Nested Categories (#1561)

* Prepare entry search for nested categories

* Subcategory implementation

* Remove caching for test stability

app/models/account/transaction_search.rb

@@ -0,0 +1,42 @@
+class Account::TransactionSearch
+  include ActiveModel::Model
+  include ActiveModel::Attributes
+
+  attribute :search, :string
+  attribute :amount, :string
+  attribute :amount_operator, :string
+  attribute :types, array: true
+  attribute :accounts, array: true
+  attribute :account_ids, array: true
+  attribute :start_date, :string
+  attribute :end_date, :string
+  attribute :categories, array: true
+  attribute :merchants, array: true
+  attribute :tags, array: true
+
+  # Returns array of Account::Entry objects to stay consistent with partials, which only deal with Account::Entry
+  def build_query(scope)
+    query = scope
+
+    if categories.present?
+      if categories.exclude?("Uncategorized")
+        query = query
+                  .joins(:category)
+                  .where(categories: { name: categories })
+      else
+        query = query
+                  .left_joins(:category)
+                  .where(categories: { name: categories })
+                  .or(query.where(category_id: nil))
+      end
+    end
+
+    query = query.joins(:merchant).where(merchants: { name: merchants }) if merchants.present?
+
+    query = query.joins(:tags).where(tags: { name: tags }) if tags.present?
+
+    entries_scope = Account::Entry.account_transactions.where(entryable_id: query.select(:id))
+
+    Account::EntrySearch.from_entryable_search(self).build_query(entries_scope)
+  end
+end