/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2021-2022 - Libretro team
 *
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __RARCH_NATT_H
#define __RARCH_NATT_H

#include <libretro.h>
#include <boolean.h>

#include <net/net_compat.h>
#include <net/net_socket.h>

enum natt_forward_type
{
   NATT_FORWARD_TYPE_NONE,
   NATT_FORWARD_TYPE_ANY
};

/* Use this enum to implement a higher-level interface. */
enum nat_traversal_status
{
   NAT_TRAVERSAL_STATUS_DISCOVERY,
   NAT_TRAVERSAL_STATUS_SELECT_DEVICE,
   NAT_TRAVERSAL_STATUS_QUERY_DEVICE,
   NAT_TRAVERSAL_STATUS_EXTERNAL_ADDRESS,
   NAT_TRAVERSAL_STATUS_OPEN,
   NAT_TRAVERSAL_STATUS_OPENING,
   NAT_TRAVERSAL_STATUS_OPENED,
   NAT_TRAVERSAL_STATUS_CLOSE,
   NAT_TRAVERSAL_STATUS_CLOSING,
   NAT_TRAVERSAL_STATUS_CLOSED
};

struct natt_discovery
{
   retro_time_t timeout;
   int fd;
};

struct natt_device
{
   struct sockaddr_in addr;
   struct sockaddr_in ext_addr;
   char desc        [256];
   char control     [256];
   char service_type[256];
   bool busy;
};

struct natt_request
{
   struct sockaddr_in addr;
   struct natt_device *device;
   enum socket_protocol proto;
   bool success;
};

/* Use this struct to implement a higher-level interface. */
struct nat_traversal_data
{
   struct natt_request request;
   enum natt_forward_type forward_type;
   enum nat_traversal_status status;
};

/**
 * natt_init:
 *
 * @discovery : Pointer to a discovery object that will be written to.
 *
 * Starts a multicast discovery for UPnP devices.
 *
 * Returns: true if the discovery was started.
 */
bool natt_init(struct natt_discovery *discovery);

/**
 * natt_device_next:
 *
 * @discovery : Pointer to a discovery object.
 * @device    : Pointer to a device object that will be written to.
 *
 * Grabs the next device that has reported in to our discovery.
 *
 * Returns: true if we've retrieved a new device or
 * if timeout has not yet been reached. If device->desc is not an empty string,
 * a new valid device was retrieved.
 */
bool natt_device_next(struct natt_discovery *discovery,
   struct natt_device *device);

/**
 * natt_device_end:
 *
 * @discovery : Pointer to a discovery object.
 *
 * Stop checking for new devices and close the discovery socket.
 *
 */
void natt_device_end(struct natt_discovery *discovery);

/**
 * natt_query_device:
 *
 * @device : Pointer to a device to query into.
 * @block  : Blocks until the HTTP task is finished.
 *
 * Query an IGD for its service type and control URL.
 *
 * Returns: true if the task was successfully started.
 * If both device->service_type and device->control are not empty strings,
 * the task completed successfully.
 */
bool natt_query_device(struct natt_device *device, bool block);

/**
 * natt_external_address:
 *
 * @device : Pointer to a device to retrieve its external address.
 * @block  : Blocks until the HTTP task is finished.
 *
 * Retrieve the external IP address of an IGD.
 * natt_query_device must have been successfully called.
 *
 * Returns: true if the task was successfully started.
 * If device->ext_addr.sin_family is AF_INET,
 * the task completed successfully.
 */
bool natt_external_address(struct natt_device *device, bool block);

/**
 * natt_open_port:
 *
 * @device       : Pointer to a device to forward a port.
 * @request      : Port forwarding request information.
 * @forward_type : UPnP port forwarding command type.
 * @block        : Blocks until the HTTP task is finished.
 *
 * Forward a port.
 * natt_query_device must have been successfully called.
 *
 * Returns: true if the task was successfully started.
 * If request->success is true, the task completed successfully.
 */
bool natt_open_port(struct natt_device *device,
   struct natt_request *request, enum natt_forward_type forward_type,
   bool block);

/**
 * natt_close_port:
 *
 * @device       : Pointer to a device to unforward a port.
 * @request      : Port unforwarding request information.
 * @block        : Blocks until the HTTP task is finished.
 *
 * Unforward a port.
 * natt_query_device must have been successfully called.
 *
 * Returns: true if the task was successfully started.
 * If request->success is true, the task completed successfully.
 */
bool natt_close_port(struct natt_device *device,
   struct natt_request *request, bool block);

#endif /* __RARCH_NATT_H */