# encoding: utf-8

require "amq/protocol/client"
require "uri"

module AMQP
  # @see AMQP::Settings.configure
  module Settings
    # @private
    AMQP_PORTS = {"amqp" => 5672, "amqps" => 5671}.freeze

    # @private
    AMQPS = "amqps".freeze

    # Default connection settings used by AMQ clients
    #
    # @see AMQP::Settings.configure
    def self.default
      @default ||= {
        # server
        :host  => "127.0.0.1",
        :port  => AMQ::Protocol::DEFAULT_PORT,

        # login
        :user           => "guest",
        :pass           => "guest",
        :auth_mechanism => "PLAIN",
        :vhost          => "/",

        # connection timeout
        :timeout => nil,

        # logging
        :logging => false,

        # ssl
        :ssl => false,

        :frame_max => 131072,
        :heartbeat => 0
      }
    end

    CLIENT_PROPERTIES = {
      :platform    => ::RUBY_DESCRIPTION,
      :product     => "amqp gem",
      :information => "http://github.com/ruby-amqp/amqp",
      :version     => AMQP::VERSION
    }

    def self.client_properties
      @client_properties ||= CLIENT_PROPERTIES
    end


    # Merges given configuration parameters with defaults and returns
    # the result.
    #
    # @param [Hash] Configuration parameters to use.
    #
    # @option settings [String] :host ("127.0.0.1") Hostname AMQ broker runs on.
    # @option settings [String] :port (5672) Port AMQ broker listens on.
    # @option settings [String] :vhost ("/") Virtual host to use.
    # @option settings [String] :user ("guest") Username to use for authentication.
    # @option settings [String] :pass ("guest") Password to use for authentication.
    # @option settings [String] :ssl (false) Should be use TLS (SSL) for connection?
    # @option settings [String] :timeout (nil) Connection timeout.
    # @option settings [String] :logging (false) Turns logging on or off.
    # @option settings [String] :broker (nil) Broker name (use if you intend to use broker-specific features).
    # @option settings [Fixnum] :frame_max (131072) Maximum frame size to use. If broker cannot support frames this large, broker's maximum value will be used instead.
    #
    # @return [Hash] Merged configuration parameters.
    def self.configure(settings = nil)
      case settings
      when Hash then
        settings = Hash[settings.map {|k, v| [k.to_sym, v] }] # symbolize keys
        if username = settings.delete(:username)
          settings[:user] ||= username
        end

        if password = settings.delete(:password)
          settings[:pass] ||= password
        end


        self.default.merge(settings)
      when String then
        settings = self.parse_amqp_url(settings)
        self.default.merge(settings)
      when NilClass then
        self.default
      end
    end

    # Parses AMQP connection URI and returns its components as a hash.
    #
    # h2. vhost naming schemes
    #
    # It is convenient to be able to specify the AMQP connection
    # parameters as a URI string, and various "amqp" URI schemes
    # exist.  Unfortunately, there is no standard for these URIs, so
    # while the schemes share the basic idea, they differ in some
    # details.  This implementation aims to encourage URIs that work
    # as widely as possible.
    #
    # The URI scheme should be "amqp", or "amqps" if SSL is required.
    #
    # The host, port, username and password are represented in the
    # authority component of the URI in the same way as in http URIs.
    #
    # The vhost is obtained from the first segment of the path, with the
    # leading slash removed.  The path should contain only a single
    # segment (i.e, the only slash in it should be the leading one).
    # If the vhost is to include slashes or other reserved URI
    # characters, these should be percent-escaped.
    #
    # @example How vhost is parsed
    #
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com")            # => vhost is nil, so default (/) will be used
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com/")           # => vhost is an empty string
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com/%2Fvault")   # => vhost is /vault
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com/production") # => vhost is production
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com/a.b.c")      # => vhost is a.b.c
    #   AMQP::Settings.parse_amqp_url("amqp://dev.rabbitmq.com/foo/bar")    # => ArgumentError
    #
    #
    # @param [String] connection_string AMQP connection URI, à la JDBC connection string. For example: amqp://bus.megacorp.internal:5877.
    # @return [Hash] Connection parameters (:username, :password, :vhost, :host, :port, :ssl)
    #
    # @raise [ArgumentError] When connection URI schema is not amqp or amqps, or the path contains multiple segments
    #
    # @see http://bit.ly/ks8MXK Connecting to The Broker documentation guide
    # @api public
    def self.parse_amqp_url(connection_string)
      uri = URI.parse(connection_string)
      raise ArgumentError.new("Connection URI must use amqp or amqps schema (example: amqp://bus.megacorp.internal:5766), learn more at http://rubyamqp.info") unless %w{amqp amqps}.include?(uri.scheme)

      opts = {}

      opts[:scheme] = uri.scheme
      opts[:user]   = URI.unescape(uri.user) if uri.user
      opts[:pass]   = URI.unescape(uri.password) if uri.password
      opts[:host]   = uri.host if uri.host
      opts[:port]   = uri.port || AMQP::Settings::AMQP_PORTS[uri.scheme]
      opts[:ssl]    = uri.scheme == AMQP::Settings::AMQPS
      if uri.path =~ %r{^/(.*)}
        raise ArgumentError.new("#{uri} has multiple-segment path; please percent-encode any slashes in the vhost name (e.g. /production => %2Fproduction). Learn more at http://rubyamqp.info") if $1.index('/')
        opts[:vhost] = URI.unescape($1)
      end

      opts
    end

    def self.parse_connection_uri(connection_string)
      parse_amqp_url(connection_string)
    end
  end
end