# -*- encoding: utf-8 -*-

#
# OverSIP - Logic.
#
#


class OverSIP::SIP::Logic

  ### Custom configuration options:
  #
  # Set this to _true_ if the SIP registrar behind OverSIP does not support Path.
  USE_MODULE_REGISTRAR_WITHOUT_PATH = true
  #
  # Set this to _true_ if the SIP proxy/server behind OverSIP performing the authentication
  # is ready to accept a P-Asserted-Identity header from OverSIP indicating the already
  # asserted SIP user of the client's connection (this avoids authenticating all the requests
  # but the first one).
  USE_MODULE_USER_ASSERTION = true


  def run

    log_info "#{@request.sip_method} from #{@request.from.uri} (UA: #{@request.header("User-Agent")}) to #{@request.ruri} via #{@request.transport.upcase} #{@request.source_ip} : #{@request.source_port}"

    # Check Max-Forwards value (max 10).
    return unless @request.check_max_forwards 10

    # Assume all the traffic is from clients and help them with NAT issues
    # by forcing rport usage and Outbound mechanism.
    @request.fix_nat


    ### In-dialog requests.

    if @request.in_dialog?
      if @request.loose_route
        log_debug "proxying in-dialog #{@request.sip_method}"
        @request.proxy(:proxy_in_dialog).route
      else
        unless @request.sip_method == :ACK
          log_notice "forbidden in-dialog request without top Route pointing to us => 403"
          @request.reply 403, "forbidden in-dialog request without top Route pointing to us"
        else
          log_notice "ignoring not loose routing ACK"
        end
      end
      return
    end


    ### Initial requests.

    # Check that the request does not contain a top Route pointing to another server.
    if @request.loose_route
      unless @request.sip_method == :ACK
        log_notice "pre-loaded Route not allowed here => 403"
        @request.reply 403, "Pre-loaded Route not allowed"
      else
        log_notice "ignoring ACK initial request"
      end
      return
    end


    if USE_MODULE_REGISTRAR_WITHOUT_PATH
      # Extract the Outbound flow token from the RURI.
      OverSIP::SIP::Modules::RegistrarWithoutPath.extract_outbound_from_ruri @request
    end


    # The request goes to a client using Outbound through OverSIP.
    if @request.incoming_outbound_requested?
      log_info "routing initial request to an Outbound client"

      proxy = @request.proxy(:proxy_to_users)

      proxy.on_success_response do |response|
        log_info "incoming Outbound on_success_response: #{response.status_code} '#{response.reason_phrase}'"
      end

      proxy.on_failure_response do |response|
        log_info "incoming Outbound on_failure_response: #{response.status_code} '#{response.reason_phrase}'"
      end

      # on_error() occurs when no SIP response was received fom the peer and, instead, we
      # got some other internal error (timeout, connection error, DNS error....).
      proxy.on_error do |status, reason|
        log_notice "incoming Outbound on_error: #{status} '#{reason}'"
      end

      # Route the request and return.
      proxy.route
      return
    end


    # An initial request with us (OverSIP) as final destination, ok, received, bye...
    if @request.destination_myself?
      log_info "request for myself => 404"
      @request.reply 404, "Ok, I'm here"
      return
    end


    # An outgoing initial request.
    case @request.sip_method

    when :INVITE, :MESSAGE, :OPTIONS, :SUBSCRIBE, :PUBLISH

      if USE_MODULE_USER_ASSERTION
        ::OverSIP::SIP::Modules::UserAssertion.add_pai @request
      end

      proxy = @request.proxy(:proxy_out)

      proxy.on_provisional_response do |response|
        log_info "on_provisional_response: #{response.status_code} '#{response.reason_phrase}'"
      end

      proxy.on_success_response do |response|
        log_info "on_success_response: #{response.status_code} '#{response.reason_phrase}'"
      end

      proxy.on_failure_response do |response|
        log_info "on_failure_response: #{response.status_code} '#{response.reason_phrase}'"
      end

      proxy.on_error do |status, reason|
        log_notice "on_error: #{status} '#{reason}'"
      end

      proxy.route
      return

    when :REGISTER

      if USE_MODULE_REGISTRAR_WITHOUT_PATH
        # Contact mangling for the case in which the registrar does not support Path.
        ::OverSIP::SIP::Modules::RegistrarWithoutPath.add_outbound_to_contact @request
      end

      proxy = @request.proxy(:proxy_out)

      proxy.on_success_response do |response|
        if USE_MODULE_REGISTRAR_WITHOUT_PATH
          # Undo changes done to the Contact header provided by the client, so it receives
          # the same value in the 200 response from the registrar.
          ::OverSIP::SIP::Modules::RegistrarWithoutPath.remove_outbound_from_contact response
        end

        if USE_MODULE_USER_ASSERTION
          # The registrar replies 200 after a REGISTER with credentials so let's assert
          # the current SIP user to this connection.
          ::OverSIP::SIP::Modules::UserAssertion.assert_connection response
        end
      end

      proxy.on_failure_response do |response|
        if USE_MODULE_USER_ASSERTION
          # We don't add PAI for re-REGISTER, so 401 will be replied, and after it let's
          # revoke the current user assertion (will be re-added upon REGISTER with credentials).
          ::OverSIP::SIP::Modules::UserAssertion.revoke_assertion response
        end
      end

      proxy.route
      return

    else

      log_info "method #{@request.sip_method} not implemented => 501"
      @request.reply 501, "Not Implemented"
      return

    end

  end  # def run

end  # class OverSIP::SIP::Logic