<?php

namespace PHPCensor\Helper;

use PHPCensor\Config;

/**
 * Helper class for dealing with SSH keys.
 */
class SshKey
{
    /**
     * Uses ssh-keygen to generate a public/private key pair.
     *
     * @return array
     */
    public function generate()
    {
        $tempPath = sys_get_temp_dir() . '/';
        $keyFile  = $tempPath . md5(microtime(true));

        if (!is_dir($tempPath)) {
            mkdir($tempPath);
        }

        $return = [
            'ssh_private_key' => '',
            'ssh_public_key'  => ''
        ];

        $sshStrength = Config::getInstance()->get('php-censor.ssh.strength', 2048);
        $sshComment  = Config::getInstance()->get('php-censor.ssh.comment', 'admin@php-censor');

        $output = @shell_exec(
            sprintf(
                'ssh-keygen -t rsa -b %s -f %s -N "" -C "%s"',
                $sshStrength,
                $keyFile,
                $sshComment
            )
        );

        if (!empty($output)) {
            $pub = file_get_contents($keyFile . '.pub');
            $prv = file_get_contents($keyFile);

            if (!empty($pub)) {
                $return['ssh_public_key'] = $pub;
            }

            if (!empty($prv)) {
                $return['ssh_private_key'] = $prv;
            }
        }

        return $return;
    }
}