require "net/http/persistent"
require "yajl"
require "nokogiri"

class Hugs
  Headers = {
    :json => "application/json",
    :xml  => "application/xml",
  }.freeze

  Verbs = %w(get delete post put).freeze

  ##
  # Required options:
  #   +host+: A String with the host to connect.
  # Optional:
  #   +user+: A String containing the username for use in HTTP Basic auth.
  #   +password+: A String containing the password for use in HTTP Basic auth.
  #   +port+: An Integer containing the port to connect.
  #   +scheme+: A String containing the HTTP scheme.

  def initialize options
    @user     = options[:user]
    @password = options[:password]
    @host     = options[:host]
    @port     = options[:port]   || 80
    @scheme   = options[:scheme] || "https"
    @type     = options[:type]   || :json
  end

  ##
  # Perform an HTTP get, delete, post, or put.
  # +path+: A String with the path to the HTTP resource.
  # +params+: A Hash with the following keys:
  #   - +:query+: Query String in the format "foo=bar"
  #   - +:body+: A sub Hash to be JSON encoded, and  posted in
  #     the message body.

  Verbs.each do |verb|
    define_method verb do |*args|
      path   = args[0]
      params = args[1] || {}
      clazz  = eval "Net::HTTP::#{verb.capitalize}"

      response      = response_for(clazz, path, params)
      response.body = parse response.body
      response
    end
  end

  ##
  # :method: get

  ##
  # :method: delete

  ##
  # :method: post

  ##
  # :method: put

private
  ##
  # Worker method to be called by #get, #delete, #post, #put.
  # Method arguments have been documented in the callers.

  def response_for request, path, params
    query = params[:query] && params.delete(:query)
    body  = params[:body] && params.delete(:body)

    @http ||= Net::HTTP::Persistent.new
    @url  ||= URI.parse "#{@scheme}://#{@host}:#{@port}"

    request      = request.new [path, query].compact.join "?"
    request.body = encode(body) if body
    common_headers request

    @http.request(@url, request)
  end

  def common_headers request
    request.basic_auth(@user, @password) if requires_authentication?
    case request.class.to_s
      when Net::HTTP::Get.to_s, Net::HTTP::Delete.to_s
        request.add_field "accept", Headers[@type]
      when Net::HTTP::Post.to_s, Net::HTTP::Put.to_s
        request.add_field "accept", Headers[@type]
        request.add_field "content-type", Headers[@type]
    end
  end

  def parse data
    if is_json?
      Yajl::Parser.parse data
    elsif is_xml?
      Nokogiri::XML.parse data
    end
  end

  def encode body
    is_json? ? (Yajl::Encoder.encode body) : body
  end

  def requires_authentication?
    @user && @password
  end

  def is_xml?
    @type == :xml
  end

  def is_json?
    @type == :json
  end
end