metrics.rb

# Add this to Core's QueryExtensions
module Decidim
  module QueryExtensions
    type.field :metrics, [Decidim::Core::MetricType]
    argument :names, types[String], "The names of the metrics you want to retrieve"

    resolve lambda { | _, args, ctx|
      manifests = if args[:names].blank?
                    metrics_registry.all
                  else
                    metrics_registry.all.select do |manifest|
                      args[:names].include?(manifest.metric_name.to_s)
                    end
                  end

      manifests.map do |manifest|
        Decidim::Core::MetricResolver.new(manifest.metric_name, ctx[:current_organization])
      end
    }
  end
end

# These replace all the metric types.
module Decidim
  module Core
    MetricType = GraphQL::ObjectType.define do
      name "Metric"

      field :name, !types.String, "The name of the metric"
      field :count, !types.Int, "The last value of the metric"
      field :history, [!MetricHistoryType], "The historic values for this metric"
  end
end

module Decidim
  module Core
    MetricHistoryType = GraphQL::ObjectType.define do
      name "Metric History"
      field :day, !types.Date, "The date when the value was registered"
      field :value, !types.Int, "The value of the metric"
    end
  end
end

# This replaces Decidim::MetricCount and all the metric resolvers
module Decidim
  module Core
    class MetricResolver
      attr_reader :name

      def initialize(name, organization)
        @name = name
        @organization = organization
      end

      def count
        metric_scope.last.cumulative.to_i
      end

      def history
        metric_scope.limit(60).pluck(:day, :quantity).map do |day, quantity|
          OpenStruct.new(day: day, value: quantity)
        end
      end

      private

      def metric_scope
        Decidim::Metric
          .where(organization: organization, metric_name: name)
          .order(:day, :desc)
      end

      attr_reader :organization
    end
  end
end