Optimize the conflicts table and summary models

app/models/conflicts_summary.rb

@@ -11,8 +11,34 @@ class ConflictsSummary
     talk_ids.map do |talk_id|
       {
        talk_id: talk_id,
-       conflicts: ConflictsTable.new(talk_id: talk_id, other_talks_ids: talk_ids.reject { |id| id == talk_id }).conflicts
+       conflicts: conflicts_table[talk_id]
       }
     end
   end
+
+  private
+
+  def conflicts_table
+    @conflicts_table ||= blank_conflicts_table.merge(database_conflicts_table)
+  end
+
+  def database_conflicts_table
+    Conflicts.where(left: talk_ids, right: talk_ids).group_by(&:left).map do |left, conflicts|
+      conflicts_row = blank_conflicts_row(talk_ids_without(left))
+      conflicts_row.merge! conflicts.map { |right_conflicts| [right_conflicts.right, right_conflicts.conflicts] }.to_h
+      [left, conflicts_row]
+    end.to_h
+  end
+
+  def talk_ids_without(talk_id)
+    talk_ids.reject { |id| id == talk_id }
+  end
+
+  def blank_conflicts_row(other_talk_ids)
+    other_talk_ids.map { |talk_id| [talk_id, 0] }.to_h
+  end
+
+  def blank_conflicts_table
+    talk_ids.map { |talk_id| [talk_id, blank_conflicts_row(talk_ids_without(talk_id))] }.to_h
+  end
 end

app/models/conflicts_table.rb

@@ -11,8 +11,16 @@ class ConflictsTable
     other_talks_ids.map do |right|
       {
        talk_id: right,
-       number_of_conflicts: Conflicts.new(left: talk_id, right: right).conflicts
+       number_of_conflicts: conflicts_hash[right] || 0
       }
     end
   end
+
+  private
+
+  def conflicts_hash
+    @conflicts_hash ||= Conflicts.where(left: talk_id, right: other_talks_ids).map do |conflicts|
+      [conflicts.right, conflicts.conflicts]
+    end.to_h
+  end
 end