<?php

namespace ActivityPhp\Server\Http;

use ActivityPhp\Server;
use ActivityPhp\Type\Util;
use Symfony\Component\HttpFoundation\Request;
use phpseclib3\Crypt\RSA;

/**
 * HTTP signatures tool
 */
class HttpSignature
{
    public 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.
        $rsa = RSA::createKey()
                  ->loadPublicKey($publicKeyPem)
                  ->withHash('sha256');

        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:----MzYyMDcyMDA2NDYzMjIwOSA0NTQ2NDY1NzgxNjc0NDQ0IDI3OTM5NzcxNDM4NzkyMzc=