# Copyright (C) 2012-2022 Zammad Foundation, https://zammad-foundation.org/

class Sequencer
  class Unit
    module Import
      module Common
        module Ticket
          module Article
            class InlineImages < Sequencer::Unit::Base
              include ::Sequencer::Unit::Import::Common::Mapping::Mixin::ProvideMapped

              uses :mapped

              def process
                return if !contains_inline_image?(mapped[:body])

                provide_mapped do
                  {
                    body: replaced_inline_images,
                  }
                end
              end

              def self.inline_data(image_url)
                clean_image_url = image_url.gsub(%r{^cid:}, '')
                return if !%r{^(http|https)://.+?$}.match?(clean_image_url)

                @cache ||= {}
                return @cache[clean_image_url] if @cache[clean_image_url]

                image_data = download(clean_image_url)
                return if image_data.blank?

                @cache[clean_image_url] = "data:image/png;base64,#{Base64.strict_encode64(image_data)}"
                @cache[clean_image_url]
              end

              def self.download(image_url)
                logger.debug { "Downloading inline image from #{image_url}" }

                response = UserAgent.get(
                  image_url,
                  {},
                  {
                    open_timeout: 20,
                    read_timeout: 240,
                    verify_ssl:   true,
                  },
                )

                return response.body if response.success?

                logger.error response.error
                nil
              end

              private

              def contains_inline_image?(string)
                return false if string.blank?

                string.include?(inline_image_url_prefix)
              end

              def replaced_inline_images
                body_html = Nokogiri::HTML(mapped[:body])

                body_html.css('img').each do |node|
                  next if !contains_inline_image?(node['src'])

                  node.attributes['src'].value = self.class.inline_data(node['src'])
                end

                body_html.to_html
              end

              def inline_image_url_prefix
                raise NotImplementedError
              end
            end
          end
        end
      end
    end
  end
end