/*
 * This file is part of OpenTTD.
 * OpenTTD 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 Foundation, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file tcp_coordinator.h Basic functions to receive and send TCP packets to/from the Game Coordinator server.
 */

#ifndef NETWORK_CORE_TCP_COORDINATOR_H
#define NETWORK_CORE_TCP_COORDINATOR_H

#include "os_abstraction.h"
#include "tcp.h"
#include "packet.h"
#include "game_info.h"

/**
 * Enum with all types of TCP Game Coordinator packets. The order MUST not be changed.
 *
 * GC     -> packets from Game Coordinator to either Client or Server.
 * SERVER -> packets from Server to Game Coordinator.
 * CLIENT -> packets from Client to Game Coordinator.
 **/
enum PacketCoordinatorType {
	PACKET_COORDINATOR_GC_ERROR,        ///< Game Coordinator indicates there was an error.
	PACKET_COORDINATOR_SERVER_REGISTER, ///< Server registration.
	PACKET_COORDINATOR_GC_REGISTER_ACK, ///< Game Coordinator accepts the registration.
	PACKET_COORDINATOR_SERVER_UPDATE,   ///< Server sends an set intervals an update of the server.
	PACKET_COORDINATOR_CLIENT_LISTING,  ///< Client is requesting a listing of all public servers.
	PACKET_COORDINATOR_GC_LISTING,      ///< Game Coordinator returns a listing of all public servers.
	PACKET_COORDINATOR_END,             ///< Must ALWAYS be on the end of this list!! (period).
};

/**
 * The type of connection the Game Coordinator can detect we have.
 */
enum ConnectionType {
	CONNECTION_TYPE_UNKNOWN,  ///< The Game Coordinator hasn't informed us yet what type of connection we have.
	CONNECTION_TYPE_ISOLATED, ///< The Game Coordinator failed to find a way to connect to your server. Nobody will be able to join.
	CONNECTION_TYPE_DIRECT,   ///< The Game Coordinator can directly connect to your server.
};

/**
 * The type of error from the Game Coordinator.
 */
enum NetworkCoordinatorErrorType {
	NETWORK_COORDINATOR_ERROR_UNKNOWN,             ///< There was an unknown error.
	NETWORK_COORDINATOR_ERROR_REGISTRATION_FAILED, ///< Your request for registration failed.
};

/** Base socket handler for all Game Coordinator TCP sockets. */
class NetworkCoordinatorSocketHandler : public NetworkTCPSocketHandler {
protected:
	bool ReceiveInvalidPacket(PacketCoordinatorType type);

	/**
	 * Game Coordinator indicates there was an error. This can either be a
	 * permanent error causing the connection to be dropped, or in response
	 * to a request that is invalid.
	 *
	 *  uint8   Type of error (see NetworkCoordinatorErrorType).
	 *  string  Details of the error.
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_GC_ERROR(Packet *p);

	/**
	 * Server is starting a multiplayer game and wants to let the
	 * Game Coordinator know.
	 *
	 *  uint8   Game Coordinator protocol version.
	 *  uint8   Type of game (see ServerGameType).
	 *  uint16  Local port of the server.
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_SERVER_REGISTER(Packet *p);

	/**
	 * Game Coordinator acknowledges the registration.
	 *
	 *  uint8   Type of connection was detected (see ConnectionType).
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_GC_REGISTER_ACK(Packet *p);

	/**
	 * Send an update of the current state of the server to the Game Coordinator.
	 *
	 *  uint8   Game Coordinator protocol version.
	 *  Serialized NetworkGameInfo. See game_info.hpp for details.
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_SERVER_UPDATE(Packet *p);

	/**
	 * Client requests a list of all public servers.
	 *
	 *  uint8   Game Coordinator protocol version.
	 *  uint8   Game-info version used by this client.
	 *  string  Revision of the client.
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_CLIENT_LISTING(Packet *p);

	/**
	 * Game Coordinator replies with a list of all public servers. Multiple
	 * of these packets are received after a request till all servers are
	 * sent over. Last packet will have server count of 0.
	 *
	 *  uint16  Amount of public servers in this packet.
	 *  For each server:
	 *    string  Connection string for this server.
	 *    Serialized NetworkGameInfo. See game_info.hpp for details.
	 *
	 * @param p The packet that was just received.
	 * @return True upon success, otherwise false.
	 */
	virtual bool Receive_GC_LISTING(Packet *p);

	bool HandlePacket(Packet *p);
public:
	/**
	 * Create a new cs socket handler for a given cs.
	 * @param s The socket we are connected with.
	 */
	NetworkCoordinatorSocketHandler(SOCKET s = INVALID_SOCKET) : NetworkTCPSocketHandler(s) {}

	bool ReceivePackets();
};

#endif /* NETWORK_CORE_TCP_COORDINATOR_H */