DEV: Sentiment analysis report follow-up updates

app/controllers/discourse_ai/sentiment/sentiment_controller.rb

@@ -6,6 +6,9 @@ class SentimentController < ::Admin::StaffController
       include Constants
       requires_plugin ::DiscourseAi::PLUGIN_NAME
 
+      DEFAULT_POSTS_LIMIT = 50
+      MAX_POSTS_LIMIT = 100
+
       def posts
         group_by = params.required(:group_by)&.to_sym
         group_value = params.required(:group_value).presence
@@ -15,10 +18,13 @@ def posts
 
         raise Discourse::InvalidParameters if %i[category tag].exclude?(group_by)
 
+        limit = fetch_limit_from_params(default: DEFAULT_POSTS_LIMIT, max: MAX_POSTS_LIMIT)
+        offset = params[:offset].to_i || 0
+
         case group_by
         when :category
           grouping_clause = "c.name"
-          grouping_join = "INNER JOIN categories c ON c.id = t.category_id"
+          grouping_join = "" # categories already joined
         when :tag
           grouping_clause = "tags.name"
           grouping_join =
@@ -38,6 +44,11 @@ def posts
             u.username,
             u.name,
             u.uploaded_avatar_id,
+            c.id AS category_id,
+            c.name AS category_name,
+            c.color AS category_color,
+            c.slug AS category_slug,
+            c.description AS category_description,
             (CASE 
               WHEN (cr.classification::jsonb->'positive')::float > :threshold THEN 'positive'
               WHEN (cr.classification::jsonb->'negative')::float > :threshold THEN 'negative'
@@ -47,6 +58,7 @@ def posts
           INNER JOIN topics t ON t.id = p.topic_id
           INNER JOIN classification_results cr ON cr.target_id = p.id AND cr.target_type = 'Post'
           LEFT JOIN users u ON u.id = p.user_id
+          LEFT JOIN categories c ON c.id = t.category_id
           #{grouping_join}
           WHERE
             #{grouping_clause} = :group_value AND
@@ -56,22 +68,31 @@ def posts
             ((:start_date IS NULL OR p.created_at > :start_date) AND (:end_date IS NULL OR p.created_at < :end_date))
             AND p.deleted_at IS NULL
           ORDER BY p.created_at DESC
+          LIMIT :limit OFFSET :offset
         SQL
             group_value: group_value,
             start_date: start_date,
             end_date: end_date,
             threshold: threshold,
+            limit: limit + 1,
+            offset: offset,
           )
 
+        has_more = posts.length > limit
+        posts.pop if has_more
+
         render_json_dump(
-          serialize_data(
-            posts,
-            AiSentimentPostSerializer,
-            scope: guardian,
-            add_raw: true,
-            add_excerpt: true,
-            add_title: true,
-          ),
+          posts:
+            serialize_data(
+              posts,
+              AiSentimentPostSerializer,
+              scope: guardian,
+              add_raw: true,
+              add_excerpt: true,
+              add_title: true,
+            ),
+          has_more: has_more,
+          next_offset: has_more ? offset + limit : nil,
         )
       end
     end

app/serializers/ai_sentiment_post_serializer.rb

@@ -10,7 +10,8 @@ class AiSentimentPostSerializer < ApplicationSerializer
              :avatar_template,
              :excerpt,
              :sentiment,
-             :truncated
+             :truncated,
+             :category
 
   def avatar_template
     User.avatar_template(object.username, object.uploaded_avatar_id)
@@ -23,4 +24,14 @@ def excerpt
   def truncated
     true
   end
+
+  def category
+    {
+      id: object.category_id,
+      name: object.category_name,
+      color: object.category_color,
+      slug: object.category_slug,
+      description: object.category_description,
+    }
+  end
 end