<?php

namespace Orbit;

use Monolog\Logger;
use Monolog\Handler\StreamHandler;

class Server
{
    public static $version = "0.2";

    public $config;
    public $pemfile = "./server.pem";
    public $pem_passphrase = "";
    public $timeout = 60;

    private $ssl_context;
    private $logger;

    public function __construct(Config $config = null)
    {
        if ($config == null) {
            $this->config = new Config();
        } else {
            $this->config = $config;
        }

        $this->timeout = ini_get("default_socket_timeout");

        if (file_exists($this->pemfile)) {
            $this->log(Logger::DEBUG, "Using existing cert.");
        } else {
            $this->log(Logger::DEBUG, "Generating new cert.");
            $this->generateCert();
        }
        $this->ssl_context = $this->createSslContext();
    }

    public function setLogger(Logger $logger)
    {
        $this->logger = $logger;
    }

    public function getLogger()
    {
        if (!$this->logger) {
            $this->logger = new Logger('orbit');
            $this->logger->pushHandler(new StreamHandler($this->config->log_file, Logger::INFO));
        }

        return $this->logger;
    }

    public function listen()
    {
        $server = stream_socket_server(
            $this->getListenAddress(),
            $errno, $errstr,
            STREAM_SERVER_BIND|STREAM_SERVER_LISTEN,
            $this->ssl_context
        );

        if (!$server) {
            throw new \Exception("Error " . $errno . ": " . $errstr);
        }

        $protocol = "gemini";
        $name = stream_socket_get_name($server, false);
        $this->log(Logger::NOTICE, "Listening on $protocol://$name ...");

        while (true) {
            # This is to swallow up the `timeout` warning
            set_error_handler([$this, 'onWarning']);
            $client = stream_socket_accept($server, $this->timeout, $client_name);
            restore_error_handler();

            if ($client) {
                $this->log(Logger::DEBUG, "$client_name Accepted");
                $request_buffer = stream_get_line($client, 1024, "\r\n");
                $this->log(Logger::INFO, "REQ: $request_buffer", ["client" => $client_name]);
                $request = new Request($request_buffer);

                // Respond to client
                $response = implode("\r\n", ['20 text/gemini', "Thanks for all the fish\n"]);
                fwrite($client,  $response);
                fclose($client);
                $this->log(Logger::DEBUG, "$client_name Closed");
            }
        }
    }

    public function log($level, $message, $context = [])
    {
        $this->getLogger()->log($level, $message, $context);
    }

    public function onWarning($id, $message)
    {
        if (strpos($message, "Operation timed out") !== false) {
            // Do nothing
            return;
        }

        // Something else happened.
        throw new \Exception($id . ' ' . $message);
    }

    public function getListenAddress()
    {
        return sprintf('tls://%s:%s', $this->config->host, $this->config->port);
    }

    private function generateCert()
    {
        // Certificate data
        $dn = [
            "countryName" => "UK",
            "stateOrProvinceName" => "X",
            "localityName" => "X",
            "organizationName" => "X",
            "organizationalUnitName" => "X",
            "commonName" => "orbit1.0",
            "emailAddress" => "X"
        ];

        // Generate certificate
        $privkey = openssl_pkey_new();
        $cert = openssl_csr_new($dn, $privkey);
        $cert = openssl_csr_sign($cert, null, $privkey, 365);

        // Generate PEM file
        $pem = [];
        openssl_x509_export($cert, $pem[0]);
        openssl_pkey_export($privkey, $pem[1], $this->pem_passphrase);
        $pem = implode($pem);

        // Save PEM file
        file_put_contents($this->pemfile, $pem);
    }

    public function createSslContext()
    {
        $context = stream_context_create();

        // local_cert must be in PEM format
        stream_context_set_option($context, 'ssl', 'local_cert', $this->pemfile);
        stream_context_set_option($context, 'ssl', 'passphrase', $this->pem_passphrase);

        stream_context_set_option($context, 'ssl', 'allow_self_signed', true);
        stream_context_set_option($context, 'ssl', 'verify_peer', false);

        return $context;
    }
}