module MethodHooks

# File lib/method_hooks.rb, line 8
def self.extended(base)
  base.send :include, InstanceMethods
end

# File lib/method_hooks.rb, line 85
def after(*method_names, &block)
  if block.nil?
    callback_method = method_names.pop
    block = proc { method(callback_method).call }
  end

  method_names.each do |method_name|
    after_callbacks[method_name] << block
  end

  subclasses.each do |subclass|
    subclass.after(method_names, &block)
  end
end

# File lib/method_hooks.rb, line 51
def after_callbacks
  @after_callbacks ||= Hash.new { |hash, key| hash[key] = Array.new }
end

# File lib/method_hooks.rb, line 70
def around(*method_names, &block)
  if block.nil?
    callback_method = method_names.pop
    block = proc { |method| method(callback_method).call(method) }
  end

  method_names.each do |method_name|
    around_callbacks[method_name] << block
  end

  subclasses.each do |subclass|
    descendant.around(method_names, &block)
  end
end

# File lib/method_hooks.rb, line 47
def around_callbacks
  @around_callbacks ||= Hash.new { |hash, key| hash[key] = Array.new }
end

# File lib/method_hooks.rb, line 55
def before(*method_names, &block)
  if block.nil?
    callback_method = method_names.pop
    block = proc { method(callback_method).call }
  end

  method_names.each do |method_name|
    before_callbacks[method_name] << block
  end

  subclasses.each do |subclass|
    descendant.before(method_names, &block)
  end
end

# File lib/method_hooks.rb, line 43
def before_callbacks
  @before_callbacks ||= Hash.new { |hash, key| hash[key] = Array.new }
end

# File lib/method_hooks.rb, line 14
def inherited(child_class)
  child_class.instance_variable_set(:@new_method, true)
  child_class.instance_variable_set(:@before_callbacks, before_callbacks.deep_dup)
  child_class.instance_variable_set(:@around_callbacks, around_callbacks.deep_dup)
  child_class.instance_variable_set(:@after_callbacks, after_callbacks.deep_dup)

  super
end

# File lib/method_hooks.rb, line 23
def method_added(method_name)
  super
  return if @new_method == false || [:initialize, :call_before_callbacks, :call_around_callbacks, :call_after_callbacks].include?(method_name)

  method = instance_method(method_name)
  undef_method(method_name)

  @new_method = false

  define_method(method_name) do |*args, &block|
    call_before_callbacks(method_name)
    return_value = call_around_callbacks(method_name) { method.bind(self).call(*args, &block) }
    call_after_callbacks(method_name)

    return_value
  end

  @new_method = true
end