From c321ff8e7c64e37e83d555181dd47875674ddb1b Mon Sep 17 00:00:00 2001
From: Justin Coyne <jcoyne@justincoyne.com>
Date: Fri, 17 Nov 2023 15:47:36 -0600
Subject: [PATCH] Extract a resource deserializer

So that the models don't have to know about their serialization
---
 app/models/embed/purl.rb                      |  2 +-
 app/models/embed/purl/resource.rb             | 31 ++++---------
 .../embed/purl/resource_xml_deserializer.rb   | 29 ++++++++++++
 spec/models/embed/purl/resource_spec.rb       | 44 +++++++++----------
 .../purl/resource_xml_deserializer_spec.rb    | 28 ++++++++++++
 5 files changed, 89 insertions(+), 45 deletions(-)
 create mode 100644 app/models/embed/purl/resource_xml_deserializer.rb
 create mode 100644 spec/models/embed/purl/resource_xml_deserializer_spec.rb

diff --git a/app/models/embed/purl.rb b/app/models/embed/purl.rb
index 5a9c7c9d2..62a2035cd 100644
--- a/app/models/embed/purl.rb
+++ b/app/models/embed/purl.rb
@@ -32,7 +32,7 @@ def valid?
 
     def contents
       @contents ||= ng_xml.xpath('//contentMetadata/resource').map do |resource|
-        Purl::Resource.new(@druid, resource, rights)
+        ResourceXmlDeserializer.new(druid, resource, rights).deserialize
       end
     end
 
diff --git a/app/models/embed/purl/resource.rb b/app/models/embed/purl/resource.rb
index 71bd5b8da..1091a6db8 100644
--- a/app/models/embed/purl/resource.rb
+++ b/app/models/embed/purl/resource.rb
@@ -4,33 +4,20 @@ module Embed
   class Purl
     class Resource
       # @param [String] druid identifier without a namespace
-      # @param [Nokogiri::XML::Element] resource
-      # @param [Dor::RightsAuth] rights
-      def initialize(druid, resource, rights)
+      # @param [String] type the resource type
+      # @param [String] description the resource description
+      # @param [Array<ResourceFile>] files
+      def initialize(druid:, type:, description:, files: [])
         @druid = druid
-        @resource = resource
-        @rights = rights
+        @type = type
+        @description = description
+        @files = files
       end
 
-      attr_reader :druid
-
-      def type
-        @resource.attributes['type'].value
-      end
-
-      def description
-        @description ||= @resource.xpath('./label').text
-      end
+      attr_reader :druid, :type, :description, :files
 
       def three_dimensional?
-        @resource.attributes['type']&.value == '3d'
-      end
-
-      # @return [Array<ResourceFile>]
-      def files
-        @files ||= @resource.xpath('./file').map do |file|
-          FileXmlDeserializer.new(druid, description, file, @rights).deserialize
-        end
+        type == '3d'
       end
 
       def size
diff --git a/app/models/embed/purl/resource_xml_deserializer.rb b/app/models/embed/purl/resource_xml_deserializer.rb
new file mode 100644
index 000000000..36a5c9815
--- /dev/null
+++ b/app/models/embed/purl/resource_xml_deserializer.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Embed
+  class Purl
+    class ResourceXmlDeserializer
+      # @param [String] druid the identifier of the resource
+      # @param [Nokogiri::XML::Element] resource
+      # @param [Dor::RightsAuth] rights
+      def initialize(druid, resource, rights)
+        @druid = druid
+        @resource = resource
+        @rights = rights
+      end
+
+      def deserialize
+        description = @resource.xpath('./label').text
+        files = @resource.xpath('./file').map do |file|
+          FileXmlDeserializer.new(@druid, description, file, @rights).deserialize
+        end
+        Resource.new(
+          druid: @druid,
+          type: @resource.attributes['type'].value,
+          description:,
+          files:
+        )
+      end
+    end
+  end
+end
diff --git a/spec/models/embed/purl/resource_spec.rb b/spec/models/embed/purl/resource_spec.rb
index ef6122d0a..9bb631620 100644
--- a/spec/models/embed/purl/resource_spec.rb
+++ b/spec/models/embed/purl/resource_spec.rb
@@ -20,35 +20,35 @@
   end
 
   describe '#thumbnail' do
-    let(:resource) { described_class.new('12345', resource_element, instance_double(Dor::RightsAuth)) }
+    let(:resource) do
+      described_class.new(
+        druid: '12345',
+        type: 'file',
+        description: 'great',
+        files: [
+          Embed::Purl::ResourceFile.new(filename: 'Non thumb', mimetype: 'image/tiff'),
+          Embed::Purl::ResourceFile.new(filename: 'The thumb', mimetype: 'image/jp2')
+        ]
+      )
+    end
 
     context 'when the resource has a thumbnail' do
-      let(:resource_element) do
-        Nokogiri::XML(
-          <<~XML
-            <resource sequence="1" type="file">
-              <file id="Non thumb" mimetype="image/tiff" size="2799535" />
-              <file id="The Thumb" mimetype="image/jp2" size="2799535" />
-            </resource>
-          XML
-        ).xpath('//resource').first
-      end
-
       it 'is the thumbnail' do
-        expect(resource.thumbnail.title).to eq 'The Thumb'
+        expect(resource.thumbnail.title).to eq 'The thumb'
       end
     end
 
     context 'when the resource does not have a file specific thumbnail' do
-      let(:resource_element) do
-        Nokogiri::XML(
-          <<~XML
-            <resource sequence="1" type="file">
-              <file id="Non thumb" mimetype="image/tiff" size="2799535" />
-              <file id="Another non Thumb" mimetype="audio/aiff" size="2799535" />
-            </resource>
-          XML
-        ).xpath('//resource').first
+      let(:resource) do
+        described_class.new(
+          druid: '12345',
+          type: 'file',
+          description: 'bland',
+          files: [
+            Embed::Purl::ResourceFile.new(filename: 'Non thumb', mimetype: 'image/tiff'),
+            Embed::Purl::ResourceFile.new(filename: 'Another non Thumb', mimetype: 'audio/aiff')
+          ]
+        )
       end
 
       it 'is nil' do
diff --git a/spec/models/embed/purl/resource_xml_deserializer_spec.rb b/spec/models/embed/purl/resource_xml_deserializer_spec.rb
new file mode 100644
index 000000000..8296727c4
--- /dev/null
+++ b/spec/models/embed/purl/resource_xml_deserializer_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Embed::Purl::ResourceXmlDeserializer do
+  describe '#deserialize' do
+    let(:resource_element) do
+      Nokogiri::XML(
+        <<~XML
+          <resource sequence="1" type="image">
+            <label>What a great image</label>
+            <file id="Non thumb" mimetype="image/tiff" size="2799535" />
+            <file id="The Thumb" mimetype="image/jp2" size="2799535" />
+          </resource>
+        XML
+      ).xpath('//resource').first
+    end
+
+    let(:resource) { described_class.new('abc123', resource_element, nil).deserialize }
+
+    it 'creates a resource' do
+      expect(resource.druid).to eq 'abc123'
+      expect(resource.description).to eq 'What a great image'
+      expect(resource.type).to eq 'image'
+      expect(resource.files).to all(be_a Embed::Purl::ResourceFile)
+    end
+  end
+end