Add FinancialLinksController#incomplete

app/models/financial_link.rb

@@ -2,4 +2,29 @@ class FinancialLink < ApplicationRecord
   has_many :bank_transactions
   has_many :financial_transactions
   has_many :invoices
+
+  scope :incomplete, -> { with_full_sum.where.not('full_sums.full_sum' => 0) }
+  scope :with_full_sum, -> {
+    select(:id, :note, :full_sum).joins(<<-SQL)
+      LEFT JOIN (
+        SELECT id, COALESCE(bt_sum, 0) - COALESCE(ft_sum, 0) + COALESCE(i_sum, 0) AS full_sum
+        FROM financial_links fl
+        LEFT JOIN (
+          SELECT financial_link_id, SUM(amount) AS bt_sum
+          FROM bank_transactions
+          GROUP BY financial_link_id
+        ) bt ON bt.financial_link_id = fl.id
+        LEFT JOIN (
+          SELECT financial_link_id, SUM(amount) AS ft_sum
+          FROM financial_transactions
+          GROUP BY financial_link_id
+        ) ft ON ft.financial_link_id = fl.id
+        LEFT JOIN (
+          SELECT financial_link_id, SUM(amount) AS i_sum
+          FROM invoices
+          GROUP BY financial_link_id
+        ) i ON i.financial_link_id = fl.id
+      ) full_sums ON full_sums.id = financial_links.id
+    SQL
+  }
 end