Account:: namespace simplifications and cleanup (#2110)

* Flatten Holding model

* Flatten balance model

* Entries domain renames

* Fix valuations reference

* Fix trades stream

* Fix brakeman warnings

* Fix tests

* Replace existing entryable type references in DB

app/models/balance/syncer.rb

@@ -0,0 +1,71 @@
+class Balance::Syncer
+  attr_reader :account, :strategy
+
+  def initialize(account, strategy:)
+    @account = account
+    @strategy = strategy
+  end
+
+  def sync_balances
+    Balance.transaction do
+      sync_holdings
+      calculate_balances
+
+      Rails.logger.info("Persisting #{@balances.size} balances")
+      persist_balances
+
+      purge_stale_balances
+
+      if strategy == :forward
+        update_account_info
+      end
+
+      account.sync_required_exchange_rates
+    end
+  end
+
+  private
+    def sync_holdings
+      @holdings = Holding::Syncer.new(account, strategy: strategy).sync_holdings
+    end
+
+    def update_account_info
+      calculated_balance = @balances.sort_by(&:date).last&.balance || 0
+      calculated_holdings_value = @holdings.select { |h| h.date == Date.current }.sum(&:amount) || 0
+      calculated_cash_balance = calculated_balance - calculated_holdings_value
+
+      Rails.logger.info("Balance update: cash=#{calculated_cash_balance}, total=#{calculated_balance}")
+
+      account.update!(
+        balance: calculated_balance,
+        cash_balance: calculated_cash_balance
+      )
+    end
+
+    def calculate_balances
+      @balances = calculator.calculate
+    end
+
+    def persist_balances
+      current_time = Time.now
+      account.balances.upsert_all(
+        @balances.map { |b| b.attributes
+               .slice("date", "balance", "cash_balance", "currency")
+               .merge("updated_at" => current_time) },
+        unique_by: %i[account_id date currency]
+      )
+    end
+
+    def purge_stale_balances
+      deleted_count = account.balances.delete_by("date < ?", account.start_date)
+      Rails.logger.info("Purged #{deleted_count} stale balances") if deleted_count > 0
+    end
+
+    def calculator
+      if strategy == :reverse
+        Balance::ReverseCalculator.new(account)
+      else
+        Balance::ForwardCalculator.new(account)
+      end
+    end
+end