class Shoulda::Matchers::ActiveModel::ValidationMatcher

def allow_value_matcher(value, message)
  matcher = AllowValueMatcher.new(value).for(@attribute).
    with_message(message)
  if defined?(@context)
    matcher.on(@context)
  end
  if strict?
    matcher.strict
  end
  matcher
end

def allows_value_of(value, message = nil, &block)
  allow = allow_value_matcher(value, message)
  yield allow if block_given?
  if allow.matches?(@subject)
    @failure_message_when_negated = allow.failure_message_when_negated
    true
  else
    @failure_message = allow.failure_message
    false
  end
end

def disallow_value_matcher(value, message)
  matcher = DisallowValueMatcher.new(value).for(@attribute).
    with_message(message)
  if defined?(@context)
    matcher.on(@context)
  end
  if strict?
    matcher.strict
  end
  matcher
end

def disallows_value_of(value, message = nil, &block)
  disallow = disallow_value_matcher(value, message)
  yield disallow if block_given?
  if disallow.matches?(@subject)
    @failure_message_when_negated = disallow.failure_message_when_negated
    true
  else
    @failure_message = disallow.failure_message
    false
  end
end

def failure_message_when_negated
  @failure_message_when_negated || @failure_message
end

def initialize(attribute)
  @attribute = attribute
  @strict = false
  @failure_message = nil
  @failure_message_when_negated = nil
end

def matches?(subject)
  @subject = subject
  false
end

def on(context)
  @context = context
  self
end

def strict
  @strict = true
  self
end

def strict?
  @strict
end