Investment Portfolio Sync (#974)

* Add investment portfolio models

* Add portfolio to demo data

* Setup initial tests

* Rough sketch of sync logic

* Clean up trade sync logic

* Add trade validation

* Integrate trades into sync process

app/models/account/balance/syncer.rb

@@ -27,13 +27,9 @@ class Account::Balance::Syncer
     attr_reader :sync_start_date, :account
 
     def upsert_balances!(balances)
+      current_time = Time.now
       balances_to_upsert = balances.map do |balance|
-        {
-          date: balance.date,
-          balance: balance.balance,
-          currency: balance.currency,
-          updated_at: Time.now
-        }
+        balance.attributes.slice("date", "balance", "currency").merge("updated_at" => current_time)
       end
 
       account.balances.upsert_all(balances_to_upsert, unique_by: %i[account_id date currency])
@@ -49,9 +45,9 @@ class Account::Balance::Syncer
       return valuation.amount if valuation
       return derived_sync_start_balance(entries) unless prior_balance
 
-      transactions = entries.select { |e| e.date == date && e.account_transaction? }
+      entries = entries.select { |e| e.date == date }
 
-      prior_balance - net_transaction_flows(transactions)
+      prior_balance - net_entry_flows(entries)
     end
 
     def calculate_daily_balances
@@ -95,19 +91,19 @@ class Account::Balance::Syncer
     end
 
     def derived_sync_start_balance(entries)
-      transactions = entries.select { |e| e.account_transaction? && e.date > sync_start_date }
+      transactions_and_trades = entries.reject { |e| e.account_valuation? }.select { |e| e.date > sync_start_date }
 
-      account.balance + net_transaction_flows(transactions)
+      account.balance + net_entry_flows(transactions_and_trades)
     end
 
     def find_prior_balance
       account.balances.where("date < ?", sync_start_date).order(date: :desc).first&.balance
     end
 
-    def net_transaction_flows(transactions, target_currency = account.currency)
-      converted_transaction_amounts = transactions.map { |t| t.amount_money.exchange_to(target_currency, date: t.date) }
+    def net_entry_flows(entries, target_currency = account.currency)
+      converted_entry_amounts = entries.map { |t| t.amount_money.exchange_to(target_currency, date: t.date) }
 
-      flows = converted_transaction_amounts.sum(&:amount)
+      flows = converted_entry_amounts.sum(&:amount)
 
       account.liability? ? flows * -1 : flows
     end

app/models/account/entry.rb

@@ -11,6 +11,7 @@ class Account::Entry < ApplicationRecord
 
   validates :date, :amount, :currency, presence: true
   validates :date, uniqueness: { scope: [ :account_id, :entryable_type ] }, if: -> { account_valuation? }
+  validate :trade_valid?, if: -> { account_trade? }
 
   scope :chronological, -> { order(:date, :created_at) }
   scope :reverse_chronological, -> { order(date: :desc, created_at: :desc) }
@@ -123,7 +124,7 @@ class Account::Entry < ApplicationRecord
 
     def income_total(currency = "USD")
       without_transfers.account_transactions.includes(:entryable)
-                          .where("account_entries.amount <= 0")
+        .where("account_entries.amount <= 0")
                        .map { |e| e.amount_money.exchange_to(currency, date: e.date, fallback_rate: 0) }
                        .sum
     end
@@ -191,4 +192,14 @@ class Account::Entry < ApplicationRecord
         previous: previous_entry&.amount_money,
         favorable_direction: account.favorable_direction
     end
+
+    def trade_valid?
+      if account_trade.sell?
+        current_qty = account.holding_qty(account_trade.security)
+
+        if current_qty < account_trade.qty.abs
+          errors.add(:base, "cannot sell #{account_trade.qty.abs} shares of #{account_trade.security.symbol} because you only own #{current_qty} shares")
+        end
+      end
+    end
 end

app/models/account/entryable.rb

@@ -1,7 +1,7 @@
 module Account::Entryable
   extend ActiveSupport::Concern
 
-  TYPES = %w[ Account::Valuation Account::Transaction ]
+  TYPES = %w[ Account::Valuation Account::Transaction Account::Trade ]
 
   def self.from_type(entryable_type)
     entryable_type.presence_in(TYPES).constantize

app/models/account/holding.rb

@@ -0,0 +1,6 @@
+class Account::Holding < ApplicationRecord
+  belongs_to :account
+  belongs_to :security
+
+  scope :chronological, -> { order(:date) }
+end

app/models/account/holding/syncer.rb

@@ -0,0 +1,96 @@
+class Account::Holding::Syncer
+  attr_reader :warnings
+
+  def initialize(account, start_date: nil)
+    @account = account
+    @warnings = []
+    @sync_date_range = calculate_sync_start_date(start_date)..Date.current
+    @portfolio = {}
+
+    load_prior_portfolio if start_date
+  end
+
+  def run
+    holdings = []
+
+    sync_date_range.each do |date|
+      holdings += build_holdings_for_date(date)
+    end
+
+    upsert_holdings holdings
+  end
+
+  private
+
+    attr_reader :account, :sync_date_range
+
+    def sync_entries
+      @sync_entries ||= account.entries
+                               .account_trades
+                               .includes(entryable: :security)
+                               .where("date >= ?", sync_date_range.begin)
+                               .order(:date)
+    end
+
+    def build_holdings_for_date(date)
+      trades = sync_entries.select { |trade| trade.date == date }
+
+      @portfolio = generate_next_portfolio(@portfolio, trades)
+
+      @portfolio.map do |isin, holding|
+        price = Security::Price.find_by!(date: date, isin: isin).price
+
+        account.holdings.build \
+          date: date,
+          security_id: holding[:security_id],
+          qty: holding[:qty],
+          price: price,
+          amount: price * holding[:qty]
+      end
+    end
+
+    def generate_next_portfolio(prior_portfolio, trade_entries)
+      trade_entries.each_with_object(prior_portfolio) do |entry, new_portfolio|
+        trade = entry.account_trade
+
+        price = trade.price
+        prior_qty = prior_portfolio.dig(trade.security.isin, :qty) || 0
+        new_qty = prior_qty + trade.qty
+
+        new_portfolio[trade.security.isin] = {
+          qty: new_qty,
+          price: price,
+          amount: new_qty * price,
+          security_id: trade.security_id
+        }
+      end
+    end
+
+    def upsert_holdings(holdings)
+      current_time = Time.now
+      holdings_to_upsert = holdings.map do |holding|
+        holding.attributes
+               .slice("date", "currency", "qty", "price", "amount", "security_id")
+               .merge("updated_at" => current_time)
+      end
+
+      account.holdings.upsert_all(holdings_to_upsert, unique_by: %i[account_id security_id date currency])
+    end
+
+    def load_prior_portfolio
+      prior_day_holdings = account.holdings.where(date: sync_date_range.begin - 1.day)
+
+      prior_day_holdings.each do |holding|
+        @portfolio[holding.security.isin] = {
+          qty: holding.qty,
+          price: holding.price,
+          amount: holding.amount,
+          security_id: holding.security_id
+        }
+      end
+    end
+
+    def calculate_sync_start_date(start_date)
+      start_date || account.entries.account_trades.order(:date).first.try(:date) || Date.current
+    end
+end

app/models/account/sync.rb

@@ -17,6 +17,7 @@ class Account::Sync < ApplicationRecord
     start!
 
     sync_balances
+    sync_holdings
 
     complete!
   rescue StandardError => error
@@ -33,6 +34,14 @@ class Account::Sync < ApplicationRecord
       append_warnings(syncer.warnings)
     end
 
+    def sync_holdings
+      syncer = Account::Holding::Syncer.new(account, start_date: start_date)
+
+      syncer.run
+
+      append_warnings(syncer.warnings)
+    end
+
     def append_warnings(new_warnings)
       update! warnings: warnings + new_warnings
     end

app/models/account/trade.rb

@@ -0,0 +1,26 @@
+class Account::Trade < ApplicationRecord
+  include Account::Entryable
+
+  belongs_to :security
+
+  validates :qty, presence: true, numericality: { other_than: 0 }
+  validates :price, presence: true
+
+  class << self
+    def search(_params)
+      all
+    end
+
+    def requires_search?(_params)
+      false
+    end
+  end
+
+  def sell?
+    qty < 0
+  end
+
+  def buy?
+    qty > 0
+  end
+end