Add Opening Balance manager, add tests to forward calculator

Author: zachgoll

app/models/account.rb

@@ -1,6 +1,5 @@
 class Account < ApplicationRecord
-  include Syncable, Monetizable, Chartable, Linkable, Enrichable
-  include AASM
+  include AASM, Syncable, Monetizable, Chartable, Linkable, Enrichable, Anchorable
 
   validates :name, :balance, :currency, presence: true
 

app/models/account/anchorable.rb

@@ -0,0 +1,32 @@
+# All accounts are "anchored" with start/end valuation records, with transactions,
+# trades, and reconciliations between them.
+module Account::Anchorable
+  extend ActiveSupport::Concern
+
+  included do
+    include Monetizable
+
+    monetize :opening_balance, :opening_cash_balance
+  end
+
+  def set_opening_balance(**opts)
+    opening_balance_manager.set_opening_balance(**opts)
+  end
+
+  def opening_date
+    opening_balance_manager.opening_date
+  end
+
+  def opening_balance
+    opening_balance_manager.opening_balance
+  end
+
+  def opening_cash_balance
+    opening_balance_manager.opening_cash_balance
+  end
+
+  private
+    def opening_balance_manager
+      @opening_balance_manager ||= Account::OpeningBalanceManager.new(self)
+    end
+end

app/models/account/opening_balance_manager.rb

@@ -5,6 +5,19 @@ def initialize(account)
     @account = account
   end
 
+  # Most accounts should have an opening anchor. If not, we derive the opening date from the oldest entry date
+  def opening_date
+    opening_anchor_valuation&.entry&.date || account.entries.order(:date).first&.date || Date.current
+  end
+
+  def opening_balance
+    opening_anchor_valuation&.balance || 0
+  end
+
+  def opening_cash_balance
+    opening_anchor_valuation&.cash_balance || 0
+  end
+
   def set_opening_balance(balance:, cash_balance: nil, date: nil)
     resolved_date = date || default_date
     resolved_cash_balance = cash_balance || default_cash_balance(balance)

app/models/balance/forward_calculator.rb

@@ -13,16 +13,18 @@ def calculate
 
   private
     def calculate_balances
-      current_cash_balance = 0
+      current_cash_balance = account.opening_cash_balance
       next_cash_balance = nil
 
       @balances = []
 
-      account.start_date.upto(Date.current).each do |date|
+      end_date = [ account.entries.order(:date).last&.date, account.holdings.order(:date).last&.date ].compact.max || Date.current
+
+      account.opening_date.upto(end_date).each do |date|
         entries = sync_cache.get_entries(date)
         holdings = sync_cache.get_holdings(date)
         holdings_value = holdings.sum(&:amount)
-        valuation = sync_cache.get_valuation(date)
+        valuation = sync_cache.get_reconciliation_valuation(date)
 
         next_cash_balance = if valuation
           valuation.amount - holdings_value

app/models/balance/sync_cache.rb

@@ -7,6 +7,10 @@ def get_valuation(date)
     converted_entries.find { |e| e.date == date && e.valuation? }
   end
 
+  def get_reconciliation_valuation(date)
+    converted_entries.find { |e| e.date == date && e.valuation? && e.valuation.reconciliation? }
+  end
+
   def get_holdings(date)
     converted_holdings.select { |h| h.date == date }
   end

app/models/balance/trend_calculator.rb

@@ -18,7 +18,7 @@ def trend_for(date)
     BalanceTrend.new(
       trend: Trend.new(
         current: Money.new(balance.balance, balance.currency),
-        previous: Money.new(prior_balance.balance, balance.currency),
+        previous: prior_balance.present? ? Money.new(prior_balance.balance, balance.currency) : nil,
         favorable_direction: balance.account.favorable_direction
       ),
       cash: Money.new(balance.cash_balance, balance.currency),