summaryrefslogtreecommitdiff
path: root/lib/exirc/client.ex
blob: 9d6905b666ab92f6defe7ca2d139c972dce162d9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
defmodule ExIrc.Client do
  @moduledoc """
  Maintains the state and behaviour for individual IRC client connections
  """
  use    Irc.Commands
  use    GenServer
  import ExIrc.Logger

  alias ExIrc.Channels
  alias ExIrc.Utils
  alias ExIrc.SenderInfo
  alias ExIrc.Client.Transport

  # Client internal state
  defmodule ClientState do
    defstruct event_handlers:   [],
              server:           "localhost",
              port:             6667,
              socket:           nil,
              nick:             "",
              pass:             "",
              user:             "",
              name:             "",
              ssl?:             false,
              connected?:       false,
              logged_on?:       false,
              autoping:         true,
              channel_prefixes: "",
              network:          "",
              user_prefixes:    "",
              login_time:       "",
              channels:         [],
              debug?:           false,
              retries:          0,
              inet:             :inet,
              owner:            nil
  end

  #################
  # External API
  #################

  @doc """
  Start a new IRC client process

  Returns either {:ok, pid} or {:error, reason}
  """
  @spec start!(options :: list() | nil) :: {:ok, pid} | {:error, term}
  def start!(options \\ []) do
    start_link(options)
  end
  @doc """
  Start a new IRC client process.

  Returns either {:ok, pid} or {:error, reason}
  """
  @spec start_link(options :: list() | nil, process_opts :: list() | nil) :: {:ok, pid} | {:error, term}
  def start_link(options \\ [], process_opts \\ []) do
    options = Keyword.put_new(options, :owner, self())
    GenServer.start_link(__MODULE__, options, process_opts)
  end
  @doc """
  Stop the IRC client process
  """
  @spec stop!(client :: pid) :: {:stop, :normal, :ok, ClientState.t}
  def stop!(client) do
    GenServer.call(client, :stop)
  end
  @doc """
  Connect to a server with the provided server and port

  Example:
    Client.connect! pid, "localhost", 6667
  """
  @spec connect!(client :: pid, server :: binary, port :: non_neg_integer, options :: list() | nil) :: :ok
  def connect!(client, server, port, options \\ []) do
    GenServer.call(client, {:connect, server, port, options, false}, :infinity)
  end
  @doc """
  Connect to a server with the provided server and port via SSL

  Example:
    Client.connect! pid, "localhost", 6697
  """
  @spec connect_ssl!(client :: pid, server :: binary, port :: non_neg_integer, options :: list() | nil) :: :ok
  def connect_ssl!(client, server, port, options \\ []) do
    GenServer.call(client, {:connect, server, port, options, true}, :infinity)
  end
  @doc """
  Determine if the provided client process has an open connection to a server
  """
  @spec is_connected?(client :: pid) :: true | false
  def is_connected?(client) do
    GenServer.call(client, :is_connected?)
  end
  @doc """
  Logon to a server

  Example:
    Client.logon pid, "password", "mynick", "username", "My Name"
  """
  @spec logon(client :: pid, pass :: binary, nick :: binary, user :: binary, name :: binary) :: :ok | {:error, :not_connected}
  def logon(client, pass, nick, user, name) do
    GenServer.call(client, {:logon, pass, nick, user, name}, :infinity)
  end
  @doc """
  Determine if the provided client is logged on to a server
  """
  @spec is_logged_on?(client :: pid) :: true | false
  def is_logged_on?(client) do
    GenServer.call(client, :is_logged_on?)
  end
  @doc """
  Send a message to a nick or channel
  Message types are:
    :privmsg
    :notice
    :ctcp
  """
  @spec msg(client :: pid, type :: atom, nick :: binary, msg :: binary) :: :ok | {:error, atom}
  def msg(client, type, nick, msg) do
    GenServer.call(client, {:msg, type, nick, msg}, :infinity)
  end
  @doc """
  Send an action message, i.e. (/me slaps someone with a big trout)
  """
  @spec me(client :: pid, channel :: binary, msg :: binary) :: :ok | {:error, atom}
  def me(client, channel, msg) do
    GenServer.call(client, {:me, channel, msg}, :infinity)
  end
  @doc """
  Change the client's nick
  """
  @spec nick(client :: pid, new_nick :: binary) :: :ok | {:error, atom}
  def nick(client, new_nick) do
    GenServer.call(client, {:nick, new_nick}, :infinity)
  end
  @doc """
  Send a raw IRC command
  """
  @spec cmd(client :: pid, raw_cmd :: binary) :: :ok | {:error, atom}
  def cmd(client, raw_cmd) do
    GenServer.call(client, {:cmd, raw_cmd})
  end
  @doc """
  Join a channel, with an optional password
  """
  @spec join(client :: pid, channel :: binary, key :: binary | nil) :: :ok | {:error, atom}
  def join(client, channel, key \\ "") do
    GenServer.call(client, {:join, channel, key}, :infinity)
  end
  @doc """
  Leave a channel
  """
  @spec part(client :: pid, channel :: binary) :: :ok | {:error, atom}
  def part(client, channel) do
    GenServer.call(client, {:part, channel}, :infinity)
  end
  @doc """
  Kick a user from a channel
  """
  @spec kick(client :: pid, channel :: binary, nick :: binary, message :: binary | nil) :: :ok | {:error, atom}
  def kick(client, channel, nick, message \\ "") do
    GenServer.call(client, {:kick, channel, nick, message}, :infinity)
  end
  @spec names(client :: pid, channel :: binary) :: :ok | {:error, atom}
  def names(client, channel) do
    GenServer.call(client, {:names, channel}, :infinity)
  end
  @doc """
  Change mode for a user or channel
  """
  @spec mode(client :: pid, channel_or_nick :: binary, flags :: binary, args :: binary | nil) :: :ok | {:error, atom}
  def mode(client, channel_or_nick, flags, args \\ "") do
    GenServer.call(client, {:mode, channel_or_nick, flags, args}, :infinity)
  end
  @doc """
  Invite a user to a channel
  """
  @spec invite(client :: pid, nick :: binary, channel :: binary) :: :ok | {:error, atom}
  def invite(client, nick, channel) do
    GenServer.call(client, {:invite, nick, channel}, :infinity)
  end
  @doc """
  Quit the server, with an optional part message
  """
  @spec quit(client :: pid, msg :: binary | nil) :: :ok | {:error, atom}
  def quit(client, msg \\ "Leaving..") do
    GenServer.call(client, {:quit, msg}, :infinity)
  end
  @doc """
  Get details about each of the client's currently joined channels
  """
  @spec channels(client :: pid) :: list(binary) | [] | {:error, atom}
  def channels(client) do
    GenServer.call(client, :channels)
  end
  @doc """
  Get a list of users in the provided channel
  """
  @spec channel_users(client :: pid, channel :: binary) :: list(binary) | [] | {:error, atom}
  def channel_users(client, channel) do
    GenServer.call(client, {:channel_users, channel})
  end
  @doc """
  Get the topic of the provided channel
  """
  @spec channel_topic(client :: pid, channel :: binary) :: binary | {:error, atom}
  def channel_topic(client, channel) do
    GenServer.call(client, {:channel_topic, channel})
  end
  @doc """
  Get the channel type of the provided channel
  """
  @spec channel_type(client :: pid, channel :: binary) :: atom | {:error, atom}
  def channel_type(client, channel) do
    GenServer.call(client, {:channel_type, channel})
  end
  @doc """
  Determine if a nick is present in the provided channel
  """
  @spec channel_has_user?(client :: pid, channel :: binary, nick :: binary) :: true | false | {:error, atom}
  def channel_has_user?(client, channel, nick) do
    GenServer.call(client, {:channel_has_user?, channel, nick})
  end
  @doc """
  Add a new event handler process
  """
  @spec add_handler(client :: pid, pid) :: :ok
  def add_handler(client, pid) do
    GenServer.call(client, {:add_handler, pid})
  end
  @doc """
  Add a new event handler process, asynchronously
  """
  @spec add_handler_async(client :: pid, pid) :: :ok
  def add_handler_async(client, pid) do
    GenServer.cast(client, {:add_handler, pid})
  end
  @doc """
  Remove an event handler process
  """
  @spec remove_handler(client :: pid, pid) :: :ok
  def remove_handler(client, pid) do
    GenServer.call(client, {:remove_handler, pid})
  end
  @doc """
  Remove an event handler process, asynchronously
  """
  @spec remove_handler_async(client :: pid, pid) :: :ok
  def remove_handler_async(client, pid) do
    GenServer.cast(client, {:remove_handler, pid})
  end
  @doc """
  Get the current state of the provided client
  """
  @spec state(client :: pid) :: [{atom, any}]
  def state(client) do
    state = GenServer.call(client, :state)
    [server:            state.server,
     port:              state.port,
     nick:              state.nick,
     pass:              state.pass,
     user:              state.user,
     name:              state.name,
     autoping:          state.autoping,
     ssl?:              state.ssl?,
     connected?:        state.connected?,
     logged_on?:        state.logged_on?,
     channel_prefixes:  state.channel_prefixes,
     user_prefixes:     state.user_prefixes,
     channels:          Channels.to_proplist(state.channels),
     network:           state.network,
     login_time:        state.login_time,
     debug?:            state.debug?,
     event_handlers:    state.event_handlers]
  end

  ###############
  # GenServer API
  ###############

  @doc """
  Called when GenServer initializes the client
  """
  @spec init(list(any) | []) :: {:ok, ClientState.t}
  def init(options \\ []) do
    autoping = Keyword.get(options, :autoping, true)
    debug    = Keyword.get(options, :debug, false)
    owner    = Keyword.fetch!(options, :owner)
    # Add event handlers
    handlers =
      Keyword.get(options, :event_handlers, [])
      |> List.foldl([], &do_add_handler/2)
    ref = Process.monitor(owner)
    # Return initial state
    {:ok, %ClientState{
      event_handlers: handlers,
      autoping:       autoping,
      logged_on?:     false,
      debug?:         debug,
      channels:       ExIrc.Channels.init(),
      owner:          {owner, ref}}}
  end
  @doc """
  Handle calls from the external API. It is not recommended to call these directly.
  """
  # Handle call to get the current state of the client process
  def handle_call(:state, _from, state), do: {:reply, state, state}
  # Handle call to stop the current client process
  def handle_call(:stop, _from, state) do
    # Ensure the socket connection is closed if stop is called while still connected to the server
    if state.connected?, do: Transport.close(state)
    {:stop, :normal, :ok, %{state | connected?: false, logged_on?: false, socket: nil}}
  end
  # Handles call to add a new event handler process
  def handle_call({:add_handler, pid}, _from, state) do
    handlers = do_add_handler(pid, state.event_handlers)
    {:reply, :ok, %{state | event_handlers: handlers}}
  end
  # Handles call to remove an event handler process
  def handle_call({:remove_handler, pid}, _from, state) do
    handlers = do_remove_handler(pid, state.event_handlers)
    {:reply, :ok, %{state | event_handlers: handlers}}
  end
  # Handle call to connect to an IRC server
  def handle_call({:connect, server, port, options, ssl}, _from, state) do
    # If there is an open connection already, close it.
    if state.socket != nil, do: Transport.close(state)
    # Set SSL mode
    state = %{state | ssl?: ssl}
    # Open a new connection
    case Transport.connect(state, String.to_char_list(server), port, [:list, {:packet, :line}, {:keepalive, true}] ++ options) do
      {:ok, socket} ->
        send_event {:connected, server, port}, state
        {:reply, :ok, %{state | connected?: true, server: server, port: port, socket: socket}}
      error ->
        {:reply, error, state}
    end
  end
  # Handle call to determine if the client is connected
  def handle_call(:is_connected?, _from, state), do: {:reply, state.connected?, state}
  # Prevents any of the following messages from being handled if the client is not connected to a server.
  # Instead, it returns {:error, :not_connected}.
  def handle_call(_, _from, %ClientState{connected?: false} = state), do: {:reply, {:error, :not_connected}, state}
  # Handle call to login to the connected IRC server
  def handle_call({:logon, pass, nick, user, name}, _from, %ClientState{logged_on?: false} = state) do
    Transport.send state, pass!(pass)
    Transport.send state, nick!(nick)
    Transport.send state, user!(user, name)
    {:reply, :ok, %{state | pass: pass, nick: nick, user: user, name: name} }
  end
  # Handles call to change the client's nick.
  def handle_call({:nick, new_nick}, _from, %ClientState{logged_on?: false} = state) do
    Transport.send state, nick!(new_nick)
    # Since we've not yet logged on, we won't get a nick change message, so we have to remember the nick here.
    {:reply, :ok, %{state | nick: new_nick}}
  end
  # Handle call to determine if client is logged on to a server
  def handle_call(:is_logged_on?, _from, state), do: {:reply, state.logged_on?, state}
  # Prevents any of the following messages from being handled if the client is not logged on to a server.
  # Instead, it returns {:error, :not_logged_in}.
  def handle_call(_, _from, %ClientState{logged_on?: false} = state), do: {:reply, {:error, :not_logged_in}, state}
  # Handles call to send a message
  def handle_call({:msg, type, nick, msg}, _from, state) do
    data = case type do
      :privmsg -> privmsg!(nick, msg)
      :notice  -> notice!(nick, msg)
      :ctcp    -> notice!(nick, ctcp!(msg))
    end
    Transport.send state, data
    {:reply, :ok, state}
  end
  # Handle /me messages
  def handle_call({:me, channel, msg}, _from, state) do
    data = me!(channel, msg)
    Transport.send state, data
    {:reply, :ok, state}
  end
  # Handles call to join a channel
  def handle_call({:join, channel, key}, _from, state) do
    Transport.send(state, join!(channel, key))
    {:reply, :ok, state}
  end
  # Handles a call to leave a channel
  def handle_call({:part, channel}, _from, state) do
    Transport.send(state, part!(channel))
    {:reply, :ok, state}
  end
  # Handles a call to kick a client
  def handle_call({:kick, channel, nick, message}, _from, state) do
    Transport.send(state, kick!(channel, nick, message))
    {:reply, :ok, state}
  end
  # Handles a call to send the NAMES command to the server
  def handle_call({:names, channel}, _from, state) do
    Transport.send(state, names!(channel))
    {:reply, :ok, state}
  end
  # Handles a call to change mode for a user or channel
  def handle_call({:mode, channel_or_nick, flags, args}, _from, state) do
    Transport.send(state, mode!(channel_or_nick, flags, args))
    {:reply, :ok, state}
  end
  # Handle call to invite a user to a channel
  def handle_call({:invite, nick, channel}, _from, state) do
    Transport.send(state, invite!(nick, channel))
    {:reply, :ok, state}
  end
  # Handle call to quit the server and close the socket connection
  def handle_call({:quit, msg}, _from, state) do
    if state.connected? do
      Transport.send state, quit!(msg)
      send_event(:disconnected, state)
      Transport.close state
    end
    {:reply, :ok, %{state | connected?: false, logged_on?: false, socket: nil}}
  end
  # Handles call to change the client's nick
  def handle_call({:nick, new_nick}, _from, state) do Transport.send(state, nick!(new_nick)); {:reply, :ok, state} end
  # Handles call to send a raw command to the IRC server
  def handle_call({:cmd, raw_cmd}, _from, state) do Transport.send(state, command!(raw_cmd)); {:reply, :ok, state} end
  # Handles call to return the client's channel data
  def handle_call(:channels, _from, state), do: {:reply, Channels.channels(state.channels), state}
  # Handles call to return a list of users for a given channel
  def handle_call({:channel_users, channel}, _from, state), do: {:reply, Channels.channel_users(state.channels, channel), state}
  # Handles call to return the given channel's topic
  def handle_call({:channel_topic, channel}, _from, state), do: {:reply, Channels.channel_topic(state.channels, channel), state}
  # Handles call to return the type of the given channel
  def handle_call({:channel_type, channel}, _from, state), do: {:reply, Channels.channel_type(state.channels, channel), state}
  # Handles call to determine if a nick is present in the given channel
  def handle_call({:channel_has_user?, channel, nick}, _from, state) do
    {:reply, Channels.channel_has_user?(state.channels, channel, nick), state}
  end
  # Handles message to add a new event handler process asynchronously
  def handle_cast({:add_handler, pid}, state) do
    handlers = do_add_handler(pid, state.event_handlers)
    {:noreply, %{state | event_handlers: handlers}}
  end
  @doc """
  Handles asynchronous messages from the external API. Not recommended to call these directly.
  """
  # Handles message to remove an event handler process asynchronously
  def handle_cast({:remove_handler, pid}, state) do
    handlers = do_remove_handler(pid, state.event_handlers)
    {:noreply, %{state | event_handlers: handlers}}
  end
  @doc """
  Handle messages from the TCP socket connection.
  """
  # Handles the client's socket connection 'closed' event
  def handle_info({:tcp_closed, _socket}, %ClientState{server: server, port: port} = state) do
    info "Connection to #{server}:#{port} closed!"
    send_event :disconnected, state
    new_state = %{state |
      socket:     nil,
      connected?: false,
      logged_on?: false,
      channels:   Channels.init()
    }
    {:noreply, new_state}
  end
  @doc """
  Handle messages from the SSL socket connection.
  """
  # Handles the client's socket connection 'closed' event
  def handle_info({:ssl_closed, socket}, state) do
    handle_info({:tcp_closed, socket}, state)
  end
  # Handles any TCP errors in the client's socket connection
  def handle_info({:tcp_error, socket, reason}, %ClientState{server: server, port: port} = state) do
    error "TCP error in connection to #{server}:#{port}:\r\n#{reason}\r\nClient connection closed."
    new_state = %{state |
      socket:     nil,
      connected?: false,
      logged_on?: false,
      channels:   Channels.init()
    }
    {:stop, {:tcp_error, socket}, new_state}
  end
  # Handles any SSL errors in the client's socket connection
  def handle_info({:ssl_error, socket, reason}, state) do
    handle_info({:tcp_error, socket, reason}, state)
  end
  # General handler for messages from the IRC server
  def handle_info({:tcp, _, data}, state) do
    debug? = state.debug?
    case Utils.parse(data) do
      %IrcMessage{ctcp: true} = msg ->
        handle_data msg, state
        {:noreply, state}
      %IrcMessage{ctcp: false} = msg ->
        handle_data msg, state
      %IrcMessage{ctcp: :invalid} = msg when debug? ->
        send_event msg, state
        {:noreply, state}
      _ ->
        {:noreply, state}
    end
  end
  # Wrapper for SSL socket messages
  def handle_info({:ssl, socket, data}, state) do
    handle_info({:tcp, socket, data}, state)
  end
  # If the owner process dies, we should die as well
  def handle_info({:DOWN, ref, _, pid, reason}, %{owner: {pid, ref}} = state) do
    {:stop, reason, state}
  end
  # If an event handler process dies, remove it from the list of event handlers
  def handle_info({:DOWN, _, _, pid, _}, state) do
    handlers = do_remove_handler(pid, state.event_handlers)
    {:noreply, %{state | event_handlers: handlers}}
  end
  # Catch-all for unrecognized messages (do nothing)
  def handle_info(_, state) do
    {:noreply, state}
  end
  @doc """
  Handle termination
  """
  def terminate(_reason, state) do
    if state.socket != nil do
      Transport.close state
      %{state | socket: nil}
    end
    :ok
  end
  @doc """
  Transform state for hot upgrades/downgrades
  """
  def code_change(_old, state, _extra), do: {:ok, state}

  ################
  # Data handling
  ################

  @doc """
  Handle IrcMessages received from the server.
  """
  # Called upon successful login
  def handle_data(%IrcMessage{cmd: @rpl_welcome}, %ClientState{logged_on?: false} = state) do
    if state.debug?, do: debug "SUCCESFULLY LOGGED ON"
    new_state = %{state | logged_on?: true, login_time: :erlang.timestamp()}
    send_event :logged_in, new_state
    {:noreply, new_state}
  end
  # Called when the server sends it's current capabilities
  def handle_data(%IrcMessage{cmd: @rpl_isupport} = msg, state) do
    if state.debug?, do: debug "RECEIVING SERVER CAPABILITIES"
    {:noreply, Utils.isup(msg.args, state)}
  end
  # Called when the client enters a channel
  def handle_data(%IrcMessage{nick: nick, cmd: "JOIN"} = msg, %ClientState{nick: nick} = state) do
    channel = msg.args |> List.first |> String.strip
    if state.debug?, do: debug "JOINED A CHANNEL #{channel}"
    channels  = Channels.join(state.channels, channel)
    new_state = %{state | channels: channels}
    send_event {:joined, channel}, new_state
    {:noreply, new_state}
  end
  # Called when another user joins a channel the client is in
  def handle_data(%IrcMessage{nick: user_nick, cmd: "JOIN", host: host, user: user} = msg, state) do
    sender = %SenderInfo{nick: user_nick, host: host, user: user}
    channel = msg.args |> List.first |> String.strip
    if state.debug?, do: debug "ANOTHER USER JOINED A CHANNEL: #{channel} - #{user_nick}"
    channels  = Channels.user_join(state.channels, channel, user_nick)
    new_state = %{state | channels: channels}
    send_event {:joined, channel, sender}, new_state
    {:noreply, new_state}
  end
  # Called on joining a channel, to tell us the channel topic
  # Message with three arguments is not RFC compliant but very common
  # Message with two arguments is RFC compliant
  # Message with a single argument is not RFC compliant, but is present
  # to handle poorly written IRC servers which send RPL_TOPIC with an empty
  # topic (such as Slack's IRC bridge), when they should be sending RPL_NOTOPIC
  def handle_data(%IrcMessage{cmd: @rpl_topic} = msg, state) do
    {channel, topic} = case msg.args do
      [_nick, channel, topic] -> {channel, topic}
      [channel, topic]        -> {channel, topic}
      [channel]               -> {channel, "No topic is set"}
    end
    if state.debug? do
      debug "INITIAL TOPIC MSG"
      debug "1. TOPIC SET FOR #{channel} TO #{topic}"
    end
    channels  = Channels.set_topic(state.channels, channel, topic)
    new_state = %{state | channels: channels}
    send_event {:topic_changed, channel, topic}, new_state
    {:noreply, new_state}
  end
  def handle_data(%IrcMessage{cmd: @rpl_notopic, args: [channel]}, state) do
    if state.debug? do
      debug "INITIAL TOPIC MSG"
      debug "1. NO TOPIC SET FOR #{channel}}"
    end
    channels = Channels.set_topic(state.channels, channel, "No topic is set")
    new_state = %{state | channels: channels}
    {:noreply, new_state}
  end
  # Called when the topic changes while we're in the channel
  def handle_data(%IrcMessage{cmd: "TOPIC", args: [channel, topic]}, state) do
    if state.debug?, do: debug "TOPIC CHANGED FOR #{channel} TO #{topic}"
    channels  = Channels.set_topic(state.channels, channel, topic)
    new_state = %{state | channels: channels}
    send_event {:topic_changed, channel, topic}, new_state
    {:noreply, new_state}
  end
  # Called when joining a channel with the list of current users in that channel, or when the NAMES command is sent
  def handle_data(%IrcMessage{cmd: @rpl_namereply} = msg, state) do
    if state.debug?, do: debug "NAMES LIST RECEIVED"
    {_nick, channel_type, channel, names} = case msg.args do
      [nick, channel_type, channel, names]  -> {nick, channel_type, channel, names}
      [channel_type, channel, names]        -> {nil, channel_type, channel, names}
    end
    channels = Channels.set_type(
      Channels.users_join(state.channels, channel, String.split(names, " ", trim: true)),
      channel,
      channel_type)

    send_event({:names_list, channel, names}, state)

    {:noreply, %{state | channels: channels}}
  end
  # Called when our nick has succesfully changed
  def handle_data(%IrcMessage{cmd: "NICK", nick: nick, args: [new_nick]}, %ClientState{nick: nick} = state) do
    if state.debug?, do: debug "NICK CHANGED FROM #{nick} TO #{new_nick}"
    new_state = %{state | nick: new_nick}
    send_event {:nick_changed, new_nick}, new_state
    {:noreply, new_state}
  end
  # Called when someone visible to us changes their nick
  def handle_data(%IrcMessage{cmd: "NICK", nick: nick, args: [new_nick]}, state) do
    if state.debug?, do: debug "#{nick} CHANGED THEIR NICK TO #{new_nick}"
    channels  = Channels.user_rename(state.channels, nick, new_nick)
    new_state = %{state | channels: channels}
    send_event {:nick_changed, nick, new_nick}, new_state
    {:noreply, new_state}
  end
  # Called upon mode change
  def handle_data(%IrcMessage{cmd: "MODE", args: [channel, op, user]}, state) do
    if state.debug?, do: debug "MODE #{channel} #{op} #{user}"
    send_event {:mode, [channel, op, user]}, state
    {:noreply, state}
  end
  # Called when we leave a channel
  def handle_data(%IrcMessage{cmd: "PART", nick: nick} = msg, %ClientState{nick: nick} = state) do
    channel = msg.args |> List.first |> String.strip
    if state.debug?, do: debug "WE LEFT A CHANNEL: #{channel}"
    channels  = Channels.part(state.channels, channel)
    new_state = %{state | channels: channels}
    send_event {:parted, channel}, new_state
    {:noreply, new_state}
  end
  # Called when someone else in our channel leaves
  def handle_data(%IrcMessage{cmd: "PART", nick: from, host: host, user: user} = msg, state) do
    sender = %SenderInfo{nick: from, host: host, user: user}
    channel = msg.args |> List.first |> String.strip
    if state.debug?, do: debug "#{from} LEFT A CHANNEL: #{channel}"
    channels  = Channels.user_part(state.channels, channel, from)
    new_state = %{state | channels: channels}
    send_event {:parted, channel, sender}, new_state
    {:noreply, new_state}
  end
  def handle_data(%IrcMessage{cmd: "QUIT", nick: from, host: host, user: user} = msg, state) do
    sender = %SenderInfo{nick: from, host: host, user: user}
    reason = msg.args |> List.first
    if state.debug?, do: debug "#{from} QUIT"
    channels = Channels.user_quit(state.channels, from)
    new_state = %{state | channels: channels}
    send_event {:quit, reason, sender}, new_state
    {:noreply, new_state}
  end
  # Called when we receive a PING
  def handle_data(%IrcMessage{cmd: "PING"} = msg, %ClientState{autoping: true} = state) do
    if state.debug?, do: debug "RECEIVED A PING!"
    case msg do
      %IrcMessage{args: [from]} ->
        if state.debug?, do: debug("SENT PONG2")
        Transport.send(state, pong2!(from, msg.server))
      _ ->
        if state.debug?, do: debug("SENT PONG1")
        Transport.send(state, pong1!(state.nick))
    end
    {:noreply, state};
  end
  # Called when we are invited to a channel
  def handle_data(%IrcMessage{cmd: "INVITE", args: [nick, channel], nick: by, host: host, user: user} = msg, %ClientState{nick: nick} = state) do
    sender = %SenderInfo{nick: by, host: host, user: user}
    if state.debug?, do: debug "RECEIVED AN INVITE: #{msg.args |> Enum.join(" ")}"
    send_event {:invited, sender, channel}, state
    {:noreply, state}
  end
  # Called when we are kicked from a channel
  def handle_data(%IrcMessage{cmd: "KICK", args: [channel, nick], nick: by, host: host, user: user} = _msg, %ClientState{nick: nick} = state) do
    sender = %SenderInfo{nick: by, host: host, user: user}
    if state.debug?, do: debug "WE WERE KICKED FROM #{channel} BY #{by}"
    send_event {:kicked, sender, channel}, state
    {:noreply, state}
  end
  # Called when someone else was kicked from a channel
  def handle_data(%IrcMessage{cmd: "KICK", args: [channel, nick], nick: by, host: host, user: user} = _msg, state) do
    sender = %SenderInfo{nick: by, host: host, user: user}
    if state.debug?, do: debug "#{nick} WAS KICKED FROM #{channel} BY #{by}"
    send_event {:kicked, nick, sender, channel}, state
    {:noreply, state}
  end
  # Called when someone sends us a message
  def handle_data(%IrcMessage{nick: from, cmd: "PRIVMSG", args: [nick, message], host: host, user: user} = _msg, %ClientState{nick: nick} = state) do
    sender = %SenderInfo{nick: from, host: host, user: user}
    if state.debug?, do: debug "#{from} SENT US #{message}"
    send_event {:received, message, sender}, state
    {:noreply, state}
  end
  # Called when someone sends a message to a channel we're in, or a list of users
  def handle_data(%IrcMessage{nick: from, cmd: "PRIVMSG", args: [to, message], host: host, user: user} = _msg, %ClientState{nick: nick} = state) do
    sender = %SenderInfo{nick: from, host: host, user: user}
    if state.debug?, do: debug "#{from} SENT #{message} TO #{to}"
    send_event {:received, message, sender, to}, state
    # If we were mentioned, fire that event as well
    if String.contains?(message, nick), do: send_event({:mentioned, message, sender, to}, state)
    {:noreply, state}
  end
  # Called when someone uses ACTION, i.e. `/me dies`
  def handle_data(%IrcMessage{nick: from, cmd: "ACTION", args: [channel, message], host: host, user: user} = _msg, state) do
    sender = %SenderInfo{nick: from, host: host, user: user}
    if state.debug?, do: debug "* #{from} #{message} in #{channel}"
    send_event {:me, message, sender, channel}, state
    {:noreply, state}
  end
  # Called when a NOTICE is received by the client.
  def handle_data(%IrcMessage{nick: from, cmd: "NOTICE", args: [target, message], host: host, user: user} = _msg, state) do
    sender = %SenderInfo{nick: from,
                         host: host,
                         user: user}

    if String.contains?(message, "identify") do
        if state.debug?, do: debug("* Told to identify by #{from}: #{message}")
        send_event({:identify, message, sender}, state)
    else
      if state.debug?, do: debug("* #{message} from #{sender}")
      send_event({:notice, message, sender}, state)
    end

    {:noreply, state}
  end

  # Called any time we receive an unrecognized message
  def handle_data(msg, state) do
    if state.debug? do debug "UNRECOGNIZED MSG: #{msg.cmd}"; IO.inspect(msg) end
    send_event {:unrecognized, msg.cmd, msg}, state
    {:noreply, state}
  end

  ###############
  # Internal API
  ###############
  defp send_event(msg, %ClientState{event_handlers: handlers}) when is_list(handlers) do
    Enum.each(handlers, fn({pid, _}) -> Kernel.send(pid, msg) end)
  end

  defp do_add_handler(pid, handlers) do
    case Enum.member?(handlers, pid) do
      false ->
        ref = Process.monitor(pid)
        [{pid, ref} | handlers]
      true ->
        handlers
    end
  end

  defp do_remove_handler(pid, handlers) do
    case List.keyfind(handlers, pid, 0) do
      {pid, ref} ->
        Process.demonitor(ref)
        List.keydelete(handlers, pid, 0)
      nil ->
        handlers
    end
  end

  defp debug(msg) do
    IO.puts(IO.ANSI.green() <> msg <> IO.ANSI.reset())
  end

end