/* $Id$ */

#ifndef NETWORK_CORE_UDP_H
#define NETWORK_CORE_UDP_H

#ifdef ENABLE_NETWORK

#include "os_abstraction.h"
#include "game.h"
#include "packet.h"
#include "../../newgrf_config.h"

/**
 * @file udp.h Basic functions to receive and send UDP packets.
 *
 *
 * *** Requesting game information from a server ***
 *
 * This describes the on-the-wire structure of the request and reply
 * packet of the NetworkGameInfo (see game.h) data.
 *
 * --- Points of attention ---
 *  - all > 1 byte integral values are written in little endian,
 *    unless specified otherwise.
 *      Thus, 0x01234567 would be sent as {0x67, 0x45, 0x23, 0x01}.
 *  - all sent strings are of variable length and terminated by a '\0'.
 *      Thus, the length of the strings is not sent.
 *  - years that are leap years in the 'days since X' to 'date' calculations:
 *     (year % 4 == 0) and ((year % 100 != 0) or (year % 400 == 0))
 *
 * --- Request ---
 * Bytes:  Description:
 *   2       size of the whole packet, in this case 3
 *   1       type of packet, in this case PACKET_UDP_CLIENT_FIND_SERVER (0)
 * This packet would look like: { 0x03, 0x00, 0x00 }
 *
 * --- Reply ---
 * Version: Bytes:  Description:
 *   all      2       size of the whole packet
 *   all      1       type of packet, in this case PACKET_UDP_SERVER_RESPONSE (1)
 *   all      1       the version of this packet's structure
 *
 *   4+       1       number of GRFs attached (n)
 *   4+       n * 20  unique identifier for GRF files. Constists of:
 *                     - one 4 byte variable with the GRF ID
 *                     - 16 bytes (sent sequentially) for the MD5 checksum
 *                       of the GRF
 *
 *   3+       4       current game date in days since 1-1-0 (DMY)
 *   3+       4       game introduction date in days since 1-1-0 (DMY)
 *
 *   2+       1       maximum number of companies allowed on the server
 *   2+       1       number of companies on the server
 *   2+       1       maximum number of spectators allowed on the server
 *
 *   1+       var     string with the name of the server
 *   1+       var     string with the revision of the server
 *   1+       1       the language run on the server
 *                    (0 = any, 1 = English, 2 = German, 3 = French)
 *   1+       1       whether the server uses a password (0 = no, 1 = yes)
 *   1+       1       maximum number of clients allowed on the server
 *   1+       1       number of clients on the server
 *   1+       1       number of spectators on the server
 *   1 & 2    2       current game date in days since 1-1-1920 (DMY)
 *   1 & 2    2       game introduction date in days since 1-1-1920 (DMY)
 *   1+       var     string with the name of the map
 *   1+       2       width of the map in tiles
 *   1+       2       height of the map in tiles
 *   1+       1       type of map:
 *                    (0 = temperate, 1 = arctic, 2 = desert, 3 = toyland)
 *   1+       1       whether the server is dedicated (0 = no, 1 = yes)
 */

///** Sending/receiving of UDP packets **////

bool NetworkUDPListen(SOCKET *udp, const uint32 host, const uint16 port, const bool broadcast);
void NetworkUDPClose(SOCKET *udp);

void NetworkSendUDP_Packet(const SOCKET udp, Packet *p, const struct sockaddr_in *recv);
void NetworkUDPReceive(const SOCKET udp);

/**
 * Function that is called for every received UDP packet.
 * @param udp         the socket the packet is received on
 * @param packet      the received packet
 * @param client_addr the address of the sender of the packet
 */
void NetworkHandleUDPPacket(const SOCKET udp, Packet *p, const struct sockaddr_in *client_addr);


///** Sending/receiving of (large) chuncks of UDP packets **////


/** Enum with all types of UDP packets. The order MUST not be changed **/
enum {
	PACKET_UDP_CLIENT_FIND_SERVER,   ///< Queries a game server for game information
	PACKET_UDP_SERVER_RESPONSE,      ///< Reply of the game server with game information
	PACKET_UDP_CLIENT_DETAIL_INFO,   ///< Queries a game server about details of the game, such as companies
	PACKET_UDP_SERVER_DETAIL_INFO,   ///< Reply of the game server about details of the game, such as companies
	PACKET_UDP_SERVER_REGISTER,      ///< Packet to register itself to the master server
	PACKET_UDP_MASTER_ACK_REGISTER,  ///< Packet indicating registration has succedeed
	PACKET_UDP_CLIENT_GET_LIST,      ///< Request for serverlist from master server
	PACKET_UDP_MASTER_RESPONSE_LIST, ///< Response from master server with server ip's + port's
	PACKET_UDP_SERVER_UNREGISTER,    ///< Request to be removed from the server-list
	PACKET_UDP_CLIENT_GET_NEWGRFS,   ///< Requests the name for a list of GRFs (GRF_ID and MD5)
	PACKET_UDP_SERVER_NEWGRFS,       ///< Sends the list of NewGRF's requested.
	PACKET_UDP_END                   ///< Must ALWAYS be on the end of this list!! (period)
};

void NetworkSend_GRFIdentifier(Packet *p, const GRFConfig *c);
void NetworkSend_NetworkGameInfo(Packet *p, const NetworkGameInfo *info);

void NetworkRecv_GRFIdentifier(NetworkClientState *cs, Packet *p, GRFConfig *c);
void NetworkRecv_NetworkGameInfo(NetworkClientState *cs, Packet *p, NetworkGameInfo *info);

/**
 * Function that is called for every GRFConfig that is read when receiving
 * a NetworkGameInfo. Only grfid and md5sum are set, the rest is zero. This
 * function must set all appropriate fields. This GRF is later appended to
 * the grfconfig list of the NetworkGameInfo.
 * @param config the GRF to handle
 */
void HandleIncomingNetworkGameInfoGRFConfig(GRFConfig *config);

#endif /* ENABLE_NETWORK */

#endif /* NETWORK_CORE_UDP_H */