# Gnip PowerTrack Rules API
#
# Create, delete and list rules of a powetrack stream.

module GnipApi
  module PowerTrack
    class Rules
      attr_reader :adapter

      # In order to do any operation, you need to specify:
      # - label: the label of your stream
      # - source: which data source to use (I think only twitter is available)
      def initialize params={}
        @adapter = GnipApi::Adapter.new
        @label = params[:label] || GnipApi.config.label
      end

      # Returns an array of defined rules
      def list
        request = create_get_request
        rules = adapter.get(request)
        parse_rules(rules)
      end

      # Creates the specified rule. Parameters:
      # - rules: GnipApi::PowerTrack::Rule object
      def create rules
        raise GnipApi::Errors::PowerTrack::MissingRules.new if rules.nil? || rules.empty?
        request = create_post_request(construct_rules(rules))
        response = adapter.post(request)
        return true if response.nil?
        return GnipApi::JsonParser.new.parse(response)
      end

      # Deletes the specified rule. Parameters:
      # - rules: GnipApi::PowerTrack::Rule object
      def delete rules
        raise GnipApi::Errors::PowerTrack::MissingRules.new if rules.nil? || rules.empty?
        request = create_delete_request(construct_rules(rules))
        response = adapter.delete(request)
        return true if response.nil?
        return GnipApi::JsonParser.new.parse(response)
      end

      # Parses an array of GnipApi::PowerTrack::Rule objects
      # to the necesary JSON format for the endpoint
      def construct_rules rules
        parsed_rules = {:rules => []}
        rules.each do |rule|
          parsed_rules[:rules] << rule.attributes
        end
        parsed_rules.to_json
      end

      def parse_rules data
        parsed_data = GnipApi::JsonParser.new.parse(data)
        parsed_data['rules'].map{|rule| GnipApi::PowerTrack::Rule.new(:value => rule['value'], :tag => rule['tag'], :id => rule['id'])}
      end

      private
      def endpoint
        GnipApi::Endpoints.powertrack_rules(@label)
      end

      def create_get_request
        GnipApi::Request.new_get(endpoint)
      end

      def create_post_request payload
        GnipApi::Request.new_post(endpoint, payload)
      end
      
      def create_delete_request payload
        delete_url = endpoint
        delete_url.query = '_method=delete'
        GnipApi::Request.new_delete(delete_url, payload)
      end

    end
  end
end