Creating a MediafluxTime class to handle timezone inconsistencies (#730)

* Creating a mediaflux class to settle timezones
Converts all times from mediaflux to UTC based on the gmt offset before converting to an america/new_york timezone and iso format
closes #568

* removing unnecessary migration

* Adding tests for mediaflux time conversion

* refactoring comments to be compatable with yardocs

app/models/mediaflux/http/asset_metadata_request.rb

@@ -32,6 +32,7 @@ def metadata
           metadata[:total_file_count] = asset.xpath("./collection/accumulator/value/non-collections").text
           metadata[:size] = asset.xpath("./collection/accumulator/value/total/@h").text
           metadata[:quota_allocation] = asset.xpath("./collection/quota/allocation/@h").text
+          metadata[:ctime] = asset.xpath("./ctime")
 
         end
 

app/models/mediaflux_time.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+class MediafluxTime
+  # Converts the givin time snippet into local princeton time while accounting for potential time zone of the asset.
+  #
+  # @param xml_snip [:nokigiri], response_xml from a mediaflux request
+  # @return [String] returns a iso8601 Princeton time value.
+  def convert(xml_snip:)
+    xml = xml_snip
+    time = xml.text.to_time
+    gmt = xml.xpath("./@gmt-offset").text.to_f
+
+    if gmt.zero?
+      return time.in_time_zone("America/New_York").iso8601
+    elsif gmt.positive?
+      time -= gmt.hours
+    else
+      time += gmt.hours
+    end
+
+    princeton_time = time.in_time_zone("America/New_York").iso8601
+    princeton_time
+  end
+end

spec/models/mediaflux_time_spec.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe MediafluxTime, type: :model do
+  let(:project) { FactoryBot.build :project_with_doi }
+  let(:current_user) { FactoryBot.create(:user, uid: "jh1234") }
+  subject(:instance) { described_class.new }
+
+  describe "#convert", connect_to_mediaflux: true do
+    it "converts mediaflux time objects to utc before converting to america/new_york" do
+      project = FactoryBot.create(:project_with_doi)
+      ProjectMediaflux.create!(project: project, session_id: current_user.mediaflux_session)
+      metadata = Mediaflux::Http::AssetMetadataRequest.new(
+        session_token: current_user.mediaflux_session, 
+        id: project.mediaflux_id
+        ).metadata
+
+
+      xml_snip = metadata[:ctime]
+      initial_tz = xml_snip.xpath("./@tz").text
+      expect(initial_tz).to eq "Etc/UTC" 
+
+      final_tz = instance.convert(xml_snip:)
+      expect(final_tz).to include("-04:00") or include("-05:00") #America/New_York changes based on daylights savings time
+    end
+  end
+end