Account::Sync model and test fixture simplifications (#968)

* Add sync model

* Fresh fixtures for sync tests

* Sync tests overhaul

* Fix entry tests

* Complete remaining model test updates

* Update system tests

* Update demo data task

* Add system tests back to PR checks

* More simplifications, add empty family to fixtures for easier testing

app/models/account/syncable.rb

@@ -1,89 +1,21 @@
 module Account::Syncable
   extend ActiveSupport::Concern
 
-  def sync_later(start_date = nil)
-    AccountSyncJob.perform_later(self, start_date)
+  class_methods do
+    def sync(start_date: nil)
+      all.each { |a| a.sync_later(start_date: start_date) }
+    end
   end
 
-  def sync(start_date = nil)
-    update!(status: "syncing")
-
-    if multi_currency? || foreign_currency?
-      sync_exchange_rates
-    end
-
-    calculator = Account::Balance::Calculator.new(self, { calc_start_date: start_date })
-
-    self.balances.upsert_all(calculator.daily_balances, unique_by: :index_account_balances_on_account_id_date_currency_unique)
-    self.balances.where("date < ?", effective_start_date).delete_all
-    new_balance = calculator.daily_balances.select { |b| b[:currency] == self.currency }.last[:balance]
-
-    update! \
-      status: "ok",
-      last_sync_date: Date.current,
-      balance: new_balance,
-      sync_errors: calculator.errors,
-      sync_warnings: calculator.warnings
-  rescue => e
-    update!(status: "error", sync_errors: [ :sync_message_unknown_error ])
-    logger.error("Failed to sync account #{id}: #{e.message}")
+  def syncing?
+    syncs.syncing.any?
   end
 
-  def can_sync?
-    # Skip account sync if account is not active or the sync process is already running
-    return false unless is_active
-    return false if syncing?
-    # If last_sync_date is blank (i.e. the account has never been synced before) allow syncing
-    return true if last_sync_date.blank?
-
-    # If last_sync_date is not today, allow syncing
-    last_sync_date != Date.today
+  def sync_later(start_date: nil)
+    AccountSyncJob.perform_later(self, start_date: start_date)
   end
 
-  # The earliest date we can calculate a balance for
-  def effective_start_date
-    @effective_start_date ||= entries.order(:date).first.try(:date) || Date.current
-  end
-
-  # Finds all the rate pairs that are required to calculate balances for an account and syncs them
-  def sync_exchange_rates
-    rate_candidates = []
-
-    if multi_currency?
-      transactions_in_foreign_currency = self.entries.where.not(currency: self.currency).pluck(:currency, :date).uniq
-      transactions_in_foreign_currency.each do |currency, date|
-        rate_candidates << { date: date, from_currency: currency, to_currency: self.currency }
-      end
-    end
-
-    if foreign_currency?
-      (effective_start_date..Date.current).each do |date|
-        rate_candidates << { date: date, from_currency: self.currency, to_currency: self.family.currency }
-      end
-    end
-
-    return if rate_candidates.blank?
-
-    existing_rates = ExchangeRate.where(
-      from_currency: rate_candidates.map { |rc| rc[:from_currency] },
-      to_currency: rate_candidates.map { |rc| rc[:to_currency] },
-      date: rate_candidates.map { |rc| rc[:date] }
-    ).pluck(:from_currency, :to_currency, :date)
-
-    # Convert to a set for faster lookup
-    existing_rates_set = existing_rates.map { |er| [ er[0], er[1], er[2].to_s ] }.to_set
-
-    rate_candidates.each do |rate_candidate|
-      rc_from = rate_candidate[:from_currency]
-      rc_to = rate_candidate[:to_currency]
-      rc_date = rate_candidate[:date]
-
-      next if existing_rates_set.include?([ rc_from, rc_to, rc_date.to_s ])
-
-      logger.info "Fetching exchange rate from provider for account #{self.name}: #{self.id} (#{rc_from} to #{rc_to} on #{rc_date})"
-      ExchangeRate.find_rate_or_fetch from: rc_from, to: rc_to, date: rc_date
-    end
-
-    nil
+  def sync(start_date: nil)
+    Account::Sync.for(self, start_date: start_date).run
   end
 end