Merge pull request #985 from basecamp/refactor-summarizer

Refactor: Separate method with two outputs into two

app/models/event/activity_summary.rb

@@ -8,11 +8,11 @@ class Event::ActivitySummary < ApplicationRecord
       key = key_for(events)
 
       # Outside to avoid holding the transaction during the LLM request
-      summary, cost_in_microcents = Event::Summarizer.new(events).summarize
+      summarizer = Event::Summarizer.new(events)
 
       create_or_find_by!(key: key) do |record|
-        record.content = summary
-        record.cost_in_microcents = cost_in_microcents
+        record.content = summarizer.summarized_content
+        record.cost_in_microcents = summarizer.cost.in_microcents
       end
     end
 

app/models/event/summarizer.rb

@@ -27,9 +27,12 @@ class Event::Summarizer
     @llm_model = llm_model
   end
 
-  def summarize
-    response = chat.ask join_prompts("Summarize the following content:", summarizable_content)
-    [ response.content, Ai::UsageCost.from_llm_response(response).in_microcents ]
+  def summarized_content
+    llm_response.content
+  end
+
+  def cost
+    Ai::UsageCost.from_llm_response(llm_response)
   end
 
   def summarizable_content
@@ -39,6 +42,10 @@ class Event::Summarizer
   private
     attr_reader :prompt, :llm_model
 
+    def llm_response
+      @llm_response ||= chat.ask join_prompts("Summarize the following content:", summarizable_content)
+    end
+
     def chat
       chat = RubyLLM.chat(model: llm_model)
       chat.with_instructions(join_prompts(prompt, domain_model_prompt, user_data_injection_prompt))