Add description of functionality

Author: edgenard

refactoring_external_service/youtube_video_list.rb

@@ -1,28 +1,45 @@
-class VideoService…
+class VideoService
   def video_list
+     # Read a json file  and store the contents in an instance variable
     @video_list = JSON.parse(File.read('videos.json'))
+    # Get all the ids of the stored in the contents and JSON file that was just
     ids = @video_list.map{|v| v['youtubeID']}
+    # Get authorized with Google to be allowed to make API calls
     client = GoogleAuthorizer.new(
       token_key: 'api-youtube',
       application_name: 'Gateway Youtube Example',
       application_version: '0.1'
       ).api_client
+    # Not sure what this does, but I think its a way to tell youtube what I'm asking for
     youtube = client.discovered_api('youtube', 'v3')
+    # Send the request to Youtube passing in the ids of the videos from out Json file and telling which
+    # data we want from youtube. We want a video snippet, contentDetails(probably a description)
+    # and statistics about the video
     request = {
-      api_method: youtube.videos.list,
+      api_method: youtube.videos.list, # This looks like there are many api_methods and the one
+      # we are asking for is the one that returns a list of videos.
       parameters: {
         id: ids.join(","),
         part: 'snippet, contentDetails, statistics',
       }
     }
+    # Get the body of the response and parse it with JSON.parse to make into a Ruby hash
     response = JSON.parse(client.execute!(request).body)
-    ids.each do |id|
+    # Go through the array of ids
+    ids.each do |id| 
+      # Find the video object that matches the this specific id
       video = @video_list.find{|v| id == v['youtubeID']}
+       # Go through the items from the response and find one that matches the id 
       youtube_record = response['items'].find{|v| id == v['id']}
+      # Update the views key in the video object(the one we got from our JSON file)
+      # with the viewCount from the response we got from youtube.
       video['views'] = youtube_record['statistics']['viewCount'].to_i
+      # Find out how many days the video has been live from the response from youtube
       days_available = Date.today - Date.parse(youtube_record['snippet']['publishedAt'])
+       # Update the monthly views of the video
       video['monthlyViews'] = video['views'] * 365.0 / days_available / 12      
     end
+    # return the updated video list in a JSON dump
     return JSON.dump(@video_list)
   end
 end