<?php

namespace ActivityPhp\Server\Http;

use ActivityPhp\Server;
use ActivityPhp\Type\Util;
use Symfony\Component\HttpFoundation\Request;
use phpseclib\Crypt\RSA;

/**
 * HTTP signatures tool
 */
class HttpSignature
{
    const SIGNATURE_PATTERN = "/^\n        keyId="(?P<keyId>\n            (https?:\/\/[\w\-\.]+[\w]+)\n            (:[\d]+)?\n            ([\w\-\.#\/@]+)\n        )",\n        (algorithm="(?P<algorithm>[\w\s-]+)",)?\n        (headers="\(request-target\) (?P<headers>[\w\s-]+)",)?\n        signature="(?P<signature>[\w+\/]+={0,2})"\n    /x";

    /**
     * Allowed keys when splitting signature
     *
     * @var array
     */
    private $allowedKeys = [
        'keyId',
        'algorithm', // optional
        "headers",   // optional
        "signature",
    ];

    /** @var \ActivityPhp\Server */
    protected $server;

    /**
     * Inject a server instance
     */
    public function __construct(Server $server)
    {
        $this->server = $server;
    }

    /**
     * Verify an incoming message based upon its HTTP signature
     *
     * @param  \Symfony\Component\HttpFoundation\Request $request
     * @return bool True if signature has been verified. Otherwise false
     */
    public function verify(Request $request): bool
    {
        // Read the Signature header,
        $signature = $request->headers->get('signature');

        if (!$signature) {
            $this->server->logger()->info(
                'Signature header not found',
                [$request->headers->all()]
            );
            return false;
        }

        // Split it into its parts (keyId, headers and signature)
        $parts = $this->splitSignature($signature);
        if (!count($parts)) {
            return false;
        }

        extract($parts);

        $this->server->logger()->debug('Signature', [$signature]);

        // Build a server-oriented actor
        // Fetch the public key linked from keyId
        $actor = $this->server->actor($keyId);

        $publicKeyPem = $actor->getPublicKeyPem();

        $this->server->logger()->debug('publicKeyPem', [$publicKeyPem]);

        // Create a comparison string from the plaintext headers we got
        // in the same order as was given in the signature header,
        $data = $this->getPlainText(
            explode(' ', trim($headers)),
            $request
        );

        // Verify that string using the public key and the original
        // signature.
        $rsa = new RSA();
        $rsa->setHash("sha256");
        $rsa->setSignatureMode(RSA::SIGNATURE_PSS);
        $rsa->loadKey($publicKeyPem);

        return $rsa->verify($data, base64_decode($signature, true));
    }

    /**
     * Split HTTP signature into its parts (keyId, headers and signature)
     */
    public function splitSignature(string $signature): array
    {
        if (!preg_match(self::SIGNATURE_PATTERN, $signature, $matches)) {
            $this->server->logger()->info(
                'Signature pattern failed',
                [$signature]
            );

            return [];
        }

        // Headers are optional
        if (!isset($matches['headers']) || $matches['headers'] == '') {
            $matches['headers'] = 'date';
        }

        return array_filter($matches, function($key) {
                return !is_int($key) && in_array($key, $this->allowedKeys);
        },  ARRAY_FILTER_USE_KEY );
    }

    /**
     * Get plain text that has been originally signed
     *
     * @param  array $headers HTTP header keys
     * @param  \Symfony\Component\HttpFoundation\Request $request
     */
    private function getPlainText(array $headers, Request $request): string
    {
        $strings = [];
        $strings[] = sprintf(
            '(request-target) %s %s%s',
            strtolower($request->getMethod()),
            $request->getPathInfo(),
            $request->getQueryString()
                ? '?' . $request->getQueryString() : ''
        );

        foreach ($headers as $key) {
            if ($request->headers->has($key)) {
                $strings[] = "$key: " . $request->headers->get($key);
            }
        }

        return implode("\n", $strings);
    }
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----Mzg2NzYwMTAwMDc0ODg5OSA0MTAwMDAyNDYyNDEyOTQxIDEzMDk5Nzc4ODA5NjA0Mjk=