# frozen_string_literal: true

module Lcms
  module Engine
    #
    # Generates and uploads PDF/GDoc files for material
    #
    class MaterialPreviewGenerator
      GDOC_RE = %r{docs.google.com/document/d/([^/]*)}i.freeze
      GDOC_BROKEN_RE = %r{/open\?id=$}i.freeze
      PDF_S3_FOLDER = 'temp-materials-pdf'

      attr_reader :error, :url

      def initialize(material, options = {})
        @material = material
        @options = options
      end

      def perform
        return false unless assign_document

        options[:type] == :pdf ? generate_pdf : generate_gdoc
      rescue StandardError => e
        @error = e.message
        false
      end

      private

      attr_reader :material, :options

      def assign_document
        document = material.documents.last || Document.last
        unless document.present?
          @error = "Can't generate PDF for preview: no documents exist"
          return false
        end
        material.document = DocumentGenerator.document_presenter.new document

        true
      end

      def generate_gdoc
        folder_id = options[:folder_id]
        file_id = material.preview_links['gdoc'].to_s.match(GDOC_RE)&.[](1)
        @url = DocumentExporter::Gdoc::Material.new(material)
                 .export_to(folder_id, file_id: file_id)
                 .url
        return true if @url !~ GDOC_BROKEN_RE

        raise 'GDoc generation failed. Please try again later'
      end

      def generate_pdf
        pdf_filename = "#{PDF_S3_FOLDER}/#{material.id}/#{material.base_filename}#{ContentPresenter::PDF_EXT}"
        pdf = DocumentExporter::Pdf::Material.new(material).export
        @url = S3Service.upload pdf_filename, pdf
        true
      end
    end
  end
end