From 40a234c6e59d2ea9ef309850b8f38ad30e55017e Mon Sep 17 00:00:00 2001
From: href <href@random.sh>
Date: Tue, 14 Jan 2020 16:03:05 +0100
Subject: =?UTF-8?q?=E2=80=A6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md                         |  16 +-
 lib/irc/application.ex            |   8 +-
 lib/irc/base_client.ex            | 170 -------------------
 lib/irc/base_client/capabs.ex     |   0
 lib/irc/client.ex                 | 265 ++++++++++++++++++++++++++---
 lib/irc/client/command.ex         |  50 ++++++
 lib/irc/client/command/account.ex |  18 ++
 lib/irc/client/command/away.ex    |  25 +++
 lib/irc/client/command/chghost.ex |  15 ++
 lib/irc/client/command/invite.ex  |  21 +++
 lib/irc/client/command/join.ex    |  40 +++++
 lib/irc/client/command/names.ex   |  22 +++
 lib/irc/client/command/who.ex     |  62 +++++++
 lib/irc/client/user_cache.ex      |  31 ++++
 lib/irc/connection.ex             | 347 +++++++++++++++++++++++++++-----------
 lib/irc/mask.ex                   |  52 ++++++
 lib/irc/parser.ex                 |   6 +
 lib/irc/parser/isupport.ex        |  32 +++-
 lib/irc/parser/line.ex            | 161 ++++++++++++++----
 lib/irc/parser/numeric.ex         |   5 +-
 lib/irc/parser/prefix.ex          |  47 ++++++
 lib/irc/sts.ex                    | 169 +++++++++++++++++++
 lib/irc/user.ex                   |  46 +++++
 priv/numerics.txt                 |   2 +
 test/mask_test.exs                |  22 +++
 test/parser/isupport_test.exs     |  36 ++++
 test/parser/line_parser.exs       |  45 -----
 test/parser/line_test.exs         |  87 ++++++++++
 test/parser/prefix_test.exs       |  39 +++++
 29 files changed, 1449 insertions(+), 390 deletions(-)
 delete mode 100644 lib/irc/base_client.ex
 delete mode 100644 lib/irc/base_client/capabs.ex
 create mode 100644 lib/irc/client/command.ex
 create mode 100644 lib/irc/client/command/account.ex
 create mode 100644 lib/irc/client/command/away.ex
 create mode 100644 lib/irc/client/command/chghost.ex
 create mode 100644 lib/irc/client/command/invite.ex
 create mode 100644 lib/irc/client/command/join.ex
 create mode 100644 lib/irc/client/command/names.ex
 create mode 100644 lib/irc/client/command/who.ex
 create mode 100644 lib/irc/client/user_cache.ex
 create mode 100644 lib/irc/mask.ex
 create mode 100644 lib/irc/parser/prefix.ex
 create mode 100644 lib/irc/sts.ex
 create mode 100644 lib/irc/user.ex
 create mode 100644 test/mask_test.exs
 create mode 100644 test/parser/isupport_test.exs
 delete mode 100644 test/parser/line_parser.exs
 create mode 100644 test/parser/line_test.exs
 create mode 100644 test/parser/prefix_test.exs

diff --git a/README.md b/README.md
index 8e99077..4b81d33 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,26 @@
 # Irc
 
-An IRC toolkit for Elixir. Compatible IRCv3!
+An modern IRC toolkit for Elixir. Compatible IRCv3!
 
 * `Irc.Parser` a versatile IRC parser;
 * `Irc.Connection` a basic IRC connection (handling registration and socket);
-* `Irc.BaseClient` an extensible IRC client;
-* `Irc.Client` a classical IRC client (implemented on BasicClient).
+* `Irc.Client` a fully featured and extensible IRC client.
 
 Examples of usage: `Irc.Shout` (a simple connect-join-message-quit on Connection), `Irc.Client` on BaseClient.
 
 Future versions may include: bots, server parser, server-to-server connections, ….
 
+### Supported features
+
+The eventual goal is to support most of the modern IRC specifications.
+
+The parser supports the following capabs: `message-tags`, `multi-prefix`, `account-tag`, `server-time`.
+
+The connection supports the following: `sasl`, `sts`, `cap-notify`, `batch`.
+
+The client has modules for the following: `account-notify`, `away-notify`, `userhost-in-names`, `chghost`,
+`invite-notify`, `extended-join`; and `labeled-response` - `echo-message`.
+
 ## Installation
 
 If [available in Hex](https://hex.pm/docs/publish), the package can be installed
diff --git a/lib/irc/application.ex b/lib/irc/application.ex
index 82fc053..70b3d0f 100644
--- a/lib/irc/application.ex
+++ b/lib/irc/application.ex
@@ -1,19 +1,13 @@
 defmodule Irc.Application do
-  # See https://hexdocs.pm/elixir/Application.html
-  # for more information on OTP Applications
   @moduledoc false
 
   use Application
 
   def start(_type, _args) do
-    # List all child processes to be supervised
     children = [
-      # Starts a worker by calling: Irc.Worker.start_link(arg)
-      # {Irc.Worker, arg}
+      {Irc.STS, []}
     ]
 
-    # See https://hexdocs.pm/elixir/Supervisor.html
-    # for other strategies and supported options
     opts = [strategy: :one_for_one, name: Irc.Supervisor]
     Supervisor.start_link(children, opts)
   end
diff --git a/lib/irc/base_client.ex b/lib/irc/base_client.ex
deleted file mode 100644
index 8da45be..0000000
--- a/lib/irc/base_client.ex
+++ /dev/null
@@ -1,170 +0,0 @@
-defmodule Irc.BaseClient do
-  @behaviour :gen_statem
-  require Logger
-  alias Irc.Parser.Line
-  alias Irc.Connection
-  require Irc.Parser.Numeric
-  import Irc.Parser.Numeric
-
-  @moduledoc """
-  Extensible fully-featured IRC client.
-
-  ## Behaviour
-
-  The BaseClient requires a callback module. You can check out `Irc.Client`.
-
-  ## Capabs
-
-  IRCv3 Capabs are handled by separates modules. 
-  """
-
-  @internal {:next_event, :internal, nil}
-
-  defstruct [:conn, :conn_mon, :module, :modstate, :args, :nick, :modes, :info, :error]
-
-  def callback_mode, do: [:state_functions, :state_enter]
-
-  @type event ::event_connected | event_nick | event_modes | event_line | event_down
-
-  @type event_connected :: {:connected, Connection.Info.t}
-  @type event_nick :: {:nick, prev_nick :: String.t, new_nick :: String.t}
-  @type event_modes :: {:modes, changes :: String.t, prev :: list, modes :: list}
-  @type event_line :: {:line, line :: Irc.Parser.Line.t}
-  @type event_down :: {:down, Connection.error, delay :: integer}
-
-  @type modstate :: any
-  @type handle_return :: {:ok, modstate()}
-  @type handle_call_return :: {:reply, any(), modstate()} | {:noreply,  modstate()}
-
-  @callback init(Keyword.t) :: {:ok, modstate} | any
-  @callback handle_event(event(), modstate()) :: handle_return()
-  @callback handle_info(any(), modstate()) :: handle_return()
-  @callback handle_cast(any(), modstate()) :: handle_return()
-  @callback handle_call(any(), reference(), modstate()) :: handle_call_return()
-  @callback stop(Connection.error, modstate) :: any()
-
-  @type start_opt :: Connection.start_opt
-                  | {:module, module()}
-                  | {:conn_statem_opts, [:gen_statem.start_opt]}
-  @type start_ret :: {:ok, pid} | {:error, Connection.error} | :gen_statem.start_ret
-
-  @spec start(Connection.nick, Connection.host, [start_opt], [:gen_statem.start_opt]) :: start_ret
-  def start(nick, host, opts \\ [], start_opts \\ []) do
-    :gen_statem.start(__MODULE__, [nick, host, prepare_args(opts)], start_opts)
-  end
-
-  @spec start_link(Connection.nick, Connection.host, [start_opt], [:gen_statem.start_opt]) :: start_ret
-  def start_link(nick, host, opts \\ [], start_opts \\ []) do
-    :gen_statem.start_link(__MODULE__, [nick, host, prepare_args(opts)], start_opts)
-  end
-
-
-  @doc false
-  def init([args]) do
-    capabs = ["account-notify", "away-notify"]
-    args = args
-           |> Keyword.put(:capabs, capabs)
-    with \
-         {:ok, conn} <- Connection.start(Keyword.get(args, :nick), Keyword.get(args, :host), args, Keyword.get(args, :conn_statem_opts, [])),
-         conn_mon <- Process.monitor(conn),
-         {:ok, module} <- Keyword.fetch(args, :module),
-         {:ok, modstate} <- module.init(args)
-    do
-      data = %__MODULE__{
-        conn: conn, conn_mon: conn_mon,
-        module: module, modstate: modstate,
-        args: args
-      }
-      {:ok, :disconnected, data}
-    else
-      error -> {:stop, error}
-    end
-  end
-
-  def disconnected(:enter, :connected, data) do
-    Logger.debug "#{inspect data} disconnected: #{inspect data.error}"
-    :keep_state_and_data
-  end
-
-  def disconnected(:info, msg = {:irc_conn_up, _, info}, data) do
-    data = run_handler_event({:connected, info}, data)
-    {:next_state, :connected, %__MODULE__{data | nick: info.nick, info: info, modes: info.modes, error: nil}}
-  end
-
-  def disconnected(type, content, data) do
-    handle_common(:disconnected, type, content, data)
-  end
-
-  def connected(:enter, _, data) do
-    Logger.debug "#{inspect data} UP"
-    :keep_state_and_data
-  end
-
-  def connected(:info, msg = {:irc_conn_nick, _, prev_nick, new_nick}, data) do
-    data = run_handler_event({:nick, prev_nick, new_nick}, data)
-    {:keep_state, %__MODULE__{data | nick: new_nick}}
-  end
-
-  def connected(:info, msg = {:irc_conn_modes, _, changes, prev, modes}, data) do
-    data = run_handler_event({:modes, changes, prev, modes}, data)
-    {:keep_state, %__MODULE__{data | modes: modes}}
-  end
-
-  def connected(:info, {:irc_conn_down, _, reason, delay}, data) do
-    data = run_handler_event({:down, reason, delay}, data)
-    {:next_state, :disconnected, %__MODULE__{data | error: reason}}
-  end
-
-  # TODO: REMOVE?
-  def connected(:info, {:irc_conn_line, _, line}, data) do
-    data = run_handler_event({:line, line}, data)
-    :keep_state_and_data
-  end
-
-  def connected(type, content, data) do
-    handle_common(:connected, type, content, data)
-  end
-
-  # TODO: Callback stop?
-  def error(:internal, reason, data) do
-    Logger.error "#{inspect data}: #{inspect reason}"
-    data.module.stop(reason, data.modstate)
-    {:stop, :normal}
-  end
-
-  def handle_common(_, :info, {:irc_conn_error, _, reason}, data) do
-    {:next_state, :error, data, {:next_event, :internal, reason}}
-  end
-
-  def handle_common(_, :enter, _, _) do
-    :keep_state_and_data
-  end
-
-  def terminate(reason, state, data) do
-    Logger.error("#{inspect(data)} terminating in #{inspect(state)}: #{inspect reason}")
-  end
-
-  def code_change(_old_vsn, old_state, old_data, _extra) do
-    {:ok, old_state, old_data}
-  end
-
-  defp prepare_args(args) do
-    args
-  end
-
-  defp run_handler_event(event, data) do
-    case data.module.handle_event(event, data.modstate) do
-      {:ok, modstate} -> %__MODULE__{data | modstate: modstate}
-      :ok -> data
-    end
-  end
-
-  defimpl Inspect, for: __MODULE__ do
-    import Inspect.Algebra
-    def inspect(struct, _opts) do
-      concat(["#Irc.Client<", inspect(self()), ">"])
-    end
-  end
-
-
-end
diff --git a/lib/irc/base_client/capabs.ex b/lib/irc/base_client/capabs.ex
deleted file mode 100644
index e69de29..0000000
diff --git a/lib/irc/client.ex b/lib/irc/client.ex
index 1c4b0c5..d8a7b77 100644
--- a/lib/irc/client.ex
+++ b/lib/irc/client.ex
@@ -1,48 +1,269 @@
 defmodule Irc.Client do
-  alias Irc.BaseClient
-  @behaviour Irc.BaseClient
+  @behaviour :gen_statem
   require Logger
+  alias Irc.Parser.Line
+  alias Irc.Connection
+  require Irc.Parser.Numeric
+  import Irc.Parser.Numeric
 
   @moduledoc """
-  Fully-featured IRC client.
+  Fully-featured IRC Client.
 
-  The client uses message passing.
+  Events emanating from the client are sent to the owner PID, `t:message/0`, and commands can be sent using `command/3`. The response is asynchronous.
 
+  If a command is sent when the client is disconnected, it will be postponed until the client is connected again.
+
+  Known IRC users are cached into `Irc.Client.UserCache`. Depending on the connection capabilities, data returned by the cache may not be up-to-date, and can be retreived with `whois/2`.
+
+  ## Extending
+
+  Most of the commands and capabs are implemented in separate modules. Additional modules can be set in the start options. See `Irc.Client.Capabs`.
   """
 
-  @type message :: Irc.BaseClient.event
-  @type start_ret :: BaseClient.start_ret
+  @commands [
+    Irc.Client.Command.Join,
+    Irc.Client.Command.Who,
+    Irc.Client.Command.Names,
+    Irc.Client.Command.Away,
+    Irc.Client.Command.Chghost,
+    Irc.Client.Command.Account,
+  ]
+
+  @internal {:next_event, :internal, nil}
+
+  defstruct [:conn, :conn_mon, :module, :modstate, :args, :nick, :modes, :info, :error, :commands, :buffer]
+
+  def callback_mode, do: [:state_enter]
+
+  @type message :: {:irc_client, pid(), event}
+
+  @type event :: event_connected | event_nick | event_modes | event_line | event_down
+  | Irc.Client.Command.Join.t
+  | Irc.Client.Command.Names.t
+  | Irc.Client.Command.Who.t
+  | Irc.Client.Command.Away.t
+  | Irc.Client.Command.Chghost.t
+  | Irc.Client.Command.AccountNotify.t
 
-  @spec start(Irc.Connection.nick, Irc.Connection.host, [BaseClient.start_opt], [:gen_statem.start_opt]) :: start_ret
+  @type event_connected :: {:connected, Connection.Info.t}
+  @type event_nick :: {:nick, {prev_nick :: String.t, new_nick :: String.t}}
+  @type event_modes :: {:modes, {changes :: String.t, prev :: list, modes :: list}}
+  @type event_line :: {:line, line :: Irc.Parser.Line.t}
+  @type event_down :: {:down, {Connection.error, delay :: integer}}
+
+
+  @type start_opt :: Connection.start_opt
+                  | {:module, module() | Irc.Client}
+                  | {:commands, [module()]}
+                  | {:conn_statem_opts, [:gen_statem.start_opt]}
+  @type start_ret :: {:ok, pid} | {:error, Connection.error} | :gen_statem.start_ret
+
+  @spec start(Connection.nick, Connection.host, [start_opt], [:gen_statem.start_opt]) :: start_ret
   def start(nick, host, opts \\ [], start_opts \\ []) do
     :gen_statem.start(__MODULE__, [nick, host, prepare_args(opts)], start_opts)
   end
 
-  @spec start_link(Irc.Connection.nick, Irc.Connection.host, [BaseClient.start_opt], [:gen_statem.start_opt]) :: start_ret
+  @spec start_link(Connection.nick, Connection.host, [start_opt], [:gen_statem.start_opt]) :: start_ret
   def start_link(nick, host, opts \\ [], start_opts \\ []) do
     :gen_statem.start_link(__MODULE__, [nick, host, prepare_args(opts)], start_opts)
   end
 
-  @doc false
-  def init(_) do
-    Logger.debug("CLIENT initiated")
-    {:ok, %{process: nil}}
+  def command(pid, command, args) do
+    ref = make_ref()
+    Process.send(pid, {:irc_command, command, ref, args})
+    ref
   end
 
-  @doc false
-  def handle_event(event, state) do
-    Logger.debug("CLIENT EVENT: #{inspect event}")
-    :ok
+  @doc "Whois an user. Depending on the connection capabilities and cache contents, a `WHOIS` irc command may not be executed; unless `cached: false`."
+  @type whois_opt :: {:cached, true | false}
+  @spec whois(pid(), String.t, Keyword.t) :: Irc.User.t()
+  def whois(pid, nick, opts \\ []) do
+  end
+
+  def call_command(pid, command, args, opts \\ []) do
+    timeout = Keyword.get(opts, :timeout, 10_000)
+    ref = command(pid, command, args)
+    receive do
+      {:irc_command, command, result} -> result
+    after
+      timeout -> {:error, :timeout}
+    end
   end
 
   @doc false
-  def stop(reason, state) do
-    Logger.debug("CLIENT: Stopping, #{inspect reason}")
+  def init([args]) do
+    with \
+         commands <- init_commands(args),
+         capabs <- Enum.uniq(commands.capabs ++ Keyword.get(args, :capabs, [])),
+         args <- Keyword.put(args, :capabs, capabs),
+         {:ok, conn} <- Connection.start(Keyword.get(args, :nick), Keyword.get(args, :host), args, Keyword.get(args, :conn_statem_opts, [])),
+         conn_mon <- Process.monitor(conn)
+    do
+      Logger.info("Commands registered: #{inspect commands}")
+      data = %__MODULE__{
+        conn: conn, conn_mon: conn_mon,
+        args: args,
+        commands: commands
+      }
+      {:ok, :disconnected, data}
+    else
+      error -> {:stop, error}
+    end
   end
 
-  defp prepare_args(opts) do
-    opts
-    |> Keyword.put_new(:module, __MODULE__)
+  def handle_event(:enter, :connected, :disconnected, data) do
+    Logger.debug "#{inspect data} disconnected: #{inspect data.error}"
+    :keep_state_and_data
   end
-end
 
+  def handle_event(:info, msg = {:irc_conn_up, _, info}, :disconnected, data) do
+    data = run_handler_event({:connected, info}, data)
+    {:next_state, :connected, %__MODULE__{data | nick: info.nick, info: info, modes: info.modes, error: nil}}
+  end
+
+  #
+  # --- Connected
+  #
+
+  def handle_event(:enter, _, :connected, data) do
+    Logger.debug "#{inspect data} UP"
+    :keep_state_and_data
+  end
+
+  def handle_event(:info, msg = {:irc_conn_nick, _, prev_nick, new_nick}, :connected, data) do
+    data = run_handler_event({:nick, prev_nick, new_nick}, data)
+    {:keep_state, %__MODULE__{data | nick: new_nick}}
+  end
+
+  def handle_event(:info, msg = {:irc_conn_modes, _, changes, prev, modes}, :connected, data) do
+    data = run_handler_event({:modes, changes, prev, modes}, data)
+    {:keep_state, %__MODULE__{data | modes: modes}}
+  end
+
+  def handle_event(:info, {:irc_conn_down, _, reason, delay}, :connected, data) do
+    data = run_handler_event({:down, reason, delay}, data)
+    {:next_state, :disconnected, %__MODULE__{data | error: reason}}
+  end
+
+  def handle_event(:info, {:irc_command, command, args}, :connected, data) do
+    if module = get_in(data, [:commands, :user, command]) do
+      {next, actions} = case module.handle_command(command, args, data.info) do
+        {next, next_arg} -> {{next, next_arg}, []}
+        {next, next_arg, actions} -> {{next, next_arg}, List.wrap(actions)}
+        next when is_atom(next) -> {{next, nil}, []}
+      end
+
+      data = handle_actions(actions, data)
+
+      case next do
+        {:buffer, acc} -> {:next_state, {:buffer, module}, %__MODULE__{data | buffer: acc}}
+      end
+    else
+      data = run_handler_event({:irc_command, command, {:error, :unsupported_command, command}}, data) # MEH?
+      {:keep_state, data}
+    end
+  end
+
+  # DOES NOT HANDLE ERROR (actions can just return data now)
+  defp handle_actions([{:send, line} | rest], data) do
+    case Connection.sendline(data.conn, line) do
+      :ok -> handle_actions(rest, data)
+      error -> {:next_state, :disconnected, %__MODULE__{data | error: error}}
+    end
+    data
+  end
+  defp handle_actions([{:event, event} | rest], data) do
+    run_handler_event(event, data)
+  end
+  defp handle_actions([], data), do: data
+
+  # TODO: REMOVE?
+  def handle_event(:info, {:irc_conn_line, _, line}, :connected, data) do
+    data = run_handler_event({:line, line}, data)
+    :keep_state_and_data
+  end
+
+  #
+  # --- Buffer
+  #
+
+  def handle_event(:info, {:irc_conn_line, _, line}, {:buffer, module}, data) do
+    {next, actions} = case module.handle_buffer(line, data.buffer, data.info) do
+      {next, next_arg} -> {{next, next_arg}, []}
+      {next, next_arg, actions} -> {{next, next_arg}, List.wrap(actions)}
+      next when is_atom(next) -> {{next, nil}, []}
+    end
+
+    data = handle_actions(actions, data)
+
+    case next do
+      {:finish, _} -> {:next_state, :connected, %__MODULE__{data | buffer: nil}}
+      {:buffer, acc} -> {:keep_state, %__MODULE__{data | buffer: acc}}
+    end
+  end
+
+  # TODO: Callback stop?
+  def handle_event(:internal, reason, :error, data) do
+    Logger.error "#{inspect data}: #{inspect reason}"
+    data.module.stop(reason, data.modstate)
+    {:stop, :normal}
+  end
+
+  def handle_event(:info, {:irc_conn_error, _, reason}, _, data) do
+    {:next_state, :error, data, {:next_event, :internal, reason}}
+  end
+
+  def handle_event(:enter, _, _, _) do
+    :keep_state_and_data
+  end
+
+  def terminate(reason, state, data) do
+    Logger.error("#{inspect(data)} terminating in #{inspect(state)}: #{inspect reason}")
+  end
+
+  def code_change(_old_vsn, old_state, old_data, _extra) do
+    {:ok, old_state, old_data}
+  end
+
+  defp prepare_args(args) do
+    args
+  end
+
+  defp run_handler_event(event, data) do
+    case data.module.handle_event(event, data.modstate) do
+      {:ok, modstate} -> %__MODULE__{data | modstate: modstate}
+      :ok -> data
+    end
+  end
+
+  defp init_commands(args) do
+    commands = @commands ++ Keyword.get(args, :commands, [])
+    Enum.reduce(commands, %{server: %{}, user: %{}, capabs: []}, fn(module, acc) ->
+      {server_commands, user_commands, capabs} = module.init()
+
+      get_value = fn(option) ->
+        case option do
+          str when is_binary(str) -> [str]
+          nil -> []
+          list when is_list(list) -> list
+        end
+      end
+
+      reduce_fun = fn(command, acc) -> Map.put(acc, command, module) end
+
+      server = Enum.reduce(List.wrap(server_commands), acc.server, reduce_fun)
+      user = Enum.reduce(List.wrap(user_commands), acc.user, reduce_fun)
+      capabs = List.concat(acc.capabs, List.wrap(capabs))
+      %{server: server, user: user, capabs: capabs}
+    end)
+  end
+
+  defimpl Inspect, for: __MODULE__ do
+    import Inspect.Algebra
+    def inspect(struct, _opts) do
+      concat(["#Irc.Client<", inspect(self()), ">"])
+    end
+  end
+
+
+end
diff --git a/lib/irc/client/command.ex b/lib/irc/client/command.ex
new file mode 100644
index 0000000..a84324f
--- /dev/null
+++ b/lib/irc/client/command.ex
@@ -0,0 +1,50 @@
+defmodule Irc.Client.Command do
+
+  @moduledoc """
+  Implementations of IRC protocol commands and capabilities.
+
+  The Capabs modules are used by the BaseClient to implement everything.
+
+  Capabs modules are mostly stateless, except when they enter the buffering FSM state.
+
+  It is recommended that event names matches the command name, to help awaiting response.
+  """
+
+  @doc """
+  Returns which server-initiated and client-initiated commands the module supports, and IRCv3 capabs to be requested to the server.
+  """
+  @callback init(Keyword.t) :: {commands :: [String.t],
+    client_commands :: [atom],
+    capabs :: [String.t]}
+
+  @type buffer :: any()
+  @type event :: {client_command :: atom | atom, any()}
+
+  @type buffer_ret :: :buffer | {:buffer, buffer()}
+  @type line_return :: :ok | {:ok, [action]} | {:error, any()} | buffer_ret
+  @type buffer_return :: buffer_ret | line_return | :postpone
+
+  @type send_action :: {:send, Line.t()}
+  @type event_action :: {:event, event()}
+  @type action :: send_action | event_action
+
+  @doc """
+  Handles an incoming line.
+  """
+  @callback handle_line(Irc.Line.t(), Irc.Connection.t()) :: line_return
+
+  @doc """
+  Handles an incoming line when in buffering state.
+
+  Returning anything else than `:buffer` or `:postpone` will exit the buffering state.
+
+  Postponed lines will be treated as usual (per their respective module) once the buffering state exits.
+  """
+  @callback handle_buffer(Irc.Line.t(), buffer, Irc.Connection.t()) :: buffer_return
+
+  @doc """
+  Handles a user requested command.
+  """
+  @callback handle_command(client_command :: atom, args :: list, Irc.Connection.t()) :: line_return
+
+end
diff --git a/lib/irc/client/command/account.ex b/lib/irc/client/command/account.ex
new file mode 100644
index 0000000..c5ec1a9
--- /dev/null
+++ b/lib/irc/client/command/account.ex
@@ -0,0 +1,18 @@
+defmodule Irc.Client.Command.Account do
+  alias Irc.Parser.Line
+
+  @type t :: logout :: {:account, Irc.Mask.t} | login :: {:account, Irc.Mask.t, String.t}
+
+  def init() do
+    {"ACCOUNT", nil, "account-notify"}
+  end
+
+  def handle_line(%Line{command: "ACCOUNT", source: target, args: ["*"]}) do
+    {:event, {:account, target}}
+  end
+
+  def handle_line(%Line{command: "ACCOUNT", source: target, args: [account_name]}) do
+    {:event, {:account, target, account_name}}
+  end
+
+end
diff --git a/lib/irc/client/command/away.ex b/lib/irc/client/command/away.ex
new file mode 100644
index 0000000..3b6b38e
--- /dev/null
+++ b/lib/irc/client/command/away.ex
@@ -0,0 +1,25 @@
+defmodule Irc.Client.Command.Away do
+  alias Irc.Parser.Line
+
+  @type t :: away :: {:away, Irc.Mask.t, String.t} | unaway :: {:away, Irc.Mask.t}
+
+  def init() do
+    {"AWAY", :away, "away-notify"}
+  end
+
+  def handle_command(:away, args, _) do
+    command = case args do
+      [] -> ['AWAY']
+      [message] -> ['AWAY :', message]
+    end
+    {:send, command}
+  end
+
+  def hanle_line(%Line{command: "AWAY", source: source, args: args}, _) do
+    case args do
+      [] -> {:event, {:away, source}}
+      [message] -> {:event, {:away, {source, message}}}
+    end
+  end
+
+end
diff --git a/lib/irc/client/command/chghost.ex b/lib/irc/client/command/chghost.ex
new file mode 100644
index 0000000..2b4adab
--- /dev/null
+++ b/lib/irc/client/command/chghost.ex
@@ -0,0 +1,15 @@
+defmodule Irc.Client.Command.Chghost do
+  alias Irc.Parser.Line
+
+  @type t :: {:chghost, old_mask :: Irc.Mask.t, new_mask :: Irc.Mask.t}
+
+  def init() do
+    {"CHGHOST", nil, "chghost"}
+  end
+
+  def handle_line(%Line{source: old_mask, args: [new_user, new_host]}, _) do
+    new_mask = %Irc.Mask{old_mask | user: new_user, host: new_host}
+    {:event, {:chghost, old_mask, new_mask}}
+  end
+
+end
diff --git a/lib/irc/client/command/invite.ex b/lib/irc/client/command/invite.ex
new file mode 100644
index 0000000..833c2fc
--- /dev/null
+++ b/lib/irc/client/command/invite.ex
@@ -0,0 +1,21 @@
+defmodule Irc.Client.Command.Invite do
+  alias Irc.Parser.Line
+
+  @type invite :: {:invite, channel :: String.t(), inviter :: String.t(), invited_nick :: String.t()}
+  @type invited :: {:invite, channel :: String.t, inviter :: Irc.Mask.t}
+  @type t :: invite | invited
+
+  def init() do
+    {"INVITE", :invite, "invite-notify"}
+  end
+
+  def handle_line(%Line{command: "INVITE", source: inviter, args: [invited, channel]}) do
+    {:event, {:invite, channel, inviter, invited}}
+  end
+
+  def handle_line(%Line{command: "INVITE", source: inviter, args: [channel]}) do
+    {:event, {:invite, channel, inviter}}
+  end
+
+end
+
diff --git a/lib/irc/client/command/join.ex b/lib/irc/client/command/join.ex
new file mode 100644
index 0000000..f4728c7
--- /dev/null
+++ b/lib/irc/client/command/join.ex
@@ -0,0 +1,40 @@
+defmodule Irc.Client.Command.Join do
+  alias Irc.Parser.Line
+  require Line
+  import Line
+
+  @type t :: {:join, channel :: String.t()} | {:join, channel :: String.t(), Irc.User.t()}
+
+  def init(_args) do
+    {"JOIN", :join, ["extended-join"]}
+  end
+
+  # An user joined
+  def handle_line(line = %Line{command: "JOIN", source: source, args: [channel | args]}, conn) do
+    if Line.self?(line, conn) do
+      {:event, {:join, channel}}
+    else
+      user = Irc.User.from_mask(source)
+      user = case args do
+        [] -> user
+        [account, name] ->
+          account = if account != "*", do: account
+          {channel, %Irc.User{user | account: account, name: name}}
+      end
+      {:event, {:join, channel, user}}
+    end
+  end
+
+  # Join a channel
+  def handle_command(:join, [channel], _conn_info) do
+    {:send, ['JOIN', channel]}
+  end
+
+  # Outdated!
+  def handle_buffer(%Line{command: "JOIN", source: %Irc.Mask{nick: nick}, args: [channel]}, buffer = %{channel: channel}, %Irc.Connection{nick: nick}) do
+    {:finish, nil, {:event, {:join, channel}}}
+  end
+
+  def handle_buffer(_, _), do: :postpone
+
+end
diff --git a/lib/irc/client/command/names.ex b/lib/irc/client/command/names.ex
new file mode 100644
index 0000000..b5a84a6
--- /dev/null
+++ b/lib/irc/client/command/names.ex
@@ -0,0 +1,22 @@
+defmodule Irc.Client.Command.Names do
+  alias Irc.Parser.Line
+  require Irc.Parser.Numeric
+  import Irc.Parser.Numeric
+
+  def init() do
+    {[rpl_NAMREPLY(), rpl_ENDOFNAMES()], :names, ["userhost-in-names"]}
+  end
+
+  def handle_line(%Line{command: rpl_NAMREPLY()}) do
+    :buffer
+  end
+
+  def handle_line(%Line{command: rpl_ENDOFNAMES(), args: [_, target | _]}) do
+    :finish
+  end
+
+  def handle_buffer(buffer = [%Line{args: [_, target | _]} | _]) do
+    {:event, {:names, target, buffer}}
+  end
+
+end
diff --git a/lib/irc/client/command/who.ex b/lib/irc/client/command/who.ex
new file mode 100644
index 0000000..1654ef6
--- /dev/null
+++ b/lib/irc/client/command/who.ex
@@ -0,0 +1,62 @@
+defmodule Irc.Client.Command.Who do
+  alias Irc.Parser.Line
+  alias Irc.User
+  use Irc.Parser.Numeric
+
+  @type t :: {:who, target :: String.t, [Irc.User.t]}
+
+  def init(_) do
+    {nil, "WHO", nil}
+  end
+
+  def handle_command("WHO", [target], conn) do
+    args = if Irc.Connection.supports?(conn, "whox") do
+      " nuhs%cuhsnfdar"
+    end
+    {:buffer, %{target: target, acc: [], error: nil}, {:send, ['WHO ', target, args]}}
+  end
+
+  @errors [err_NOSUCHSERVER(), rpl_TRYAGAIN()]
+  def handle_buffer(%Line{command: error, args: args}, buffer, _conn) when error in @errors do
+    #?
+    {:buffer, %{buffer | error: {error, args}}}
+  end
+
+  def handle_buffer(%Line{command: rpl_ENDOFWHO()}, buffer, _conn) do
+    result = if buffer.error do
+      {:error, buffer.error}
+    else
+      {:ok, buffer.acc}
+    end
+    {:finish, nil, {:event, {:who, buffer.target, result}}}
+  end
+
+  def handle_buffer(%Line{command: rpl_WHOREPLY(), args: args}, buffer, conn) do
+    case args do
+      [_, c, u, h, s, n, f, d | a_r] ->
+        {a,r} = case a_r do
+          [a, r] -> {a, r}
+          [r] -> {nil, r}
+        end
+        {modes, _} = Irc.Parser.Prefix.parse(f, conn)
+        chanmodes = %{buffer.target => modes}
+        user = %Irc.User{
+          user: u,
+          host: h,
+          server: s,
+          nick: n,
+          account: a,
+          name: r,
+          channels: [buffer.target],
+          chanmodes: chanmodes
+        }
+
+      _ ->
+        {:finish, nil} # ERROFFEL
+    end
+    {:buffer, %{buffer | acc: [args | buffer.acc]}}
+  end
+
+  def handle_buffer(_, _), do: :postpone
+
+end
diff --git a/lib/irc/client/user_cache.ex b/lib/irc/client/user_cache.ex
new file mode 100644
index 0000000..2653630
--- /dev/null
+++ b/lib/irc/client/user_cache.ex
@@ -0,0 +1,31 @@
+defmodule Irc.Client.UserCache do
+
+  # tuple: {nick, user}
+
+  def init(args) do
+    opts = [{:read_concurrency, true}, :protected]
+    :ets.new(__MODULE__, opts)
+  end
+
+  def lookup(ets, nick) do
+    case :ets.lookup(ets, nick) do
+      [{^nick, user}] -> user
+      _ -> nil
+    end
+  end
+
+  def change(ets, nick, changes) do
+    initial = if user = lookup(ets, nick), do: user, else: %Irc.User{nick: nick}
+    user = User.change(initial, changes)
+    put(ets, nick, user)
+  end
+
+  defp put(ets, original_nick, user) do
+    tuple = {user.nick, user}
+    if original_nick != user.nick do
+      true = :ets.delete(ets, original_nick)
+    end
+    :ets.insert(ets, tuple)
+  end
+
+end
diff --git a/lib/irc/connection.ex b/lib/irc/connection.ex
index f43fca7..052141c 100644
--- a/lib/irc/connection.ex
+++ b/lib/irc/connection.ex
@@ -11,10 +11,39 @@ defmodule Irc.Connection do
   @reply_timeout :timer.seconds(1)
   @cap_timeout :timer.seconds(15)
   @registration_timeout :timer.seconds(30)
-  @support_capabs ["sasl", "cap-notify"]
+  @connection_capabs ["sasl", "cap-notify"]
   @internal {:next_event, :internal, nil}
 
-  defstruct [:server, :nick, :modes, :capabs, :server_version, :server_umodes, :server_cmodes, :server_cmodes_with_params, :isupport, :motd]
+  @moduledoc """
+  Lightweight implementation of an IRC Connection handling only the basics:
+
+    * the socket and reconnections,
+    * registration process,
+    * sasl authentication,
+    * capabilities negotiation,
+    * ping,
+    * nick and user mode changes.
+
+  Events and lines are sent to calling PID.
+
+  ## Usage
+
+  The client is started using `start/4` or `start_link/4`, supplying a nickname, IRC host, and options `t:start_opt/0`:
+
+  ```elixir
+  {:ok, Pid} = Irc.Connection.start("ExIrcTest", "irc.random.sh", [tls: true, port: 6697], [])
+  ```
+
+  Messages will be sent to your PID, see `t:message/0` for the possible types.
+
+  You can send lines using `sendline/3`, and disconnect with `disconnect/3`.
+
+  Status and information about the connection (`t:t/0`) can be requested with `info/1`.
+
+  If you are looking for a more featured client, you probably want `Irc.Client`!
+  """
+
+  defstruct [:server, :nick, :modes, :capabs, :version, :umodes, :cmodes, :cmodes_with_params, :isupport, :motd]
 
   @typedoc "Connection Information state"
   @type t :: %__MODULE__{
@@ -22,25 +51,24 @@ defmodule Irc.Connection do
     nick: String.t,
     capabs: list(),
     modes: String.t,
-    server_version: String.t,
-    server_umodes: String.t,
-    server_cmodes: String.t,
-    server_cmodes_with_params: String.t,
-    isupport: isupport(),
+    version: String.t,
+    umodes: String.t,
+    cmodes: String.t,
+    cmodes_with_params: String.t,
+    isupport: Irc.Parser.Isupport.t(),
     motd: [String.t],
   }
 
-  @typedoc "Server ISUPPORT"
-  @type isupport :: %{String.t() => true | nil | String.t | %{String.t() => any()}}
-
   @typedoc "Messages sent to the owning process."
   @type message :: msg_up() | msg_down() | msg_error()
-                  | msg_line() | msg_umodes() | msg_nick()
+                  | msg_line() | msg_batch() | msg_umodes() | msg_nick()
 
   @typedoc "Connection is now up and registered."
   @type msg_up :: {:irc_conn_up, pid(), t()}
   @typedoc "Message: Received an IRC line."
   @type msg_line :: {:irc_conn_line, pid(), Line.t}
+  @typedoc "Message: Line batch (only if enabled, see `batch` in `t:start_opt/0`)."
+  @type msg_batch :: {:irc_conn_batch, pid(), type :: String.t(), type_params :: [String.t()], lines :: [Line.t]}
   @typedoc "Message: Connection user modes have changed."
   @type msg_umodes :: {:irc_conn_modes, pid(), changes :: String.t, previous_modes :: list(), modes :: list()}
   @typedoc "Message: Connection nickname have changed."
@@ -58,61 +86,81 @@ defmodule Irc.Connection do
                       | {:quit, reason :: String.t}
                       | {:irc_error, reason :: String.t}
 
+
   @typedoc """
   Start options.
 
   * user: IRC user,
   * name: IRC real name,
   * pass: IRC server password,
-  * capabs: IRCv3 capabs to request (if available),
-  * port,
   * tls,
-  * reconnect,
-  * process,
-  * tcp_opts and tls_opts.
+  * port (default 6667, 6697 if tls),
+  * reconnect (automatic/backoff reconnection),
+  * [batch][batch]
+  * [sasl][sasl] options, see `t:start_opt_sasl/0`,
+  * [webirc][webirc] options, see `t:start_opt_webirc/0`,
+  * capabs: list to request,
+  * connect options (either `t:gen_tcp.connect_option/0` or `t:ssl.start_option/0`, depending on the value of the `tls`),
+  * owner process.
+
   """
   @type start_opt :: {:user, nil | String.t}
                   | {:name, nil | String.t}
                   | {:pass, nil | String.t}
-                  | {:capabs, [String.t]}
-                  | {:port, 6667 | Integer.t}
+                  | {:port, 6667 | 6697 | Integer.t}
                   | {:tls, false | true}
-                  | {:inet, nil | 4 | 6}
-                  | {:iface, nil | String.t}
-                  | {:ip, nil | String.t}
+                  | {:sts, start_opt_sts()}
                   | {:reconnect, true | false}
-                  | {:process, pid}
-                  | {:tcp_opts, [:gen_tcp.connect_option]}
-                  | {:tls_opts, [:ssl.connect_option]}
+                  | {:sasl, start_opt_sasl()}
+                  | {:batch, start_opt_batch()}
+                  | {:echo, start_opt_echo()}
+                  | {:webirc, nil | start_opt_webirc()}
+                  | {:capabs, [String.t()]}
+                  | {:connect_opts, [:gen_tcp.connect_option | :ssl.connect_option]}
+                  | {:process, pid()}
 
-  @moduledoc """
-  Lightweight implementation of an IRC Connection handling only the basics:
+  @typedoc """
+  IRCv3 [Strict Transport Security]()
 
-    * the socket and reconnections,
-    * registration process,
-    * sasl authentication,
-    * capabilities negotiation,
-    * ping,
-    * nick and user mode changes.
+  Enabled by default. If a STS policy is enabled or known and the connection not secured, the client will automatically reconnect with tls.
+  """
+  @type start_opt_sts :: true | false
 
-  Events and lines are sent to calling PID.
+  @typedoc """
+  [SASL][sasl] Authentication options
 
-  ## Usage
+  [sasl]: https://ircv3.net/specs/extensions/sasl-3.1.html
+  """
+  @type start_opt_sasl :: %{mechanism :: String.t => [mechanism_param() :: String.t]}
 
-  The client is started using `start/4` or `start_link/4`:
+  @typedoc """
+  IRCv3 [Batch][batch] support.
 
-  ```elixir
-  {:ok, Pid} = Irc.Connection.start("ExIrcTest", "irc.random.sh", [tls: true, port: 6697], [])
-  ```
+  Enabled by default. If negotiated, batched lines are sent with the `t:msg_batch/0` message.
 
-  Messages will be sent to your PID, see `t:message/0` for the possible types.
+  If the capability wasn't negotiated or disabled, individual `t:msg_line/0` messages will be sent.
 
-  You can send lines using `sendline/3`, and disconnect with `disconnect/3`.
+  [batch]: https://ircv3.net/specs/extensions/batch-3.2
+  """
+  @type start_opt_batch :: true | false
 
-  Status and information about the connection (`t:t/0`) can be requested with `info/1`.
+  @typedoc """
+  IRCv3 [echo-message](https://ircv3.net/specs/extensions/echo-message-3.2) support.
 
-  If you are looking for a more featured client, you probably want `Irc.Client`!
+  Enabled by default. If negotiated, PRIVMSG and NOTICE sent by the connection will be echoed by the server.
+  """
+  @type start_opt_echo :: true | false
+
+  @typedoc """
+  Send a [WEBIRC][webirc] command upon connection.
+
+  ```
+    {"hunter5", "web.irc.mynetwork", "some-user-hostname", "127.0.0.1", %{"secure" => true}}
+  ```
+
+  [webirc]: https://ircv3.net/specs/extensions/webirc
   """
+  @type start_opt_webirc :: {password ::String.t, gateway :: String.t, hostname :: String.t, ip :: String.t, options :: Map.t}
 
   @type nick :: String.t
   @type host :: String.t
@@ -187,6 +235,18 @@ defmodule Irc.Connection do
     result
   end
 
+  @spec capab?(t, String.t) :: boolean
+  @doc "Returns true if the capab `feature` has been negotiated for this connection."
+  def capab?(%__MODULE__{capabs: capabs}, feature) do
+    Enum.member?(capabs, feature)
+  end
+
+  @spec supports?(String.t, t) :: boolean
+  @doc "Returns true if `feature` is reported as supported by the server (ISUPPORT)."
+  def supports?(%__MODULE__{isupport: isupport}, feature) do
+    Map.has_key?(isupport, String.upcase(feature))
+  end
+
   @doc "Flush all messages from the connection."
   def flush(pid) do
     receive do
@@ -204,22 +264,23 @@ defmodule Irc.Connection do
   defmodule State do
     @moduledoc false
     defstruct [:args,
-      :backoff, :socket, :sockmodule, {:tries, 0},
+      :backoff, :socket, :sockmodule,
       :process, :monitor,
       :nick,
       :server,
-      :server_version,
-      :server_umodes,
-      :server_cmodes,
-      :server_cmodes_with_params,
+      :version,
+      :umodes,
+      :cmodes,
+      :cmodes_with_params,
       :welcomed,
+      :sts, :port, :tls,
+      {:batches, %{}},
       {:errored, false},
       {:isupport, %{}},
       {:modes, []},
       {:server_capabs, []},
-      {:req_capabs, []},
+      {:client_capabs, []},
       {:capabs, []},
-      {:buffer, []},
       {:motd, []},
       {:welcome, []},
     ]
@@ -235,11 +296,31 @@ defmodule Irc.Connection do
     process = Keyword.get(args, :process, nil)
     monitor = Process.monitor(process)
     with \
-         {:ok, processed_args} <- process_args(args),
+         {:ok, args} <- process_args(args),
          backoff <- :backoff.init(backoff_min, backoff_max)
     do
+      {tls, sts, port} = if !args.tls && args.sts do
+        case Irc.STS.lookup(args.host, args.port) do
+          {true, port} -> {true, true, port}
+          {false, port} -> {false, false, port}
+        end
+      else
+        {args.tls, false, args.port}
+      end
+      client_capabs = [Irc.Parser.capabs(),
+                      @connection_capabs,
+                      if(args.batch, do: ["batch"]),
+                      if(args.sasl, do: ["sasl"]),
+                      if(args.echo, do: ["echo-message"]),
+                      args.capabs,
+                    ]
+                    |> Enum.filter(fn(i) -> i end)
+                    |> List.flatten()
+                    |> Enum.uniq()
       data = %State{
-        args: processed_args,
+        args: args,
+        sts: sts, port: port, tls: tls,
+        client_capabs: client_capabs,
         process: process,
         monitor: monitor,
         backoff: backoff
@@ -254,14 +335,14 @@ defmodule Irc.Connection do
   # TCP Open
 
   @doc false
-  def connect(:internal, _, data = %{args: %{tls: true}}) do
+  def connect(:internal, _, data = %{tls: true}) do
     {:next_state, :connect_tls, data, {:next_event, :internal, nil}}
   end
 
   def connect(:internal, _, data) do
     Logger.debug("#{inspect(data)} connecting...")
-    options = data.args.bind ++ data.args.inet ++ [{:active, true}, {:packet, :line}] ++ data.args.tcp_opts
-    case :gen_tcp.connect(String.to_charlist(data.args.host), data.args.port, options) do
+    options = [{:active, true}, {:packet, :line}] ++ data.args.connect_opts
+    case :gen_tcp.connect(String.to_charlist(data.args.host), data.port, options) do
       {:ok, socket} ->
         {_, backoff} = :backoff.succeed(data.backoff)
         {:next_state, :connected, %State{data | backoff: backoff}, {:next_event, :internal, {:gen_tcp, socket}}}
@@ -279,8 +360,8 @@ defmodule Irc.Connection do
 
   @doc false
   def connect_tls(:internal, nil, data) do
-    options = data.args.bind ++ data.args.inet ++ [{:active, true}, {:packet, :line}] ++ data.args.tcp_opts ++ data.args.tls_opts
-    case :ssl.connect(String.to_charlist(data.args.host), data.args.port, options) do
+    options = [{:active, true}, {:packet, :line}] ++ data.args.connect_opts
+    case :ssl.connect(String.to_charlist(data.args.host), data.port, options) do
       {:ok, socket} ->
         {_, backoff} = :backoff.succeed(data.backoff)
         {:next_state, :connected, %State{data | backoff: backoff}, {:next_event, :internal, {:ssl, socket}}}
@@ -295,13 +376,43 @@ defmodule Irc.Connection do
 
   @doc false
   def connected(:internal, {module, socket}, data) do
-    {:next_state, :cap_ls, %State{data | sockmodule: module, socket: socket}, @internal}
+    next = if Map.get(data.args, :webirc) do
+      :webirc
+    else
+      :cap_ls
+    end
+
+    {:next_state, next, %State{data | sockmodule: module, socket: socket}, @internal}
   end
 
   def connected(type, content, data) do
     handle_common(:connected, type, content, data)
   end
 
+  # Registration: WEBIRC
+  # https://ircv3.net/specs/extensions/webirc
+
+  @doc false
+  def webirc(:internal, _, data = %{args: args}) do
+    {password, gateway, hostname, ip, options} = Keyword.get(args, :webirc)
+    opt_string = Enum.map(options, fn({key, value}) ->
+      if value == true do
+        key
+      else
+        key <> "=" <> value
+      end
+    end)
+    |> Enum.join(" ")
+    case socksend(data, ['WEBIRC ', password, ' ', gateway, ' ', hostname, ' ', ip, ' :', options]) do
+      :ok -> {:next_state, :cap_ls, data, @internal}
+      error -> to_disconnected(error, data)
+    end
+  end
+
+  def webirc(type, content, data) do
+    handle_common(:webirc, type, content, data)
+  end
+
   # Registration: LIST CAPABS
 
   @doc false
@@ -321,18 +432,15 @@ defmodule Irc.Connection do
         {:keep_state, %State{data | server_capabs: data.capabs ++ capabs}, {:state_timeout, @reply_timeout, nil}}
       l = %Line{command: "CAP", args: ["*", "LS", rest]} ->
         capabs = Enum.uniq(data.capabs ++ String.split(rest, " "))
-        {:next_state, :reg_pass, %State{data | server_capabs: capabs}, @internal}
-      # TODO: What do?
+        {:next_state, :cap_sts, %State{data | server_capabs: capabs}, @internal}
       l ->
         handle_common(:cap_ls, :info, msg, data)
-      #    {:next_state, :registration, data, {:next_event, :internal, nil}}
     end
   end
 
   def cap_ls(:state_timeout, _, data) do
-    capabs = Enum.uniq(data.capabs)
     Logger.debug("State timeout")
-    {:next_state, :reg_pass, %State{data | server_capabs: capabs}, @internal}
+    {:next_state, :cap_sts, data, @internal}
   end
 
   def cap_ls(type, content, data) do
@@ -340,6 +448,41 @@ defmodule Irc.Connection do
     handle_common(:cap_ls, type, content, data)
   end
 
+  # REGISTRATION: Check for STS
+
+  @doc false
+  def cap_sts(:internal, _, data = %{args: %{sts: true}}) do
+    sts? = Enum.find(data.capabs, fn(capab) -> String.starts_with?(capab, "sts=") end)
+    if sts? do
+      "sts="<>rules = sts?
+      rules = Map.reduce(String.split(rules, ","), %{}, fn(k_v, acc) ->
+        [k, v] = String.split(k_v, "=")
+        Map.put(acc, k, v)
+      end)
+      port = Map.get(rules, "port")
+      duration = Map.get(rules, "duration")
+      Irc.STS.witness(data.args.host, data.args.port, port, Map.get(rules, "duration"))
+      if !data.tls && port && duration do
+        Logger.info("#{inspect data} STS advertised, reconnecting to tls port #{port}")
+        socksend(data, ['QUIT :STS, Reconnecting'])
+        data.sockmodule.close(data.socket)
+        {:next_state, :connect, %State{data | sts: true, port: port, tls: true, socket: nil, sockmodule: nil}, @internal}
+      else
+        {:next_state, :reg_pass, %State{data | sts: true}, @internal}
+      end
+    else
+      {:next_state, :reg_pass, data, @internal}
+    end
+  end
+
+  def cap_sts(:internal, _, data) do
+    {:next_state, :reg_pass, data, @internal}
+  end
+
+  def cap_sts(type, content, data) do
+    handle_common(:cap_sts, type, content, data)
+  end
+
   # Registration: PASS
 
   @doc false
@@ -432,8 +575,7 @@ defmodule Irc.Connection do
   end
 
   def cap_req(:internal, _, data) do
-    capabs = data.args.capabs ++ @support_capabs
-    req = Enum.filter(@support_capabs, fn(capab) -> Enum.member?(data.server_capabs, capab) end)
+    req = Enum.filter(data.client_capabs, fn(capab) -> Enum.member?(data.server_capabs, capab) end)
           |> Enum.uniq()
           |> Enum.join(" ")
     case socksend(data, ['CAP REQ :', String.to_charlist(req)]) do
@@ -493,8 +635,8 @@ defmodule Irc.Connection do
           [] -> nil
           [c] -> c
         end
-        data = %State{data | welcome: [l | data.welcome], server_version: version, server_umodes: umodes,
-          server_cmodes: cmodes, server_cmodes_with_params: cmodes_with_params}
+        data = %State{data | welcome: [l | data.welcome], version: version, umodes: umodes,
+          cmodes: cmodes, cmodes_with_params: cmodes_with_params}
         {:keep_state, data, {:state_timeout, @reply_timeout, nil}}
       l = %Line{command: rpl_ISUPPORT(), args: [_ | isupport]} ->
         supports = Irc.Parser.Isupport.parse(isupport, data.isupport)
@@ -548,7 +690,7 @@ defmodule Irc.Connection do
   defp to_info(data, state \\ nil) do
     data
     |> Map.from_struct()
-    |> Map.take([:nick, :modes, :server, :server_version, :server_umodes, :server_cmodes, :server_cmodes_with_params, :capabs, :isupport, :motd])
+    |> Map.take([:nick, :modes, :server, :version, :umodes, :cmodes, :cmodes_with_params, :capabs, :isupport, :motd])
     |> Map.put(:__struct__, __MODULE__)
   end
 
@@ -652,6 +794,31 @@ defmodule Irc.Connection do
     {:keep_state, %State{data | nick: nick}}
   end
 
+  # -- BATCH
+  def process_line(%Line{command: "BATCH", args: ["+"<>batchid, type | args]}, data) do
+    batch = %{type: type, args: args, lines: []}
+    {:keep_state, %State{data | batches: Map.put(data.batches, batchid, batch)}}
+  end
+
+  def process_line(%Line{command: "BATCH", args: ["-"<>batchid | args]}, data) do
+    %{type: type, args: args, lines: lines} = Map.get(data.batches, batchid)
+    if Keyword.get(data.args, :batch, true) do
+      send(data.process, {:irc_conn_batch, self(), type, args, Enum.reverse(lines)})
+    else
+      for l <- Enum.reverse(lines), do: send(data.process, {:irc_conn_line, self(), l})
+    end
+    {:keep_state, %State{data | batches: Map.drop(data.batches, batchid)}}
+  end
+
+  def process_line(line = %Line{tags: %{"batch" => batch}}, data) do
+    if batch_data = Map.get(data.batches, batch) do
+      batch_data = Map.put(batch_data, :lines, [line | batch_data.lines])
+      {:keep_state, %State{data | batches: Map.put(data.batches, batch, batch_data)}}
+    else
+      :ignore
+    end
+  end
+
   def process_line(line, _) do
     :ignore
   end
@@ -806,6 +973,9 @@ defmodule Irc.Connection do
   end
 
   # Send helpers.
+  defp socksend(data, line = %Line{}) do
+    socksend(data, [Line.encode(line, info(data))])
+  end
   defp socksend(data = %State{sockmodule: module, socket: socket}, line) when is_list(line) do
     Logger.debug("#{inspect data} >>> #{inspect line}")
     module.send(socket, [line | [?\r, ?\n]])
@@ -830,15 +1000,10 @@ defmodule Irc.Connection do
   # Process args (in init)
   defp process_args(args) do
     host = Keyword.get(args, :host, nil)
-    port = Keyword.get(args, :port, nil) || 6667
     tls = Keyword.get(args, :tls, nil) || false
-    inet = case Keyword.get(args, :inet, nil) do
-      4 -> [:inet]
-      6 -> [:inet6]
-      _ -> []
-    end
-    ip = Keyword.get(args, :ip, nil)
-    ifaddr = Keyword.get(args, :ifaddr, nil)
+    sts = Keyword.get(args, :sts, nil) || true
+    default_port = if tls, do: 6697, else: 6667
+    port = Keyword.get(args, :port, nil) || default_port
     connect_timeout = Keyword.get(args, :connect_timeout, @connect_timeout)
     nick = Keyword.get(args, :nick, nil)
     user = Keyword.get(args, :user, nick) || nick
@@ -846,28 +1011,26 @@ defmodule Irc.Connection do
     pass = Keyword.get(args, :pass, nil)
     capabs = Keyword.get(args, :capabs, []) || []
     reconnect = Keyword.get(args, :reconnect, true)
-    tcp_opts = Keyword.get(args, :tcp_opts, []) || []
-    tls_opts = Keyword.get(args, :tls_opts, []) || []
+    batch = Keyword.get(args, :batch, true)
+    connect_opts = Keyword.get(args, :connect_opts, []) || []
 
     with \
      {:host, {:ok, host}} <- {:host, parse_host(host)},
-     {:port, {:ok, port}} <- {:port, parse_port(port)},
-     {:bind, {:ok, bind}} <- {:bind, parse_bind(ip, ifaddr)}
+     {:port, {:ok, port}} <- {:port, parse_port(port)}
     do
       {:ok, %{
         host: host,
-        port: port,
-        bind: bind,
         tls: tls,
+        sts: sts,
+        port: port,
         capabs: capabs,
-        inet: inet,
         nick: nick,
         user: user,
         name: name,
         pass: pass,
         reconnect: reconnect,
-        tcp_opts: tcp_opts,
-        tls_opts: tls_opts,
+        batch: batch,
+        connect_opts: connect_opts,
         connect_timeout: connect_timeout
       }}
     else
@@ -885,22 +1048,6 @@ defmodule Irc.Connection do
   end
   defp parse_port(port), do: {:error, {:invalid_format, :port, inspect(port)}}
 
-  defp parse_bind(ip, _) when is_binary(ip) do
-    case :inet.parse_strict_address(String.to_charlist(ip)) do
-      {:ok, ip} -> {:ok, [{:ip, ip}]}
-      {:error, :einval} -> {:error, {:invalid_format, :ip, inspect(ip)}}
-    end
-  end
-  # TODO: Verify ifaddr is a valid interface
-  defp parse_bind(_, ifaddr) when is_binary(ifaddr) do
-    {:ok, [{:ifaddr, ifaddr}]}
-  end
-  defp parse_bind(nil, nil) do
-    {:ok, []}
-  end
-  defp parse_bind(ip, ifaddr) do
-    {:error, {:invalid_format, :bind, inspect([ip, ifaddr])}}
-  end
 
   defimpl Inspect, for: State do
     @moduledoc false
diff --git a/lib/irc/mask.ex b/lib/irc/mask.ex
new file mode 100644
index 0000000..5106c26
--- /dev/null
+++ b/lib/irc/mask.ex
@@ -0,0 +1,52 @@
+defmodule Irc.Mask do
+
+  @type t :: %__MODULE__{nick: nil | String.t(), user: nil | String.t(), host: nil | String.t(), server: nil | String.t()}
+  defstruct [:nick, :user, :host, :server]
+
+  @spec parse(String.t) :: {:ok, t()} | {:error, :invalid_mask}
+  def parse(string) do
+    cond do
+      String.contains?(string, "!") -> parse_user_mask(string)
+      String.contains?(string, ".") -> parse_server_mask(string)
+      true -> {:error, :invalid_mask}
+    end
+  end
+
+  def new(nick, user, host) do
+    %__MODULE__{nick: nick, user: user, host: host}
+  end
+
+  def to_string(%__MODULE__{server: nil, nick: nick, user: user, host: host}) do
+    Enum.join([nick, "!", user, "@", host])
+  end
+
+  def to_string(%__MODULE__{server: server}), do: server
+
+  defp parse_user_mask(string) do
+    case String.split(string, ~r/[!@]/, parts: 3) do
+      [nick, user, host] ->
+        {:ok, %__MODULE__{nick: nick, user: user, host: host}}
+      _ ->
+        {:error, :invalid_mask}
+    end
+  end
+
+  defp parse_server_mask(string) do
+    {:ok, %__MODULE__{server: string}}
+  end
+
+  defimpl String.Chars, for: __MODULE__ do
+    @moduledoc false
+    defdelegate to_string(struct), to: Irc.Mask
+  end
+
+  defimpl Inspect, for: __MODULE__ do
+    @moduledoc false
+    import Inspect.Algebra
+
+    def inspect(struct, _opts) do
+      concat(["#Irc.Mask<", Irc.Mask.to_string(struct), ">"])
+    end
+  end
+
+end
diff --git a/lib/irc/parser.ex b/lib/irc/parser.ex
index 0224c16..67bb789 100644
--- a/lib/irc/parser.ex
+++ b/lib/irc/parser.ex
@@ -11,4 +11,10 @@ defmodule Irc.Parser do
 
   """
 
+  def capabs, do: ["multi-prefix",
+    "message-tags",
+    "account-tag",
+    "server-time"
+  ]
+
 end
diff --git a/lib/irc/parser/isupport.ex b/lib/irc/parser/isupport.ex
index 9dd7f30..dda4220 100644
--- a/lib/irc/parser/isupport.ex
+++ b/lib/irc/parser/isupport.ex
@@ -1,8 +1,17 @@
 defmodule Irc.Parser.Isupport do
   @moduledoc """
-  ISUPPORT list parser
+  ISUPPORT list parser.
   """
 
+  @typedoc "Server ISUPPORT."
+  @type t :: %{key => value}
+  @type key :: String.t
+  @type value :: true | Integer.t() | Map.t() | prefix_map
+
+  @type prefix :: String.t()
+  @type mode :: String.t()
+  @type prefix_map :: %{prefix() => mode()}
+
   def parse(list, acc \\ %{}) do
     list = List.flatten(list)
     Enum.reduce(list, acc, fn(entry, acc) ->
@@ -13,25 +22,36 @@ defmodule Irc.Parser.Isupport do
           else
             Map.put(acc, entry, true)
           end
-        [entry, value] -> Map.put(acc, entry, parse_value(value))
+        [entry, value] -> Map.put(acc, entry, parse_value(entry, value))
       end
     end)
   end
 
-  defp parse_value(value) do
+  defp parse_value(entry, value) do
     if String.contains?(value, ":") do
       Enum.reduce(String.split(value, ","), %{}, fn(key_and_value, acc) ->
         case String.split(key_and_value, ":", parts: 2) do
           [key] -> Map.put(acc, key, nil)
-          [key, value] -> Map.put(acc, key, format_value(value))
+          [key, value] -> Map.put(acc, key, format_value(key, value))
         end
       end)
     else
-        format_value(value)
+        format_value(entry, value)
+    end
+  end
+
+  def format_value("PREFIX", value) do
+    case String.split(value, ")", parts: 2) do
+      ["("<>modes, prefixes] ->
+        modes = String.split(modes, "", trim: true)
+        prefixes = String.split(prefixes, "", trim: true)
+        Enum.reduce(Enum.with_index(modes), %{}, fn({mode, position}, acc) ->
+          Map.put(acc, Enum.at(prefixes, position), mode)
+        end)
     end
   end
 
-  def format_value(value) do
+  def format_value(key, value) do
     case Integer.parse(value) do
       {i, ""} -> i
       _ -> value
diff --git a/lib/irc/parser/line.ex b/lib/irc/parser/line.ex
index 3ba2016..17c381c 100644
--- a/lib/irc/parser/line.ex
+++ b/lib/irc/parser/line.ex
@@ -1,24 +1,87 @@
 defmodule Irc.Parser.Line do
   @moduledoc """
-  IRC line parser
+  IRC line parser/encoder
   """
 
-  defstruct tags: %{}, source: nil, command: nil, args: []
+  @type t :: %__MODULE__{
+    tags: Map.t(),
+    source: Irc.Mask.t() | String.t() | nil,
+    command: String.t(),
+    args: list()
+  }
+  defstruct __private__: %{}, tags: %{}, source: nil, command: nil, args: []
 
+  @spec parse(string) :: t()
   @doc "Parse a server-to-client line."
   def parse(line) do
     {tags, rest} = parse_tags(line)
     {source, rest} = parse_source(rest)
     {command, rest} = parse_cmd(rest)
     args = parse_args(rest)
-    %__MODULE__{tags: tags, source: source, command: command, args: args}
+    private = %{
+      at: DateTime.utc_now()
+    }
+    %__MODULE__{__private__: private, tags: tags, source: source, command: command, args: args}
+  end
+
+  @spec encode(t()) :: String.t
+  @doc "Encode a line"
+  def encode(line = %__MODULE__{}, conn \\ %Irc.Connection{}) do
+    [line.source, line.tags, line.command, line.args]
+    src = if line.source, do: ":"<>to_string(line.source)
+    tags = Enum.reduce(line.tags, [], fn({k,v}, acc) -> ["#{k}=#{v}" | acc] end)
+                                                               |> Enum.join(";")
+    tags = if Enum.member?(conn.capabs || [], "message-tags") && tags != "", do: "@"<>tags
+    [tags, src, line.command, encode_args(line.args)]
+    |> Enum.filter(fn(x) -> x end)
+    |> Enum.join(" ")
+  end
+
+  def new(command, args \\ [], tags \\ %{}) do
+    %__MODULE__{command: command, args: args, tags: tags, __private__: %{at: DateTime.utc_now()}}
+  end
+
+  @doc "Returns the line date (server time if sent, otherwise, parse time)"
+  @spec at(t()) :: DateTime.t()
+  def at(%__MODULE__{__private__: %{at: at}, tags: %{"time" => server_time}}) do
+    case DateTime.from_iso8601(server_time) do
+      {:ok, date} -> date
+      _ -> at
+    end
+  end
+  def at(%__MODULE__{__private__: %{at: at}}), do: at
+  def at(_), do: nil
+
+  @spec to?(t(), Irc.Connection.t() | Irc.Mask.t() | Irc.User.t()) :: boolean
+  @doc "Returns true if the line is adressed to the connection."
+  def to?(%__MODULE__{args: [nick | _]}, %{__struct__: s, nick: nick}) when s in [Irc.Connection, Irc.Mask, Irc.User] do
+    true
   end
+  def to?(%__MODULE__{}, %{__struct__: s}) when s in [Irc.Connection, Irc.Mask, Irc.User], do: false
+
+  @spec self?(t(), Irc.Connection.t() | Irc.Mask.t() | Irc.User.t()) :: boolean
+  @doc "Returns true if the line source is the from the given connection/mask."
+  def self?(%__MODULE__{source: %Irc.Mask{nick: nick}}, %Irc.Connection{nick: nick}) do
+    true
+  end
+  def self?(%__MODULE__{source: mask = %Irc.Mask{}}, mask = %Irc.Mask{}) do
+    true
+  end
+  def self?(line = %__MODULE__{source: mask = %Irc.Mask{}}, user = %Irc.User{}) do
+    self?(line, Irc.User.to_mask(user))
+  end
+  def self?(%__MODULE__{source: nick}, %Irc.Connection{nick: nick}) do
+    true
+  end
+  def self?(%__MODULE__{}, %Irc.Connection{}), do: false
+  def self?(%__MODULE__{}, %Irc.User{}), do: false
+  def self?(%__MODULE__{}, %Irc.Mask{}), do: false
 
   # ARGS
 
-  def parse_args(input), do: parse_args(input, [])
+  defp parse_args(input), do: parse_args(input, [])
 
-  def parse_args(input, acc) do
+  defp parse_args(input, acc) do
     case parse_arg(input, []) do
       {:continue, new, rest} -> parse_args(rest, [new | acc])
       {:finished, new} ->
@@ -28,37 +91,37 @@ defmodule Irc.Parser.Line do
   end
 
   # Final argument is the only argument.
-  def parse_arg([?: | rest], acc) when length(acc) == 0 do
+  defp parse_arg([?: | rest], acc) when length(acc) == 0 do
     final = parse_final_arg(rest, [])
     {:finished, [final]}
   end
 
-  def parse_arg([0x20, ?: | rest], acc) do
+  defp parse_arg([0x20, ?: | rest], acc) do
     final = parse_final_arg(rest, [])
     {:finished, [final, acc]}
   end
 
-  def parse_arg([0x20 | rest], acc) do
+  defp parse_arg([0x20 | rest], acc) do
     {:continue, acc, rest}
   end
 
-  def parse_arg([char | rest], acc) do
+  defp parse_arg([char | rest], acc) do
     parse_arg(rest, [char | acc])
   end
 
-  def parse_arg([], acc) do
+  defp parse_arg([], acc) do
     {:finished, [acc]}
   end
 
-  def parse_final_arg([char | rest], acc) do
+  defp parse_final_arg([char | rest], acc) do
     parse_final_arg(rest, [char | acc])
   end
 
-  def parse_final_arg([], acc) do
+  defp parse_final_arg([], acc) do
     acc
   end
 
-  def format_args(list) when is_list(list) do
+  defp format_args(list) when is_list(list) do
     list
     |> Enum.map(fn(arg) -> String.trim(acc_to_str(arg)) end)
     |> Enum.reverse()
@@ -66,64 +129,69 @@ defmodule Irc.Parser.Line do
 
   # COMMAND
 
-  def parse_cmd(input), do: parse_cmd(input, [])
+  defp parse_cmd(input), do: parse_cmd(input, [])
 
-  def parse_cmd([0x20 | rest], acc) do
+  defp parse_cmd([0x20 | rest], acc) do
     {acc_to_str(acc), rest}
   end
 
-  def parse_cmd([char | rest], acc) do
+  defp parse_cmd([char | rest], acc) do
     parse_cmd(rest, [char | acc])
   end
 
   # SOURCE
 
-  def parse_source([?: | input]), do: parse_source(input, [])
-  def parse_source(input), do: {nil, input}
+  defp parse_source([?: | input]), do: parse_source(input, [])
+  defp parse_source(input), do: {nil, input}
 
-  def parse_source([0x20 | rest], acc) do
-    {acc_to_str(acc), rest}
+  defp parse_source([0x20 | rest], acc) do
+    string = acc_to_str(acc)
+    result = case Irc.Mask.parse(string) do
+      {:error, _} -> string
+      {:ok, mask} -> mask
+    end
+    {result, rest}
   end
-  def parse_source([char | rest], acc), do: parse_source(rest, [char | acc])
+  defp parse_source([char | rest], acc), do: parse_source(rest, [char | acc])
 
   # TAGS
 
-  def parse_tags([?@ | input]), do: parse_tags(input, [])
-  def parse_tags(input), do: {%{}, input}
+  defp parse_tags([?@ | input]), do: parse_tags(input, [])
+  defp parse_tags(input), do: {%{}, input}
 
-  def parse_tags(input, acc) do
+  defp parse_tags(input, acc) do
     case parse_tag(input) do
       {:continue, new, rest} -> parse_tags([new | acc], rest)
       {:finished, new, rest} -> {format_tags([new | acc]), rest}
     end
   end
 
-  def parse_tag(input) do
+  defp parse_tag(input) do
     parse_tag({[], nil}, input)
   end
 
-  def parse_tag({acc, nil}, [?= | rest]) do
+  defp parse_tag({acc, nil}, [?= | rest]) do
     parse_tag({acc, []}, rest)
   end
-  def parse_tag({acc, nil}, [?; | rest]) do
+  defp parse_tag({acc, nil}, [?; | rest]) do
     {:continue, {acc, true}, rest}
   end
-  def parse_tag({acc, nil}, [char | rest]) do
+  defp parse_tag({acc, nil}, [char | rest]) do
     parse_tag({[char | acc], nil}, rest)
   end
 
-  def parse_tag({key, acc}, [?; | rest]) do
+  defp parse_tag({key, acc}, [?; | rest]) do
     {:continue, {key, acc}, rest}
   end
 
-  def parse_tag({key, acc}, [0x20 | rest]) do
+  defp parse_tag({key, acc}, [0x20 | rest]) do
     {:finished, {key, acc}, rest}
   end
-  def parse_tag({key, acc}, [char | rest]) do
+  defp parse_tag({key, acc}, [char | rest]) do
     parse_tag({key, [char | acc]}, rest)
   end
 
-  def format_tags(list) do
+  defp format_tags(list) do
     list
     |> Enum.map(fn({k,v}) ->
       {acc_to_str(k), acc_to_str(v)}
@@ -131,13 +199,36 @@ defmodule Irc.Parser.Line do
     |> Enum.into(Map.new)
   end
 
-  def acc_to_str([]), do: nil
-  def acc_to_str(list) when is_list(list) do
+  defp acc_to_str([]), do: nil
+  defp acc_to_str(list) when is_list(list) do
     list
     |> Enum.reverse()
     |> to_string()
   end
-  def acc_to_str(other), do: other
+  defp acc_to_str(other), do: other
+
+
+  defp encode_args(args) do
+    encode_args(args, [])
+    |> Enum.reverse()
+    |> Enum.join(" ")
+  end
+
+  defp encode_args([arg], acc) do
+    [":"<>arg | acc]
+  end
+
+  defp encode_args([arg | rest], acc) do
+    encode_args(rest, [arg | acc])
+  end
+
+  defp encode_args([], acc), do: acc
+
+  defimpl String.Chars, for: __MODULE__ do
+    def to_string(line) do
+      Irc.Parser.Line.encode(line)
+    end
+  end
 
 end
 
diff --git a/lib/irc/parser/numeric.ex b/lib/irc/parser/numeric.ex
index 3a6e27f..413f13c 100644
--- a/lib/irc/parser/numeric.ex
+++ b/lib/irc/parser/numeric.ex
@@ -13,8 +13,9 @@ defmodule Irc.Parser.Numeric do
 
   defmacro __using__(_) do
     quote do
-      require Irc.Numeric
-      import Irc.Numeric
+      alias Irc.Parser.Numeric
+      require Irc.Parser.Numeric
+      import Irc.Parser.Numeric
     end
   end
 
diff --git a/lib/irc/parser/prefix.ex b/lib/irc/parser/prefix.ex
new file mode 100644
index 0000000..e446d7c
--- /dev/null
+++ b/lib/irc/parser/prefix.ex
@@ -0,0 +1,47 @@
+defmodule Irc.Parser.Prefix do
+
+  @moduledoc """
+  Parser for prefixes.
+
+  Supports multi-prefix.
+  """
+
+  @spec parse(String.t, Irc.Connection.t) :: {modes :: [String.t], rest :: nil | String.t}
+  @doc """
+  If `lax` is set to true, the parser will ignore chars until it meets a known prefix.
+  """
+  def parse(string, conn, lax \\ false) do
+    map = Map.get(conn.isupport, "PREFIX") || %{}
+    {prefixes, rest} = parse_prefix(string, Map.keys(map), lax)
+    modes = Enum.map(prefixes, fn(p) -> Map.get(map, p) end)
+            |> Enum.filter(fn(p) -> p end)
+    {Enum.reverse(modes), to_string(Enum.reverse(rest))}
+  end
+
+  defp parse_prefix(string, all_prefixes, lax) do
+    parse_prefix(to_charlist(string), to_charlist(all_prefixes), [], [], lax)
+  end
+
+  defp parse_prefix(all = [prefix | rest], all_prefixes, acc, ign, lax) do
+    prefix_str = to_string([prefix])
+    cond do
+      Enum.member?(all_prefixes, prefix_str) -> parse_prefix(rest, all_prefixes, [prefix_str | acc], ign, lax)
+      lax && acc == [] -> parse_prefix(rest, all_prefixes, acc, [prefix | ign], lax)
+      true -> parse_lax(all, acc, [])
+    end
+  end
+
+  defp parse_prefix([], _, acc, ign, _) do
+    {acc, ign}
+  end
+
+  defp parse_lax([a | rest], prefixes, acc) do
+    parse_lax(rest, prefixes, [a | acc])
+  end
+
+  defp parse_lax([], prefixes, acc) do
+    {prefixes, acc}
+  end
+
+end
+
diff --git a/lib/irc/sts.ex b/lib/irc/sts.ex
new file mode 100644
index 0000000..9980f8c
--- /dev/null
+++ b/lib/irc/sts.ex
@@ -0,0 +1,169 @@
+defmodule Irc.STS do
+  @moduledoc """
+  # STS Store.
+
+  When a connection encounters a STS policy, it signals it using `witness/4`. The store will consider the policy valid indefinitely as long as
+  any connection are still alive for that host/port pair. Once all connections or the system stops, the latest policy expiration date will be computed.
+
+  By default, the store is not persistent. If you wish to enable persistance, set the `:irc, :sts_cache_file` app environment.
+  """
+
+  @ets __MODULE__.ETS
+  # tuple {{host,port}, tls_port, period, until | true, at}
+
+  @doc "Lookup a STS entry"
+  @spec lookup(host :: String.t(), port :: Integer.t()) :: {enabled :: boolean, port :: Integer.t()}
+  def lookup(host,port) do
+    with \
+      [{_, port, period, until}] <- :ets.lookup(@ets, {host,port}),
+      true <- verify_validity(period, until)
+    do
+      {true, port}
+    else
+      [] -> {false, port}
+      false ->
+        GenServer.cast(__MODULE__, {:expired, {host,port}})
+        {false, port}
+    end
+  end
+
+  @doc """
+  Signal a STS policy.
+
+  The STS cache will consider the policy as infinitely valid as long as the calling PID is alive,
+  or signal a new `witness/4`.
+  """
+  def witness(host, port, sts_port, period) do
+    GenServer.call(__MODULE__, {:witness, host, port, sts_port, period, self()})
+  end
+
+  @doc """
+  Revoke a STS policy. This is the same as calling `witness/4` with sts_port = nil and period = nil.
+  """
+  def revoke(host, port) do
+    GenServer.call(__MODULE__, {:witness, {host,port,nil,nil,self()}})
+  end
+
+  @doc "Returns all entries in the STS store"
+  def all() do
+    fold = fn(el, acc) -> [el | acc] end
+    :ets.foldl(fold, @ets, [])
+  end
+
+  def start_link() do
+    GenServer.start_link(__MODULE__, [], [name: __MODULE__])
+  end
+
+  def init(_) do
+    ets = :ets.new(@ets, [:named_table, :protected])
+    cache_file = Application.get_env(:irc, :sts_cache_file)
+    dets = if cache_file do
+      {:ok, dets} = :dets.open_file(cache_file)
+      true = :ets.from_dets(ets, dets)
+    end
+    {:ok, %{ets: ets, dets: dets, map: %{}}}
+  end
+
+  def handle_continue(nil, state) do
+    {:noreply, state}
+  end
+  def handle_continue(_, state = %{dets: nil}) do
+    {:noreply, state}
+  end
+  def handle_continue({:write, entry}, state = %{dets: dets}) do
+    :ok = :dets.insert(dets, entry)
+    :ok = :dets.sync(dets)
+    {:noreply, state}
+  end
+  def handle_continue({:remove, key}, state = %{dets: dets}) do
+    :ok = :dets.delete(dets, key)
+    :ok = :dets.sync(dets)
+    {:noreply, state}
+  end
+
+  # Duration 0 -- Policy is removed
+  def handle_call({:witness, host, port, _tls_port, period, pid}, from, state) when period in ["0", 0, nil] do
+    state = remove({host,port}, state)
+    {:reply, :ok, state, {:handle_continue, {:remove, {host,port}}}}
+  end
+
+  # Witnessed policy.
+  # As long as caller PID is alive, consider the policy always valid
+  def handle_call({:witness, host, port, tls_port, period, pid}, _, state) do
+    entry = {{host,port}, tls_port, period, true}
+    :ets.insert(@ets, entry)
+    mon = Process.monitor(pid)
+    state = %{state | map: Map.put(state.map, pid, {mon,{host,port}})}
+    {:reply, :ok, state, {:handle_continue, {:write, entry}}}
+  end
+
+  # Caller side encountered an expired policy, check and remove it.
+  def handle_cast({:expired, key}, state) do
+    {state, continue} = case :ets.lookup(@ets, key) do
+      [{_, _, period, until}] ->
+        if !verify_validity(period, until) do
+          {remove(key, state), {:remove, key}}
+        else
+          {state, nil}
+        end
+      [] -> {state, nil}
+    end
+    {:noreply, state, {:handle_continue, continue}}
+  end
+
+  # A connection disconnected
+  def handle_info({:DOWN, _, :process, pid, _}, state) do
+    key = Map.get(state.map, pid)
+    others = Enum.filter(state.map, fn({p, {_,k}}) -> k == key && p != pid end)
+    state = %{state | map: Map.delete(state.map, pid)}
+    if key && Enum.empty?(others) do
+      case :ets.lookup(@ets, key) do
+        [{key, tls_port, period, until}] ->
+          until = DateTime.utc_now() |> DateTime.add(period)
+          entry = {key, tls_port, period, until}
+          :ets.insert(@ets, entry)
+          {:noreply, state, {:handle_continue, {:write, entry}}}
+        [] ->
+          {:noreply, state}
+      end
+    else
+      {:noreply, state}
+    end
+  end
+
+  # Calculate expiration periods from time of shutdown.
+  def terminate(_, state) do
+    if state.dets do
+      fold = fn
+        ({key, _tls_port, period, true}, acc) ->
+          until = DateTime.utc_now() |> DateTime.add(period)
+          [{key, until} | acc]
+        (_, acc) -> acc
+      end
+      for {key, until} <- :ets.foldl(fold, [], @ets) do
+        :ets.update_element(@ets, key, {4, until})
+      end
+      :ets.to_dets(@ets, state.dets)
+      :dets.close(state.dets)
+    end
+    :ok
+  end
+
+  # Remove an entry from ETS, demonitor related PIDs, and remove from map.
+  defp remove(key, state) do
+    :ets.delete(@ets, key)
+    pids = Enum.filter(state.map, fn({p, {mon,k}}) -> k == key end) |> Enum.map(fn({p, {mon,_}}) -> {p,mon} end)
+    for {_,mon} <- pids, do: Process.demonitor(mon, [:flush])
+    map = Enum.reduce(pids, state.map, fn({p,_}, map) -> Map.delete(map, p) end)
+    %{state | map: map}
+  end
+
+  defp verify_validity(_, true) do
+    true
+  end
+
+  defp verify_validity(_period, until) do
+    DateTime.utc_now() >= until
+  end
+
+end
diff --git a/lib/irc/user.ex b/lib/irc/user.ex
new file mode 100644
index 0000000..5e2f526
--- /dev/null
+++ b/lib/irc/user.ex
@@ -0,0 +1,46 @@
+defmodule Irc.User do
+
+  @moduledoc """
+  Represents an IRC user.
+
+  Not all field may be returned in events.
+  """
+
+  defstruct [
+    :nick,
+    :user,
+    :host,
+    :name,
+    :account,
+    :server,
+    :idle,
+    :away,
+    :connected_at,
+    {:operator, false},
+    {:modes, []},
+    {:chanmodes, %{}},
+    {:channels, []},
+  ]
+  @type t :: %__MODULE__{
+    nick: String.t(),
+    user: nil | String.t(),
+    host: nil | String.t(),
+    name: nil | String.t(),
+    account: nil | String.t(),
+    server: nil | String.t(),
+    idle: nil | {non_neg_integer(), NaiveDateTime.t()},
+    operator: boolean(),
+    modes: [],
+    channels: [],
+    chanmodes: %{String.t() => String.t()}
+  }
+
+  def from_mask(%Irc.Mask{user: user, nick: nick, host: host}) when is_binary(nick) do
+    %__MODULE__{nick: nick, user: user, host: host}
+  end
+
+  def to_mask(%__MODULE__{nick: nick, user: user, host: host}) do
+    Irc.Mask.new(nick, user, host)
+  end
+
+end
diff --git a/priv/numerics.txt b/priv/numerics.txt
index 2efb9e4..1a0522d 100644
--- a/priv/numerics.txt
+++ b/priv/numerics.txt
@@ -28,6 +28,7 @@
 312 RPL_WHOISSERVER
 313 RPL_WHOISOPERATOR
 314 RPL_WHOWASUSER
+315 RPL_ENDOFWHO
 317 RPL_WHOISIDLE
 318 RPL_ENDOFWHOIS
 319 RPL_WHOISCHANNELS
@@ -45,6 +46,7 @@
 348 RPL_EXCEPTLIST
 349 RPL_ENDOFEXCEPTLIST
 351 RPL_VERSION
+352 RPL_WHOREPLY
 353 RPL_NAMREPLY
 366 RPL_ENDOFNAMES
 367 RPL_BANLIST
diff --git a/test/mask_test.exs b/test/mask_test.exs
new file mode 100644
index 0000000..9a55e01
--- /dev/null
+++ b/test/mask_test.exs
@@ -0,0 +1,22 @@
+defmodule Irc.MaskTest do
+  use ExUnit.Case
+  alias Irc.Mask
+  doctest Irc.Mask
+
+  test "user mask" do
+    assert Mask.parse("nick!user@host") == {:ok,
+      %Mask{nick: "nick", user: "user", host: "host", server: nil}}
+  end
+
+  test "server mask" do
+    assert Mask.parse("masked.irc.server") == {:ok,
+      %Mask{server: "masked.irc.server", nick: nil, user: nil, host: nil}}
+  end
+
+  test "invalid masks" do
+    assert Mask.parse("bonjour") == {:error, :invalid_mask}
+    assert Mask.parse("bang!bang") == {:error, :invalid_mask}
+    assert Mask.parse("ding@dong") == {:error, :invalid_mask}
+  end
+
+end
diff --git a/test/parser/isupport_test.exs b/test/parser/isupport_test.exs
new file mode 100644
index 0000000..e8185b7
--- /dev/null
+++ b/test/parser/isupport_test.exs
@@ -0,0 +1,36 @@
+defmodule Irc.Parser.IsupportTest do
+  use ExUnit.Case
+  alias Irc.Parser.Isupport
+  doctest Irc.Parser.Isupport
+
+  test "flag" do
+    assert Isupport.parse(["WHOX"]) == %{"WHOX" => true}
+  end
+
+  test "k-v" do
+    assert Isupport.parse(["HELLO=WORLD"]) == %{"HELLO" => "WORLD"}
+  end
+
+  test "k-v, integer value" do
+    assert Isupport.parse(["RESPONSE=42"]) == %{"RESPONSE" => 42}
+  end
+
+  test "key with multiple values" do
+    assert Isupport.parse(["TARGMAX=NAMES:1,MONITOR:,NOTICE:4"]) == %{
+      "TARGMAX" => %{
+        "NAMES" => 1,
+        "MONITOR" => "",
+        "NOTICE" => 4
+      }
+    }
+  end
+
+  test "PREFIX" do
+    assert Isupport.parse(["PREFIX=(ovh)@+%"]) == %{
+      "PREFIX" => %{
+        "%" => "h", "+" => "v", "@" => "o"
+      }
+    }
+  end
+
+end
diff --git a/test/parser/line_parser.exs b/test/parser/line_parser.exs
deleted file mode 100644
index efa0194..0000000
--- a/test/parser/line_parser.exs
+++ /dev/null
@@ -1,45 +0,0 @@
-defmodule Irc.Parser.LineTest do
-  use ExUnit.Case
-  alias Irc.Parser.Line
-  doctest Irc.Parser.Line
-
-  test "isupport" do
-    line = ':nowhere 005 hrhrhr TOPICLEN=390 TARGMAX=NAMES:1,MONITOR: EXTBAN=$,acjorsxz CLIENTVER=3.0 :are supported by this server'
-           |> Line.parse()
-    assert line.source == "nowhere"
-    assert line.command == "005"
-    assert line.args == ["hrhrhr", "TOPICLEN=390", "TARGMAX=NAMES:1,MONITOR:", "EXTBAN=$,acjorsxz", "CLIENTVER=3.0", "are supported by this server"]
-  end
-
-  test "auth notice" do
-    line = ':zoidberg.chatspike.net NOTICE Auth :Welcome to ChatSpike!'
-           |> Line.parse()
-    assert line.source == "zoidberg.chatspike.net"
-    assert line.command =="NOTICE"
-    assert line.args == ["Auth", "Welcome to ChatSpike!"]
-  end
-
-  test "connect notice" do
-    line = ':livingstone.freenode.net NOTICE * :*** Checking Ident'
-    |> Line.parse()
-    assert line.command == "NOTICE"
-    assert line.source == "livingstone.freenode.net"
-    assert line.args == ["*", "*** Checking Ident"]
-  end
-
-  test "numeric" do
-    line = ':stitch.chatspike.net 042 derp ABCDEFGHI :your unique ID'
-           |> Line.parse
-    assert line.source == "stitch.chatspike.net"
-    assert line.command == "042"
-    assert line.args == ["derp", "ABCDEFGHI", "your unique ID"]
-  end
-
-  test "ping" do
-    line = 'PING :bender.chatspike.net'
-           |> Line.parse
-    assert line.command == "PING"
-    assert line.args == ["bender.chatspike.net"]
-  end
-
-end
diff --git a/test/parser/line_test.exs b/test/parser/line_test.exs
new file mode 100644
index 0000000..242e5b0
--- /dev/null
+++ b/test/parser/line_test.exs
@@ -0,0 +1,87 @@
+defmodule Irc.Parser.LineTest do
+  use ExUnit.Case
+  alias Irc.Parser.Line
+  alias Irc.Mask
+  doctest Irc.Parser.Line
+
+  test "isupport" do
+    str = ':nowhere 005 hrhrhr TOPICLEN=390 TARGMAX=NAMES:1,MONITOR: EXTBAN=$,acjorsxz CLIENTVER=3.0 :are supported by this server'
+    line = Line.parse(str)
+    assert line.source == "nowhere"
+    assert line.command == "005"
+    assert line.args == ["hrhrhr", "TOPICLEN=390", "TARGMAX=NAMES:1,MONITOR:", "EXTBAN=$,acjorsxz", "CLIENTVER=3.0", "are supported by this server"]
+    assert Line.encode(line) == to_string(str)
+  end
+
+  test "auth notice" do
+    str = ':zoidberg.chatspike.net NOTICE Auth :Welcome to ChatSpike!'
+    line = Line.parse(str)
+    assert line.source == %Mask{server: "zoidberg.chatspike.net"}
+    assert line.command =="NOTICE"
+    assert line.args == ["Auth", "Welcome to ChatSpike!"]
+    assert Line.encode(line) == to_string(str)
+  end
+
+  test "connect notice" do
+    str = ':livingstone.freenode.net NOTICE * :*** Checking Ident'
+    line = Line.parse(str)
+    assert line.command == "NOTICE"
+    assert line.source == %Mask{server: "livingstone.freenode.net"}
+    assert line.args == ["*", "*** Checking Ident"]
+    assert Line.encode(line) == to_string(str)
+  end
+
+  test "numeric" do
+    str = ':stitch.chatspike.net 042 derp ABCDEFGHI :your unique ID'
+    line = Line.parse(str)
+    assert line.source == %Mask{server: "stitch.chatspike.net"}
+    assert line.command == "042"
+    assert line.args == ["derp", "ABCDEFGHI", "your unique ID"]
+    assert Line.encode(line) == to_string(str)
+  end
+
+  test "ping" do
+    str = 'PING :bender.chatspike.net'
+    line = Line.parse(str)
+    assert line.command == "PING"
+    assert line.args == ["bender.chatspike.net"]
+    assert Line.encode(line) == to_string(str)
+  end
+
+  test "tags" do
+    str = '@lol=dongs :href PRIVMSG #dongs :dongs dongs dongs'
+    line = Line.parse(str)
+    assert line.tags == %{"lol" => "dongs"}
+    refute Line.encode(line) == to_string(str)
+    assert Line.encode(line, %Irc.Connection{capabs: ["message-tags"]}) == to_string(str)
+  end
+
+  test "self?" do
+    line = Line.parse(':href!href@sade.random.sh PRIVMSG #dongs')
+    line2 = Line.parse(':blep PRIVMSG #blep')
+    mask = %Irc.Mask{nick: "href", user: "href", host: "sade.random.sh"}
+    user = Irc.User.from_mask(mask)
+    conn = %Irc.Connection{nick: "href"}
+    assert Line.self?(line, mask)
+    assert Line.self?(line, user)
+    assert Line.self?(line, conn)
+    refute Line.self?(line2, mask)
+    refute Line.self?(line2, user)
+    refute Line.self?(line2, conn)
+  end
+
+  test "to?" do
+    line = Line.parse(':sade.irc.random.sh 332 href #dongs :lol')
+    line2 = Line.parse(':sade.random.sh 332 blep')
+    mask = %Irc.Mask{nick: "href", user: "href", host: "sade.random.sh"}
+    user = Irc.User.from_mask(mask)
+    conn = %Irc.Connection{nick: "href"}
+    assert Line.to?(line, mask)
+    assert Line.to?(line, user)
+    assert Line.to?(line, conn)
+    refute Line.to?(line2, mask)
+    refute Line.to?(line2, user)
+    refute Line.to?(line2, conn)
+  end
+
+end
diff --git a/test/parser/prefix_test.exs b/test/parser/prefix_test.exs
new file mode 100644
index 0000000..bea651f
--- /dev/null
+++ b/test/parser/prefix_test.exs
@@ -0,0 +1,39 @@
+defmodule Irc.Parser.PrefixTest do
+  use ExUnit.Case
+  alias Irc.Parser.Prefix
+  doctest Irc.Parser.Prefix
+
+
+  @conn %Irc.Connection{isupport: %{"PREFIX" => %{"@" => "o", "+" => "v"}}}
+
+  test "who flags (lax)" do
+    assert Prefix.parse("H*@", @conn, true) == {["o"], "H*"}
+  end
+
+  test "lax, multiple" do
+    assert Prefix.parse("H*@+", @conn, true) == {["o", "v"], "H*"}
+    assert Prefix.parse("H*@+", @conn) == {[], "H*@+"}
+  end
+
+  test "not lax" do
+    assert Prefix.parse("@href", @conn) == {["o"], "href"}
+  end
+
+  test "not lax, multiple" do
+    assert Prefix.parse("@+href", @conn) == {["o", "v"], "href"}
+  end
+
+  test "not lax, prefix char in rest" do
+    assert Prefix.parse("@hr@f", @conn) == {["o"], "hr@f"}
+  end
+
+  test "no prefix, not lax" do
+    assert Prefix.parse("href", @conn) == {[], "href"}
+  end
+
+  test "no prefix, lax" do
+    assert Prefix.parse("href", @conn, true) == {[], "href"}
+  end
+
+
+end
-- 
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