function process(Request $request, RequestHandlerInterface $handler): Response
    {
        $method = $request->getMethod();
        $currentParams = $request->getParsedBody();

        // In requests that do not allow body or if the body has already been parsed, continue to next middleware
        if (
            ! empty($currentParams)
            || contains($method, [
                self::METHOD_GET,
                self::METHOD_HEAD,
                self::METHOD_OPTIONS,
            ])
        ) {
            return $handler->handle($request);
        }

        return $handler->handle($this->parseFromJson($request));
    }

    private function parseFromJson(Request $request): Request
    {
        $rawBody = $request->getBody()->__toString();
        if (empty($rawBody)) {
            return $request;
        }

        try {
            $parsedJson = json_decode($rawBody);
            return $request->withParsedBody($parsedJson);
        } catch (JsonException $e) {
            throw MalformedBodyException::forInvalidJson($e);
        }
    }
}