Come up with a basic plugin outline

lib/drill.rb

@@ -0,0 +1,32 @@
+class Drill
+  attr_reader :channel
+
+  def initialize(channel)
+    @channel = channel
+    @started = false
+  end
+
+  def start!
+    @started = true
+  end
+
+  def started?
+    @started
+  end
+
+  def exists?
+    true
+  end
+
+  class Empty < Drill
+    def initialize
+      super(nil)
+    end
+
+    def start!; end
+
+    def exists?
+      false
+    end
+  end
+end

lib/drill_plugin.rb

@@ -0,0 +1,73 @@
+require_relative "drill"
+
+class DrillPlugin
+  COMMANDS = %w[
+    init
+    start
+    end
+  ]
+
+  attr_reader :bot, :drills
+
+  def initialize(bot)
+    @bot = bot
+    @drills = Hash.new { Drill::Empty.new } 
+  end
+
+  def handle_message(message)
+    puts "[#{self.class.name}] Handling \"#{message.content}\" from #{message.author.display_name}"
+    command = strip_prefix(message.content).split.first
+    p command
+    if command.nil? || command == "" || command == "help" || command == "!drill"
+      handle_help message
+    elsif COMMANDS.include? command
+      drill = drills[message.channel.id]
+      send("handle_#{command}", message, drill)
+    else
+      message.respond "Unknown command #{command}"
+    end
+  end
+
+  def handle_init(message, drill)
+    if drill.exists?
+      message.respond "You've already got a drill running in this channel"
+    else
+      drills[message.channel.id] = Drill.new message.channel
+      message.respond "New drill created!"
+    end
+  end
+
+  def handle_start(message, drill)
+    if drill.started?
+      message.respond "This drill has already started!"
+    elsif drill.exists?
+      drill.start!
+      message.respond "Drill started!"
+    else
+      message.respond "You have to `!drill init` before you can start the drill"
+    end
+  end
+
+  def handle_end(message, drill)
+    if !drill.exists?
+      message.respond "There's no drill to end"
+    elsif drill.started?
+      drills.delete message.channel.id
+      message.respond "Ending the drill now!"
+    else
+      message.respond "You have to `!drill start` before you can end the drill"
+    end
+  end
+
+  def handle_help(message)
+    message.respond "Insert help message here"
+  end
+
+  def strip_prefix(content)
+    if content.start_with? "!drill"
+      content.sub("!drill ", "")
+    else
+      content
+    end
+  end
+end

lib/ika.rb

@@ -1,11 +1,13 @@
 require_relative './session'
 require_relative './lesson'
 require_relative './commands'
+require_relative './drill_plugin'
 
 class Ika
   attr_reader :bot
   attr_reader :lessons, :sessions
   attr_accessor :current_lesson, :current_session
+  attr_reader :drill_plugin
 
   def initialize(bot)
     @bot = bot
@@ -13,6 +15,7 @@ class Ika
     @sessions = {}
     @current_session = nil
     @current_lesson = Lesson.new
+    @drill_plugin = DrillPlugin.new(self)
   end
 
   def start!
@@ -46,6 +49,10 @@ class Ika
       command.execute
     end
 
+    if message.content.start_with? "!drill"
+      drill_plugin.handle_message message
+    end
+
     return current_session&.respond_to message
   end
 end