class Paperclip::Validators::AttachmentFileNameValidator

def self.helper_method_name
  :validates_attachment_file_name
end

def allowed
  [options[:matches]].flatten.compact
end

def check_validity!
  unless options.has_key?(:matches) || options.has_key?(:not)
    raise ArgumentError, "You must pass in either :matches or :not to the validator"
  end
end

def forbidden
  [options[:not]].flatten.compact
end

def initialize(options)
  options[:allow_nil] = true unless options.has_key?(:allow_nil)
  super
end

def mark_invalid(record, attribute, patterns)
  record.errors.add attribute, :invalid, options.merge(:names => patterns.join(', '))
end

def validate_blacklist(record, attribute, value)
  if forbidden.present? && forbidden.any? { |type| type === value }
    mark_invalid record, attribute, forbidden
  end
end

def validate_each(record, attribute, value)
  base_attribute = attribute.to_sym
  attribute = "#{attribute}_file_name".to_sym
  value = record.send :read_attribute_for_validation, attribute
  return if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
  validate_whitelist(record, attribute, value)
  validate_blacklist(record, attribute, value)
  if record.errors.include? attribute
    record.errors[attribute].each do |error|
      record.errors.add base_attribute, error
    end
  end
end

def validate_whitelist(record, attribute, value)
  if allowed.present? && allowed.none? { |type| type === value }
    mark_invalid record, attribute, allowed
  end
end