//  OpenVPN 3 Linux client -- Next generation OpenVPN client
//
//  SPDX-License-Identifier: AGPL-3.0-only
//
//  Copyright (C) 2018 - 2023  OpenVPN Inc <sales@openvpn.net>
//  Copyright (C) 2018 - 2023  Arne Schwabe <arne@openvpn.net>
//  Copyright (C) 2018 - 2023  David Sommerseth <davids@openvpn.net>
//

/**
 * @file   netcfg-options.hpp
 *
 * @brief  The implementation of options that are use by netcfg
 */

#pragma once

#include "common/cmdargparser.hpp"
#include "netcfg/netcfg-configfile.hpp"


enum class RedirectMethod : std::uint8_t
{
    NONE = 0,   //<  Do not add any additional routes
    HOST_ROUTE, //<  Add direct route to VPN server
    BINDTODEV   //<  Bind the UDP/TCP socket to the default gw interface
};



/**
 * struct to hold the setting for the Netcfg service
 */
struct NetCfgOptions
{
    /** Decides wether use the tun-builder redirect functionality */
    RedirectMethod redirect_method = RedirectMethod::HOST_ROUTE;

    /** the SO_MARK to use if > 0 */
    int so_mark = -1;

    /** Will signals be broadcast to all users? */
    bool signal_broadcast = false;

    /** Configuration file to use, if --state-dir is given */
    std::string config_file = "";


    NetCfgOptions(ParsedArgs::Ptr args, NetCfgConfigFile::Ptr config)
    {
        if (config && args->Present("state-dir"))
        {
            config_file = args->GetLastValue("state-dir") + "/netcfg.json";
            try
            {
                std::cout << "Loading configuration file: "
                          << config_file << std::endl;
                config->Load(config_file);
                args->ImportConfigFile(config);
            }
            catch (const ConfigFileException &)
            {
                // Ignore errors related to configuration file
            }
        }

        try
        {
            args->CheckExclusiveOptions({{"resolv-conf", "systemd-resolved"}});
        }
        catch (const ExclusiveOptionError &excp)
        {
            throw CommandException("openvpn3-service-netcfg",
                                   excp.what());
        }

        if (args->Present("redirect-method"))
        {
            std::string method = args->GetValue("redirect-method", 0);
            if ("none" == method)
            {
                redirect_method = RedirectMethod::NONE;
            }
            else if ("host-route" == method)
            {
                redirect_method = RedirectMethod::HOST_ROUTE;
            }
            else if ("bind-device" == method)
            {
                redirect_method = RedirectMethod::BINDTODEV;
            }
            else
            {
                throw CommandArgBaseException("Invalid argument to --redirect-method: "
                                              + method);
            }
        }

        if (args->Present("set-somark"))
        {
            so_mark = std::atoi(args->GetValue("set-somark", 0).c_str());
        }

        signal_broadcast = args->Present("signal-broadcast");
    }


    NetCfgOptions(const NetCfgOptions &origin) = default;

    /**
     *  Generate a decoded string of the current options
     *
     * @return  Returns a const std::string of the decoded options
     */
    const std::string str()
    {
        return decode_options(*this);
    }


    /**
     *  Makes it possible to write NetCfgOptions in a readable format
     *  via iostreams.
     *
     * @param os  std::ostream where to write the data
     * @param ev  NetCfgOptions to write to the stream
     *
     * @return  Returns the provided std::ostream together with the
     *          decoded NetCfgOptions information
     */
    friend std::ostream &operator<<(std::ostream &os, const NetCfgOptions &o)
    {
        return os << decode_options(o);
    }


  private:
    static const std::string decode_options(const NetCfgOptions &o)
    {
        std::stringstream s;

        s << "Redirect method: ";
        switch (o.redirect_method)
        {
        case RedirectMethod::NONE:
            s << "None";
            break;
        case RedirectMethod::BINDTODEV:
            s << "bind-device";
            break;
        case RedirectMethod::HOST_ROUTE:
            s << "host-route";
            break;
        }

        if (o.so_mark >= 0)
        {
            s << ", so-mark: " << std::to_string(o.so_mark);
        }
        return s.str();
    }
};