class Shoulda::Matchers::ActionController::SetSessionMatcher

def assigned_correct_value?
  if assigned_value?
    if @value.nil?
      true
    else
      assigned_value == @value
    end
  end
end

def assigned_value
  session[@key]
end

def assigned_value?
  !assigned_value.nil?
end

def cleared_value?
  defined?(@value) && @value.nil? && assigned_value.nil?
end

def description
  description = "set session variable #{@key.inspect}"
  if @value
    description << " to #{@value.inspect}"
  end
  description
end

def expectation
  expectation = "session variable #{@key} to be set"
  if @value
    expectation << " to #{@value.inspect}"
  end
end

def failure_message_for_should
  "Expected #{expectation}, but #{result}"
end

def failure_message_for_should_not
  "Didn't expect #{expectation}, but #{result}"
end

def in_context(context)
  @context = context
  self
end

def initialize(key)
  @key = key.to_s
end

def matches?(controller)
  @controller = controller
  if @value_block
    @value = @context.instance_eval(&@value_block)
  end
  assigned_correct_value? || cleared_value?
end

def result
  if session.empty?
    'no session variables were set'
  else
    "the session was #{session.inspect}"
  end
end

def session
  if @controller.request.respond_to?(:session)
    @controller.request.session.to_hash
  else
    @controller.response.session.data
  end
end

def to(value = nil, &block)
  @value = value
  @value_block = block
  self
end