module Typhoeus

  # This is a Factory for easies to be used in the hydra.
  # Before an easy is ready to be added to a multi the
  # on_complete callback to be set.
  # This is done by this class.
  #
  # @api private
  class EasyFactory

    # Returns the request provided.
    #
    # @return [ Typhoeus::Request ]
    attr_reader :request

    # Returns the hydra provided.
    #
    # @return [ Typhoeus::Hydra ]
    attr_reader :hydra

    # Create an easy factory.
    #
    # @example Create easy factory.
    #   Typhoeus::Hydra::EasyFactory.new(request, hydra)
    #
    # @param [ Request ] request The request to build an easy for.
    # @param [ Hydra ] hydra The hydra to build an easy for.
    def initialize(request, hydra = nil)
      @request = request
      @hydra = hydra
    end

    # Return the easy in question.
    #
    # @example Return easy.
    #   easy_factory.easy
    #
    # @return [ Ethon::Easy ] The easy.
    def easy
      @easy ||= Typhoeus::Pool.get
    end

    # Fabricated easy.
    #
    # @example Prepared easy.
    #   easy_factory.get
    #
    # @return [ Ethon::Easy ] The easy.
    def get
      begin
        easy.http_request(
          request.base_url,
          request.options.fetch(:method, :get),
          sanitize(request.options)
        )
      rescue Ethon::Errors::InvalidOption => e
        help = provide_help(e.message.match(/:\s(\w+)/)[1])
        raise $!, "#{$!}#{help}", $!.backtrace
      end
      set_callback
      easy
    end

    private

    def sanitize(options)
      sanitized = {}
      request.options.each do |k,v|
        next if [:method, :cache_ttl].include?(k.to_sym)
        if new_option = renamed_options[k.to_sym]
          warn("Deprecated option #{k}. Please use #{new_option} instead.")
          sanitized[new_option] = v
        else
          sanitized[k] = v
        end
      end
      sanitized
    end

    # Sets on_complete callback on easy in order to be able to
    # track progress.
    #
    # @example Set callback.
    #   easy_factory.set_callback
    #
    # @return [ Ethon::Easy ] The easy.
    def set_callback
      if request.streaming?
        response = nil
        easy.on_headers do |easy|
          response = Response.new(Ethon::Easy::Mirror.from_easy(easy).options)
          request.execute_headers_callbacks(response)
        end
        easy.on_body do |chunk, easy|
          request.on_body.each do |callback|
            callback.call(chunk, response)
          end
        end
      else
        easy.on_headers do |easy|
          request.execute_headers_callbacks(Response.new(Ethon::Easy::Mirror.from_easy(easy).options))
        end
      end
      easy.on_complete do |easy|
        request.finish(Response.new(easy.mirror.options))
        Typhoeus::Pool.release(easy)
        if hydra && !hydra.queued_requests.empty?
          hydra.dequeue
        end
      end
    end

    def renamed_options
      {
        :auth_method => :httpauth,
        :connect_timeout => :connecttimeout,
        :encoding => :accept_encoding,
        :follow_location => :followlocation,
        :max_redirects => :maxredirs,
        :proxy_type => :proxytype,
        :ssl_cacert => :cainfo,
        :ssl_capath => :capath,
        :ssl_cert => :sslcert,
        :ssl_cert_type => :sslcerttype,
        :ssl_key => :sslkey,
        :ssl_key_password => :keypasswd,
        :ssl_key_type => :sslkeytype,
        :ssl_version => :sslversion,
      }
    end

    def changed_options
      {
        :disable_ssl_host_verification => :ssl_verifyhost,
        :disable_ssl_peer_verification => :ssl_verifypeer,
        :proxy_auth_method => :proxyauth,
      }
    end

    def removed_options
      [:cache_key_basis, :cache_timeout, :user_agent]
    end

    def provide_help(option)
      if new_option = changed_options[option.to_sym]
        "\nPlease try #{new_option} instead of #{option}." if new_option
      elsif removed_options.include?(option.to_sym)
        "\nThe option #{option} was removed."
      end
    end
  end
end