require 'eventmachine'
require 'ostruct'

module IRCClient
  class Message
    attr_reader :client, :raw, :hostmask, :nick, :hostname, :ident, :sender, :command, :rarg, :arguments

    def initialize(client)
      @client = client
    end

    def parse!(line)
      @raw = line
      words = line.chomp.split(" ")
      if words[0][0] == ":"
        @hostmask = words[0][1..-1]
        @nick = @hostmask.split("!", 2).first
        @hostname = @hostmask.split("@", 2).last
        @ident = @hostmask.split("!", 2).last.split("@", 2).first
        @sender = client.find_user(@nick, @ident, @hostname)
        @command = words[1]
        @rarg = words[2..-1].join(" ")
      else
        @sender = @nick = @hostname = @hostmask = @ident = nil
        @command = words[0]
        @rarg = words[1..-1].join(" ")
      end
      @arguments = @rarg.split(" ")
      i = @arguments.find_index {|a| a[0] == ":" }
      @arguments[i..-1] = @arguments[i..-1].join(" ")[1..-1] if i
    end
  end

  def initialize(*args)
    super
    @buffer = BufferedTokenizer.new("\r\n")
  end

  def post_init
    puts "[CLIENT] Registering"
    send_frame "NICK", "Lime"
    send_frame "USER", "lime", "*", "*", ":Lime, the IRC bot"
    puts "[CLIENT] Registered"
  end

  def send_frame(command, *arguments)
    puts "[CLIENT] Sent: #{command} #{arguments.join(" ")}"
    send_data "#{command} #{arguments.join(" ")}\r\n"
  end

  def privmsg(to, msg)
    to = to.nick if to.respond_to?(:nick)
    send_frame "PRIVMSG", to, ":"+msg
  end

  def join(channel)
    send_frame "JOIN", channel
  end

  def receive_data(data)
    @buffer.extract(data).each do |line|
      receive_line(line.chomp)
    end
  rescue StandardError => e
    receive_error(e.to_s)
    close_connection
    return
  end

  def receive_line(line)
    @irc_message = Message.new(self)
    @irc_message.parse!(line)

    puts "[CLIENT] Received: #{@irc_message.raw}"

    case @irc_message.command
    when 'PING'
      send_frame "PONG", @irc_message.rarg
    when 'INVITE'
      join(@irc_message.arguments[1])
      privmsg(@irc_message.arguments[1], "#{@irc_message.nick}: Thanks for inviting me!")
    end
  end

  def receive_error(error)
    puts "[CLIENT] {ERROR} #{error}"
  end

  def unbind
    puts "[CLIENT] Connection lost"
    EventMachine.stop_event_loop
  end

  def find_user(nick, ident=nil, hostname=nil)
    @users ||= {}
    user = @users[nick.downcase]
    return user unless ident || hostname
    if user && user.nick == nick && user.ident == ident && user.hostname == hostname
      return user
    else
      user = OpenStruct.new
      user.nick = nick
      user.ident = ident
      user.hostname = hostname
      @users[nick.downcase] = user
      return user
    end
  end
end

EventMachine.run do
  EventMachine.connect("irc.cluenet.org", 6667, IRCClient)
end