class Roadie::NetHttpProvider

def access_granted_to?(host)
  whitelist.empty? || whitelist.include?(host)
end

def download(url)
  url = "https:#{url}" if url.start_with?("//")
  uri = URI.parse(url)
  if access_granted_to?(uri.host)
    get_response(uri)
  else
    raise CssNotFound.new(
      css_name: url,
      message: "#{uri.host} is not part of whitelist!",
      provider: self
    )
  end
end

def find_stylesheet(url)
  find_stylesheet!(url)
rescue CssNotFound
  nil
end

def find_stylesheet!(url)
  response = download(url)
  if response.is_a? Net::HTTPSuccess
    Stylesheet.new(url, response_body(response))
  else
    raise CssNotFound.new(
      css_name: url,
      message: "Server returned #{response.code}: #{truncate response.body}",
      provider: self
    )
  end
rescue Timeout::Error
  raise CssNotFound.new(css_name: url, message: "Timeout", provider: self)
end

def get_response(uri)
  if RUBY_VERSION >= "2.0.0"
    Net::HTTP.get_response(uri)
  else
    Net::HTTP.start(uri.host, uri.port, use_ssl: (uri.scheme == "https")) do |http|
      http.request(Net::HTTP::Get.new(uri.request_uri))
    end
  end
end

def host_set(hosts)
  hosts.each { |host| validate_host(host) }.to_set
end

def initialize(options = {})
  @whitelist = host_set(Array(options.fetch(:whitelist, [])))
end

def inspect
  "#<#{self.class} whitelist: #{whitelist.inspect}>"
end

def response_body(response)
  # Make sure we respect encoding because Net:HTTP will encode body as ASCII by default
  # which will break if the response is not compatible.
  supplied_charset = response.type_params["charset"]
  body = response.body
  if supplied_charset
    body.force_encoding(supplied_charset).encode!("UTF-8")
  else
    # Default to UTF-8 when server does not specify encoding as that is the
    # most common charset.
    body.force_encoding("UTF-8")
  end
end

def to_s
  inspect
end

def truncate(string)
  if string.length > 50
    string[0, 49] + "…"
  else
    string
  end
end

def validate_host(host)
  if host.nil? || host.empty? || host == "." || host.include?("/")
    raise ArgumentError, "#{host.inspect} is not a valid hostname"
  end
end