/* $Id$ */
/*
   Copyright (C) 2003 - 2009 by David White <dave@whitevine.net>
   Part of the Battle for Wesnoth Project http://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2
   or at your option any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

/** @file network.hpp */

#ifndef NETWORK_HPP_INCLUDED
#define NETWORK_HPP_INCLUDED
/**
 * Enable bandwidth stats
 **/

class config;

#include "SDL_net.h"

#include <string>
#include <vector>

#include <boost/shared_ptr.hpp>

namespace threading
{
	class waiter;
}

// This module wraps the network interface.

namespace network {

struct pending_statistics {
	int npending_sends;
	int nbytes_pending_sends;
};

pending_statistics get_pending_stats();

// A network manager must be created before networking can be used.
// It must be destroyed only after all networking activity stops.

// min_threads is the maximum number we allow to wait,
// if more threads attempt to wait, they will die.
// If min_threads == 0 no thread will ever be destroyed,
// and we will stay at the max number of threads ever needed.

// max_threads is the overall max number of helper threads.
// If we have that many threads already running, we will never create more.
// If max_threads == 0 we will always create a thread if we need it.
struct manager {
	explicit manager(size_t min_threads = 1,size_t max_threads = 0);
	~manager();

private:
	bool free_;

	manager(const manager&);
	void operator=(const manager&);
};

void set_raw_data_only();

typedef int connection;
connection const null_connection = 0;

/**
 * A server manager causes listening on a given port
 * to occur for the duration of its lifetime.
 */
struct server_manager {

	/** Parameter to pass to the constructor. */
	enum CREATE_SERVER { MUST_CREATE_SERVER,    /**< Will throw exception on failure. */
	                     TRY_CREATE_SERVER,     /**< Will swallow failure. */
	                     NO_SERVER };           /**< Won't try to create a server at all. */

	// Throws error.
	server_manager(int port, CREATE_SERVER create_server=MUST_CREATE_SERVER);
	~server_manager();

	bool is_running() const;
	void stop();

private:
	bool free_;
	connection connection_;
};


/** The number of peers we are connected to. */
size_t nconnections();

/** If we are currently accepting connections. */
bool is_server();

/**
 * Function to attempt to connect to a remote host.
 *
 * @returns                       The new connection on success, or 0 on failure.
 * @throw error
 */
connection connect(const std::string& host, int port=15000);

connection connect(const std::string& host, int port, threading::waiter& waiter);

/**
 * Function to accept a connection from a remote host.
 *
 * If no host is attempting to connect, it will return 0 immediately.
 * Otherwise returns the new connection.
 *
 * @throw error
 */
connection accept_connection();

/**
 * Function to disconnect from a certain host,
 * or close all connections if connection_num is 0.
 * Returns true if the connection was disconnected.
 * Returns false on failure to disconnect, since the socket is
 * in the middle of sending/receiving data.
 * The socket will be closed when it has finished its send/receive.
 */
bool disconnect(connection connection_num=0);

/**
 * Function to queue a disconnection.
 *
 * Next time receive_data is called, it will generate an error
 * on the given connection (and presumably then the handling of the error
 * will include closing the connection).
 */
void queue_disconnect(connection connection_num);

std::string get_bandwidth_stats();
std::string get_bandwidth_stats_all();
std::string get_bandwidth_stats(int hour);

void add_bandwidth_out(const std::string& packet_type, size_t len);
void add_bandwidth_in(const std::string& packet_type, size_t len);
struct bandwidth_in {
	bandwidth_in(int len) : len_(len), type_("unknown") {}
	~bandwidth_in();

	void set_type(const std::string& type)
	{
		type_ = type;
	}

	private:
	int len_;
	std::string type_;
};

typedef boost::shared_ptr<bandwidth_in> bandwidth_in_ptr;


/**
 * Function to receive data from either a certain connection,
 * or all connections if connection_num is 0.
 * Will store the data received in cfg.
 * Times out after timeout milliseconds.
 *
 * @returns                       The connection that data was received from,
 *                                or 0 if timeout occurred.
 *
 * @throw error                   If an error occurred.
 */
connection receive_data(config& cfg, connection connection_num=0, bool* gzipped = 0, bandwidth_in_ptr* b = 0);
connection receive_data(config& cfg, connection connection_num, unsigned int timeout, bandwidth_in_ptr* b = 0);
connection receive_data(std::vector<char>& buf, bandwidth_in_ptr* = 0);

void send_file(const std::string&, connection, const std::string& packet_type = "unknown");

/**
 * Function to send data down a given connection,
 * or broadcast to all peers if connection_num is 0.
 *
 * @throw error
 */
size_t send_data(const config& cfg, connection connection_num /*= 0*/,
		const bool gzipped, const std::string& packet_type = "unknown");

void send_raw_data(const char* buf, int len, connection connection_num,
		const std::string& packet_type = "unknown");

/**
 * Function to send any data that is in a connection's send_queue,
 * up to a maximum of 'max_size' bytes --
 * or the entire send queue if 'max_size' bytes is 0.
 */
void process_send_queue(connection connection_num=0, size_t max_size=0);

/** Function to send data to all peers except 'connection_num'. */
void send_data_all_except(const config& cfg, connection connection_num,
		const bool gzipped, const std::string& packet_type = "unknown");

/** Function to get the remote ip address of a socket. */
std::string ip_address(connection connection_num);

struct connection_stats
{
	connection_stats(int sent, int received, int connected_at);

	int bytes_sent, bytes_received;
	int time_connected;
};

connection_stats get_connection_stats(connection connection_num);

struct error
{
	error(const std::string& msg="", connection sock=0);
	std::string message;
	connection socket;

	void disconnect();
};

struct statistics
{
	statistics() : total(0), current(0), current_max(0) {}
	void fresh_current(size_t len)
	{
		current = 0;
		current_max = len;
	}
	void transfer(size_t size)
	{
		total += size;
		current += size;
	}
	bool operator==(const statistics& stats) const
	{
		return total == stats.total && current == stats.current && current_max == stats.current_max;
	}
	bool operator!=(const statistics& stats) const
	{
		return !operator==(stats);
	}
	size_t total;
	size_t current;
	size_t current_max;
};

/** Function to see the number of bytes being processed on the current socket. */
statistics get_send_stats(connection handle);
statistics get_receive_stats(connection handle);

/** Amount of seconds after the last server ping when we assume to have timed out. */
extern unsigned int ping_timeout;
} // network namespace


#endif