Improve account sync performance, handle concurrent market data syncing (#2236)

* PlaidConnectable concern

* Remove bad abstraction

* Put sync implementations in own concerns

* Sync strategies

* Move sync orchestration to Sync class

* Clean up sync class, add state machine

* Basic market data sync cron

* Fix price sync

* Improve sync window column names, add timestamps

* 30 day syncs by default

* Clean up market data methods

* Report high duplicate sync counts to Sentry

* Add sync states throughout app

* account tab session

* Persistent account tab selections

* Remove manual sleep

* Add migration to clear stale syncs on self hosted apps

* Tweak sync states

* Sync completion event broadcasts

* Fix timezones in tests

* Cleanup

* More cleanup

* Plaid item UI broadcasts for sync

* Fix account ID namespace conflict

* Sync broadcasters

* Smoother account sync refreshes

* Remove test sync delay

app/models/balance/forward_calculator.rb

@@ -1,4 +1,16 @@
-class Balance::ForwardCalculator < Balance::BaseCalculator
+class Balance::ForwardCalculator
+  attr_reader :account
+
+  def initialize(account)
+    @account = account
+  end
+
+  def calculate
+    Rails.logger.tagged("Balance::ForwardCalculator") do
+      calculate_balances
+    end
+  end
+
   private
     def calculate_balances
       current_cash_balance = 0
@@ -25,4 +37,25 @@ class Balance::ForwardCalculator < Balance::BaseCalculator
 
       @balances
     end
+
+    def sync_cache
+      @sync_cache ||= Balance::SyncCache.new(account)
+    end
+
+    def build_balance(date, cash_balance, holdings_value)
+      Balance.new(
+        account_id: account.id,
+        date: date,
+        balance: holdings_value + cash_balance,
+        cash_balance: cash_balance,
+        currency: account.currency
+      )
+    end
+
+    def calculate_next_balance(prior_balance, transactions, direction: :forward)
+      flows = transactions.sum(&:amount)
+      negated = direction == :forward ? account.asset? : account.liability?
+      flows *= -1 if negated
+      prior_balance + flows
+    end
 end