FIX: Embeddings backfill rake task was using old code

lib/tasks/modules/embeddings/database.rake

@@ -1,24 +1,21 @@
 # frozen_string_literal: true
 
 desc "Backfill embeddings for all topics and posts"
-task "ai:embeddings:backfill", %i[model concurrency] => [:environment] do |_, args|
+task "ai:embeddings:backfill", %i[embedding_def_id concurrency] => [:environment] do |_, args|
   public_categories = Category.where(read_restricted: false).pluck(:id)
 
-  if args[:model].present?
-    strategy = DiscourseAi::Embeddings::Strategies::Truncation.new
-    vector_rep =
-      DiscourseAi::Embeddings::VectorRepresentations::Base.find_representation(args[:model]).new(
-        strategy,
-      )
+  if args[:embedding_def_id].present?
+    vdef = EmbeddingDefinition.find(args[:embedding_def_id])
+    vector_rep = DiscourseAi::Embeddings::Vector.new(vdef)
   else
-    vector_rep = DiscourseAi::Embeddings::VectorRepresentations::Base.current_representation
+    vector_rep = DiscourseAi::Embeddings::Vector.instance
   end
-  table_name = DiscourseAi::Embeddings::Schema::TOPICS_TABLE
+  topics_table_name = DiscourseAi::Embeddings::Schema::TOPICS_TABLE
 
   topics =
     Topic
-      .joins("LEFT JOIN #{table_name} ON #{table_name}.topic_id = topics.id")
-      .where("#{table_name}.topic_id IS NULL")
+      .joins("LEFT JOIN #{topics_table_name} ON #{topics_table_name}.topic_id = topics.id")
+      .where("#{topics_table_name}.topic_id IS NULL")
       .where("category_id IN (?)", public_categories)
       .where(deleted_at: nil)
       .order("topics.id DESC")
@@ -29,11 +26,11 @@ task "ai:embeddings:backfill", %i[model concurrency] => [:environment] do |_, ar
     end
   end
 
-  table_name = vector_rep.post_table_name
+  posts_table_name = DiscourseAi::Embeddings::Schema::POSTS_TABLE
   posts =
     Post
-      .joins("LEFT JOIN #{table_name} ON #{table_name}.post_id = posts.id")
-      .where("#{table_name}.post_id IS NULL")
+      .joins("LEFT JOIN #{posts_table_name} ON #{posts_table_name}.post_id = posts.id")
+      .where("#{posts_table_name}.post_id IS NULL")
       .where(deleted_at: nil)
       .order("posts.id DESC")