Small touches to better fit expected behaviour defined in tests.

app/controllers/backend/quick_affairs_controller.rb

@@ -53,7 +53,7 @@ def create
         return render :new
       end
 
-      lettered = lettrable? && @payment.letter_with(@bank_statement_items)
+      lettered = @amount == @trade.amount && @payment.letter_with(@bank_statement_items)
       if lettered && @bank_statement_items
         notify_warning :saved_but_couldnt_letter_x_and_y.tl(trade: self.class::Trade.model_name.human, payment: self.class::Payment.model_name.human)
       end
@@ -108,14 +108,5 @@ def affair_params
                     :third_id,
                     :payment_id
     end
-
-    def lettrable?
-      return false unless @bank_statement_items
-      bank_statement   = @bank_statement_items.first.bank_statement
-      amount_matches   = (@amount == @payment.amount)
-      amount_matches &&= (@amount == @trade.amount)
-      mode_is_valid    = (bank_statement.cash_id == @payment.mode.cash_id)
-      amount_matches && mode_is_valid
-    end
   end
 end

app/models/incoming_payment.rb

@@ -166,8 +166,16 @@ def third
   end
 
   def letter_with(bank_statements_items)
+    return false unless bank_statements_items.present?
     return false unless journal_entry
     bank_statement = bank_statements_items.first.bank_statement
+    return false unless mode.cash_id == bank_statement.cash_id
+    unless bank_statements_items.respond_to?(:pluck)
+      ids = bank_statements_items.map { |item| item.respond_to?(:id) ? item.id : item }
+      bank_statements_items = BankStatementItem.where(id: ids)
+    end
+    matches = amount == bank_statements_items.sum(:debit) - bank_statements_items.sum(:credit)
+    return false unless matches
     letters = bank_statements_items.pluck(:letter)
     bank_statements_items.update_all(letter: nil)
     JournalEntryItem.pointed_by(bank_statement)
@@ -179,6 +187,7 @@ def letter_with(bank_statements_items)
       .where(account_id: bank_statement.cash_account_id)
       .update_all(bank_statement_id: bank_statement.id, bank_statement_letter: letter)
     bank_statements_items.update_all(letter: letter)
+    letter
   end
 
   # Returns true if payment is already deposited

app/models/outgoing_payment.rb

@@ -110,8 +110,16 @@ def third
   end
 
   def letter_with(bank_statements_items)
+    return false unless bank_statements_items.present?
     return false unless journal_entry
     bank_statement = bank_statements_items.first.bank_statement
+    return false unless mode.cash_id == bank_statement.cash_id
+    unless bank_statements_items.respond_to?(:pluck)
+      ids = bank_statements_items.map { |item| item.respond_to?(:id) ? item.id : item }
+      bank_statements_items = BankStatementItem.where(id: ids)
+    end
+    matches = amount == bank_statements_items.sum(:credit) - bank_statements_items.sum(:debit)
+    return false unless matches
     letters = bank_statements_items.pluck(:letter)
     bank_statements_items.update_all(letter: nil)
     JournalEntryItem.pointed_by(bank_statement)
@@ -123,6 +131,7 @@ def letter_with(bank_statements_items)
       .where(account_id: bank_statement.cash_account_id)
       .update_all(bank_statement_id: bank_statement.id, bank_statement_letter: letter)
     bank_statements_items.update_all(letter: letter)
+    letter
   end
 
   def check_updateable_or_destroyable?