perf(reports): skip computing hidden metrics in summary

Instead of filtering metrics after computation, skip the expensive
database queries entirely for hidden metrics. This prevents timeouts
on accounts with large datasets.

- MetricBuilder now accepts hidden_metrics param and returns nil for
  hidden metrics (compacted from response)
- Reports controller passes hidden_metrics to builder params

app/builders/v2/reports/conversations/metric_builder.rb

@@ -1,14 +1,21 @@
 class V2::Reports::Conversations::MetricBuilder < V2::Reports::Conversations::BaseReportBuilder
+  # Mapping from metric keys to canonical hidden metric names
+  METRIC_TO_HIDDEN_KEY = {
+    'incoming_messages_count' => 'incoming_messages_count',
+    'outgoing_messages_count' => 'outgoing_messages_count',
+    'reply_time' => 'reply_time'
+  }.freeze
+
   def summary
     {
       conversations_count: count('conversations_count'),
-      incoming_messages_count: count('incoming_messages_count'),
-      outgoing_messages_count: count('outgoing_messages_count'),
+      incoming_messages_count: count_unless_hidden('incoming_messages_count'),
+      outgoing_messages_count: count_unless_hidden('outgoing_messages_count'),
       avg_first_response_time: count('avg_first_response_time'),
       avg_resolution_time: count('avg_resolution_time'),
       resolutions_count: count('resolutions_count'),
-      reply_time: count('reply_time')
-    }
+      reply_time: count_unless_hidden('reply_time')
+    }.compact
   end
 
   def bot_summary
@@ -24,6 +31,18 @@ class V2::Reports::Conversations::MetricBuilder < V2::Reports::Conversations::Ba
     builder_class(metric).new(account, builder_params(metric)).aggregate_value
   end
 
+  def count_unless_hidden(metric)
+    return nil if metric_hidden?(metric)
+
+    count(metric)
+  end
+
+  def metric_hidden?(metric)
+    hidden_metrics = params[:hidden_metrics] || []
+    canonical_key = METRIC_TO_HIDDEN_KEY[metric]
+    canonical_key && hidden_metrics.include?(canonical_key)
+  end
+
   def builder_params(metric)
     params.merge({ metric: metric })
   end

app/controllers/api/v2/accounts/reports_controller.rb

@@ -15,11 +15,11 @@ class Api::V2::Accounts::ReportsController < Api::V1::Accounts::BaseController
   end
 
   def summary
-    render json: filter_summary_with_previous(build_summary(:summary))
+    render json: build_summary(:summary)
   end
 
   def bot_summary
-    render json: filter_summary_with_previous(build_summary(:bot_summary))
+    render json: build_summary(:bot_summary)
   end
 
   def agents
@@ -107,7 +107,8 @@ class Api::V2::Accounts::ReportsController < Api::V1::Accounts::BaseController
     common_params.merge({
                           since: range[:current][:since],
                           until: range[:current][:until],
-                          timezone_offset: params[:timezone_offset]
+                          timezone_offset: params[:timezone_offset],
+                          hidden_metrics: hidden_metrics
                         })
   end
 
@@ -115,7 +116,8 @@ class Api::V2::Accounts::ReportsController < Api::V1::Accounts::BaseController
     common_params.merge({
                           since: range[:previous][:since],
                           until: range[:previous][:until],
-                          timezone_offset: params[:timezone_offset]
+                          timezone_offset: params[:timezone_offset],
+                          hidden_metrics: hidden_metrics
                         })
   end