module Agents
    class TranslationAgent < Agent

        cannot_be_scheduled!

        description <<-MD
            You can use Translation Agent to translate text between natural languages. 
            Services are provided using Microsoft Translator. You can [sign up](https://datamarket.azure.com/dataset/bing/microsofttranslator) and [register your application](https://datamarket.azure.com/developer/applications/register) to get `client_id` and `client_secret` which are required to use this agent.
            `to` must be filled with a [translator language code](http://msdn.microsoft.com/en-us/library/hh456380.aspx).

            Specify what you would like to translate in `content` field, by specifying key and JSONPath of content to be translated.

            `expected_receive_period_in_days` is the maximum number of days you would allow to pass between events.
        MD

        event_description <<-MD
            User defined
        MD

        def default_options
            {
                :client_id     => "xxxxxx",
                :client_secret => "xxxxxx" ,
                :to            => "fi",
                :expected_receive_period_in_days => 1,
                :content       => {
                    :text => "$.message.text",
                    :content => "$.xyz"
                }
            }
        end

        def working?
            last_receive_at && last_receive_at > options[:expected_receive_period_in_days].to_i.days.ago
        end

        def translate(text,to,access_token)
            translate_uri = URI "http://api.microsofttranslator.com/v2/Ajax.svc/Translate"
            params = {
                :text => text,
                :to   => to
            }
            translate_uri.query = URI.encode_www_form params
            request = Net::HTTP::Get.new translate_uri
            request['Authorization'] = "Bearer" + " " + access_token
            http = Net::HTTP.new translate_uri.hostname, translate_uri.port 
            response = http.request request 
            YAML.load response.body
        end

        def validate_options
            unless options[:client_id].present? && options[:client_secret].present? && options[:to].present? && options[:content].present? && options[:expected_receive_period_in_days].present?
                errors.add :base, "client_id,client_secret,to,expected_receive_period_in_days and content are all required"
            end
        end

        def receive(incoming_events)
            auth_uri = URI "https://datamarket.accesscontrol.windows.net/v2/OAuth2-13"
            response = Net::HTTP.post_form auth_uri, :client_id => options[:client_id], 
                                                     :client_secret => options[:client_secret], 
                                                     :scope => "http://api.microsofttranslator.com", 
                                                     :grant_type =>  "client_credentials"
            access_token = JSON.parse(response.body)["access_token"]
            incoming_events.each do |event|
                translated_event = {}
                options[:content].each_pair do |key,value|
                    translate_value = Utils.values_at event.payload, value 
                    translated_event[key] = translate translate_value.first, options[:to], access_token
                end
                create_event :payload => translated_event
            end
        end
    end
end