//
//	IRCClientSession.m
//	IRCClient
/*
 * Copyright 2015 Said Achmiz (www.saidachmiz.net)
 *
 * Copyright (C) 2009 Nathan Ollerenshaw chrome@stupendous.net
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2 of the License, or (at your 
 * option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 */

/********************************/
#pragma mark Defines and includes
/********************************/

#define IRCCLIENTVERSION "2.0a3"

#import "IRCClientSession.h"
#import "IRCClientChannel.h"
#import "IRCClientChannel_Private.h"
#import "NSData+SA_NSDataExtensions.h"

/********************************************/
#pragma mark - Callback function declarations
/********************************************/

static void onConnect(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onNick(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onQuit(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onJoinChannel(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onPartChannel(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onMode(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onUserMode(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onTopic(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onKick(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onChannelPrvmsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onPrivmsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onServerMsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onChannelNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onServerNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onInvite(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onCtcpRequest(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onCtcpReply(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onCtcpAction(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onUnknownEvent(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count);
static void onNumericEvent(irc_session_t *session, unsigned int event, const char *origin, const char **params, unsigned int count);

static NSDictionary* ircNumericCodeList;

/**********************************************/
#pragma mark - IRCClientSession class extension
/**********************************************/

@interface IRCClientSession()
{
	irc_callbacks_t		_callbacks;
	irc_session_t		*_irc_session;
	NSThread			*_thread;
	
	NSMutableDictionary *_channels;
}

@property (readwrite) NSMutableDictionary *channels;

+(void)loadNumericCodes;

@end

/***************************************************/
#pragma mark - IRCClientSession class implementation
/***************************************************/

@implementation IRCClientSession

/******************************/
#pragma mark - Custom accessors
/******************************/

- (NSDictionary*)channels
{
	NSDictionary* channelsCopy = [_channels copy];
	return channelsCopy;
}

- (void)setChannels:(NSDictionary *)channels
{
	_channels = [channels mutableCopy];
}

- (bool)isConnected
{
	return irc_is_connected(_irc_session);
}

/***************************/
#pragma mark - Class methods
/***************************/

- (instancetype)init
{
    if ((self = [super init]))
	{
		_callbacks.event_connect = onConnect;
		_callbacks.event_nick = onNick;
		_callbacks.event_quit = onQuit;
		_callbacks.event_join = onJoinChannel;
		_callbacks.event_part = onPartChannel;
		_callbacks.event_mode = onMode;
		_callbacks.event_umode = onUserMode;
		_callbacks.event_topic = onTopic;
		_callbacks.event_kick = onKick;
		_callbacks.event_channel = onChannelPrvmsg;
		_callbacks.event_privmsg = onPrivmsg;
		_callbacks.event_server_msg = onServerMsg;
		_callbacks.event_notice = onNotice;
		_callbacks.event_channel_notice = onChannelNotice;
		_callbacks.event_server_notice = onServerNotice;
		_callbacks.event_invite = onInvite;
		_callbacks.event_ctcp_req = onCtcpRequest;
		_callbacks.event_ctcp_rep = onCtcpReply;
		_callbacks.event_ctcp_action = onCtcpAction;
		_callbacks.event_unknown = onUnknownEvent;
		_callbacks.event_numeric = onNumericEvent;
		_callbacks.event_dcc_chat_req = NULL;
		_callbacks.event_dcc_send_req = NULL;
		
		_irc_session = irc_create_session(&_callbacks);
		
		if (!_irc_session) {
			NSLog(@"Could not create irc_session.");
			return nil;
		}
		
		// Strip server info from nicks.
//		irc_option_set(_irc_session, LIBIRC_OPTION_STRIPNICKS);
		
		// Set debug mode.
//		irc_option_set(_irc_session, LIBIRC_OPTION_DEBUG);
		
		irc_set_ctx(_irc_session, (__bridge void *)(self));
		
		unsigned int high, low;
		irc_get_version (&high, &low);
		
		NSString* versionString = [NSString stringWithFormat:@"IRCClient Framework v%s (Said Achmiz) - libirc v%d.%d (Georgy Yunaev)", IRCCLIENTVERSION, high, low];
		_version = [NSData dataWithBytes:versionString.UTF8String length:versionString.length];
		
		_channels = [[NSMutableDictionary alloc] init];
		_encoding = NSUTF8StringEncoding;
    }
    return self;
}

- (void)dealloc
{
	if (irc_is_connected(_irc_session))
	{
		NSLog(@"Warning: IRC Session is not disconnected on dealloc");
	}
	
	irc_destroy_session(_irc_session);
}

+ (NSDictionary *)ircNumericCodes
{
	if(ircNumericCodeList == nil)
	{
		[IRCClientSession loadNumericCodes];
	}
	
	return ircNumericCodeList;
}

+ (void)loadNumericCodes
{
	NSString* numericCodeListPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"IRC_Numerics" ofType:@"plist"];
	ircNumericCodeList = [NSDictionary dictionaryWithContentsOfFile:numericCodeListPath];
	if(ircNumericCodeList)
	{
		NSLog(@"IRC numeric codes list loaded successfully.\n");
//		NSLog(@"%@", ircNumericCodeList);
	}
	else
	{
		NSLog(@"Could not load IRC numeric codes list!\n");
	}
}

- (int)connect;
{
	return irc_connect(_irc_session, _server.SA_terminatedCString, (unsigned short) _port, (_password.length > 0 ? _password.SA_terminatedCString : NULL), _nickname.SA_terminatedCString, _username.SA_terminatedCString, _realname.SA_terminatedCString);
}

- (void)disconnect
{
	irc_disconnect(_irc_session);
}

- (void)startThread
{
	@autoreleasepool {
		irc_run(_irc_session);
	}
}

- (void)run
{
	if (_thread) {
		NSLog(@"Thread already running!");
		return;
	}
	
	_thread = [[NSThread alloc] initWithTarget:self selector:@selector(startThread) object:nil];
	[_thread start];
}

- (int)setNickname:(NSData *)nickname username:(NSData *)username realname:(NSData *)realname
{
	if(self.isConnected)
	{
		return 0;
	}
	else
	{
		_nickname = nickname.SA_dataWithTerminatedCString;
		_username = username.SA_dataWithTerminatedCString;
		_realname = realname.SA_dataWithTerminatedCString;
		
		return 1;
	}
}

/**************************/
#pragma mark - IRC commands
/**************************/

- (int)sendRaw:(NSData *)message
{
	return irc_send_raw(_irc_session, message.SA_terminatedCString);
}

- (int)quit:(NSData *)reason
{
	return irc_cmd_quit(_irc_session, reason.SA_terminatedCString);
}

- (int)join:(NSData *)channel key:(NSData *)key
{
	if (!key || !key.length > 0)
	{
		return irc_cmd_join(_irc_session, channel.SA_terminatedCString, NULL);
	}

	return irc_cmd_join(_irc_session, channel.SA_terminatedCString, key.SA_terminatedCString);
}

- (int)list:(NSData *)channel
{
	return irc_cmd_list(_irc_session, channel.SA_terminatedCString);
}

- (int)userMode:(NSData *)mode
{
	return irc_cmd_user_mode(_irc_session, mode.SA_terminatedCString);
}

- (int)nick:(NSData *)newnick
{
	return irc_cmd_nick(_irc_session, newnick.SA_terminatedCString);
}

- (int)whois:(NSData *)nick
{
	return irc_cmd_whois(_irc_session, nick.SA_terminatedCString);
}

- (int)message:(NSData *)message to:(NSData *)target
{
	return irc_cmd_msg(_irc_session, target.SA_terminatedCString, message.SA_terminatedCString);
}

- (int)action:(NSData *)action to:(NSData *)target
{
	return irc_cmd_me(_irc_session, target.SA_terminatedCString, action.SA_terminatedCString);
}

- (int)notice:(NSData *)notice to:(NSData *)target
{
	return irc_cmd_notice(_irc_session, target.SA_terminatedCString, notice.SA_terminatedCString);
}

- (int)ctcpRequest:(NSData *)request target:(NSData *)target
{
	return irc_cmd_ctcp_request(_irc_session, target.SA_terminatedCString, request.SA_terminatedCString);
}

- (int)ctcpReply:(NSData *)reply target:(NSData *)target
{
	return irc_cmd_ctcp_reply(_irc_session, target.SA_terminatedCString, reply.SA_terminatedCString);
}

/****************************/
#pragma mark - Event handlers
/****************************/

- (void)connectionSucceeded
{
	[_delegate connectionSucceeded:self];
}

- (void)nickChangedFrom:(NSData *)oldNick to:(NSData *)newNick
{
	NSData* oldNickOnly = getNickFromNickUserHost(oldNick);
	
	if ([_nickname isEqualToData:oldNickOnly])
	{
		_nickname = newNick;
		[_delegate nickChangedFrom:oldNickOnly to:newNick own:YES session:self];
	}
	else
	{
		[_delegate nickChangedFrom:oldNickOnly to:newNick own:NO session:self];
	}
}

- (void)userQuit:(NSData *)nick withReason:(NSData *)reason
{
	[_delegate userQuit:nick withReason:reason session:self];
}

- (void)userJoined:(NSData *)nick channel:(NSData *)channelName
{
	NSData* nickOnly = getNickFromNickUserHost(nick);
	
	if ([_nickname isEqualToData:nickOnly])
	{
		// We just joined a channel; allocate an IRCClientChannel object and
		// add it to our channels list.
		
		IRCClientChannel* newChannel = [[IRCClientChannel alloc] initWithName:channelName andIRCSession:_irc_session];
		_channels[channelName] = newChannel;
		[_delegate joinedNewChannel:newChannel session:self];
	}
	else
	{
		// Someone joined a channel we're on.
		
		IRCClientChannel* channel = _channels[channelName];
		[channel userJoined:nick];
	}
}

- (void)userParted:(NSData *)nick channel:(NSData *)channelName withReason:(NSData *)reason
{
	IRCClientChannel* channel = _channels[channelName];
	
	NSData* nickOnly = getNickFromNickUserHost(nick);
	
	if ([_nickname isEqualToData:nickOnly])
	{
		// We just left a channel; remove it from the channels dict.
		[_channels removeObjectForKey:channelName];
		[channel userParted:nick withReason:reason us:YES];
	}
	else
	{
		[channel userParted:nick withReason:reason us:NO];
	}
}

- (void)modeSet:(NSData* )mode withParams:(NSData *)params forChannel:(NSData *)channelName by:(NSData *)nick
{
	IRCClientChannel *channel = _channels[channelName];
	
	[channel modeSet:mode withParams:params by:nick];
}

- (void)modeSet:(NSData *)mode by:(NSData *)nick
{
	[_delegate modeSet:mode by:nick session:self];
}

- (void)topicSet:(NSData *)newTopic forChannel:(NSData *)channelName by:(NSData *)nick
{
	IRCClientChannel *channel = _channels[channelName];
	
	[channel topicSet:newTopic by:nick];
}

- (void)userKicked:(NSData *)nick fromChannel:(NSData *)channelName by:(NSData *)byNick withReason:(NSData *)reason
{
	IRCClientChannel* channel = _channels[channelName];

	if (nick == nil)
	{
		// we got kicked from a channel we're on
		[_channels removeObjectForKey:channelName];
		[channel userKicked:_nickname withReason:reason by:byNick us:YES];
	}
	else
	{
		// someone else got booted from a channel we're on
		[channel userKicked:nick withReason:reason by:byNick us:NO];
	}
}

- (void)messageSent:(NSData *)message toChannel:(NSData *)channelName byUser:(NSData *)nick
{
	IRCClientChannel *channel = _channels[channelName];
	
	[channel messageSent:message byUser:nick];
}

- (void)privateMessageReceived:(NSData *)message fromUser:(NSData *)nick
{
	[_delegate privateMessageReceived:message fromUser:nick session:self];
}

- (void)serverMessageReceivedFrom:(NSData *)origin params:(NSArray *)params
{
	[_delegate serverMessageReceivedFrom:origin params:params session:self];
}

- (void)privateNoticeReceived:(NSData *)notice fromUser:(NSData *)nick
{
	[_delegate privateNoticeReceived:notice fromUser:nick session:self];
}

- (void)noticeSent:(NSData *)notice toChannel:(NSData *)channelName byUser:(NSData *)nick
{
	IRCClientChannel *channel = _channels[channelName];
	
	[channel noticeSent:notice byUser:nick];
}

- (void)serverNoticeReceivedFrom:(NSData *)origin params:(NSArray *)params
{
	[_delegate serverNoticeReceivedFrom:origin params:params session:self];
}

- (void)invitedToChannel:(NSData *)channelName by:(NSData *)nick
{
	[_delegate invitedToChannel:channelName by:nick session:self];
}

- (void)CTCPRequestReceived:(NSData *)request fromUser:(NSData *)nick
{
	const char* the_nick = getNickFromNickUserHost(nick).bytes;
	const char* the_request = request.bytes;
	
	if (strstr(the_request, "PING") == the_request)
	{
		irc_cmd_ctcp_reply(_irc_session, the_nick, the_request);
	}
	else if (!strcmp (the_request, "VERSION"))
	{
		NSMutableData* versionReply = [NSMutableData dataWithLength:8 + _version.length];
		sprintf(versionReply.mutableBytes, "VERSION %s", _version.bytes);
		
		irc_cmd_ctcp_reply (_irc_session, the_nick, versionReply.bytes);
	}
	else if (!strcmp (the_request, "FINGER"))
	{
		NSMutableData* fingerReply = [NSMutableData dataWithLength:25 + _username.length + _realname.length];
		sprintf(fingerReply.mutableBytes, "FINGER %s (%s) Idle 0 seconds)", _username.bytes, _realname.bytes);
		
		irc_cmd_ctcp_reply (_irc_session, the_nick, fingerReply.bytes);
	}
	else if (!strcmp (the_request, "TIME"))
	{
		irc_cmd_ctcp_reply(_irc_session, the_nick, [[[NSDate dateWithTimeIntervalSinceNow:0] descriptionWithCalendarFormat:@"TIME %a %b %e %H:%M:%S %Z %Y" timeZone:nil locale:[[NSUserDefaults standardUserDefaults] dictionaryRepresentation]] cStringUsingEncoding:_encoding]);
	}
	else
	{
		if ([_delegate respondsToSelector:@selector(CTCPRequestReceived:ofType:fromUser:session:)])
		{
			char* request_string = malloc(request.length);
			[request getBytes:request_string length:request.length];
			
			char* request_type = strtok(request_string, " ");
			char* request_body = strtok(NULL, " " );
			
			NSData* requestTypeData = [NSData dataWithBytes:request_body length:strlen(request_body) + 1];
			NSData* requestBodyData = [NSData dataWithBytes:request_type length:strlen(request_type) + 1];
			
			[_delegate CTCPRequestReceived:requestBodyData ofType:requestTypeData fromUser:nick session:self];
			
			free(request_string);
		}
	}
}

- (void)CTCPReplyReceived:(NSData *)reply fromUser:(NSData *)nick
{
	[_delegate CTCPReplyReceived:reply fromUser:nick session:self];
}

- (void)CTCPActionPerformed:(NSData *)action byUser:(NSData *)nick atTarget:(NSData *)target
{
	IRCClientChannel* channel = _channels[target];
	
	if(channel != nil)
	{
		// An action on a channel we're on
		[channel actionPerformed:action byUser:nick];
	}
	else
	{
		// An action in a private message
		[_delegate privateCTCPActionReceived:action fromUser:nick session:self];
	}
}

- (void)unknownEventReceived:(NSData *)event from:(NSData *)origin params:(NSArray *)params
{
	[_delegate unknownEventReceived:event from:origin params:params session:self];
}

-(void)numericEventReceived:(NSUInteger)event from:(NSData *)origin params:(NSArray *)params
{
	[_delegate numericEventReceived:event from:origin params:params session:self];
}

@end

/*************************************/
#pragma mark - Useful helper functions
/*************************************/

NSData* getNickFromNickUserHost(NSData *nickUserHost)
{
	char *nick_user_host_buf = malloc(nickUserHost.length);
	[nickUserHost getBytes:nick_user_host_buf];
	
	char *nick_buf;
	nick_buf = strtok(nick_user_host_buf, "!");
	
	NSData *nick = (nick_buf != NULL) ? [NSData dataWithBytes:nick_buf length:strlen(nick_buf) + 1] : [NSData dataWithBlankCString];
	
	free(nick_user_host_buf);
	
	return nick;
}

NSData* getUserFromNickUserHost(NSData *nickUserHost)
{
	char *nick_user_host_buf = malloc(nickUserHost.length);
	[nickUserHost getBytes:nick_user_host_buf];
	
	char *nick_buf, *user_buf;
	nick_buf = strtok(nick_user_host_buf, "!");
	user_buf = strtok(NULL, "@");
	
	NSData *user = (user_buf != NULL) ? [NSData dataWithBytes:user_buf length:strlen(user_buf) + 1] : [NSData dataWithBlankCString];
	
	free(nick_user_host_buf);
	
	return user;
}

NSData* getHostFromNickUserHost(NSData *nickUserHost)
{
	char *nick_user_host_buf = malloc(nickUserHost.length);
	[nickUserHost getBytes:nick_user_host_buf];
	
	char *nick_buf, *user_buf, *host_buf;
	nick_buf = strtok(nick_user_host_buf, "!");
	user_buf = strtok(NULL, "@");
	host_buf = strtok(NULL, "");
	
	NSData *host = (host_buf != NULL) ? [NSData dataWithBytes:host_buf length:strlen(host_buf) + 1] : [NSData dataWithBlankCString];
	
	free(nick_user_host_buf);
	
	return host;
}

/***********************************************/
#pragma mark - Callback function implementations
/***********************************************/

/*!
 * The "on_connect" event is triggered when the client successfully 
 * connects to the server, and could send commands to the server.
 * No extra params supplied; \a params is 0.
 */
static void onConnect(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	[clientSession connectionSucceeded];
}

/*!
 * The "nick" event is triggered when the client receives a NICK message,
 * meaning that someone (including you) on a channel with the client has 
 * changed their nickname. 
 *
 * \param origin the person, who changes the nick. Note that it can be you!
 * \param params[0] mandatory, contains the new nick.
 */
static void onNick(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *oldNick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *newNick = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	
	[clientSession nickChangedFrom:oldNick to:newNick];
}

/*!
 * The "quit" event is triggered upon receipt of a QUIT message, which
 * means that someone on a channel with the client has disconnected.
 *
 * \param origin the person, who is disconnected
 * \param params[0] optional, contains the reason message (user-specified).
 */
static void onQuit(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *reason = (count > 0) ? [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1] : [NSData dataWithBlankCString];

	[clientSession userQuit:nick withReason:reason];
}

/*!
 * The "join" event is triggered upon receipt of a JOIN message, which
 * means that someone has entered a channel that the client is on.
 *
 * \param origin the person, who joins the channel. By comparing it with 
 *               your own nickname, you can check whether your JOIN 
 *               command succeed.
 * \param params[0] mandatory, contains the channel name.
 */
static void onJoinChannel(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	
	[clientSession userJoined:nick channel:channelName];
}

/*!
 * The "part" event is triggered upon receipt of a PART message, which
 * means that someone has left a channel that the client is on.
 *
 * \param origin the person, who leaves the channel. By comparing it with 
 *               your own nickname, you can check whether your PART 
 *               command succeed.
 * \param params[0] mandatory, contains the channel name.
 * \param params[1] optional, contains the reason message (user-defined).
 */
static void onPartChannel(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *reason = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession userParted:nick channel:channelName withReason:reason];
}

/*!
 * The "mode" event is triggered upon receipt of a channel MODE message,
 * which means that someone on a channel with the client has changed the
 * channel's parameters.
 *
 * \param origin the person, who changed the channel mode.
 * \param params[0] mandatory, contains the channel name.
 * \param params[1] mandatory, contains the changed channel mode, like 
 *        '+t', '-i' and so on.
 * \param params[2] optional, contains the mode argument (for example, a
 *      key for +k mode, or user who got the channel operator status for 
 *      +o mode)
 */
static void onMode(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *mode = [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1];
	NSData *modeParams = (count > 2) ? [NSData dataWithBytes:params[2] length:strlen(params[2]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession modeSet:mode withParams:modeParams forChannel:channelName by:nick];
}

/*!
 * The "umode" event is triggered upon receipt of a user MODE message, 
 * which means that your user mode has been changed.
 *
 * \param origin the person, who changed the channel mode.
 * \param params[0] mandatory, contains the user changed mode, like 
 *        '+t', '-i' and so on.
 */
static void onUserMode(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *mode = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	
	[clientSession modeSet:mode by:nick];
}

/*!
 * The "topic" event is triggered upon receipt of a TOPIC message, which
 * means that someone on a channel with the client has changed the 
 * channel's topic.
 *
 * \param origin the person, who changes the channel topic.
 * \param params[0] mandatory, contains the channel name.
 * \param params[1] optional, contains the new topic.
 */
static void onTopic(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *topic = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession topicSet:topic forChannel:channelName by:nick];
}

/*!
 * The "kick" event is triggered upon receipt of a KICK message, which
 * means that someone on a channel with the client (or possibly the
 * client itself!) has been forcibly ejected.
 *
 * \param origin the person, who kicked the poor.
 * \param params[0] mandatory, contains the channel name.
 * \param params[1] optional, contains the nick of kicked person.
 * \param params[2] optional, contains the kick text
 */
static void onKick(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *byNick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *nick = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : nil;
	NSData *reason = (count > 2) ? [NSData dataWithBytes:params[2] length:strlen(params[2]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession userKicked:nick fromChannel:channelName by:byNick withReason:reason];
}

/*!
 * The "channel" event is triggered upon receipt of a PRIVMSG message
 * to an entire channel, which means that someone on a channel with
 * the client has said something aloud. Your own messages don't trigger
 * PRIVMSG event.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, contains the channel name.
 * \param params[1] optional, contains the message text
 */
static void onChannelPrvmsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *message = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];

	[clientSession messageSent:message toChannel:channelName byUser:nick];
}

/*!
 * The "privmsg" event is triggered upon receipt of a PRIVMSG message
 * which is addressed to one or more clients, which means that someone
 * is sending the client a private message.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, contains your nick.
 * \param params[1] optional, contains the message text
 */
static void onPrivmsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *message = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession privateMessageReceived:message fromUser:nick];
}

/*!
 * The "privmsg" event is triggered upon receipt of a PRIVMSG message
 * which is addressed to no one in particular, but it sent to the client
 * anyway.
 *
 * \param origin the person, who generates the message.
 * \param params optional, contains who knows what.
 */
static void onServerMsg(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *sender = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSMutableArray *paramsArray = [NSMutableArray arrayWithCapacity:count];
	for (unsigned int i = 0; i < count; i++)
	{
		[paramsArray addObject:[NSData dataWithBytes:params[i] length:strlen(params[i]) + 1]];
	}
	
	[clientSession serverMessageReceivedFrom:sender params:paramsArray];
}

/*!
 * The "notice" event is triggered upon receipt of a NOTICE message
 * which means that someone has sent the client a public or private
 * notice. According to RFC 1459, the only difference between NOTICE 
 * and PRIVMSG is that you should NEVER automatically reply to NOTICE
 * messages. Unfortunately, this rule is frequently violated by IRC 
 * servers itself - for example, NICKSERV messages require reply, and 
 * are NOTICEs.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, contains your nick.
 * \param params[1] optional, contains the message text
 */
static void onNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *notice = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];
	
	[clientSession privateNoticeReceived:notice fromUser:nick];
}

/*!
 * The "notice" event is triggered upon receipt of a NOTICE message
 * which means that someone has sent the client a public or private
 * notice. According to RFC 1459, the only difference between NOTICE
 * and PRIVMSG is that you should NEVER automatically reply to NOTICE
 * messages. Unfortunately, this rule is frequently violated by IRC
 * servers itself - for example, NICKSERV messages require reply, and
 * are NOTICEs.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, contains the target channel name.
 * \param params[1] optional, contains the message text.
 */
static void onChannelNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *notice = (count > 1) ? [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1] : [NSData dataWithBlankCString];

	[clientSession noticeSent:notice toChannel:channelName byUser:nick];
}

/*!
 * The "server_notice" event is triggered upon receipt of a NOTICE
 * message which means that the server has sent the client a notice.
 * This notice is not necessarily addressed to the client's nick
 * (for example, AUTH notices, sent before the client's nick is known).
 * According to RFC 1459, the only difference between NOTICE
 * and PRIVMSG is that you should NEVER automatically reply to NOTICE
 * messages. Unfortunately, this rule is frequently violated by IRC
 * servers itself - for example, NICKSERV messages require reply, and
 * are NOTICEs.
 *
 * \param origin the person, who generates the message.
 * \param params optional, contains who knows what.
 */
static void onServerNotice(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *sender = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSMutableArray *paramsArray = [NSMutableArray arrayWithCapacity:count];
	for (unsigned int i = 0; i < count; i++)
	{
		[paramsArray addObject:[NSData dataWithBytes:params[i] length:strlen(params[i]) + 1]];
	}
	
	[clientSession serverNoticeReceivedFrom:sender params:paramsArray];
}

/*!
 * The "invite" event is triggered upon receipt of an INVITE message,
 * which means that someone is permitting the client's entry into a +i
 * channel.
 *
 * \param origin the person, who INVITEs you.
 * \param params[0] mandatory, contains your nick.
 * \param params[1] mandatory, contains the channel name you're invited into.
 *
 * \sa irc_cmd_invite irc_cmd_chanmode_invite
 */
static void onInvite(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *channelName = [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1];
	
	[clientSession invitedToChannel:channelName by:nick];
}

/*!
 * The "ctcp" event is triggered when the client receives the CTCP 
 * request. By default, the built-in CTCP request handler is used. The 
 * build-in handler automatically replies on most CTCP messages, so you
 * will rarely need to override it.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, the complete CTCP message, including its 
 *                  arguments.
 * 
 * Mirc generates PING, FINGER, VERSION, TIME and ACTION messages,
 * check the source code of \c libirc_event_ctcp_internal function to 
 * see how to write your own CTCP request handler. Also you may find 
 * useful this question in FAQ: \ref faq4
 */
static void onCtcpRequest(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *request = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	
	[clientSession CTCPRequestReceived:request fromUser:nick];
}

/*!
 * The "ctcp" event is triggered when the client receives the CTCP reply.
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, the CTCP message itself with its arguments.
 */
static void onCtcpReply(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *reply = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	
	[clientSession CTCPReplyReceived:reply fromUser:nick];
}

/*!
 * The "action" event is triggered when the client receives the CTCP 
 * ACTION message. These messages usually looks like:\n
 * \code
 * [23:32:55] * Tim gonna sleep.
 * \endcode
 *
 * \param origin the person, who generates the message.
 * \param params[0] mandatory, the target of the message.
 * \param params[1] mandatory, the ACTION message.
 */
static void onCtcpAction(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *nick = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSData *target = [NSData dataWithBytes:params[0] length:strlen(params[0]) + 1];
	NSData *action = [NSData dataWithBytes:params[1] length:strlen(params[1]) + 1];
	
	[clientSession CTCPActionPerformed:action byUser:nick atTarget:target];
}

/*!
 * The "unknown" event is triggered upon receipt of any number of 
 * unclassifiable miscellaneous messages, which aren't handled by the
 * library.
 */
static void onUnknownEvent(irc_session_t *session, const char *event, const char *origin, const char **params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSData *eventType = [NSData dataWithBytes:event length:strlen(event) + 1];
	NSData *sender = (origin != NULL) ? [NSData dataWithBytes:origin length:strlen(origin) + 1] : [NSData dataWithBlankCString];
	NSMutableArray *paramsArray = [NSMutableArray arrayWithCapacity:count];
	for (unsigned int i = 0; i < count; i++)
	{
		[paramsArray addObject:[NSData dataWithBytes:params[i] length:strlen(params[i]) + 1]];
	}
	
	[clientSession unknownEventReceived:eventType from:sender params:paramsArray];
}

/*!
 * The "numeric" event is triggered upon receipt of any numeric response
 * from the server. There is a lot of such responses, see the full list
 * here: \ref rfcnumbers.
 *
 * See the params in ::irc_eventcode_callback_t specification.
 */
static void onNumericEvent(irc_session_t * session, unsigned int event, const char * origin, const char ** params, unsigned int count)
{
	IRCClientSession *clientSession = (__bridge IRCClientSession *) irc_get_ctx(session);
	
	NSUInteger eventNumber = event;
	NSData *sender = [NSData dataWithBytes:origin length:strlen(origin) + 1];
	NSMutableArray *paramsArray = [NSMutableArray arrayWithCapacity:count];
	for (unsigned int i = 0; i < count; i++)
	{
		[paramsArray addObject:[NSData dataWithBytes:params[i] length:strlen(params[i]) + 1]];
	}
	
	[clientSession numericEventReceived:eventNumber from:sender params:paramsArray];
}