dawarich/app/services/users/digests/chart_image_generator.rb

# frozen_string_literal: true

module Users
  module Digests
    class ChartImageGenerator
      def initialize(digest, distance_unit: 'km')
        @digest = digest
        @distance_unit = distance_unit
      end

      def call
        html = render_chart_html
        generate_image(html)
      end

      private

      attr_reader :digest, :distance_unit

      def render_chart_html
        ApplicationController.render(
          template: 'user/digests/chart',
          layout: false,
          assigns: {
            monthly_distances: digest.monthly_distances,
            distance_unit: distance_unit
          }
        )
      end

      def generate_image(html)
        grover = Grover.new(
          html,
          format: 'png',
          viewport: { width: 600, height: 320 },
          wait_until: 'networkidle0'
        )
        grover.to_png
      end
    end
  end
end